TEMPERATURE MONITORING SYSTEM

FIELD OF THE INVENTION

The present invention relates to apparatuses and methods for monitoring temperatures.

BACKGROUND

The temperature of an item may be monitored by using a temperature sensor attached to the item. The temperature sensor may be e.g. a thermocouple or a temperature-dependent resistor.

Measured temperature data may be transmitted in a wireless manner by using radio signals. Known applications include e.g. weather monitoring systems having a battery-powered sensor and transmitter unit. The transmitter unit may be arranged to send temperature data to a display unit by using a radio signal.

It is known that temperature of e.g. deep-frozen food may be monitored by using a battery-powered data logging unit, which measures temperature data and stores the temperature data in a memory. The data logging unit may comprise a transmitter for providing a radio link. The temperature data may be subsequently transmitted from the transmitter to an external receiver via the radio link.

A disadvantage of battery-operated apparatus is that the battery has limited operating life. The use of the battery may also set a certain minimum size for a temperature sensor. The use of the battery may also increase manufacturing costs and/or operating costs. Yet, the battery may comprise toxic chemicals. These drawbacks may cause problems in several potentially interesting applications. SUMMARY

An object of the present invention is to provide a system for monitoring temperatures. An object of the present invention is to provide a transponder for monitoring temperatures. An object of the present invention is to provide a method for monitoring temperatures.

According to a first aspect of the invention, there is provided a method, comprising:

- determining first temperature information (TINF1 ) based on first temperature data (TDATA1 ) obtained from a first RFID transponder (1 00a),

- determining a first identifier (F1 ) based on first identification data (ID1 ) obtained from a first RFID transponder (1 00a), and

- providing the first temperature information (TINF1 ) and the first identifier (F1 ) at an interface (500, MEM3) such that the first temperature information (TINF1 ) is associated with the first identifier (F1 ),

wherein the first transponder (1 00a) is arranged to extract operating energy from a radio frequency field (ROG).

According to a second aspect of the invention, there is provided an apparatus (700,900), comprising:

- a radio frequency unit (RXTX2) arranged to provide a radio frequency field (ROG) in order to energize a first RFI D transponder (1 00a),

- a reader (200) arranged to obtain first temperature data (TDATA1 ) and first identification data (ID1 ) from the first RFID transponder (1 00a), and

- a data processing unit (CNT2, CNT4) arranged to determine first temperature information (TINF1 ) based on the first temperature data

(TDATA1 ) and to determine a first identifier (F1 ) based on the first identification data (ID1 ),

wherein the apparatus (700,900) is arranged to provide the first temperature information (TINF1 ) and the first identifier (F1 ) at an interface (500, MEM3) such that the first temperature information (TINF1 ) is associated with the first identifier (F1 ). According to a third aspect of the invention, there is provided a method comprising:

- attaching a first RFID transponder (1 00a) to a material (31 0) or embedding the first RFID transponder in a material (31 0),

- manufacturing a first item (300a) from the material (31 0) so that the manufactured first item (300a) comprises the first transponder (1 00a),

- using the first item (300a) as a part of a system (700), and

- monitoring and/or controlling operation of the system (700) by using first temperature data (TDATA1 ) obtained from the first transponder (1 00a),

wherein the first transponder (1 00a) is arranged to extract operating energy from a radio frequency field (ROG).

According to a fourth aspect of the invention, there is provided a method, comprising:

- using the first item (300a) as a part of a first system (900),

- obtaining preliminary temperature data (TDATA0) from a first transponder (1 00a) in order to monitor and/or control operation of the first system (900), the first transponder (1 00a) being attached to the first item (300a),

- using the first item (300a) as a part of a second system (700), and

- obtaining further temperature data (TDATA1 ) from the first transponder (1 00a) in order to monitor and/or control operation of the second system (700),

wherein a location of the first system (900) is different from a location of the second system (700), and the first transponder (1 00a) is arranged to extract operating energy from a radio frequency field (ROG). According to a fifth aspect of the invention, there is provided method, comprising:

- obtaining preliminary identification data (ID1 ) from a first transponder (1 00a) in order to identify a first item (300a), the first transponder (1 00a) being attached to the first item (300a),

- using the first item (300a) as a part of a system (700), and - obtaining first temperature data (TDATA1 ) from the first transponder (1 00a) in order to monitor and/or control operation of the system (700), wherein the first transponder (1 00a) is arranged to extract operating energy from a radio frequency field (ROG), and a time difference between obtaining the preliminary identification data (ID1 ) and obtaining the first temperature data (TDATA1 ) is at least 24 hours.

According to a sixth aspect of the invention, there is provided an RFID transponder (1 00a) comprising a temperature monitoring unit (52, 55) arranged to generate a temperature-dependent digital signal (f _C LK, N _c , TDATA) by using operating energy extracted from the radio frequency field (ROG).

Further aspects of the invention are defined in the other claims.

An RFID transponder may comprise a temperature monitoring unit for providing temperature data.

Temperature data may be obtained from several transponders. Temperature data obtained from an individual transponder may be associated with identification data of said transponder.

The RFID transponder may be arranged to extract operating energy from a radio frequency field. In particular, energy for operating the temperature monitoring unit may be extracted from the radio frequency field. An RFID reader may be arranged to energize the transponder by providing a radio frequency field, and the RFID reader may be arranged to receive temperature data from the transponder. Thus, the life of a battery does not limit the lifetime of the transponder. In particular, there is no need to replace the battery of the transponder during the lifetime of the transponder. In an embodiment, operating lifetime of the temperature sensors (i.e. RFID transponders) may be very long. Thanks to the invention, there is no need to use a large battery, and the size of the transponder may be very small. In particular, the transponder may be very thin. The total thickness of the transponder may substantially equal to the thickness of the transponder chip.

Thanks to the invention, the battery may be omitted. Thus, the use of toxic chemicals may be reduced or avoided.

In an embodiment, the use of a battery in the transponder may be completely avoided.

Thanks to the invention, the manufacturing costs for the transponder may be substantially reduced. Due to the potentially low price a very high number of transponders may be used to monitor temperatures, temperature distributions, temperatures of several items and/or temperatures of large areas.

Because there is no need to change batteries, the transponder may be hermetically encapsulated to withstand various environmental conditions. In an embodiment, a transponder may be encapsulated such that it can be safely swallowed in order to monitor internal temperature of a person or animal. In an embodiment, all electrically conductive parts of the transponder may be substantially permanently covered with an insulating layer.

In an embodiment, a transponder may be permanently embedded in an item in order to monitor temperatures during manufacturing and/or use of the item. In an embodiment, the lifetime of the transponder may be e.g. longer than e.g. 50 years without a need to replace the battery of the transponder. The transponder may be e.g. permanently embedded inside a wall of a building, and the transponder may used for monitoring temperatures throughout the lifetime of the building. In an embodiment, identification data provided by the transponder may also be utilized even after the building has been demolished, e.g. in order to identify the type of materials used in the building. In an embodiment, the temperature monitoring unit of the transponder may comprise e.g. a P-N junction, a resistive sensor, or a thermocouple (TC) for measuring the temperature data. The transponder may be arranged to send a response to an interrogation signal such that the response contains the temperature data.

In an embodiment, the transponder may be arranged to determine a frequency parameter, which depends on the frequency of the local oscillator. The transponder may be arranged to store the frequency parameter in a memory of the transponder such that the value of the frequency parameter may be read by a reader. The reader may request the the frequency parameter by sending an interrogation signal to the transponder, and a response sent by the transponder may comprise the value of the frequency parameter. In an embodiment, a local oscillator of the transponder may be arranged to operate as a temperature monitoring unit. The frequency of the local oscillator may depend on the temperature of the transponder chip. The modulation frequency of a radio frequency response sent by the transponder may in turn depend on the frequency of the local oscillator. In an embodiment, a reader may be arranged to obtain temperature data from the transponder by monitoring modulation frequency of a response sent by the transponder.

In an embodiment, standard RFID transponders may be used as cheap disposable temperature sensors.

An item equipped with the transponder may be moved through a stationary reader station in order to identify the item and to obtain temperature data from the transponder. However, the potentially long lifetime also makes it possible to utilize the transponder in applications where the transponder remains in place for an extended period of time. Temperature data may be obtained from a stationary transponder by using a movable reader, in particular by using a portable reader.

Furthermore, a transponder attached to an item may be used for two or more different purposes during the lifetime of the item. For example, the transponder may be attached to the item already during the manufacturing of the item, and the manufacturing process may be monitored by using temperature data obtained from the transponder during the manufacturing. The same transponder may be subsequently used for identifying the item when the item is transported and/or stored in a storage. The item may be subsequently used as a part of a system, and temperature data obtained from the transponder may be used for monitoring operation of the system. Finally, identification data obtained from the transponder may be utilized when the item is recycled and/or demolished.

In an embodiment, temperatures of moving or rotating objects may be monitored without using sliding electrical contacts, flexing wires, or other galvanic contacts subject to wear and/or fatigue.

In an embodiment, temperatures of very large number of items or temperature distribution in very large areas may be monitored at relatively low costs. In an embodiment, temperatures may be monitored through a barrier without using galvanic feedthroughs.

Temperature information may be received from a remote transponder in a wireless manner. Communication between a reader and a transponder does not typically involve a risk of generating sparks. In an embodiment, temperatures may be safely monitored in areas having a high explosion risk due to flammable materials.

If desired, absolute temperature values may be determined from the temperature data. The use of a high number of transponders (e.g. higher than ten) to monitor a temperature of a single target may significantly increase the reliability of a measurement. If desired, failure of a single transponder may be easily detected by comparing absolute temperature data provided by a transponder with absolute temperature data of other transponders.

In an embodiment, more accurate absolute temperature values may be determined from the temperature data by using calibration data.

In an embodiment, highly reliable temperature data and/or absolute temperature data may be provided when the measuring personnel does not have access to the calibration data. In that case falsification of temperature data by the measuring personnel may be very difficult. This may provide very reliable temperature measurements

According to an embodiment, temperature data or other temperature information obtained from a transponder may be presented together with an identifier of the transponder. The identifier may be e.g. descriptive text, graphical symbol, or location information. When the transponder has been attached to an item, the identifier may also comprise an image of the item. In particular, the identifier may comprise a photograph of the item. This may facilitate handling of temperature data obtained from several transponders.

In an embodiment, a user may select temperature data based on the identifiers. The selected temperature data may be e.g. displayed and/or used for controlling a process.

In an embodiment, temperature information may be displayed only when the corresponding temperature data value is smaller than or equal to a first limit. !n an embodiment, temperature information may be displayed only when the corresponding temperature data value is higher than or equal to a second limit. The embodiments of the invention and their benefits will become more apparent to a person skilled in the art through the description and examples given herein below, and also through the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following examples, the embodiments of the invention wi!i be described in more detail with reference to the appended drawings, in which

Fig. 1a shows a reader and a transponder, wherein the temperature monitoring unit is of the transponder a local oscillator, Fig. 1b shows a reader and a transponder, wherein the transponder is arranged to determine a parameter, which depends on the frequency of the local oscillator,

Fig. 1c shows a reader and a transponder, wherein the transponder comprises a temperature monitoring unit, which is different from the local oscillator,

Fig. 1d shows a reader and a transponder, wherein the temperature monitoring unit has terminals connectabie to a temperature sensor.

Fig. 2 shows, in a three-dimensional view, a reader, an auxiliary unit, and several transponders attached to items, Fig. 3a shows, in a three dimensional view, a transponder comprising a dipoie antenna, shows, in a three dimensional view, a transponder comprising an inductive antenna, shows a portion of an interrogation signal sent from a reader, shows modulation frequency as a function of the frequency-setting parameter of interrogation signal, shows a jump of a modulation frequency curve, shows several jumps of a modulation frequency curve, shows a temperature monitoring apparatus comprising a reader and a transponder, shows a temperature monitoring apparatus comprising a reader, a transponder, and an auxiliary unit, shows moving a reader with respect to a location reference, shows amplitude of response as a function of the position of the reader, shows changing the direction of an interrogation beam, shows amplitude of response as a function of the direction of the interrogation beam, shows determining location of a transponder by varying the direction of a first interrogation beam and by varying the direction of a second interrogation beam, Fig. 7f shows determining location of a transponder by changing the position of a reader in a first direction and by changing the position of a reader in a second direction, Fig. 7g shows determining location of a transponder based on time delay of a response,

Fig. 7h shows an envelope of a first response to a first interrogation signal and an envelope of a second response to a second interrogation signal,

Fig. 7i shows determining the location of a transponder by using a reader, which has two antennae, Fig. 7j shows determining the location of a transponder by using a reader, which has two antennae,

Fig. 8a shows reference identifiers attached to different items, Fig. 8b shows reference identifiers attached to different portions of an item,

Fig. 9a shows displayed identifiers and temperature information, Fig. 9b shows a displayed identifier and temperature information,

Fig. 9c shows a displayed identifier and temperature information,

Fig. 9d shows a displayed identifier and temperature information,

Fig. 9e shows a displayed identifier and temperature information,

Fig. 9f shows a displayed identifier and temperature information, Fig. 9g shows a displayed identifier and temperature information, Fig. 9h shows displayed identifiers and a selector,

Fig. 9i shows displayed temperature information, Fig. 9j shows a displayed image and associated temperature information,

Fig. 9k shows a displayed image and associated temperature information,

Fig. 10 shows an apparatus comprising one or more transponders attached to items,

Fig. 1 1 shows an apparatus arranged to send signals through a barrier,

Fig. 12 shows an apparatus comprising a transponder attached to a moving part, Fig. 13 shows an apparatus comprising a movable reader,

Fig. 14 shows an apparatus comprising an active unit, wherein the active unit is controlled based on temperature data, Fig. 15a shows manufacturing an item, which comprises a transponder,

Fig. 15b shows controlling the manufacturing process of the item, Fig. 15c shows using the item as a part of a system,

Fig. 15d shows a system comprising a reader, which has a leaky waveguide antenna, Fig. 16a shows a tire comprising a transponder, Fig. 16b shows a vehicle comprising a reader, and

Fig. 16c shows temperature information associated with the tires of a vehicle.

All drawings are schematic.

DETAILED DESCRIPTION

Referring to Fig. 1 , an RFID transponder 100 may comprise one or more antenna elements 140 connected to an RFID chip 1 10.

RFID is an acronym for radio frequency identification.

The transponder 100 may be attached to a substrate 130 so as to form an RFID tag 1 02. The substrate 130 may be e.g. a plastic film, paper, or cardboard. The substrate 130 may be adhesive-lined so as to form an adhesive label. The transponder 100 may comprise protective layers to form a sealed structure. The transponder 100 may encapsulated so as to withstand various environmental conditions, e.g. moisture and/or other corrosive substances.

The transponder 100 may be arranged to send a response RES to an interrogation signal ROG. The interrogation signal ROG may be sent from a mobile reader 200 or a stationary reader 200. In particular, the mobile reader may be a portable reader.

The reader 200 and the transponder 100 may be arranged to communicate e.g. according to the EPC Gen2 protocol. EPC Gen2 is a abbreviation for "EPCglobal UHF Class 1 Generation 2". The protocol has been incorporated e.g. in the standard ISO 18000-6C (frequency band 860-960MHz). (Reference is made to the latest versions of the protocol and standard as in force on 12 January 201 1 ). The transponder 1 00 may comprise an RFID chip 1 1 0 connected to one or more antenna elements 1 40 via terminals T1 , T2. The chip 1 1 0 may refer to a semiconductor element, which comprises e.g. resistors and transistors.

Electromagnetic interrogation signal ROG transmitted in a wireless manner is converted into an electrical signal by the antenna elements 140. The chip 1 1 0 may comprise a radio frequency unit RXTX1 , a control unit CNT1 , and a memory MEM1 . The radio frequency unit RXTX1 may comprise a signal receiver RX1 , and a signal transmitter TX1 . The receiver RX1 may also be called as a signal demodulator. The transmitter TX1 may also be called as a signal modulator. The radio frequency unit RXTX1 may also be called as an analog radio frequency interface. The radio frequency unit RXTX1 may comprise connection terminals T1 , T2, which may be connected to at least one antenna element 1 40. The antenna elements may from e.g. a dipole antenna (Fig. 3a) or an inductive antenna (coil antenna, Fig. 3b). The radio frequency unit RXTX1 , the control unit CNT1 , the memory MEM1 , and a local oscillator 52 may be implemented on the same semiconductor chip 50.

The receiver RX1 may provide an input signal S| _N based on the received interrogation signal ROG. The control unit CNT1 may be arranged to enable transmission of first information ID1 e.g. when the input signal S| _N contains a first (correct) password code (which matches with a reference code previously stored in the chip 1 1 0). The first information I D1 may comprise e.g. identification data of the transponder 1 00. The identification data ID1 may comprise e.g. an electronic item code (EPC). A unique electronic item code assigned to an item may be stored in a transponder 1 00 as a binary number.

Optionally, the control unit CNT1 may be arranged to enable transmission of second information INF2 e.g. when the input signal S| _N contains a second (correct) password code (which matches with a reference code previously stored in the chip 1 1 0). The second information INF2 may comprise e.g. temperature history data, location data and/or calibration data. The second information INF2 may comprise a capability parameter, which specifies e.g.

- whether the transponder is capable of monitoring temperatures and/or changes in temperature,

- whether calibration data for the transponder exists,

- calibration data, and/or

- identification code for relevant calibration data.

The second information INF2 may be stored in the memory MEM1 of the transponder 1 00.

The response RES transmitted by the transponder 100 may comprise the first information ID1 and/or the second information INF2. The information ID1 and/or INF2 may be retrieved from the memory MEM1 by the control unit CNT1 . The control unit CNT1 may send an output signal SOUT to the radio frequency unit RXTX1 . The output signal SOUT may comprise the information INF2. The transmitter TX1 may generate the radio-frequency response RES based on the output signal SOUT- The input signal S| _N and the output signal SOUT may be e.g. digital signals.

A dipole antenna may transmit information from the transponder 100 to a reader 200 by back scattering. Alternatively, an inductive antenna may be used. A coil antenna of the transponder 1 00 may cause modulation of the load for the reader 200. This modulation can be used for transmitting data from the transponder 100 to the reader 200. The transponder 100 may substantially passive, i.e. the radio frequency unit RXTX1 may be powered by energy extracted from an incoming radio frequency signal, i.e. the radio frequency unit RXTX1 may operate without a battery. The transponder 100 may be powered e.g. by electro-magnetic energy transmitted from the reader 200. The combination of an antenna structure 140 and a radio frequency unit RXTX1 of a transponder 100 may be arranged to provide operating power for the transponder 1 00 by extracting energy of an in-coming electromagnetic signal ROG. The radio frequency unit RXTX1 may comprise a voltage supply VREG1 , which is arranged to extract operating power from an incoming radio frequency signal. In particular, the voltage supply VREG1 may be arranged to extract operating power from the interrogation signal ROG. The operating power may be distributed to from the voltage supply VREG1 to the radio frequency unit RXTX1 . Optionally, operating power may be distributed to from the voltage supply VREG1 to the control unit CNT1 and to the memory MEM1 .

Consequently, operating lifetime may be very long. Operating lifetime refers to a time when the transponder is capable of responding to an interrogation signal. In fact, the operating lifetime may be substantially infinite. There is no need to change a battery during the operating lifetime of the transponder. The transponder may be very small, as there it is not necessary to reserve a considerable space for the battery. The transponder may be substantially passive, i.e. energy for operating the radio frequency unit RXTX1 , the temperature monitoring unit 55, the control unit CNT1 , the local oscillator 52, and the memory MEM1 may be extracted from a radio frequency field. Energy for operating the radio frequency unit RXTX1 , the temperature monitoring unit 55, the control unit CNT1 , the local oscillator 52, and the memory MEM1 may be extracted an interrogation signals ROG sent from a readers.

A passive transponder 1 00 may comprise a capacitor or a rechargeable battery for storing operating energy extracted from an interrogation signal ROG. Operating energy for operating the radio frequency unit RXTX1 , the temperature monitoring unit 55, the control unit CNT1 , the local oscillator 52, and the memory MEM1 may be extracted from one or more interrogation signals ROG sent from one or more readers 200. The local oscillator 52 may be used as the temperature monitoring unit 55 when the clock frequency f _C i_K of the local oscillator 52 depends on the temperature of the chip 1 10. A carrier frequency of the response RES may be modulated at a modulation frequency f _LF . The modulation frequency f _LF may also be called as a "link frequency".

The modulation frequency f _LF of the response RES may, in turn, depend on the clock frequency f _C i_K of a local oscillator 52. Thus, also the modulation frequency f _LF may depend on the temperature of the chip 1 10. A change of the modulation frequency f _LF may indicate a change in the temperature. Consequently, the modulation frequency f _LF may be interpreted to be temperature data.

The local oscillator 52 may be e.g. a ring oscillator. A ring oscillator may comprise e.g. a plurality of cascaded logical gates whose operating speed depends on the temperature. The local oscillator 52 may be e.g. a relaxation oscillator.

Referring to Fig. 1 b, the transponder 100 may be arranged to determine a frequency parameter N _c , which depends on the frequency of the local oscillator 52. In particular, the frequency parameter N _c may indicate the number of pulses of the local oscillator 52 corresponding to the duration of a frequency-setting parameter TRcal. The frequency parameter N _c may be indicative of the parameter BLF (backscatter link frequency). In particular, the frequency parameter N _c may be substantially equal to the parameter BLF (backscatter link frequency), as defined in the EPC Gen2 protocol. The frequency-setting parameter may refer to the parameter TRCal, as defined in the EPC Gen2 protocol.

The frequency parameter N _c comprises information about the temperature when the frequency of the local oscillator 52 depends on the temperature. The transponder 100 may be arranged to operate such that a response sent by the transponder comprises a binary number corresponding to the value of the frequency parameter N _c . The frequency parameter N _c may be stored in digital format in a memory MEM1 (i.e. in a register) such that a reader 200 may request and access the value of the frequency parameter N _c . The transponder 100 may be arranged to operate such that a response sent by the transponder comprises a binary number corresponding to the value of the frequency parameter N _c . The transponder 100 may be arranged to operate such that the value of the frequency parameter N _c is sent as a binary number only when the interrogation signal ROG contains a request for said value. Referring to Fig. 1 c, the transponder 100 may comprise a temperature sensor 57, which is different from the local oscillator 52. The temperature sensor 57 may comprise e.g. a P-N junction, a resistive element, whose resistance depends on the temperature, or a thermocouple. The resistive element may be e.g. a NTC or PTC resistor (NTC refers to negative temperature coefficient, and PTC refers to positive temperature coefficient. The resistive element may be a Pt100 sensor.

The temperature sensor 57 may be powered by energy extracted from a radio frequency field. The temperature sensor 57 may be powered by energy extracted from a radio frequency field of one or more interrogation signals ROG.

A temperature monitoring unit 55 may have two or more terminals T3, T4, which are connectable or connected to the sensor 57. The temperature monitoring unit 55 may be arranged to convert an analog temperature signal S _T provided by the sensor 57 into a digital signal comprising temperature data TDATA. The temperature data TDATA may be stored in a memory MEM1 e.g. as digital data, in particular as binary data. The temperature monitoring unit 55 (or 52) may be arranged to generate a temperature-dependent digital signal TDATA (or f CLK _> N _C ) by using operating energy extracted from a radio frequency field, in particular by using operating energy extracted from an interrogation signal ROG.

The frequency of the electromagnetic radio frequency field may be e.g. greater than or equal to 100 kHz, in particular greater than or equal to 1 MHz. The frequency of the electromagnetic radio frequency field may be substantially equal to the carrier frequency of the interrogation signal ROG.

The transponder 100 may be arranged to transmit the temperature data TDATA to a reader 200 e.g. when requested by an interrogation signal ROG.

Referring to Fig. 1 d, the temperature monitoring unit 55 may comprise the temperature sensor 57, i.e. the sensor 57 may be integrated in the temperature monitoring unit 55. Also in this case the temperature monitoring unit 55 may be powered by using energy extracted from a radio frequency field. The unit 55 may be powered by using energy extracted from one or more interrogation signals ROG.

Referring to Fig. 2, an apparatus 700 for monitoring temperatures may comprise one or more RFID transponders 100, a reader 200, and an optional auxiliary unit 400.

The auxiliary unit 400 may also be called a data storage unit and/or a data processing unit.

The transponders 1 00a, 100b, 100c may be attached to items 300a, 300b, 300c. The transponders 100a, 100b, 1 00c may send signals RES, which allow monitoring of the temperatures of the items 300a, 300b, 300c. The item 300a may be e.g. an electronic device, battery, hard disc drive, a package containing an item, a package containing foodstuff, a package containing medicine, a package containing a chemical substance.

A plurality of tagged items 300a, 300b, 300c may stored in a storage, and a user may rapidly monitor the temperatures of the items 300a, 300b, 300c by using the reader 200. The user may also make an inventory of the items 300a, 300b, 300c stored in said storage by receiving the information carried by the responses RES.

The signals RES may be received by a reader 200. Temperature data obtained from the transponders 100a, 100b, 100c may be stored in a auxiliary unit 400, which may be separate from the reader 200. The auxiliary unit 400 may comprise e.g. a memory for storing temperature data TDATA and/or calibration data CALDATA.

The reader 200 may be movable or moved with respect to a location reference LOCREF. An item 300a may be movable or moved with respect to a location reference LOCREF. The location reference LOCREF may be e.g. a building. A reader 200 may be movable or moved with respect to a stationary item 300a. An item 300a may be movable or moved with respect to a stationary reader 200. COM1 denotes communication between the reader 200 and the auxiliary unit 400.

The reader 200 may comprise a body 202 and a user interface 500. The user interface 500 may comprise e.g. a display for visually displaying temperature information determined from signals sent from the transponders 1 00a, 100b, 100c. The user interface 500 may comprise e.g. a keypad or a touch-sensitive screen for receiving data and/or commands. A signal RES provided by the transponder 100 may be used for monitoring temperature of the chip 1 1 0. When the chip 1 10 is in thermal connection with an item 300, the signal provided by the transponder 100 may be used for monitoring temperature of the item 300. SX, SY and SZ denote orthogonal directions.

Fig. 2 shows three transponders 1 00a, 100b, 100c attached to three items 300a, 300b, 300c. The transponder 100a may attached on the surface of the item 300a or the transponder 100a may be located inside the item 300a. In particular, the transponder 100a may be embedded in the item 300a. The transponder 100a may be an integral part of the item 300a.

Each transponder 1 00a, 100b, 100c, may be arranged to transmit a response RES to an interrogation signal ROG.

A response RES1 transmitted by the first transponder 100a may comprise temperature data TDATA1 and/or identification data ID1 associated with the first transponder 100a. The temperature data TDATA1 may be used for monitoring temperature of the item 300a. The identification data ID1 may be used for identifying the item 300a.

A response RES2 transmitted by the second transponder 100b may comprise temperature data TDATA2 and/or identification data ID2 associated with the second transponder 100b. The temperature data TDATA2 may be used for monitoring temperature of the item 300b. The identification data ID2 may be used for identifying the item 300b.

A response RES3 transmitted by the third transponder 1 00c may comprise temperature data TDATA3 and/or identification data ID3 associated with the third transponder 100c. The temperature data TDATA3 may be used for monitoring temperature of the item 300c. The identification data ID3 may be used for identifying the item 300c. Based on the identification data ID1 , temperature data TDATA1 associated with the transponder 100a may be associated with the identity of the transponder 1 00a. Based on the identification data ID 1 , temperature data TDATA1 associated with the transponder 1 00a may be associated with the identity of the item 300a. Based on the identification data ID2, temperature data TDATA2 associated with the transponder 1 00b may be associated with the identity of the transponder 1 00b. Based on the identification data ID2, temperature data TDATA2 associated with the transponder 1 00b may be associated with the identity of the item 300b.

Based on the identification data ID3, temperature data TDATA3 associated with the transponder 1 00c may be associated with the identity of the transponder 1 00c. Based on the identification data ID3, temperature data TDATA3 associated with the transponder 1 00c may be associated with the identity of the item 300c.

By using the identification data ID1 , ID2, ID3, the number of the items 300a, 300b, 300c can be counted, and the type of the items can be identified.

The temperature data TDATA2 obtained from the second transponder 1 00b may be displayed such that the data TDATA2 is associated with the identification data ID2. The system 700, in particular the reader 200 may be arranged to provide first temperature information TINF1 based on the first temperature data TDATA1 (TINF1 may also be equal to TDATA1 ).

The system 700, in particular the reader 200 may be arranged to provide second temperature information TINF2 based on the second temperature data TDATA2 (TINF2 may also be equal to TDATA2).

The system 700, in particular the reader 200 may be arranged to provide third temperature information TINF3 based on the third temperature data T DAT A3 (TINF3 may also be equal to TDATA3). The system 700, in particular the reader 200 may be arranged to provide a first identifier F1 based on the first identification data ID1 (F1 may also be equal to ID1 ). The system 700, in particular the reader 200 may be arranged to provide a second identifier F2 based on the second identification data ID2 (F2 may also be equal to ID2).

The system 700, in particular the reader 200 may be arranged to provide a third identifier F3 based on the third identification data ID3 (F3 may also be equal to ID3).

When using several transponders 1 00a, 1 00b, 1 00c, temperature data obtained from the transponders may be processed effectively and reliably when temperature data obtained from a transponder is associated with identification data obtained from the same transponder.

The method for monitoring temperatures may comprise:

- determining first temperature information TINF1 based on first temperature data TDATA1 obtained from a first RFID transponder

1 00a,

- determining a first identifier F1 based on first identification data ID1 obtained from a first RFID transponder 1 00a, and

- providing the first temperature information TINF1 and the first identifier F1 at an interface 500, MEM3 such that the first temperature information TINF1 is associated with the first identifier F1 ,

wherein the first transponder 1 00a is arranged to extract operating energy from a radio frequency field ROG. The temperature data TDATA1 obtained from the first transponder 1 00a may be e.g. displayed such that the data TDATA1 is associated with the identification data ID1 . The temperature data TDATA and the identification data are typically numerical codes, i.e. not in a very user- friendly format. The identifiers F1 , F2, F3 and/or the temperature information TINF1 , TINF2, TINF3 may be determined such that they are more illustrative to a human user. For example, the identifiers and the temperature information may be presented as graphical symbols (See Figs. 8a - 9j).

Also a machine-readable register (memory) outside the first transponder 100a may be used as an interface for providing temperature information associated with identification data.

The reader 200 may be movable or stationary. A mobile (portable) reader 200 may be moved in the vicinity of tagged items 300a, 300b, 300c. The reader 200 may be moved e.g. between receiving a first response and a second response.

In case of a stationary reader 200, the items 300a, 300b, 300c may also be moved between receiving a first response and a second response.

Fig. 3a shows a transponder 100 comprising a dipole antenna. The chip 1 10 and the antenna elements 140 may be attached to a substrate 130 in order to form a tag 102. The tag 102 may be attached to an item 300a e.g. by using an adhesive. The transponder 100 may also be directly attached to the item 300a or encapsulated inside the item 300a without using using an additional substrate 130 (i.e. the material of the item 300a may be used as the substrate). Fig. 3b shows a transponder 100 comprising an inductive antenna 140.

The total thickness of a tag 102 or a transponder 100 (in the direction SZ) may be smaller than or equal to 1 mm. The tag 1 02 or a transponder 1 00 may be flexible. A tag 102 may further comprise an adhesive layer (not shown). A tag 1 02 may further comprise a release layer, which protects the adhesive layer. The release layer can be removed before the tag 102 is attached to an item (e.g. 300a) by the adhesive layer. Figs. 4 - 5c describe how temperature data can be obtained based on frequency of the local oscillator 52. Referring to Fig. 4, an interrogation signal ROG sent from a reader 200 to a transponder 100 may comprise a frequency-setting parameter TRcal (reference is made to the EPC Gen2 protocol). The transponder 100 may be arranged to set a modulation frequency ("link frequency") fi_F based on the value of the parameter TRcal. The value of the TRcal may be directly proportional to the temporal duration of the data sequence TRcal. The value of the parameter TRcal may be e.g. 50 με.

The "Delimiter", "data-0", "Tari", and "RTcal" may refer to other portions of the interrogation signal ROG, as defined in the EPC Gen2 protocol.

The transponder 100 may be arranged to set the modulation frequency fi_F according to the following equation:

The modulation frequency f I_F may also be called as a "backscatter link frequency" BLF.

In practice, the transponder may be arranged to calculate the modulation frequency f I_F by using integer numbers as follows: f _LF = ^{DR ' fcLK} (1 b)

ROUND{TRcal ^■ f _CLK ) where DR denotes a division ratio parameter. The value of the division ratio parameter DR may be e.g. 8 or 64/3. f _C u< denotes the frequency of the local oscillator 52. ROUND denotes a rounding or truncating function, i.e. it rounds or truncates an arbitrary number format to an integer number. Fig. 5a shows, by way of example, the modulation frequency f _LF as a function of the frequency-setting parameter TRcal. The curve CU R1 plotted with the solid line refers to a situation where the clock frequency f _C LK is equal to 2.00 MHz. The curve CU R2 plotted with the dashed line refers to a situation where the clock frequency f _C i_K is equal to 2.02 MHz.

The difference 0.02 MHz difference (1 %) in the clock frequency f _C u< may be caused by a change of temperature of the local oscillator 52.

When the value of the frequency-setting parameter TRcal is increased, the modulation frequency f _LF may decrease in several (abrupt) jumps J 1 , J2, .., as can be derived from the equation (1 ). The jumps may be marked e.g. as J 1 , J2, J3, J4, J5, J6, J7, J8, J9,... The modulation frequency f _LF may be substantially constant between TRcal values corresponding to two adjacent jumps J 1 , J2, provided that the clock frequency f _C i_K is constant.

When the clock frequency f _C i_K increases or decreases due to temperature-induced drift, the modulation frequency f _LF may be changed when the TRcal value remains constant. In a region between jumps J6 and J7, the clock frequency f _C i_K may be changed e.g. by an amount Af _7-7 shown in Fig. 5a. In case of a larger change in the temperature, the curve CU R2 may be shifted sideways with respect to the curve CU R1 such that also a step height AfjuMP is added to the amount Af _7-7 .

When the value of the frequency-setting parameter TRcal is varied by a small amount in the vicinity of a jump (e.g. J7), the clock frequency f _C i_K being substantially constant, the modulation frequency f _LF may be abruptly changed from a first value f _LF i to a second value f _LF2 , i-θ. by the amount AfjuMP-

It may be derived from the equation (1 b) that

In other words, the clock frequency f _C u< may be calculated from the upper modulation frequency f _LF1 and lower modulation frequency f _LF1 associated with a single jump (e.g. J7).

In particular, the temperature of the local oscillator 52 (and an estimate for the temperature of an item attached to the transponder 100) may be determined by using a difference between the first modulation frequency(f _L F,i ) and the second modulation frequency( f _LFi2 ).

A first response RES1 modulated at the first frequency f _LF1 may be provided by sending a first interrogation signal ROG1 from a reader 200 to the transponder 100 such that the first interrogation signal ROG1 comprises a first frequency-setting parameter TRcaM . A second response RES2 from the same transponder 1 00 modulated at the second frequency f _LF2 may be provided by sending a second interrogation signal ROG2 from a reader 200 to the transponder 1 00 such that the second interrogation signal ROG2 comprises a second frequency-setting parameter TRcal2. The second frequency-setting parameter TRcal2 may be different from the first frequency-setting parameter TRcaM .

The time period between sending the first and second interrogation signals ROG1 , ROG2 may be selected to be so short that the temperature of the local oscillator is not significantly changed during said time period.

Thus, a method for monitoring temperatures may comprise:

- sending a first interrogation signal ROG1 and a second interrogation signal ROG2 to the RFID transponder 100,

- receiving a first response signal RES1 from the RFID transponder 100 at a first modulation frequency f LF,I and a second response signal RES2 from the RFID transponder 1 00 at a second modulation frequency f _L F,2,

- determining a clock frequency f _C i_K from the first modulation frequency fi_F,i and the second modulation frequency f _LFi2 .

wherein the first response signal RES1 is a response to the first interrogation signal ROG1 and the second response signal RES2 is a response to the second interrogation signal ROG2.

The determined clock frequency f _C i_K comprises temperature-dependent information. For example, a change in the clock frequency f _C i_K may indicate a change in the temperature. Therefore, the clock frequency f _C i_K may be interpreted to be temperature data TDATA as such.

The relationship between clock frequency f _C i_K and absolute temperature values may be established e.g. by calibration measurements. One or more calibration measurements may provide calibration data. For example, the chip of transponder may be positioned at a known temperature, and the clock frequency f _C i_K associated with the known temperature may be stored in a memory as calibration data.

Absolute temperature values specify a temperature e.g. in the units of Centigrade, Kelvin or Fahrenheit. An absolute temperature value may be derived from temperature data by using the calibration data. The chip may be positioned in two or more different temperatures, and corresponding clock frequency values f _C i_K may be recorded as a function of the temperature.

For example, calibration data may contain e.g. a plurality of pairs, wherein an individual pair may comprise an absolute temperature value TABS associated with a clock frequency value f _C i_K-

A calibration function defining the relationship between the clock frequency values f _C i_K and the corresponding temperatures may be defined by selecting the type of function and the parameters of the function such that the function substantially fits to the experimentally determined values. The function may be e.g. a linear function, a polynomial function or an exponential function.

For example, calibration data may contain parameters of a function, which defines a relationship between clock frequency values f _C i_K and absolute temperature value T _A BS-

Absolute temperature data may be determined from temperature data by using the calibration data.

Temperature data may refer to any data, which depends on the temperature of the chip of the transponder such that a change of temperature of the chip can be detected based on a change in temperature data values.

In particular, temperature data may refer to any data, which depends on the temperature of the chip of the transponder such that an absolute temperature of the chip may be determined from the temperature data by using calibration data.

The temperature data may comprise e.g.

- frequency values (e.g. 500 kHz, 501 KHz...),

- frequency difference values (e.g. 1 0.0 kHz, 1 0.7 kHz,...),

- values of TRCal (e.g. 20.1 μβ, 20.7 μβ, ...)

- values, which are proportional to the frequency values, to the frequency difference values, and/or to the TRCal values (e.g. 0.999, 1 .003, ...), and/or

- values which are determined from the frequency values, from the frequency difference values, and/or from the TRCal values by using a predetermined function (e.g. 0.999, 1 .003,...). The function may be e.g. a linear function or a logarithmic function.

The absolute temperature data may comprise e.g.

- absolute temperature values in Celsius (e.g. -5°C, +1 2°C, +72°C,...), - absolute temperature values in Fahrenheit (e.g. +23°F, +53.6°F,

+1 61 .6°F,...), - absolute temperature values in Kelvin (268 K, 285 K, 345 K,...),

- temperature difference values (e.g. 1 °C, 1 0 °C,...)

- values, which indicate whether the absolute temperature value is greater than a predetermined (known) temperature (e.g. true, false,...), and/or

- values which have been determined from the absolute temperature values by using a predetermined function.

The term "temperature data" may also comprise the "absolute temperature data". In other words, when temperature data is stored in a memory, the stored temperature data may also contain absolute temperature values (e.g. +25°C). For example, an expression "a process is controlled based on temperature data" may also mean that the process is controlled based on absolute temperature data.

When the clock frequency is f _C i_K is equal to 2.00 MHz, the location of the jump J7 may be associated with a frequency-setting parameter TRcaM . When the clock frequency is f _C i_K is equal to 2.02 MHz, the location of the jump J7 may be associated with a frequency-setting parameter TRcal2. AKJUMP denotes the difference TRcal2 - TRcaM .

A temperature or a temperature change between a first time and a second time may be detected or determined from the transverse shift of the curve CU R2 with respect to the curve CU R2. The temperature or a temperature change may be detected or determined by monitoring the magnitude of the difference TRcal2 - TRcaM

The magnitude of the difference TRcal2 - TRcaM may also be expressed by calculating the number of jumps (e.g. J6, J7, J8) covered by the difference TRcal2 - TRcaM

A temperature or a temperature change may be detected or determined by monitoring the magnitude of the difference Af _7-7 . A pair of modulation frequency values (f _LF1 , f _LF2 ), the difference TRcal2 - TRcaU , and/or the difference Af _7-7 may be interpreted to be temperature data TD _A TA- If desired, absolute temperature values ABSDATA may be determined from temperature data by using calibration data CALDATA.

Calibration data for a first transponder 1 00a may be substantially different from calibration data for a second transponder 1 00b. Thus, it may be relevant to store calibration data in a memory MEM1 located in the transponder. Alternatively, the calibration data may be stored in an external memory MEM8 such that relevant calibration data may be retrieved based on identification data of a transponder. Referring to Fig. 5b, the frequency-setting parameter TRcaU matching with a jump J7 may be experimentally determined e.g. by the mathematical up-and down method. In the first step, a first value TRcalA and a second value TRcalA may be experimentally determined such that a first modulation frequency f _LF1 associated with the frequency-setting parameter TRcalA is different from a second modulation frequency f _LF1 associated with the frequency-setting parameter TRcalB. Now, it is known that TRcaU resides somewhere between TRcalA and TRcalB, and any value in the range from TRcalA to TRcalB may be used as a coarse estimate for the TRcaU . ΔΚ| _ΤΕ1 denotes the difference TRcalB - TRcalA. A more accurate estimate for the TRcaU may be found by measuring the modulation frequency f _LF2 associated with a frequency-setting parameter TRcalC, which is located substantially half-way between TRcalA and TRcalB. ΔΚ| _ΤΕ2 denotes the difference TRcalC - TRcalA. ΔΚ| _ΤΕ2 may be e.g. in the range of 20% to 80% of ΔΚ| _ΤΕ1 . Preferably, ΔΚ| _ΤΕ2 is substantially equal to 50% ofAK| _TE1 . If the modulation frequency f _LF1 associated with the frequency-setting parameter TRcalC is substantially equal to f _{LF1 l} it may be determined that TRcaU resides somewhere between TRcalC and TRcalB. If the modulation frequency f _LF1 associated with the frequency-setting parameter TRcalC is substantially equal to f _LF2 , it may be determined that TRcaU resides somewhere between TRcalA and TRcalC. More accurate estimates for TRcaM may be determined by iteratively repeating the above-mentioned steps.

The method for monitoring temperatures may comprise:

- sending a first interrogation signal ROG1 and a second interrogation signal ROG2 to the RFID transponder 100, and

- receiving a first response signal RES1 from the RFID transponder 100 at a first modulation frequency f LF _, I and a second response signal RES2 from the RFID transponder 100 at a second different modulation frequency f _L F _, 2, wherein the first response signal RES1 is a response to the first interrogation signal ROG1 , the second response signal RES2 is a response to the second interrogation signal ROG2, the first interrogation signal ROG1 contains a first frequency-setting parameter TRcalA, the second interrogation signal ROG2 contains a second frequency-setting parameter TRcalB, and - determining an estimate for a frequency-setting parameter TRcaM associated with a location of a jump J7 such that the estimate resides between first frequency-setting parameter TRcalA and the second frequency-setting parameter TRcalB. Referring to Fig. 5c, temperature data may be determined based on two or more jumps J7, J8, J9. The signals may contain noise, which in turn may cause an error in the measured modulation frequencies f _{LF1 l}

A more accurate estimate for the difference AfjuMP7 may be determined e.g. by fitting a theoretical curve (e.g. CU R1 ) obtained from equation (1 ) to experimentally measured data.

A more accurate estimate for the difference AfjuMP7 may be determined e.g. by calculating a weighted average from two or more difference values AfjuMPe, AfjuMPs- Weighing coefficients for calculating the weighted average may be derived e.g. by fitting a theoretical curve (e.g. CU R1 ) obtained from equation (1 b) to experimentally measured data. TRcal6, TRcal7, TRcal8 denote frequency-setting parameters matching with jumps J6, J7, J8. ΔΚ _6-7 denotes a difference between TRcal7 and TRcal6. ΔΚ _7-8 denotes a difference between TRcal8 and TRcal7. F _LF0 may denote an upper frequency associated with the jump J6. f I_F ₃ may denote an upper frequency associated with the jump J8.

Absolute temperature values ABSDATA may be determined from the temperature data TDATA by using calibration data CALDATA The relationship between absolute temperature data ABSDATA and temperature data (frequency parameter) N _c (Fig. 1 b) may be established by calibration measurements also when the frequency parameter N _c is included in the response RES as a binary number. The relationship between absolute temperature data ABSDATA and temperature data TDATA (Figs 1 c and 1 d) may be established by calibration measurements also when the temperature data TDATA is included in the response RES as a binary number. One or more calibration measurements may provide calibration data CALDATA. For example, the chip 1 10 of transponder 1 00 may be positioned at a known temperature, and a frequency parameter N _c or a temperature data value (TDATA) associated with the known temperature may be stored in a memory as calibration data CALDATA.

The chip 1 10 may be positioned in two or more different temperatures, and corresponding frequency parameters N _c or a temperature data values (TDATA) may be recorded as a function of the temperature. For example, calibration data may contain e.g. a plurality of pairs, wherein an individual pair may comprise an absolute temperature value TABS associated with a frequency parameter value (N _c ) or a temperature data value (TDATA) A calibration function defining the relationship between the frequency parameter values (N _c ) and the corresponding temperatures may be defined by selecting the type of function and the parameters of the function such that the function substantially fits to the experimentally determined values. The function may be e.g. a linear function, a polynomial function or an exponential function.

A calibration function defining the relationship between the temperature data values (TDATA) and the corresponding temperatures may be defined by selecting the type of function and the parameters of the function such that the function substantially fits to the experimentally determined values. The function may be e.g. a linear function, a polynomial function or an exponential function.

The calibration data CALDATA may be determined before or after the actual temperature measurement. The calibration data may be determined e.g. when the transponder is manufactured. The calibration data may be determined e.g. one year after the temperature data serving as a basis for the measurement was received from the transponder. Calibration data CALDATA for a first transponder 1 00a may also be provided by positioning the first transponder 1 00a and a second transponder 1 00b substantially at the same ambient temperature. This situation may be realized e.g. when tagged items are stored or transported in the same container. The relationship between the temperature data TDATA1 obtained from the first transponder 1 00a and the ambient temperature may now be established because the ambient temperature may now be determined from second temperature data TDATA2 obtained from the second transponder 1 00b by using second calibration data CALDATA2 associated with the second transponder 1 00b.

The calibration data CALDATA may be temporally constant, i.e. absolute temperature values may be determined from temperature data measured at two different times by using the same calibration data CALDATA. However, properties of the chip 1 1 0 may also change in time such that there is a temporal drift in the calibration data values. First calibration data values may be determined at a first time. Second calibration data values may be determined at a second different time. Third calibration data values may be determined from the first calibration data values and the second calibration data values by extrapolation or interpolation.

Operation of the temperature monitoring unit 52, 55 may slightly depend on the voltage provided by the voltage supply VREG1 . The voltage supply VREG1 may comprise a voltage regulator arranged to reduce variation of voltage caused by variation of the amplitude of the interrogation signal ROG at the location of the antenna 140 of the transponder 100. However, this may reduce the maximum interrogation range.

Calibration data CALDATA may be determined e.g. as a function of the amplitude of the response RES provided by the transponder. The amplitude of the response RES may correspond to amplitude of the interrogation signal ROG at the location of the antenna 140.

Calibration and actual temperature measurements may also be made such that the amplitude of the interrogation signal ROG at the location of the antenna 140 during calibration substantially corresponds to the amplitude of the interrogation signal ROG at the location of the antenna 140 during the actual measurements.

The actual temperature measurements may be made using a predetermined distance between the reader 200 and the transponder 100.

The reader 200 may be arranged to adjust the amplitude of the interrogation signal ROG based on a distance between the reader 200 and a transponder 1 00. The reader 200 may be arranged to measure the distance between the reader 200 and a transponder 100. Referring to Fig. 6a, a temperature monitoring apparatus 700 may comprise one or more transponders 100, and a reader 200.

The reader 200 may stationary or movable with respect to the location reference LOCREF. In particular, the reader 200 may be portable.

The reader 200 may comprise a control unit 210 (CNT2) for controlling operation of the reader 200, and a radio frequency unit RXTX2 for transmitting interrogation signals ROG, and for receiving response signals RES. The radio frequency unit RXTX2 may be arranged to operate such that it provides a radio frequency field which provides operating energy for the transponder 1 00. The system 700 may be arranged to operate such that the transponder 100 extracts operating energy from the interrogation signal ROG provided by the reader 200.

The radio frequency unit RXTX2 may comprise a transmitter TX2 and a receiver RX2.

The reader 200 comprises at least one antenna 205 for transmitting an interrogation signal ROG. Also the response RES may be received by the (same) antenna 205. The antenna 205 may be e.g. a dipole antenna or an inductive antenna (i.e. a coil).

The antenna 205 may also be a leaky waveguide antenna (See Fig. 15d) arranged to distribute the electromagnetic radio frequency interrogation signal ROG to a large area. A leaky waveguide antenna may also be arranged to obtain electromagnetic radio frequency response signals RES from said large area. In particular, the leaky waveguide antenna 205 may comprise a microstrip waveguide.

The reader 200 may comprise a memory MEM2 for storing identification data ID1 (identifier F1 ) and temperature data TDATA1 (temperature information TINF1 ) associated with the identification data ID1 (identifier F1 ). The memory MEM2 (or a memory MEM10, see Fig. 6b) may further comprise computer program code, which when executed by the control unit CNT2 is for carrying out the method according to the present invention.

The reader 200 may comprise a user interface 500. The user interface 500 may comprise e.g. a display 501 (See e.g. Fig. 9a or 16c) for displaying temperature information and/or identification data. The system 700 may comprise a display 501 arranged to visually display temperature information and/or identification data.

Referring to Fig. 6b, the apparatus 700 may comprise one or more additional units and/or functionalities when compared with the set-up of Fig. 6a. The apparatus 700 (i.e. a system 700) may comprise an auxiliary unit 400.

The auxiliary unit 400 may comprise a control unit CNT4 (410) for processing data. In this case, the auxiliary unit 400 may also be called as a data processing unit. The control unit 410 (CNT4) may be arranged to control operation of the auxiliary unit 400 and/or for controlling operation of the reader 200.

The control unit CNT4 may be arranged to provide a control signal S _C NT based on the temperature data TDATA or based on absolute temperature data ABSDATA. The control signal S _C NT may be used for controlling e.g. a heater element or a ventilation fan (See Fig. 15c). The control signal S _C NT may be used for controlling an actuator, heater, cooling unit, ventilation unit, pump etc. based on temperature data obtained from the transponder(s).

The auxiliary unit 400 may optionally comprise one or more of the following memory units or memory areas MEM3, MEM4, MEM5, MEM6, MEM7, MEM8, MEM9, MEM10, MEM1 1 .MEM12. The auxiliary unit 400 (or the reader 200) may comprise a memory MEM3 for storing temperature data TDATA (temperature information). The control unit CNT4 may be arranged to store the temperature data TDATA (temperature information) such that temperature data TDATA obtained from a transponder 1 00 is associated with identification data ID1 (identification data) obtained from said transponder 1 00.

The auxiliary unit 400 (or the reader 200) may comprise a memory MEM4 for storing identifier data FDATA. The control unit CNT4 may be arranged to determine an identifier F1 based on identification data ID1 by using identifier data stored in the memory MEM4. Identifiers may be stored in a memory MEM4 such that the identifiers are associated with the corresponding identification data ID 1 . First temperature information TINF1 and a first identifier F1 may be determined based on first temperature data TDATA1 and a first identification data ID 1 obtained from a first transponder 1 00a. Second temperature information TINF2 and a second identifier F2 may be determined based on second temperature data TDATA2 and second identification data I D2 obtained from a second transponder 1 00b.

The first temperature information TINF1 and the first identifier F1 may be stored in the memory MEM3 or in the memories MEM3 and MEM4 such that the first temperature information TINF1 is associated with the first identifier F1 . The second temperature information TINF2 and the second identifier F2 may be stored in the memory MEM3 or in the memories MEM3 and MEM4 such that the second temperature information TINF2 is associated with the second identifier F2. The auxiliary unit 400 (or the reader 200) may comprise a memory MEM5 for storing absolute temperature data ABSDATA. The control unit CNT4 may be arranged to determine absolute temperature data ABSDATA from temperature data TDATA e.g. by using calibration data CALDATA stored in the memory MEM8. The auxiliary unit 400 (or the reader 200) may comprise a memory MEM6 for storing time data TIMEDATA. The control unit CNT4 may be arranged to retrieve a time associated with a specific temperature data value stored in the memory MEM3 by using the time data TIMEDATA stored in the memory MEM6.

The memory MEM6 may store time data associated with the temperature data TDATA and/or absolute temperature data ABSDATA. Time data TIMEDATA associated with temperature data TDATA may represent temperature history data. A time data element stored in the memory MEM6 may e.g. specify the time and date of a specific temperature measurement result. The apparatus 700 may be arranged to store temperature history data associated with the transponder 100. The temperature history data may comprise a plurality of temperature data values obtained at different times from the same transponder 100. The temperature history data may be stored e.g. in the memory MEM2, MEM3 and/or MEM6.

The control unit CNT4 may be arranged to determine a minimum temperature data value, a maximum temperature data value, an average temperature data, and/or a statistical value based on the temperature history data.

Temperature history data values may stored such that an individual temperature data value is associated with a time and/or a location. The auxiliary unit 400 (or the reader 200) may comprise a memory MEM7 for storing location data LOCDATA. The control unit CNT4 may be arranged to retrieve a location associated with a specific temperature data value stored in the memory MEM3 by using the location data LOCDATA stored in the memory MEM7. The memory MEM8 may store calibration data CALDATA associated with the identifier I D1 of a transponder 1 00. Absolute temperature data ABSDATA may be provided from the temperature data TDATA by using the calibration data CALDATA.

The memory MEM5 may store location data LOCDATA associated with temperature data TDATA or with absolute temperature data ABSDATA. The location data may specify a location e.g. verbally or by using location coordinates (e.g. "wall section #5 of 7th storey of building #7" or by indicating GPS coordinates).

Data stored in the memory MEM5 may be used to to determine a location of a transponder 1 00 based on the identification data ID1 . The auxiliary unit 400 (or the reader 200) may comprise a memory MEM9 for storing party data PARDATA. The control unit CNT4 may be arranged to determine a party based on the party data PARDATA by using the identification data ID1 . The party may be e.g. an owner of an item 300a associated with the transponder 1 00 or a party which is responsible for handling the item 300a.

The auxiliary unit 400 may comprise a user interface 500 (not shown). The reader does not need to comprise a user interface 500. A memory MEM1 0 may store computer program code PROG, which when executed by a data processor is for operating the apparatus 700 according to the invention. The apparatus 700 may comprise a computer-readable medium MEM10 storing computer program code PROG, which when executed by data processor CNT2, CNT4 is for executing a temperature measurement, displaying and/or control.

A memory MEM1 1 may comprise reference data REFDATA. The control unit CNT4 may be arranged to perform an action based on a comparison between temperature data TDATA and reference data REFDATA. Temperature data TDATA may be compared with the reference data REFDATA e.g. in order to determine whether a value of the temperature data TDATA is lower than or equal to a first value of the reference data REFDATA.

Temperature data TDATA may be compared with the reference data REFDATA e.g. in order to determine whether a value of the temperature data TDATA is higher than or equal to a second value of the reference data REFDATA.

Temperature data TDATA may be compared with the reference data REFDATA e.g. in order to determine whether a value of the temperature data TDATA is in a range between the first value of the reference data REFDATA and the second value of the reference data REFDATA.

The control unit CNT4 may be arranged to control a system 700, 900 based on the comparison between temperature data TDATA and reference data REFDATA.

The control unit CNT4 may be arranged to provide a control signal S _C NT based on the comparison between temperature data TDATA and reference data REFDATA. The control unit CNT4 may be arranged to initiate an alarm procedure based on the comparison between temperature data TDATA and reference data REFDATA.

Temperature data TDATA1 obtained from a first transponder 100a may be e.g. compared with reference data REFDATA, which has been determined based on temperature data TDATA2, which has been obtained earlier from the same transponder 100a.

Temperature data TDATA1 obtained from a first transponder 100a may be e.g. compared with reference data REFDATA, which has been determined based on temperature data TDATA2 obtained from a different transponder 1 00b.

The transponder 1 00 may be attached to an item 300a or otherwise associated with the item 300a. A memory MEM1 2 may comprise material information MATDATA about material(s) of the item 300a. The material information may be retrieved from the memory MEM1 2 according to the identification data ID1 obtained from the transponder 1 00.

COM1 denotes communication between the reader 200 and the auxiliary unit 400. The communication COM1 may take place e.g. via a mobile telephone network, internet, Wireless Local Area Network (WLAN), Bluetooth, electrical cable, and/or optical cable.

The reader 200 may optionally comprise a navigation unit NAV1 for determining the position of the reader 200. The navigation unit NAV1 may comprise e.g. a satellite navigation device, a laser distance meter and/or an ultrasonic distance meter. In particular, the navigation unit NAV1 may be a GPS device (GPS is an acronym for Global Positioning System). The navigation unit NAV1 may be arranged to determine the position of the reader 200 with respect to one or more reference devices. The reference devices may be e.g. optical prisms, crosshair patterns, laser units, or radio beacons.

The reader 200 may optionally comprise an optical sensor CAM1 for receiving information from a reference identifier R1 attached in the vicinity of the transponder. In particular, the optical sensor CAM1 may be e.g. a digital camera. The reference identifier R1 may be attached to the transponder 1 00 or to the item 300. The reference identifier R1 may be e.g. a graphical symbol "TC1 ". The reference identifier R1 may also be a barcode, matrix barcode, hologram or another optical machine- readable pattern specifying or confirming the identity of the transponder 1 00 and/or the identity of the item 300. The optical sensor CAM1 may be arranged to e.g. capture an image of the reference identifier R1 . An identifier F1 may now be determined based on the captured image or based on information extracted from the image. In an embodiment, the captured image is used as the identifier F1 . The determined identifier F1 may now be associated with the identification data ID1 obtained from the transponder 1 00. The identifier F1 may be stored in the memory MEM4 such that the identifier F1 is associated with the identification data ID 1 obtained from the transponder 1 00.

The reader 200 and/or the auxiliary unit 400 may comprise a user interface 500. The user interface 500 may comprise e.g. a display 501 (See e.g. Fig. 9a or 1 6c) for displaying temperature information and/or identifiers.

The user interface 500 may comprise e.g. a keypad (not shown) or a touch screen for receiving commands from a user.

Several transponders 1 00a, 1 00b, 1 00c may be simultaneously within the interrogation range of the reader 200. Sometimes the user can not be sure whether he is gathering temperature data from the right transponder. For that purpose, the maximum interrogation range of the reader 200 may be adjustable. The interrogation range may be adjusted to be so short that only the transponder closest to the reader responds to an interrogation signal. In this case, the position of the (responding) transponder may be approximated by the position of the transponder (during the transmission of the response).

The interrogation range may be adjusted e.g. by using the user interface 500.

The interrogation range may also be called as the maximum reading distance. However, the temperature monitoring system 700 may be arranged to temperature information TINF1 such that the temperature information TINF1 is associated with an identifier F1 . Consequently, reliable temperature measurements may also be made when several transponders 100a, 100b, 100c are simultaneously within the interrogation range of the reader 200.

The identity of a transponder 100a may also be associated with the location of said transponder 100a. For that purpose, the location of the transponder 100a should be determined. In particular, the the location of the transponder 100a may be measured.

Sometimes a transponder may be embedded in materials such that is is not directly visible. Referring to Figs. 7a - 7h, the location of a transponder 1 00 may be measured with respect to a location reference LOCREF by using a reader 200.

Determining the location (x,y) of a transponder 100a with respect to the location reference LOCREF may comprise:

- determining the location of a reader 200 with respect to the location reference LOCREF, and

- determining the position of the transponder 100a with respect to the reader 200.

The location of the reader 200 may refer to the location of an antenna 205 of the reader 200. The location of the transponder 100a may refer to the location of the antenna 140 of the transponder 100a.

In an embodiment, the interrogation range of the reader 200 may be set to be so short that the position of a responding transponder 100a may be approximated by the location of the reader 200. In other words, the position of the transponder 100a may be approximated by the position of the reader 200a if the distance η is smaller than a predetermined value.

The interrogation range may be limited e.g. by adjusting the amplitude of the interrogation signal ROG and/or by setting a minimum level (see the "low limit" in Fig. 7b) for an acceptable response RES. If the amplitude of the response RES is not greater than or equal to the minimum level, the response RES received by the reader 200 may be rejected. Referring to Figs. 7a and 7b, the reader 200 may be moved with respect to the location reference LOCREF. The amplitude of a response RES may be monitored as a function of the position x of the reader 200. A response obtained from a first transponder 1 00a may attain a maximum level when the reader 200 (transmitting antenna of a reader) is at a position x _a . A response obtained from a second transponder 1 00b may attain a maximum level when the reader 200 (transmitting antenna of a reader) is at a position x _b .

In this case, the position of the transponder 1 00a with respect to the location reference LOCREF may be approximated by the position x _a of the transponder 200 with respect to the location reference LOCREF, wherein the position x _a is associated with maximum amplitude of the response RES obtained from the transponder 1 00a, and the interrogation range of the reader 200 is set such that the level of a response obtained from other transponders 1 00b is substantially lower than the level of the response obtained from the transponder 1 00a.

It is not necessary to move the reader 200. The spatial distribution of an interrogation signal field may be varied. A single reader 200 may comprise a first antenna for sending a first interrogation signal from a first position x _a and a second antenna for sending a second interrogation signal from a second position x _b (See Figs. 7i and 7j).

Referring to Fig. 7c, the position of the transponder 1 00a may also be determined by providing a directional interrogation beam from the reader 200, and by varying the direction of the interrogation beam.

The directional interrogation beam refers to an interrogation signal, which has a first amplitude in a first direction and second substantially different amplitude in a second direction. The direction of the interrogation beam may be varied e.g. by mechanically changing the orientation of a directional antenna, and/or by electronically adjusting phase difference of signals coupled to antenna elements.

Referring to Fig. 7d, an interrogation beam ROG1 sent in a direction may impinge on a transponder 100a such that the interrogation beam ROG1 provides a maximum level for a response from a transponder 100a.

An angle Θ may represent e.g. an angle between the direction -SY and the centerline of an interrogation beam. A direction specified by an angle Θ may also be called as the "direction Θ". If an interrogation beam ROG1 ' does not impinge on the transponder 100a, the transponder 100a does not respond or the response may be substantially weaker than in case of the interrogation beam ROG1 sent in the direction Q^ . Referring to Fig. 7e, the location of a transponder 100a may be determined by triangulation.

Maximum amplitudes of the responses may be obtained when a first interrogation beam ROG1 is sent from the reader 200a to a first direction and a second interrogation beam ROG2 is sent from the reader 200b to a second direction θ ₂ . The second reader 200b should be at a different position than the first reader 200a.

The location of a transponder 100a with respect to the reader 200a may be determined based on the angle of the first directional interrogation beam ROG1 obtained from a reader 200a at a first position and based on the angle θ ₂ of a second directional interrogation beam ROG2 obtained from a reader 200b at a second position. Instead of using the second reader 200a, the first reader 200a may be used to make a first directional measurement at a first position and a second directional measurement at a second position, i.e. the first reader 200a may be moved to the position of the second reader 200a.

Referring to Fig. 7f, a first reader 200a may be moved in a first direction SX, and a second reader 200b may be moved in a second direction SY in order to determine the position of a transponder 100a.

In this case, the interrogation range may be short and/or the reader 200a, 200b may be arranged to send a directional interrogation beam.

The same reader 200a may also be moved in two or more different directions SX, SY in order to determine the position of the transponder 100a. Referring to Fig. 7g, a distance η between a first reader 200a and the transponder 100a may be determined based on a time delay At and/or based on the level of a response RES.

Refering to Fig. 7h, the time delay between sending a first interrogation signal ROG1 and receiving a corresponding (backscattered) response RES depends on the distance η between a first reader 200a and the transponder 1 00a.

The time delay At ₂ between sending a second interrogation signal ROG2 and receiving a corresponding (backscattered) response RES depends on the distance r ₂ between a second reader 200b and the transponder 100b. (Instead of using the second reader 200b, the first reader 200a may be moved to a different location). The amplitude of a response corresponding to the interrogation signal ROG1 from the first reader 200a may depend on the distance η between the first reader 200a and the transponder 100a.

The amplitude A ₂ of a response corresponding to the interrogation signal ROG2 from the second reader 200b may depend on the distance r ₂ between the second reader 200a and the transponder 100a. Referring back to Fig. 7g, the distance η between the reader 200a and the transponder 100a may be determined based on the time delay Δ^ . The distance r ₂ between the reader 200b and the transponder 1 00a may be determined based on the delay At ₂ . In this case, the interrogation signals ROG1 , ROG2 may also be substantially omnidirectional.

The distance η between the reader 200a and the transponder 1 00a may also be determined based on the amplitude of a response corresponding to the interrogation signal ROG1 sent from the reader 200a. The distance r ₂ between the reader 200b and the transponder 100a may also be determined based on the amplitude A ₂ of a response corresponding to the interrogation signal ROG2 sent from the reader 200b.

The position of the transponder 1 00a with respect to the reader 200a may be determined based on the distance η and the direction of an interrogation beam ROG1 , which provides the maximum response amplitude. The position of the transponder with respect to the location reference LOCREF may now be determined when the position of the reader 200a is known with respect to the location reference LOCREF. The position of the reader 200a and/or 200b with respect to the location reference LOCREF may be determined e.g. by using the navigation unit NAV1 (Fig. 6b).

The position of transponder with respect to the reader 200a may be determined based on the distance η and based on the distance r ₂ . These two distances η and r ₂ define together a circle where the transponder 1 00a may reside. A more precise position may be determined by additionally using a directional interrogation beam and/or by using a reader at a third position in order to provide a third distance r ₃ . The position of the transponder 100a may be unambiguously determined based on a first distance η between the transponder 1 00a and a first reader location, based on a second distance r ₂ between the transponder 100a and a second reader location, and based on a third distance r ₃ between the transponder 100a and a third reader location.

Determining the position of a transponder 100a with respect a location reference LOCREF may comprise:

- determining a location of a reader 200a with respect to the location reference LOCREF, and

- determining a position of the transponder with respect to the location of the reader 200a.

Determining the position of the transponder with respect to the reader 200a may comprise:

- varying spatial distribution of an interrogation signal field,

- varying a position of the reader 200a,

- varying the direction of an interrogation beam ROG1 sent from a reader 200a,

- measuring a time delay between an interrogation signal ROG1 and a response RES,

measuring amplitude of a response RES corresponding to an interrogation signal ROG1 , and/or

- varying a maximum interrogation range between a reader 200a and the transponder 1 00a.

The apparatus 700, and in particular the control unit CNT2, CNT4 may be arranged to determine the location of the first transponder 100a with respect to the reader 200 based on a time delay (Δ^) and/or an amplitude of a response RES obtained from the first transponder 100a. The apparatus 700, and in particular the control unit CNT2, CNT4 may be arranged to determine the location of the first transponder 100a with respect to the reader 200 by spatially varying radio frequency fields of interrogation signals ROG. The apparatus 700, and in particular the control unit CNT2, CNT4 may be arranged to determine location data LOCDATA based on the measured location of the first transponder 1 00a, and to store the location data LOCDATA in a memory MEM7 such that the location data LOCDATA is associated with the first identifier F1 . Referring to Figs. 7i ajd 7j, The location of the transponder may be measured also by using a reader 200, which has a first antenna 205a and a second antenna 205b. The first antenna 205a may be arranged to send a first interrogation signal ROG1 , and the second antenna 205b may be arranged to send a second interrogation signal ROG2 such that the spatial amplitude distribution of the first interrogation signal ROG1 is different from the the spatial amplitude distribution of the second interrogation signal ROG2. d205 denotes the distance between the first antenna 205a and the second antenna 205b. Knowledge about the distance d205 may be used in the triangulation algorithm. The system 700 of Fig. 7i may be used e.g. instead of the system shown in Fig. 7e. The system 700 of Fig. 7j may be used e.g. instead of the system shown in Fig. 7g.

When determining the location of the transponder, the first antenna 205a and the second antenna 205b may be arranged to operate such that they do not transmit the signals ROG1 , ROG2 simultaneously. When determining the location of the transponder, the first reader 200a and the second reader 200b may be arranged to operate such that they do not transmit the signals ROG1 , ROG2 simultaneously.

Referring to Fig. 8a, a first transponder 100a may be attached to a first item 300a, a second transponder 100b may be attached to a second item 300b, and a third transponder 100c may be attached to a third item 300c.

Optionally, a first reference identifier R1 may be attached to the first item 300a. A second reference identifier R2 may be attached to the second item 300b. A third reference identifier R3 may be attached to the third item 300b. Optionally, the first reference identifier R1 may be attached in the vicinity of the first transponder 1 00a. The distance between the reference identifier R1 and the transponder may be e.g. smaller than or equal to 1 .0 m, advantageously smaller than 0.5 m, preferably smaller than or equal to 0.1 m. The reference identifier R1 may be attached to the transponder 1 00a. The second reference identifier R2 may be attached in the vicinity of the second transponder 1 00b. The third reference identifier R3 may be attached in the vicinity of the third transponder 1 00c.

The reference identifiers R1 , R2, R3 may be optical identifiers, i.e. they can be inspected visually or by using a camera. The reference identifiers R1 , R2, R3 may be e.g. graphical symbols or codes printed on an adhesive label. For example, the reference identifier R1 may be a circle pattern, the reference identifier R2 may be a triangle pattern, and the reference identifier R3 may be a star pattern.

The purpose of the (optional) reference identifier R1 is to facilitate finding the approximate location of the first transponder 1 00a and/or to improve the reliability of data transfer. A user who wishes to obtain data from the transponder 1 00a may compare the identifier F1 of the transponder 1 00a displayed on the display 501 of the reader 200 with the reference identifier R1 attached on the item 300a. If the identifier F1 does not correspond to the reference identifier R1 , it is likely that the reader 200 is obtaining data from a wrong transponder.

Fig. 8b shows three transponders 1 00a, 1 00b, 1 00c attached to different portions 301 a, 301 b, 301 c of an item 300. A first reference identifier R1 may be attached on the first portion 301 a, a second reference identifier R2 may be attached on the second portion 301 b, and a third reference identifier R3 may be attached on the third portion 301 c.

Referring to Fig. 9a, temperature information TINF1 may be determined based on temperature data TDATA1 obtained from the first transponder 1 00a. An identifier F1 may be determined based on identification data ID 1 obtained from a first transponder 1 00a. The identifier F1 may be e.g. retrieved from a memory MEM4 according to the identification data ID1 . Alternatively, the identifier F1 may be determined from the identification data I D1 by using a (predetermined) algorithm.

Preferably, identifiers F1 , F2, F3 associated with transponders 1 00a, 1 00b, 1 00c should be different from each other. A method for monitoring temperatures may comprise:

- determining first temperature information TINF1 based on first temperature data TDATA1 obtained from a first RFID transponder 1 00a,

- determining a first identifier F1 based on first identification data ID1 obtained from a first RFID transponder 1 00a, and

- providing the first temperature information TINF1 and the first identifier F1 at an interface 500, MEM3 such that the first temperature information TINF1 is associated with the first identifier F1 . The interface may be located outside the transponder 1 00a.

The interface may be e.g. a user interface 500 comprising a display 501 (Fig. 6b). The first temperature information TINF1 may be displayed to a user together with the first identifier F1 .

The interface may be a machine-readable register, which comprises the first temperature information TINF1 and the first identifier F1 . For example, the memory MEM3 may be arranged to operate as an interface, which provides the first temperature information TINF1 and the first identifier F1 such that the first temperature information TINF1 is associated with the first identifier F1 .

A display 501 may be arranged to display the first temperature information TINF1 . A display 501 may be arranged to display the first identifier F1 . In particular, the first identifier F1 may be displayed such that the first identifier F1 is associated with the first temperature information TINF1 .

The first identifier F1 and the first temperature information TINF1 may be provided at an interface 500 such that the first identifier F1 is associated with the first temperature information TINF1 .

For example, the identifier F1 may be displayed next to the temperature information INF1 .

The first identifier F1 may comprise at least a part of a reference identifier R1

- attached to the transponder 1 00a,

- attached to the item 300a, or

- attached in the vicinity of the item 300a.

The first identifier F1 may comprise a descriptor indicative of

- a property of a first reference identifier R1 attached to the first transponder 1 00a,

- a property of a first reference identifier R1 attached to the first item 300a,

- a property of a first reference identifier R1 located in the vicinity of the first item 300a,

- a property of the first item 300a,

- the location of the first transponder 1 00a, and/or

- the location of the first item 300a,

The descriptor may be e.g.

- a verbal descriptor,

- a digest,

- a numerical descriptor, in particular a checksum,

- a graphical descriptor,

- a symbolic descriptor,

- a portion of an image, in particular a portion of a photograph.

The first identifier F1 may comprise at least a part of an image IMG1 - of a first reference identifier R1 attached to the first transponder 1 00a,

- of a first reference identifier R1 attached to the first item 300a,

- of a first reference identifier R1 located in the vicinity of the first item 300a, and/or

- of the first item 300a.

The measuring system 700 may comprise a plurality of transponders 300a, 300b, 300c. Thanks to the identifier F1 a user may rapidly check whether he is obtaining temperature data from a predetermined transponder 1 00a. In particular, the user may subsequently compare the displayed identifier F1 with a reference identifier R1 attached in the vicinity of the transponder 1 00a. If the identifier F1 does not correspond to the reference identifier R1 , it is likely that the reader 200 is obtaining data from a wrong transponder.

Thanks to the identifier F1 , the user may rapidly move a reader 200 so that a predetermined transponder 1 00a is within a interrogation range of the reader 200. A second identifier F2 may be determined based on second identification data I D2 obtained from a second transponder 1 00b. Second temperature information INF2 may be determined based on second temperature data TDATA2 obtained from the second transponder 1 00b. A third identifier F3 may be determined based on third identification data ID3 obtained from a third transponder 1 00c. Third temperature information INF3 may be determined based on third temperature data TDATA3 obtained from the third transponder 1 00b.

The second identifier F2 and the second temperature information TINF2 may be provided at an interface 500 such that the second identifier F2 is associated with the second temperature information TINF2. The third identifier F3 and the third temperature information TINF3 may be provided at an interface 500 such that the third identifier F3 is associated with the third temperature information TINF3. The identifier F1 may be e.g. a circle pattern. The identifier F2 may be e.g. a triangle pattern. The identifier F3 may be e.g. a star pattern. The temperature information TINF1 , TINF2, TINF3 may comprise e.g. absolute temperature values.

The display 501 may be arranged to display an identifier F1 , which helps the user to make sure that temperature data is gathered from the right transponder. Referring to back to Figs. 6b, 8a and 8b, an optical device comprising a reference identifier R1 may be attached to the transponder 1 00 or to the item 300. The optical device may be e.g. a label having a printed graphical symbol or code. A control unit CNT4 of the measuring system 700 may be arranged to determine an identifier F1 based on identification data ID 1 obtained from the transponder 1 00a. A display 501 may be arranged to display the identifier F1 . If the identifier F1 shown by the display 501 does not correspond to the reference identifier R1 , this may be an indication that temperature data is obtained from a wrong transponder.

Referring to Fig. 9b, the identifier F1 may also comprise one or more numbers, letters and/or other characters, e.g. a string "TC1 ". The temperature information TINF3 may comprise e.g. a string "OK", which may indicate that the absolute temperature is in a preferred range.

Referring to Fig. 9c, a display 501 may be arranged to display information associated with a transponder 1 00a when the absolute temperature is outside a preferred range. A display 501 may be arranged to display information associated with a transponder 1 00a only when the absolute temperature associated with the transponder 1 00a is smaller than a first limit and/or higher than a second limit.

Referring to Fig. 9d, an identifier may comprise location information LOCDATA. The identifier may comprise e.g. coordinates of an item 300c, coordinates of a transponder 1 00c, or coordinates of a reference identifier R3.

Referring to Fig. 9e, displayed temperature information may comprise e.g. an indication that the temperature is changing. In particular, the temperature information may comprise e.g. an indication that the temperature is increasing or decreasing.

Referring to Fig. 9e, displayed temperature information may comprise e.g. an indication that the temperature is higher than a second limit, e.g. a symbol showing "heat waves" over a horizontal line.

Referring to Fig. 9e, displayed temperature information may comprise e.g. an exclamation mark " !" in order to attract special attention.

Referring to Fig. 9h, a user may select one or more identifiers F1 , F2, F3 e.g. in order to request information associated with the selected identifier(s) F3. The selected identifier(s) F3 may be displayed on a display 501 .

Referring to Fig. 9i, temperature information TINF3 associated with the selected identifier(s) F3 may be displayed on a display 501 .

The temperature information INF3 may be displayed together with the selected identifier F3. The temperature information INF3 and the associated identifier may be displayed substantially simultaneously or in an alternating manner (i.e. the identifier F3 may be displayed for a few seconds, and the corresponding temperature information TINF3 may be subsequently displayed at the same location of the display).

Also the location of the temperature information INF3 on the display 501 may be used as an identifier (e.g. upper part, = F1 , center = F2, lower part = F3). The user may also request temperature information from a predetermined group of transponders 1 00a, 1 00b, by selecting an additional identifier corresponding to said group. Identifiers corresponding to transponders of said group may also be selected individually. The transponders of said group may have a common property, e.g. they may be located within a predetermined area.

Referring to Fig. 9j, the identifier F3 may also comprise an image IMG3. The image IMG3 may be e.g. an image of an item 300c and/or an image of a reference identifier R3 attached on the item 300c. The image IMG3 may be e.g. an image of a portion 301 c of an item 300 and/or an image of a reference identifier R3 attached on the item 300. In particular, the identifier may be a photograph.

The image of the item 300c, portion 301 c or reference identifier R3 related to a transponder 1 00c may be captured e.g. by using a camera CAM1 of a reader 200. The image may be subsequently stored e.g. in a memory MEM4 as an identifier F3.

Referring to Fig. 9k, the identifier F1 may comprise an image IMG1 . The image IMG1 may be e.g. an image of an item 300a and/or an image of a reference identifier R1 attached to the item 300a. Temperature information TINF1 may be provided such that the temperature information TINF1 is associated with the identifier F1 .

The position of the transponder 1 00c may be determined e.g. by using a method discussed with reference to the Figs. 7a - 7h. In particular, the interrogation range may be set to be so short that only one transponder is responding. When the determined position of a transponder 1 00c substantially corresponds to the location of the captured image, the captured identifier may be stored in the memory MEM4 such that the identifier is associated with identification data ID 1 obtained from the transponder 1 00c. Consequently, the temperature information TINF3 derived from temperature data TDATA3 obtained from the transponder 1 00c and the identifier F3 corresponding to the transponder 1 00c may be stored in a memory of the temperature monitoring system 700 such the temperature information TINF3 is associated with the identifier F3. In general, temperature information TINF1 determined based on temperature data TDATA1 obtained from a transponder 1 00a and an identifier F1 determined based on identification data ID1 obtained from the transponder 1 00a may be provided at an interface outside the transponder such that the temperature information TINF1 is associated with the identifier F1 .

Temperature information TINF1 determined based on temperature data TDATA1 obtained from a transponder 1 00a and an identifier F1 determined based on identification data ID1 obtained from the transponder 1 00a may be stored in a memory of the system 700 outside the transponder such that the temperature information TINF1 is associated with the identifier F1 . The memory of of the system 700 outside the transponder may further comprise temperature information TINF2 determined based on temperature data TDATA2 obtained from a second transponder 1 00b and a second identifier F2 determined based on identification data ID2 obtained from the second transponder 1 00b. Temperature information TINF1 determined based on temperature data TDATA1 obtained from a transponder 1 00a and an identifier F1 determined based on identification data ID1 obtained from the transponder 1 00a may be displayed on a display 501 such that the temperature information TINF1 is associated with the identifier F1 .

A method for monitoring temperatures by using a transponder 1 00 may comprise providing temperature information IN F1 to a user via an interface 500 (e.g. displaying visual information, providing an audio signal, vibration).

A method for monitoring temperatures by using a transponder may comprise displaying temperature information (e.g. numbers, codes, colors, flashing) A method for monitoring temperatures by using a transponder may comprise displaying a visual indicator indicative of a temperature, temperature range or a change of temperature of the chip of the transponder.

A method for monitoring temperatures by using a transponder may comprise displaying temperatures as list of numbers or symbols or graphs or images. An image may be based on an image taken from the measurement area with temperature readings presented in the image at locations corresponding the locations of the transponders. The image may a 2-dimensional or 3-dimensional image.

For example, a display of the interface 500 and/or a display 501 of the reader 200 may be arranged to show one or more of the following:

- a numerical temperature information (e.g. 47°C),

- a temperature curve,

- a bar whose height or length indicates a temperature,

- a color associated with a specific temperature or temperature range (e.g. "red" = temperature exceeds 50°C),

- symbol, which appears when the temperature or a rate of temperature change reaches a predetermined limit,

- a flashing indicator.

A color, flashing frequency, or brightness may be adjusted according to the temperature data. It is emphasized that temperature information INF1 and/or an identifier F1 may be provided to a user also by non-visual means.

The reader 200 or the interface 500 may be arranged to make an audible alarm when the temperature or a rate of temperature change reaches a predetermined limit. The frequency of an audible signal may be adjusted or modulated according to the temperature data. Temperature values may be provided by playing pre-recorded messages or by using speech synthesis. The reader 200 or the interface 500 may be arranged to vibrate in case of an alarm at frequency which is in the range of 1 Hz to 50 Hz. , i.e. an alarm may be provided by low-frequency vibration. Also the identifier F1 may be provided by an audio signal, e.g. one beep may refer to the identifier F1 , two beeps may refer to the identifier F2, and three beeps may refer to the identifier F3.

The user interface 500 may a haptic interface.

Information may be presented e.g. by providing mild electric shocks to a user who operates a touch screen. Information may be presented e.g. by heating a surface of a device in order to indicate that an internal part of the device operates at a too high temperature. A surface of the interface 500 may be heated and/or cooled to a temperature, which corresponds to the temperature of the chip 1 10. A surface of the interface 500 may be heated and/or cooled to a temperature, which is substantially equal to the temperature of the chip 1 10.

Temperature values may be derived from temperature data obtained from a transponder attached to the internal part.

Referring back to Fig. 6b the reader 200 may be movable or stationary with respect to the location reference LOCREF.

The location of the reader 200 may refer to the location of an antenna 205 of the reader. The antenna 205 of the reader 200 may be stationary or movable with respect to a location reference. The location reference may be e.g. a building or a road. The antenna 205 of the reader 200 may be moved with respect to the location reference between receiving a first response RES1 and a second response RES2. The reader 200 may be movable or moved with respect to the transponder 100, i.e. a distance between the reader 200 and the transponder 1 00 may be variable or varied. The antenna 205 of the reader 200 may be moved with respect to the transponder 1 00 between receiving a first response and a second response. The transponder 1 00 may be stationary or movable with respect to the location reference. The transponder 1 00 may be moved with respect to the location reference between sending a first response and a second response. The auxiliary unit 400 may be stationary or movable with respect to the location reference. The auxiliary unit 400 may be moved with respect to the location reference between sending a first response and a second response from the transponder. The reader 200 may be movable or moved with respect to the auxiliary unit 400, i.e. a distance between the reader 200 and the auxiliary unit 400 may be variable or varied. The antenna 205 of the reader 200 may be moved with respect to the auxiliary unit 400 between receiving a first response and a second response.

In an embodiment, the transponder 1 00 may be immobile with respect to a user interface 500. A display 501 may be attached to the transponder 1 00 or to an item 300 in order to visually display temperature information. The transponder 1 00 may comprise the display. The display may be based on e.g. on the use of electronic ink.

Referring to Figs. 1 0 - 1 4, a temperature monitoring system 700 may comprise one or more transponders arranged to provide temperature data.

Referring to Fig. 1 0, one or more transponders 1 00a, 1 00b may be attached to an item 300 for monitoring temperature of the item 300, a change of temperature of the item 300, a minimum temperature of the item 300 and/or a maximum temperature of the item 300. Referring to Fig. 1 1 , the interrogation signals ROG and the response signals RES may be sent through a barrier 800. The material of the barrier 800 should allow transmission of the signals through the barrier 800. The barrier 800 may be e.g. a dielectric barrier without metallic structure (e.g. glass, plastic, wood, or a dielectric barrier with reinforcing metal elements (reinforced concrete). Thus, the set-up may be used for measuring temperatures inside reaction vessels, containers or bottles. The set-up may be used for measuring temperatures inside a thermos bottle or Dewar container, which is thermally insulated by vacuum.

A transponder 1 00 may be positioned inside a vessel. A transponder 1 00 may be positioned inside a pressurized vessel. A transponder 1 00 may be positioned in a vacuum or in an environment, whose absolute pressure is lower than 1 00 kPa. A transponder 1 00 may be positioned in a hermetically sealed vessel. A transponder 1 00 may be positioned inside a hermetically sealed package.

A first side of the barrier 800 may be at a first pressure p1 , and a second side of the barrier 800 may be at a second different pressure p2.

The reader 200 may be on a first side of barrier and the transponder 100 may be on a second side of the barrier 800. The set-up may be used for measuring temperatures inside pressurized (or low pressure) reaction vessels, containers or bottles without using a galvanic electric feedthrough in the barrier 800.

A further advantage of the apparatus 700 is that it may be safely used in environments having a high explosion risk such as oil refineries and storages for explosives.

Referring to Fig. 1 2, the apparatus may be used for monitoring temperatures of moving items 300. In particular, the moving items may be rotating items. For example, the item 300 may be e.g. an automobile tire. The item 300 may be a piston or a crankshaft of a marine diesel engine or an air compressor. The item 300 may be e.g. a blade of a windmill. The item 300 may be a rotating roll of a paper- making machine, calendar, or printing machine. Referring to Fig. 13, the apparatus may be used for monitoring temperatures or temperature distributions in very large objects 300. The object 300 may be e.g. a runway of an airport, road, railroad, or a pavement. For example, the apparatus may be used for monitoring depth of frost in Nordic dirt roads.

The reader 200 may be moved with respect to the object 300 in order to gather information from the various transponders 100a, 100b, 100c attached or embedded in the object 300. Referring to Fig. 14, the apparatus 700 may be arranged to control operating temperature of an item 300. A control signal S _C NT provided by the auxiliary unit 400 (data processing unit 400) may be used to control an active element 710. The active element 710 may comprise e.g. a heater unit, a cooling unit, and/or a ventilation unit. The heater unit may be e.g. a resistive electric heater or a radiative heater (e.g. an infrared light emitting heater). The cooling unit may be e.g. a refrigeration system. The cooling unit may be a Peltier element. The ventilation unit may be a ventilation unit of an automobile, airplane or building. The apparatus 700 may be arranged to control temperature distribution of the item 300. For that purpose, the apparatus 700 may comprise two or more transponders 1 00 and/or two or more separately controllable active elements 710.

EXAMPLES

The various aspects of the invention are illustrated by the following examples:

Elements for buildings and/or construction One or more RFID transponders may be attached to a building element in order to monitor temperatures, changes in temperature, and/or temperature distributions. The building element may be e.g. a building board, thermal insulation, brick, tile, stone, concrete element, metal element, plastic element, felt, cardboard, composite element, window glass, window frame, door, door frame, beam, truss, and/or column. An RFID transponder may be buried in ground in the vicinity of a building.

Depending on the material, the RFID transponder can be read through the material without need for line-of-sight access. Sometimes conductive structures e.g. ventilation ducts may substantially increase the reading range of a transponder embedded in a building element.

This can be achieved especially by arranging the reader device (i.e. an antenna of the reader device) to transmit signals into conductive and/or hollow elements, and to receive signals from said conductive/hollow elements.

Temperature data, identification data and/or location information may be subsequently gathered from the transponders by using portable and/or stationary readers. Temperature data, identification data and/or location information may be stored in the transponders and/or in an external database memory. The information may be utilized in various different phases during the lifetime of a building element. The information may be utilized to monitor production. The information may be utilized to monitor delivery to a construction site. The information may be utilized to monitor delivery to a wrong construction site. The information may be utilized to control heating, cooling and ventilation of a building. The information may be utilized to monitor condition of a building. The information may be utilized when the building element is demolished or recycled. A control unit may be arranged to control heating, cooling and/or ventilation of a building based on the temperature data provided by the one or more RFID transponders. This may provide considerable savings in energy costs. A control unit may be arranged to control temperature distribution in a building based on the temperature data provided by two or more RFID transponders. The control unit may be arranged to send a control signal to a heater unit, to a ventilation unit and/or to an air cooling unit based on the temperature data.

The control unit may be arranged to send a control signal for adjusting a curtain, Venetian blind and/or awling blind (i.e. sun blind). The control unit may be arranged to send a control signal for opening/closing a door, window or ventilation opening.

The control unit may be arranged to send a control signal for adjusting heating power of an electrically heatable window. The window may comprise an electrical heating element. The window may be at least partially coated with a substantially transparent resistive layer, e.g. a layer comprising Indium Tin Oxide (ITO).

The control unit may be arranged to send a control signal for adjusting transparency of a smart glass element, which has electrically controllable transmittance.

The control unit may be arranged to send a control signal for adjusting under floor heating. The control unit may be arranged to send a control signal for adjusting an infrared light emitting element.

A transponder may also be attached to a heating or cooling element. A control unit may be arranged to control heating/cooling of the element based on temperature data provided by the transponder. The control unit may be arranged to compare the temperature of the heating or cooling element with a reference value. The control unit may be arranged to provide an alarm and/or to stop operation of the heating or cooling element if significant deviation from the reference value is detected (defective apparatus). In case of a heating element attached to ceiling of a room, a transponder may be attached to the floor of the room in order to control operation of the heating element. In case of a heating element attached to the floor of a room, a transponder may be attached to the ceiling of the room in order to control operation of the heating element.

A control unit may be arranged set the parameters of a temperature controller based on the temperature data provided by the one or more RFID transponders. In particular, the controller may be e.g. a PID controller (Proportional-lntegral-Derivative controller) or a PI controller (Proportional-Integral controller). A control unit may be arranged to detecting a fire or an increased risk of fire based on the temperature data provided by the one or more RFID transponders. A control unit may be arranged to detecting location of a fire or a location of increased risk of fire based on the temperature data. A control unit may be arranged to initiate a fire alarm, e.g. by providing an audio signal and/or by sending a message to a rescue center when the temperature at a location exceeds a predetermined value. A control unit may be arranged to initiate a fire alarm when the rate of change of temperature exceeds a predetermined value. A control unit may be arranged to initiate a fire alarm when the rate of change of a temperature signal exceeds a predetermined value.

A transponder may be arranged to monitor temperature deep inside a building element e.g. in the vicinity of an electric cable or a ventilation duct. Temperature data provided by the transponder may be used to provide an (early) alarm in case of fire in the duct or in case of overheating of the cable.

A control unit may be arranged to initiate an emergency procedure, e.g. cooling, sprinkler, automatic closing of a fire door, closing of a gas valve, switching off electricity when the temperature of the building element exceeds a predetermined limit.

The control unit may be arranged to provide status information by comparing the temperature information with reference information and/or by comparing temperature information provided by one or more first transponders with temperature information provided by one or more second transponders. The status information may be e.g. visually displayed to a user. The status information may be used to indicate an abnormal condition of a building element. The status information may also be called as condition information.

For example, if the temperature of a first construction element substantially deviates from the temperature of other similar construction elements, this may indicate e.g. that the first construction element has become wet and/or that the thermal insulation in the vicinity of the first element has been damaged.

Temperature history of a building element may be gathered by using temperature data provided by a transponder. Temperature data gathered from a transponder may be stored in the transponder and/or in an external database. For example, if the temperature of a transponder attached to an interior structure of a building has been several days or several weeks at a low temperature (e.g. below 5°C), this may indicate that the building has not been adequately heated. This may cause an increased risk of blight (i.e. fungus growth) in the building structures.

One or more transponders may be attached to a building element already when the building element is made. One or more transponders may be attached to a material of a building element before the building element is made. Temperature data provided by the transponder may be used for monitoring the manufacturing process of the element. For example, producing plywood, laminated beam and/or concrete elements may comprise treating the element at an optimum temperature or in an optimum temperature range. If the element is not treated in the correct temperature range, the element may be damaged or it may have degraded properties. An adhesive used for making plywood or laminated beam may have an optimum curing temperature range. The adhesive may have low strength if cured below the optimum curing temperature range. The adhesive may be irreversibly damaged if cured above the optimum curing temperature range.

A concrete element may be typically made by mixing cement, (crushed) stone and water. The concrete element may comprise reinforcing (steel) elements. The strength of the concrete element may be improved by treating the element with hot steam during hardening. Temperature data provided by a transponder may be used for monitoring and/or controlling temperature of the element during the treatment.

Hardening of concrete is an exothermic process. Thick portions of a concrete element may be overheated during hardening. Temperature of a thin portion of a concrete element may be too low during hardening.

On the other hand, thick portions of a concrete element have a higher heat capacity than thin portions of the concrete element. In case of external heating by using a flame or an electric heater, the temperature of a thick portion of a concrete element may be too low during hardening. Thin portions of a concrete element may be overheated during hardening.

A concrete element may be made on a building site, at temperatures determined by the weather. In cold temperatures, wet cement may freeze instead of hardening. Freezing of unhardened concrete may be dangerous. If the frozen cement structure is subsequently loaded, it may collapse, causing severe damage. Temperature data provided by one or more transponders embedded in concrete may be used to detect freezing.

A transponder may be (permanently) embedded between veneer layers. A transponder may be (permanently) embedded in a concrete element. A transponder may be (permanently) embedded between layers of a laminated beam. The transponder may be embedded in a building element such that it cannot be removed without damaging the element. A building element may comprise a plurality of transponders embedded in different locations such that it would difficult (and expensive) to remove all of the from the element after the element has been produced.

A transponder may be attached to a building element such that the transponder cannot be removed without damaging the transponder. The absence of a visually detectable transponder at may indicate that the transponder has been removed (without authorization).

A transponder embedded in the element may comprise identification data ID 1 . The identification data may allow tracking the manufacturer and/or manufacturing batch of a building element. Delivery a specific building element may be confirmed by monitoring the identification data I D1 . Arrival of a specific building element at the construction site may be confirmed by monitoring the identification data ID1 .

An amount of money debited from an account of a purchaser may be determined based on identification data ID1 of transponders attached to building elements, when the building elements are transported away from a factory or a storage.

Transponders attached to building elements may help to prevent theft of construction material. If the element is accidentally or intentionally installed in a wrong building, the element may be later detected and identified by using the identification data in a random or systematic search. The building element may be later identified when the building is demolished and/or when the building element is carried to a recycling facility or dumping place. The recycling facility or dumping place may determine the material(s) of the element based on the identification data stored in the transponder, and the element may be based on the information about the materials.

Recycling or dumping of a building element may be associated with payment of a tax fee and/or a deposit fee. If the owner of the element should pay a recycling or dumping fee, the owner may be may be determined by using identification data stored in the transponder. If the owner of the element is entitled to a refund of a deposit fee, the owner may be may be determined by using identification data stored in the transponder. If demolition waste is dumped to ground without permission, the owner or the responsible party may be traced by using the identification data stored in a transponder.

A system 700 may comprise a building. The system may be arranged to monitor the temperature of a first building element based on first temperature data provided by a first transponder attached to the first building element.

The temperature data TDATA may be gathered by using a portable reader 200. The reader 200 may be moved with respect to the first transponder.

The system 700 may be arranged

- to compare a temperature data value of the first building element with a first reference value, and

- to perform an action based the comparison.

The first reference value may be a previously determined temperature data value associated with the first building element. The first reference value may be stored in a memory MEM1 of the first RFID transponder. Also calibration data may be stored in a memory MEM1 of the first RFI D transponder. Alternatively, the first reference value may be determined based on second temperature data obtained from a second transponder.

The system 700 may be arranged to adjust temperature of the building based on the temperature data provided by the first transponder attached to a first building element.

The system 700 may be arranged to adjust temperature distribution of the building based on first temperature data provided by a first transponder attached to a first building element, and based on second temperature data provided by a second RFID transponder attached to the first building element or to a second building element.

The system 700 may be arranged to initiate a fire alarm when a temperature data value provided by a first RFID transponder attached to the first building element exceeds a limit value.

The system 700 may be arranged to initiate a fire alarm when a rate of change of temperature data provided by a first RFID transponder attached to the first building element is greater than or equal to a limit value.

A transponder attached to a building element of the system 700 may comprise location data indicative of the location of the transponder. A reader 200 may be arranged to retrieving location data based on identification data of the first RFID transponder, by using location data stored in an external memory.

A reader 200 may be arranged to visually display temperature information determined from a temperature data obtained from the first transponder. A reader 200 may be arranged to retrieve material information from a memory based on identification data obtained from the first transponder.

Water pipelines

Water may be delivered to/from a building via a water pipeline. The water pipeline may comprise e.g. metal or plastic tubing buried in ground, attached to a building structure, or embedded in a building structure. At cold temperatures, the water in the pipeline may freeze. This may stop the water flow, damage the tubing, and/or cause severe flooding in a building. The freezing or an increased risk of freezing may be detected by monitoring temperature of the pipeline by using a transponder attached to the pipeline, a transponder attached to a structure in the vicinity of the pipeline, or a transponder buried in ground in the vicinity of the pipeline.

A control unit may be arranged to control heating of the pipeline and/or flow in the pipeline based on temperature data provided by the transponder. The control unit may be arranged to control heating of a heating element attached to the pipeline. The control unit may be arranged to adjust a valve so as to keep water flow rate above a predetermined flow rate value when the temperature of the transponder is below a predetermined temperature value.

A control unit may be arranged to provide an alarm when freezing or an increased risk of freezing is detected. A control unit may be arranged to provide an alarm when the temperature of the transponder is smaller than or equal to a predetermined value. Plywood, chipboard, fiberboard, gypsum board

One or more transponders may be laminated inside a plywood element a chipboard element, fiberboard, or a gypsum board element during the manufacturing process. A plywood element, a chipboard element, fiberboard, or a gypsum board element may comprise one or more transponders. A transponder may be used to monitor temperatures of the plywood element during manufacturing and use of the plywood element. The plywood element may be subsequently used e.g. as building element in a building. The transponder may comprise e.g. identification data, manufacturer data, manufacturing batch data, calibration data, location data and/or temperature history data.

Laminated beam

One or more transponders may be laminated inside a laminated (wooden) beam during the manufacturing process. A laminated (wooden) beam may comprise one or more transponders. A transponder may be used to monitor temperatures of the beam during manufacturing and use. The laminated beam may be subsequently used e.g. as building element in a building. The transponder may comprise e.g. identification data, manufacturer data, manufacturing batch data, calibration data, location data and/or temperature history data.

Paper and cardboard One or more transponders may be attached to a paper layer or to a cardboard layer. A plurality of transponders may be attached to to a paper layer or to a cardboard layer in an one-dimensional or two- dimensional formation. The paper layer or the a cardboard layer may be adhesive-lined in order to facilitate attaching the layer to the surface of an item, in particular to the surface of a building element. The layer may be subsequently used to monitor temperature distributions of the building element (item) during use.

Sauna

A sauna may refer to a room for accommodating at least one person in a sitting position, and which has means for heating the room to a temperature, which is greater than or equal to 55°C.

A (Finnish-type) sauna may typically comprise a heating device, which may be called as a "kiuas". The heating device "kiuas" may comprise a plurality of heated stones and/or ceramic pieces. The stones and/or ceramic pieces may be heated by fire or by electricity.

Instead of the kiuas, or in addition to the kiuas, the sauna may comprise further heating elements, e.g. convective electric heaters and/or radiative infrared heaters. One or more transponders may be attached to structures of a sauna. A control unit may be arranged to control temperature in the sauna, and/or to control temperature distribution in the sauna based on temperature data provided by the one or more transponders. A control unit may be arranged to provide a control signal for adjusting one or more heating elements and/or for adjusting ventilation of the sauna based on temperature data provided by the one or more transponders.

Storage and transportation of food

Food should be stored in an optimum temperature range. The optimum temperature range may depend on the type of foodstuff. A high storage temperature may accelerate ripening of fruits. A high storage temperature may increase growth of bacteria in the food. A high storage temperature may spoil a foodstuff. Premium meat and fish should not be stored at temperature below 0°C. Certain vegetables should not be stored at temperatures below 5°C. For example, the optimum storage temperature for cucumber is 10°C to 12°C.

Temperature of a foodstuff may be monitored by using temperature data provided by a transponder. The transponder may be attached to the foodstuff. The transponder may be positioned in the vicinity of the foodstuff.

For example:

- A transponder may be embedded in foodstuff. For example, a transponder may be inserted inside a piece of meat.

- A transponder may be attached to a foodstuff. For example, an adhesive RFID tag may be attached to a banana.

- A food package may comprise a transponder. The food package may contain a foodstuff.

- A tray, a plate, a bowl, or a barrel may comprise a transponder, foodstuff may be transported or stored on/in the tray, plate, bowl, or barrel.

- A pallet may comprise a transponder. Foodstuff may be transported on the pallet.

- A container may comprise a transponder. The container may be e.g. an intermodal container. The container may comprise foodstuff.

Temperature data provided by the transponder may be recorded during initial cooling of a foodstuff. Temperature data provided by the transponder may be recorded during transportation of a foodstuff. Temperature data provided by the transponder may be recorded during storage of a foodstuff. Temperature data provided by the transponder may be recorded when the foodstuff is forwarded from one party to another. The reader may be a movable (portable) reader or a stationary reader. A reader may be positioned e.g. in the vicinity of the door of a storage. The temperature data may be stored in an external memory. A display may be arranged to display information according to the temperature data. Temperature data provided by the transponder may be used to control cooling, heating and/or ventilation of a container or a storage. Temperature data provided by the transponder may be used to estimate storage life of a foodstuff. Temperature data provided by the transponder may be used to determine quality and/or price of a foodstuff. Temperature history data may be used to determine liability if the quality of the foodstuff has been degraded.

Chemicals, sensitive substances

Instead of food, the temperature of another sensitive substance may be monitored and/or controlled in a manner described above. The sensitive substance may be e.g. a medicament, in particular a vaccine.

The sensitive substance may be a chemical which should be stored in a predetermined temperature range. For example, certain adhesives should be stored at temperatures below a predetermined temperature. The adhesive may be e.g. a cyanoacrylate adhesive or an epoxy resin. For example, certain water-based paints and adhesives should be stored at temperatures above 0°C.

Smart refrigerator

A transponder may be attached to food and/or to a food package. A reader may be arranged to monitor temperatures food, food packages and internal surfaces a refrigerator. A control unit may be arranged to control internal temperature of a refrigerator based on temperature data. The control unit may be arranged to communicate with an RFID reader. The refrigerator may comprise the control unit. The refrigerator may comprise the reader. A refrigerator may comprise reader arranged to monitor temperature of the transponder. A control unit may be arranged to provide an alarm when the temperature is higher than a predetermined limit (during a predetermined monitoring period). A control unit may be arranged control the internal temperature of a refrigerator based on the temperature data. A control unit may be arranged control internal temperature distribution of a refrigerator based on the temperature data.

A control unit may be arranged provide an advice to a user based on the temperature data. The transponder may comprise reference temperature data, which specifies an optimum storage temperature for an item. The transponder may comprise identification data. A control unit may be arranged control the internal temperature of a refrigerator based on the temperature data and based on the reference temperature data. A control unit may be arranged provide an advice to a user based on the temperature data, based on the reference temperature data, and based on the identification data. For example, the refrigerator may comprise a display, which is arranged to display a message "the temperature of the milk container is too high, please move the item to the section two." For example, the control unit may be arranged determine an estimated storage life for a product based on based on the temperature data, based on the reference temperature data, and based on the identification data. The estimated storage life may be displayed to a user. For example, the following message may be displayed "estimated storage life of the milk container is three days". The refrigerator may comprise a deep freezer portion. A transponder may comprise temperature history data. The temperature history data may be stored in the transponder and/or in a memory. The reader of the refrigerator may be arranged to read the temperature history data. A display may be arranged to display temperature history data to a user. For example, the following message may be displayed based on the temperature history data and identification data: "warning: the temperature of the ice cream package has been above 0°C." Smart oven

A transponder may be attached to food and/or to a food package. A control unit may be arranged to control temperature of an oven based on temperature data. The control unit may be arranged to communicate with an RFID reader. The oven may comprise the control unit. The oven may comprise the reader.

A control unit may be arranged control the internal temperature of the oven based on the temperature data. A control unit may be arranged control internal temperature distribution of the oven based on the temperature data.

The transponder may further comprise identification data and/or reference temperature data. The reference temperature data may e.g. specify an optimum temperature or an optimum temperature range for the oven. The reference temperature data may e.g. specify an optimum final temperature of a food. The user may select the desired state or condition of the foodstuff (the options in case of meat may be e.g. rare, medium, well done). For example, if the foodstuff is a beef roast, the optimum oven temperature may be e.g. 1 75°C and the optimum final temperature (internal temperature of meat) may be e.g. 58°C (medium). The transponder may be embedded substantially in the center of the foodstuff.

The control unit of a "differential" may be arranged to adjust the heating of the oven such a difference ΔΤ between gas temperature in the oven and internal temperature of the foodstuff is kept in a predetermined range (until a predetermined internal target temperature is attained). The difference ΔΤ may be e.g. in the range of 20°C to 50°C. This method may be suitable e.g. for roasting meat.

The control unit may be arranged to adjust the heating of the oven such that in a first step the internal temperature of the oven is kept at the optimum oven temperature (e.g. 1 75°C) in order to cook the foodstuff. In a second step, the internal temperature of the oven may be lowered so as prevent overcooking. In a second step, the internal temperature of the oven may be set such that the foodstuff is kept warm. The internal temperature of the oven may be adjusted such that the peak temperature of the transponder embedded in the foodstuff reaches but does not substantially exceed the optimum final temperature (e.g. 58°C).

If the initial temperature of the foodstuff is too low, a display may be arranged to display a warning based on the temperature data and based on the identification data, e.g. "warning: the meat is frozen, meat should be defrosted before cooking". The oven may be arranged to warm (thaw) frozen foodstuff at a predetermined temperature (e.g. 30°C) until the temperature of the transponder reaches a predetermined temperature (e.g. 20°C).

The transponder may comprise size data associated with the foodstuff. The oven may be arranged to estimate when the foodstuff is ready to eat based on the temperature data, based on the identification data, and based on the size data. For example, a display may be arranged to display the following message: "the roast will be ready to eat at 18:00 PM".

A small piece of food is typically heated at a higher rate than a large piece of food, when they are placed in the same oven temperature.

The oven may comprise a timer for timing operation of the oven. The control unit may be arranged to estimate the size of the foodstuff and/or the estimated cooking time based on the rate of change of the temperature of the transponder.

Temperature of soil

Temperature of soil may have an effect on the rate of growth of plants. A transponder may be embedded in soil in order to monitor temperature of the soil. The reader may be a movable reader. The reader may be carried manually, or it may be attached to a vehicle, e.g. to a tractor or helicopter.

Temperature data provided by the transponder may be used e.g. to determine an optimum date for sowing (seeding). Temperature data provided by the transponder may be used e.g. to determine an optimum date for harvesting.

A display may be arranged to display visual information based on the temperature data provided by the transponder.

Temperatures in a greenhouse Temperature of a greenhouse has an effect on the growth of plants. A transponder may be used to monitor temperatures in the vicinity of a plant. A transponder may be embedded in soil. A transponder may be attached to a pot. A transponder may be attached to a table or to a shelf. A transponder may be attached to a wall of a greenhouse.

A control unit may be arranged to control heating, cooling, ventilation and/or lighting of the greenhouse based on temperature data provided by the transponder. A control unit may be arranged to control heating, cooling, ventilation and/or lighting of the greenhouse based on temperature distribution information provided by a plurality of transponders.

The reader may be a movable reader. The reader may be carried manually. The reader may be attached to a vehicle, in particular to an electric vehicle. The reader may be a stationary reader. The reader may be attached to a structure of the greenhouse. Roads, forest truck roads, railroads, runways, temporary roads built on ice

Roads may become slippery when the temperature of the surface of the road is below 0°C, due to formation of ice. One or more transponders may be embedded in the road in order to monitor the temperature of the road. A transponder may be embedded in asphalt or concrete. A transponder may be embedded in gravel. Temperature data from the transponder may be gathered e.g. by using a portable reader or by using a reader attached to a vehicle. The temperature data may be stored in a memory outside the reader.

Ground may freeze during winter. The freezing of the ground may makes digging more difficult, which should be taken into consideration in construction sites. The freezing of the ground may deform the structure of a road, due to expansion of ground.

The freezing of the ground may temporarily increase load carrying capacity of a road. This may be important e.g. in case of forest truck roads, where heavy loads may be carried during wintertime.

The depth of frost in the ground may be monitored by positioning one or more transponders in the ground. In particular, a first transponder may be positioned in ground at a first depth, and a second transponder may be positioned in ground at a second different depth.

The depth of a transponder may be determined e.g. based on identification data, by using depth retrieval data associated with the identification data. Information about the depth of a transponder may also be stored in the transponder. The depth may also be determined by using one or more readers, which is/are arranged to determine the depth e.g. by triangulation. Temporary ice roads may be built on lakes, rivers and sea. The ice may lose strength if it becomes too thin and/or too warm. Temperature of the ice may be monitored by using temperature data provided by one or more transponders inserted in the ice. A transponder may be inserted e.g. in a drilled hole. A reader may be attached e.g. to a car or a snowmobile. A control unit may be arranged to display visual information when the temperature is higher than a predetermined value. A control unit may be arranged to provide an alarm when the temperature is higher than a predetermined value. A control unit may be arranged to provide an alarm or visual indication if a transponder should be located at a predetermined position but a response to an interrogation signal is not received from the transponder at said predetermined location. This may indicate that the bottom side of the ice has melted so much that the transponder has been lost.

Temperature of skating ice

Ice hockey, speed skating, figure skating, and/or recreational skating may be performed on artificially cooled ice. Transponders may be embedded in the ice during freezing in order to monitor temperature of the ice and/or in order to control temperature of the ice. A control unit may be arranged to control an ice cooling device based on temperature data provided by the transponders. The control unit may communicate with a reader. A reader may be attached e.g. to an ice maintenance vehicle (e.g. to an ice resurfacer machine. Ice resurfacer machines are manufactured e.g. by a company Frank J. Zamboni & Co).

Warm ice (temperature above -1 °C) may be softer and more slippery than cold ice (temperature below -5°C). The temperature of the ice may be selected according to the application. For example, the temperature of the ice may set to a higher value (near 0°C) during nighttime in order to save cooling energy. For example, the temperature of the ice may set to a lower value (e.g. -5°C) during an ice hockey game in order to provide more durable ice and/or in order to provide rapid re-icing when water is sprayed or wiped onto the surface of the ice. An optimum temperature of ice for speed skating may be e.g. -5.5°C. An optimum temperature of ice for figure skating may be e.g. -3°C.

A plurality of transponders embedded in different locations may be used to equalize temperature distribution of the ice. This may provide considerable savings in the energy costs.

The controller may be arranged to control an ice cooling device based on temperature data provided by the transponders and based on information provided by a pyrometer or thermal imaging system.

A plurality of transponders may be distributed on the surface of ice from a vehicle so that the transponders are embedded within the ice when a new layer of ice is frozen over the transponders.

Temperature of snow

Properties of snow may play a role in various winter sports such as e.g. downhill skiing, cross-country skiing, telemark, ski jumping and mountain climbing. Temporary roads or airplane runways may be built on snow. The properties of snow depend on the temperature of the snow. Equipment used in winter sports may be selected or prepared according to the the temperature of the snow. The surface of the snow may be prepared (e.g. groomed) according to the temperature of the snow.

A plurality of transponders may be embedded in snow so as to monitor temperatures and/or temperature distribution in snow. The transpon- ders may be distributed e.g. manually or from a vehicle, in particular from a motor sledge, snowcat or a helicopter. The transponders may be distributed on the surface of the snow before artificial or natural snowfall. Alternatively, the transponders may be injected under the surface of the snow. The reader may be portable. The reader may be carried manually or it may be attached to a vehicle. The vehicle may be a motor sledge, snowcat, a helicopter or a remote-controlled airborne vehicle. A snow track or a snow hill may be artificially cooled. The cooling may be controlled based on temperature data provided a plurality of transponders.

In mountain areas, the temperature of the snow may be used to estimate the risk of avalanche.

A transponder may be encapsulated such that it can tolerate the environmental conditions in nature during the intended operating life (e.g. 6 months or more). When the snow melts, the transponder may be flushed along with flowing water or it may remain in the ground. As the use of a battery is not necessary, the transponder may be manufactured from environmentally friendly materials. A transponder may have a bright color, which is easy to detect visually in the nature (e.g. red, yellow orange), in order to facilitate collecting and re-use.

Products comprising resin

Items may be made from composite materials. Composite materials may comprise a reinforcing carbon fibers, polyaramid fibres, wood fibers (cellulose fibers), glass fibers and/or metal structures combined with a resin. The resin is cured (hardened) by mixing one or more suitable additives and/or by a heat treatment in a suitable temperature range. The hardening process may generate heat and have an effect on the temperature distribution in the product. If the curing temperature is too low or too high, this may lead to degraded properties of the composite material. Transponders 1 00 may be embedded in the item prior to hardening in order to monitor temperatures during the hardening. The item may be rejected if monitored temperatures are outside the predetermined range during the hardening process. An apparatus 700 may be arranged to control the temperature distribution during hardening by using adjustable heating and/or cooling elements.

The transponders 100 may remain in the manufactured item 300, and the transponders 100 may be used for monitoring operating temperatures during the use of the item 300.

One or more transponders embedded in the item 300 may be used e.g. when the item 300 is a part of a vehicle, airplane, train, ship, or windmill (blades). For example the transponders 100 may be used for monitoring temperature distributions in a vehicle, airplane, train, or ship during regular use. The measured temperature distributions may be used for controlling heating, cooling and/or ventilation.

Monitoring of operation of machines

A machine may comprise hot, cold, and/or moving parts. Operational reliability and/or operating life of the machine may depend on the temperature of one or more parts of the machine. The machine may be be arranged to produce a product. The temperature of a part of the machine may have an effect on the quality of the product and/or on the production rate. The machine may be e.g. a paper-making machine, a refiner, a printing machine, a compressor, a diesel engine, or a gas turbine.

A transponder may be attached to a part of the machine in order to monitor operating temperature of the part. A plurality of transponders may be attached to a part in order to monitor temperature distribution of the part.

The reader may be a movable (portable) reader or to a stationary reader. The reader may be a part of the machine. Temperature data provided by the transponder may be stored in a memory. Information may be displayed visually based on the temperature data. A control unit may be arranged to control operation of the machine based on the temperature data. A control unit may be arranged to control temperature of the part based on the temperature data. The part may be a moving part. The part may be reciprocating part. The part may be a rotating part. The part may be positioned inside a structure. The part may be positioned at a pressure, which deviates from atmospheric pressure. The transponder may be encapsulated such that it can tolerate environmental conditions of the machine. There is no need to replace a battery or service the transponder. Temperature data may be read from the transponder in a wireless manner. There is no need to install electrical or optical cables between the transponder and the reader. The signal may be read read through a (dielectric) wall. There is no need to use a galvanic feedthrough. In case of rotating parts, there is no need to use any sliding electrical contacts.

The part may be e.g. a bearing, a brake, a shaft, a piston, or a crankshaft.

A transponder may be arranged to monitor temperature of a pipeline. A transponder may be arranged to monitor temperature of a pipeline enclosed by thermal insulation. The pipeline may be arranged to convey e.g. exhaust gas, water, steam, fuel, heated fuel, oil, heated oil, liquid coolant, or liquefied gas. A control unit may be arranged to control temperature of the pipeline based on the temperature data provided by the transponder. A control unit may be arranged to provide an alarm based on the temperature data provided by the transponder. A display may be arranged to display visual information based on the temperature data provided by the transponder. Paper-making machines, calenders and printing machines comprise coated rolls, which are critical to the operational reliability. If the coating is accidentally broken, the pieces of the coating may cause serious damage in the device and in the manufactured product (e.g. paper). A plurality of transponders 1 00 may be embedded in the coating or under the coating. An uneven temperature distribution during the use of the roll may indicate a possible failure in the coating.

A transponder 1 00 may be attached to a computer hard disc drive (HDD) or to a solid state drive (SSD) in order to monitor operating temperatures of the disc drive and/or in order to determine identity of the disc drive.

A transponder 1 00 may be attached to a semiconductor component in order to monitor operating temperatures of the component and/or in order to determine identity of the component.

The component may be e.g. a microprocessor, (power) transistor, (power) rectifier, inductor, transformer, capacitor, circuit board, cooling fan, (power) connector, or electrical cable. At the end of the lifetime, the materials of an electronic component may be identified and recycled based on identification data obtained from the transponder.

A transponder 1 00 may be attached to a component, which is arranged to operate at a high voltage. The minimum (safety) distance between the transponder and the reader may be selected according to safety regulations. For example, in case of 1 1 0 kV voltage, the distance may be greater than or equal to 1 .1 m. A transponder may be be arranged to monitor temperature of a solar panel.

Vehicles, in particular automobiles A vehicle, in particular a car may comprise several parts, which may operate at elevated temperatures. The part may be e.g. an engine, generator, starter motor, battery, motor controller of an electric car, drive motor of an electric car, exhaust tube, catalytic converter, turbocharger, silencer, radiator, electrically heated seat, gearbox, engine oil reservoir, hydraulic oil pump, brake, tire (rubber wheel), cabin heater unit, engine heater unit, electrically heated windscreen, electrically heated mirror, or headlamp. An air conditioning unit may comprise cooled parts.

A transponder may be attached to a part of a vehicle in order to monitor and/or control operating temperature of the part. A control unit may be arranged to control temperature of the part based on temperature data provided by the transponder.

A part of the interior of a vehicle may comprise a transponder. A control unit may be arranged to control temperature of the interior of the vehicle (cabin temperature) based on temperature data provided by the transponder. A control unit may be arranged to control temperature distribution of the interior of the vehicle (cabin temperature distribution) based on temperature data provided by a plurality of transponders positioned at different locations. The control unit may be arranged to control heater unit, a cooling unit, ventilation fan, and/or a ventilation valve based on temperature data provided by one or more transponders. Thus, a desired temperature or a temperature distribution may be implemented.

Thanks to the wireless operation of the transponders, considerable savings may be expected. There is no need to install electrical or optical cables to the temperature sensors (transponders). There is no need to service the transponders. In particular, there is no need to change batteries of the transponders.

In certain cases, temperature data provided by the transponder may also be used to control and/or monitor manufacturing process of the part. For example, the part may be made of a composite material, which should be manufactured in an optimum temperature range. Identification data stored in the transponder may be used to determine e.g. the manufacturer of the part, a manufacturing batch of the part, and/or legal owner of the part. This may be used e.g. to prevent stealing of the part, because a stolen part may be later detected in a random or systematic search.

A transponder may be attached to a part or embedded in the part such that it cannot be removed without damaging the part, the transponder, or a security seal.

Finally, when the part is dumped or recycled at the end of its operating life, the identification data stored in the transponder may be used to determine the material(s) of the part. The transponder may comprise material data, which specifies the materials(s) of the part.

The above-mentioned vehicle may be a car.

Instead of a car, the above-mentioned vehicle may be a train. A part of a train may comprise a transponder suitable for monitoring temperatures.

Instead of a car, the above-mentioned vehicle may be a boat. A part of an airplane may comprise a transponder suitable for monitoring temperatures.

Instead of a car, the above-mentioned vehicle may be an airplane. A part of a boat may comprise a transponder suitable for monitoring temperatures.

Tires for vehicles

The manufacturing process for a tire comprises a heat treatment, which has an effect on the properties of the tire. The tire may comprise an elastomer, in particular natural rubber. The tire may further comprise a reinforcing textile layer or reinforcing metallic structures. In particular, the manufactured tire may be used in a car, motorbike, or another vehicle. The tire may be used in an airplane.

Referring to Fig. 1 6a, a tire 300a may comprise a transponder 1 00a. The transponder 1 00a may be embedded in the tire during the manufacturing process. The transponder 1 00a may be e.g. mixed with an elastomer precursor prior to curing and/or solidification (in particular prior to vulcanizing). The transponder 1 00a may be e.g. attached to a textile or metal belt prior to curing and/or solidification of an elastomer precursor onto the belt.

The manufacturing process of a tire 300a may be controlled based on preliminary temperature data TDATA0 obtained from the first transponder 1 00a embedded in the tire 300a.

Maximum temperatures during the manufacturing process of a tire 300a may temporarily exceed the maximum operating temperature of the transponder 1 00a. However, the transponder 1 00a may provide preliminary temperature data TDATA0 as soon as the temperature decreases below the maximum operating temperature of the transponder 1 00a.

Identification data obtained from the transponder 1 00a may be utilized during storage and transportation of the tire 300a. The temperature of the tire may be monitored during storage. Storing at a high temperature may degrade properties of the tire, in particular if the tire is intended to be used in motor sports.

Referring to Fig. 1 6b, the tire 300a may be subsequently used in a system 700, in particular in a vehicle. Operating temperatures of the tires 300a, 300b may be monitored by obtaining temperature data TDATA1 , TDATA2 from the transponders 1 00a, 1 00b embedded in the tires 300a, 300b. The vehicle 700 may comprise a reader 200 for receiving the temperature data TDATA1 , TDATA2. The vehicle 700 may comprise a user interface 500 for displaying temperature information TINF1 , TINF2 determined based on the temperature data TDATA1 , TDATA2.

Fig. 1 6c shows temperature information TINF1 , TINF2, TINF3, TINF4 related to four tires of the vehicle 700. The temperature information TINF1 , TINF2, TINF3, TINF4 may be associated with corresponding identifiers F1 , F2, F3, F4. Additional temperature information TINF3B may indicate that the tire 300b is exceptionally hot. When a single reader 200 is arranged to obtain temperature data from several transponders 1 00a, 1 00b, the temperature data TDATA1 obtained from a first tire 300a may be associated with the identifier F1 e.g. by using identification data ID1 obtained from the first transponder 1 00a embedded in the first tire 300a and by using location data LOCDATA (Fig. 6b).

The location data LOCDATA may be determined e.g. by

- obtaining identification data ID1 from a first transponder 1 00a,

- determining location data LOCDATA based on a measured location of the reader 200, and

- storing the location data LOCDATA in a memory MEM7 such that the location data LOCDATA is associated with the identification data ID1 .

Alternatively, the vehicle 700 may comprise several readers 200. An individual reader 200 may be arranged to obtain temperature data TDATA1 only from a single transponder 1 00a and/or from several transponders of a single tire 300a.

The temperature data TDATA obtained from the transponders 1 00a, 1 00b may be used for controlling operation of the vehicle 700. For example, the suspension of the vehicle may be adjusted, air pressure in the tire may be adjusted, speed of the vehicle may be adjusted, and/or operating mode of a gearbox may be changed based on the temperature data TDATA. If the operating temperature of a tire 300a is too high, this may indicate that the air pressure (gas pressure) inside the tire is too low.

Monitoring and/or controlling operating temperature of the tires is important e.g. in motor sports and/or in case of lorries, buses, trucks, and trailers. If the temperature is too high, the tire may even explode. If the temperature is too low, the friction between the tire and ground may be too low for automobile and motorcycle competition purposes. When the tire 300a is recycled or dumped, the materials of the tire may be identified based on the identification data obtained from the transponder. Recycling may be associated with a recycling fee, and the responsible party may be identified based on the identification data. Temperature data obtained from the transponder may be utilized for monitoring and/or control purposes also when the tire 300a is retreaded (i.e. coated with a new layer of rubber).

Fire alarm system

A transponder may be attached to an element of a building.

A control unit may be arranged to detecting a fire or an increased risk of fire based on the temperature data provided by the one or more RFID transponders. A control unit may be arranged to detecting location of a fire or a location of increased risk of fire based on the temperature data. A control unit may be arranged to initiate a fire alarm, e.g. by providing an audio signal and/or by sending a message to a rescue center when the temperature at a location exceeds a predetermined value. A control unit may be arranged to initiate a fire alarm when the rate of change of temperature exceeds a predetermined value. A control unit may be arranged to initiate a fire alarm when the rate of change of a temperature signal exceeds a predetermined value. A transponder may be arranged to monitor temperature deep inside a building element e.g. in the vicinity of an electric cable or a ventilation duct. Temperature data provided by the transponder may be used to provide an (early) alarm in case of fire in the duct or in case of overheating of the cable.

A control unit may be arranged to initiate an emergency procedure, e.g. cooling, sprinkler, automatic closing of a fire door, closing of a gas valve, switching off electricity when the temperature of the building element exceeds a predetermined limit.

Conductive structures may substantially increase the interrogation range of a reader. In particular, a metallic ventilation duct may act as a guide for radio waves. A transponder may be attached inside a metallic ventilation duct in order to monitor temperatures of gases in the duct, to monitor temperatures of building elements in the vicinity of the ventilation duct, and/or in order to increase the interrogation range. The antenna of the reader may be positioned near an opening of the ventilation duct in order to obtain data from the transponder.

Storage of dangerous chemicals

Flammable, toxic and/or explosive chemicals may be stored in a building or in a storage area. The dangerous chemical may be e.g. gasoline.

One or more transponders may be attached to a container, which contains a dangerous chemical.

The chemical may be dangerous if overheated. Formation of sparks should be prevented in the vicinity of flammable materials. The use of the RFID transponder may provide a safe way for monitoring the the temperature of the chemical. The temperature of the chemical may be monitored even through a wall. The reader may be a portable reader or a stationary reader. A portable reader may be carried e.g. by firemen or rescue personnel. A stationary reader may be attached to a storage room. Firemen or rescue personnel may evaluate based on the temperature data whether it is relatively safe to enter a building containing the chemical, or whether the area should be rapidly evacuated.

Temperature data may be transmitted to an external memory in order to record temperature history. The external memory may be located such that it will not be damaged in a possible explosion of the explosive material.

Temperature data may be transmitted to an external memory in order to record temperature history. The external memory may be located such that it will not be damaged in possible fire or explosion of the chemical.

A control unit may be arranged to initiate an alarm when the temperature of the chemical exceeds a predetermined limit. A control unit may be arranged to initiate an alarm when the temperature of the chemical has exceeded a predetermined limit. The alarm may be e.g. an audible alarm (siren) and/or a visible alarm (visually displayed information, flashing beacon).

A control unit may be arranged to initiate an emergency procedure, e.g. cooling, sprinkler, automatic closing of fire doors when the temperature of the chemical exceeds a predetermined limit. Presence of the container containing the chemical may be determined by using the reader and the transponder.

Gas bottles Gas bottles may be used in various industrial, household, and mobile systems. The gas bottle may contain e.g. oxygen, acetylene, propane, hydrogen or anesthetic gas. Gas bottles may explode or cause serious damage if overheated. The material of the gas bottle may be damaged if overheated.

A gas bottle may be overheated e.g. in case of a fire or when left in direct sunshine. A transponder may be attached to a gas bottle. The use of the RFID transponder may provide a safe way for remote monitoring of the temperature of the gas bottle. The temperature of the gas bottle may be monitored even through a wall. The reader may be a portable reader or a stationary reader. A portable reader may be carried e.g. by firemen or rescue personnel. A stationary reader may be attached to a storage room.

Firemen or rescue personnel may evaluate based on the temperature data whether it is relatively safe to enter a building containing the gas bottle, or whether the area should be rapidly evacuated.

Temperature data may be transmitted to an external memory in order to record temperature history. The external memory may be located such that it will not be damaged in a possible explosion of the gas bottle.

A control unit may be arranged to initiate an alarm when the temperature of the gas bottle exceeds a predetermined limit. A control unit may be arranged to initiate an alarm when the temperature of the gas bottle has exceeded a predetermined limit. The alarm may be e.g. an audible alarm (siren) and/or a visible alarm (visually displayed information, flashing beacon). A control unit may be arranged to initiate an emergency procedure, e.g. cooling, sprinkler, automatic closing of fire doors when the temperature of the gas bottle exceeds a predetermined limit. Identification data stored in the RFID transponder may be used to determine an owner, a responsible party, a manufacturer, a manufacturing batch and/or a registered location of the gas bottle.

Presence of a gas bottle may be determined by using the reader and the transponder.

Storage of explosives Explosive materials may be used e.g. in mining, construction work, fireworks (pyrotechnics). Several safety devices may contain explosives, e.g. automobile airbags, ejection seats, explosive bolts, emergency breakers in electric power networks. Explosive materials may be used in hunting. Weapons systems and ammunition may contain explosives.

Explosive material may be dangerous if overheated. Also cooled explosive material may dangerous if it has been previously overheated. Formation of sparks should be prevented in the vicinity of explosives. The use of the RFID transponder may provide a safe way for monitoring the the temperature of the explosive material. The temperature of the explosive material may be monitored even through a wall.

The reader may be a portable reader or a stationary reader. A portable reader may be carried e.g. by firemen or rescue personnel. A stationary reader may be attached to a storage room. Firemen or rescue personnel may evaluate based on the temperature data whether it is relatively safe to enter a building containing explosives, or whether the area should be rapidly evacuated. Temperature data may be transmitted to an external memory in order to record temperature history. The external memory may be located such that it will not be damaged in a possible explosion of the explosive material. A control unit may be arranged to initiate an alarm when the temperature of the explosive material exceeds a predetermined limit. A control unit may be arranged to initiate an alarm when the temperature of the explosive material has exceeded a predetermined limit. The alarm may be e.g. an audible alarm (siren) and/or a visible alarm (visually displayed information, flashing beacon).

A control unit may be arranged to initiate an emergency procedure, e.g. cooling, sprinkler, automatic closing of fire doors when the temperature of the explosive material exceeds a predetermined limit.

An RFID transponder may be attached to a device containing explosive material. An RFID transponder may be embedded in the explosive material. A device containing explosive material may be manufactured such that the RFID transponder cannot be removed without damaging (or exploding) the device.

Identification data stored in the RFID transponder may be used to determine an owner, a responsible party, a manufacturer, a manufacturing batch and/or a registered location of the explosive material.

Presence of explosive material may be determined by using the reader and the transponder. Owner or responsible party of explosive material may be determined by using the identification data. The identification data may be used to detect stolen explosives.

Charging and use of batteries

Rechargeable batteries are used in a plurality of applications, including e.g. mobile phones, laptop computers, electric power tools, household appliances, cars, electrical cars, boats, trains, airplanes, solar panel systems, emergency power systems.

The type of a rechargeable battery may be e.g. lead acid, NiCd (nickel cadmium), NiMH (nickel metal hydride), Lithium ion, or Lithium polymer.

A battery has typically an optimum operating temperature range. The efficiency of the battery may be reduced when the temperature of the battery is lower than a first predetermined limit. The efficiency of the battery may be reduced when the temperature of the battery is higher than a second predetermined limit. The battery may be damaged if the temperature of the battery is higher than a predetermined limit. Some battery types may even explode if overheated. An RFID transponder may be attached to a battery in order to monitor and/or control the temperature of the battery. An RFID transponder may be embedded in a battery.

A reader may be attached to e.g. to the body of an electric car. An external memory may be located e.g. in the electric car and/or in a stationary computer center.

A control unit may be arranged to control charging current and/or a discharging current based on temperature data provided by the transponder. The control unit may be arranged to switch off the charging/discharging current when the temperature of the battery exceeds a predetermined limit.

The charging current may be controlled based on temperature data obtained from a transponder. In particular, this may be used during "fast" charging of a battery. Fast charging may refer e.g. to a process where at least 30% of the maximum capacity of the battery is charged in a time period shorter than 1 hour. Typically, a battery may be fully recharged 100 - 3000 times. Operation near an upper limit may permanently damage the battery. The energy storing capacity of the battery may be decreased and/or the number of recharging times may be reduced due to high operating temperature. Temperature history data of the battery may be stored in the RFID transponder. Thus, the owner of the battery or another party may determine (estimate) the economical value of the battery based on the temperature history data.

Charging of a battery may take 1 hour to 50 hours. In particular, charging of a battery of a electric car may take several hours. In an embodiment, a discharged first battery may be rapidly replaced with a second charged battery. In an embodiment, a user may deliver a first discharged battery to a charging station or to a recycling facility, and a deposit fee may be refunded based on the economical value of the (discharged) battery. The value of the first discharged battery may be refunded to the user. If the first battery has been overheated, the refund may be denied. If the temperature of the first battery has been higher than a predetermined limit during a predetermined time period (e.g. 10 days), a smaller amount may be refunded. In an embodiment, the user may purchase a second charged battery by paying for energy stored in the second battery and by paying for the value of the second battery. In an embodiment, the user may rent a second charged battery by paying a rental fee and by paying for the energy stored in the second battery. In an embodiment, also the user may determine the value of the second battery based on temperature history data of the second battery. In an embodiment, an identifier together with checksum data derived from the temperature data may be stored in an external memory in order to make counterfeiting of the temperature data more difficult. Also temperature data may be stored in the external memory in order to make counterfeiting of the temperature data more difficult.

The RFID transponder may be attached to the battery such that it is difficult to remove the transponder from the battery without damaging the battery, the transponder and/or a security seal.

As there is no need to replace a (miniature) battery of the RFID transponder, the transponder may be substantially permanently positioned inside the structure of the battery. The chip of the transponder may be encapsulated so as to tolerate corrosive environment. As there is no need to replace a (miniature) battery of the RFID transponder, the whole transponder may be hermetically encapsulated.

A battery may release flammable gases (e.g. hydrogen) during operation. Thanks to the RFID transponder, temperature may be monitored in an explosion hazard environment so that the use of temperature monitoring system represents a negligible risk of explosion or fire. A control unit may be arranged to initiate an alarm and/or an emergency shutdown procedure when the temperature of battery exceeds a predetermined limit during use. Thus, for example, a building or an electric car may be evacuated if an overheated battery is detected.

Identification data stored in the transponder may be used to determine the owner of the battery.

Identification data stored in the transponder may be used to determine a suitable charging procedure or temporal charging profile (i.e. suitable magnitude of charging current as a function of time) for the battery. Identification data stored in the transponder may be used to determine a responsible party (e.g. owner) when the battery is recycled or dumped at the end of the lifetime of the battery. A recycling fee may be debited from an account of the responsible party. Alternatively, a deposit fee may be refunded to the responsible party.

Identification data and/or material information stored in the transponder may be used to determine material of the battery when the battery is recycled or dumped at the end of its lifetime.

Healthcare

A transponder may be used to monitor skin temperature of a person or animal. A transponder may be attached to the skin of a person e.g. by an adhesive or an adhesive tape. The person may wear a garment, which comprise a transponder. A mattress, a bed, bed linen, a blanket and/or a sleeping bag may comprise a transponder. A transponder may be used to monitor internal temperature of a person. For example, the person may swallow a hermetically encapsulated transponder.

The person may suffer from fever or hypothermia. An apparatus may be arranged to monitor the body temperature of a person.

Body temperature of a person may be controlled based on the temperature data. The amount of clothes and or blankets over the person may be controlled based on the temperature data. Heating, cooling and/or ventilation may be controlled based on the temperature data. A control unit may be arranged to control the temperature of a person or animal based on the temperature data.

Temperature of a patient (or animal) may be monitored and/or controlled. Temperature of a patient in intensive care may be monitored and/or controlled. Temperature of a baby in an incubator may be monitored and/or controlled.

Dosing of a medicament to the patient (or animal) may be determined or controlled based on the temperature data. Dosing of a medicament may be determined or controlled based on temperature history data. A device may be arranged to control dosing of a medicament based on the temperature data. A control unit may be arranged to detect a sick animal based on the temperature data.

A control unit may be arranged to monitor/control temperature of an incubator containing eggs and/or chicken.

Baby monitoring

Babies should wear the correct amount of clothes or blankets, according to the ambient temperature. Babies younger than 1 year cannot typically express verbally whether they are feeling hot or cold. Skin temperature of a baby may be monitored by using one or more transponders. A transponder may be attached e.g. to a garment or to a diaper (i.e. nappy) in order to monitor the temperature of the baby. The transponder may be a portable transponder. The transponder may be temporarily attached e.g. to a bed or to a baby carriage.

A control unit may be arranged to provide an alarm when the temperature of the transponder is below a first predetermined limit or above a second predetermined limit. A control unit may be arranged to provide an alarm when the rate of change of temperature data is higher than a predetermined limit.

If a transponder is attached to a diaper, and if the rate of change of temperature data provided by the transponder is higher than the predetermined limit, this may indicate that the diaper should be replaced with a clean one. The diaper may comprise a transponder such that the distance between the contact surface of the diaper and the chip is greater than 2 mm, preferably greater than 5 mm When in use, the contact surface of the diaper is positioned in contact with the skin of the baby.

Garments An RFID transponder may be attached to a garment in order to monitor skin temperature of a user, in order to monitor ambient (air) temperature and/or in order to monitor temperature of the garment.

If the local skin temperature of the user is too low, this may lead to reduced muscle performance, hypothermia, muscle injury, cramp, and/or joint injuries. If the local skin temperature of the user is too high, this may lead to a excessive sweating, dehydration, reduced muscle performance and/or heat stroke. Temperature data provided by the transponder may be used to determine an optimum combination of clothes for the user in a current situation.

The reader may be a portable reader or a stationary reader.

A ventilation hole of a garment may be adjusted based on the temperature data.

(Electrically) heated clothes may be controlled based the temperature data.

Temperature history data may be recorded in a memory and subsequently retrieved in order to assist in training of an athlete. A user may operate in conditions where he may be exposed to high temperatures and/or low temperatures. For example, firemen, rescue personnel, foundry personnel (people working with hot metals), seamen, military personnel, scuba divers, mountain climbers may be exposed to high temperatures and/or low temperatures. An RFID transponder may be attached to a garment of a person operating in hot or cold temperatures. A control unit may be arranged to initiate an alarm and/or an emergency cooling/warming procedure when the temperature or a rate of change of temperature exceeds a predetermined limit.

Detection of presence

Presence of a person, animal and/or an item may be detected based on temperature data provided by an RFID transponder.

For example, an RFID transponder may be attached to a chair so that the heat of the body of a person sitting on the chair changes the temperature of the RFID transponder. In particular, the temperature of the transponder may be increased by the heat of the body. Thus, information about the presence of a body in the vicinity of the transponder may be determined based on temperature data provided by the transponder. Thus, presence information may be determined based on temperature data provided by the transponder.

A control unit may be arranged to control e.g. heating, cooling and/or ventilation of a building based on the presence information. Heating, cooling and/or ventilation may be reduced in areas where presence is not detected or where only few people are present. This may lead to considerable cost savings.

In a restaurant, the number of personnel and/or the amount of food ordered from a supplier may be determined based on the number of occupied seats. Heating of an animal shelter may be controlled based on the presence information. Distribution of food and/or water may be controlled based the presence information. In direct sunshine, a person, animal and/or an item may block radiation that would impinge on the transponder without the presence of the person, animal and/or item. Thus, information about the presence of a body in the vicinity of the transponder may be determined based on temperature data provided by the transponder.

The presence of a body in the vicinity of a first transponder may increase the time constant of the transponder. Thus, when ambient temperature is varied, the rate of change of temperature data provided by the first transponder may be lower than a reference value. The reference value may be determined based on temperature data provided by a second transponder. Alternatively, the reference value may be a predetermined value.

The presence information provided by the transponder is anonymous, i.e. it does not comprise information about the identity of the detected persons. Detection of presence by using a transponder respects the privacy of the detected person and the detected person may remain anonymous. In certain applications, this may be an advantage when compared e.g. with video camera surveillance. For example, an automatic toilet flushing system may be controlled based on a transponder attached to the toilet seat.

Monitoring of processes

One or more RFID transponders may be used to monitor temperatures or temperature distributions in flowing fluids.

The temperature data may be used to control a process, to develop a process and/or to optimize a process. A plurality of transponders may be entrained in the fluid in order to monitor temporal and/or spatial temperature profiles in the fluid.

A plurality of transponders may be attached to a surface or surfaces of devices of the process in order to monitor temporal and/or spatial temperature profiles in the fluid. The transponders may be arranged as a regular or irregular one-dimensional array, two-dimensional array, or three-dimensional array. A control unit may be arranged to control the process based on temperature data provided by the one or more transponders.

The process may be e.g. an oil refining process, or a fermentation process for making alcohol.

Monitoring of electric current

Electric current may cause heating of an electric cable. A transponder may be attached to an electric cable in order to monitor the temperature of the cable and/or in order to monitor the electric current in the cable. The magnitude of the electric current may be determined based on temperature data provided by the transponder. This may provide an easy and safe way for monitoring electric currents e.g. in high voltage cables, underground cables, or cables embedded in building structures.

A transponder may also be attached to a conductor detect high resistance. A transponder may also be attached to a an electrically contacting element in order to detect a high contact resistance.

The reader may be mobile reader or a stationary reader.

Monitoring temperature of gas A transponder may exchange heat by radiation and by convective heat exchange. A transponder may be positioned in a duct, which comprises thermally insulating material arranged to reduce the contribution of radiative heat transfer to the transponder. In particular, a gas temperature sensor may comprise:

- a duct, and

- an RFI D transponder positioned in the duct,

wherein the duct comprises thermally insulating material arranged to reduce the contribution of radiative heat transfer to the transponder.

A duct made of conductive material may also be arranged to operate as a radio waveguide in order to increase the interrogation range of a reader.

Monitoring of thermal radiation

A transponder may be heated by radiation impinging on the transponder. In particular, a transponder may be heated by sunshine.

A radiation sensor may comprise a first transponder, a second transponder, and a radiation shield arranged to prevent propagation of radiation to the second transponder. The intensity of thermal radiation impinging on the radiation sensor may be determined based on a temperature difference between the first transponder and the second transponder.

Monitoring temperature of an item

When a transponder is attached to an outer surface of an item, the transponder may exchange heat with ambient gas and with the item. Heat exchange between the ambient gas and the transponder may cause an error in the measurement, i.e. the temperature of the transponder may substantially deviate from the surface temperature of the item.

A temperature sensor may comprise:

- an RFI D transponder, and

- a piece of thermal insulation attached to the transponder such that the insulation reduces heat transfer from ambient gas to one side of the transponder. When the temperature sensor is attached to an item e.g. by an adhesive, the thermal insulation may be facing outwards from the item such that the thermal insulation reduces heat transfer from ambient gas to the transponder.

Small temperature sensor

A width of the antenna of an RFI D transponder may be e.g. greater than 1 0 times the largest dimension of the chip. The chip may be connected to the antenna by using extension wires so that the chip together with the extension wires can be inserted in a small volume.

A temperature sensor may comprise

- an RFI D chip,

- an antenna, and

- extension wires connecting the antenna to the chip,

wherein the chip and the extension wires form a protruding portion such that the diameter of the protruding portion is smaller than or equal to 5 mm and the length of the protruding portion is greater than or equal to 1 0 mm.

The extension wires may have an effect on the coupling impedance of the combination of the wires and the antenna. The dimensions of the antenna may be selected such that the combination of the extension wires and the antenna has a suitable coupling impedance. Lifecvcle applications

A transponder 1 00 attached to an item 300 may be utilized in several different phases of the lifetime of the item. The lifetime of the item 300 may be e.g. longer than one week, longer than one year, or even longer than 50 years.

For example, the temperature data TDATA obtained from the transponder may be used for two or more of the following steps:

- monitoring temperature of a material or a temperature of the item during manufacturing of the item,

- controlling manufacturing of the item based on temperature data obtained from the transponder,

- identifying the item in a storage based on identification data obtained from the transponder,

- identifying the item during transportation of the item based on identification data obtained from the transponder,

monitoring operation of a system based on temperature data obtained from the transponder,

- identifying the item for recycling or dumping of the item based on identification data obtained from the transponder,

- identifying a responsible party for recycling or dumping of the item based on identification data obtained from the transponder, In particular, a method for monitoring temperatures of an item may comprise:

- attaching a first RFID transponder 1 00a to a material 31 0 or embedding the first RFID transponder in a material 31 0,

- manufacturing a first item 300a from the material 31 0 so that the manufactured first item 300a comprises the first transponder 1 00a,

- using the first item 300a as a part of a system 700, and

- monitoring and/or controlling operation of the system 700 by using first temperature data TDATA1 obtained from the first transponder 1 00a,

wherein the first transponder 1 00a is arranged to extract operating energy from a radio frequency field ROG. In particular, a method for monitoring temperatures of an item may comprise:

- using the first item 300a as a part of a first system 900,

- obtaining preliminary temperature data TDATA0 from a first transponder 1 00a in order to monitor and/or control operation of the first system 900, the first transponder 1 00a being attached to the first item 300a,

- using the first item 300a as a part of a second system 700, and

- obtaining first temperature data TDATA1 from the first transponder 1 00a in order to monitor and/or control operation of the second system

700,

wherein a location of the first system 900 is different from a location of the second system 700, and the first transponder 1 00a is arranged to extract operating energy from a radio frequency field ROG.

In particular, a method for monitoring temperatures of an item may comprise:

- obtaining preliminary identification data ID1 from a first transponder 1 00a in order to identify a first item 300a, the first transponder 1 00a being attached to the first item 300a,

- using the first item 300a as a part of a system 700, and

- obtaining first temperature data TDATA1 from the first transponder 1 00a in order to monitor and/or control operation of the system 700, wherein the first transponder 1 00a is arranged to extract operating energy from a radio frequency field ROG, and a time difference between obtaining the preliminary identification data ID1 and obtaining the first temperature data TDATA1 is at least 24 hours.

Manufacturing of the first item 300a may be controlled based on temperature data TDATA1 obtained from the first transponder 1 00a.

The first transponder may be utilized for identification (for example) at least 24 hours before (or after) the first transponder is utilized for temperature monitoring and/or temperature control. For example, the first item may be identified in a storage by using the transponder, and the first item may be later used as a part of a system such that the transponder is simultaneously used for identification and temperature control.

The first item 300a may be moved after attaching the the first transponder 1 00a to the first item 300a. Items may be e.g. stored during long periods and/or transported over a long distance. Sometimes information about the owner and/or destination of a transported item may be lost during transportation. The owner and/or destination may be subsequently determined based on the identity of an item. Identification data ID1 may be obtained from the first transponder 1 00a after transporting in order to identify the first item 300a.

Identification data ID 1 may be obtained from the first transponder 1 00a in order to identify the first item e.g. when the item is manufactured and/or stored. The item may be subsequently transported to a site where it is used as a part of a system 700. Temperature data TDATA1 may be obtained from the first transponder 1 00a in order to monitor and/or control operation of the system 700.

The first item 300a may be located in the vicinity of other items 300b, 300c e.g. during manufacturing, storage, transportation, and/or use in the system 700. Thus, the first transponder 1 00a may be located in the vicinity of other transponders 1 00b, 1 00c during manufacturing, storage, transportation, and/or use in the system 700.

The method may comprise obtaining first temperature data TDATA1 from the first transponder 1 00a, and additional temperature data TDATA2 from a second transponder 200a, e.g. during manufacturing, storage, transportation, and/or use in the system 700.

Absolute temperature data ABSDATA may be determined from temperature data TDATA by using calibration data CALDATA. The calibration data CALDATA may be retrieved from a memory MEM6 according to identification data ID1 obtained from the first transponder 100a. Temperature information TINF1 may be determined based on temperature data TDATA1 obtained from the first transponder 100a. The temperature information TINF1 may be displayed on a display 501 . A first identifier F1 may be determined based on identification data ID1 obtained from the first transponder 100a. The temperature information TINF1 and the first identifier F1 may be displayed such that the temperature information TINF1 is associated with the first identifier F1 . The temperature information TINF1 and the first identifier F1 may be stored in a memory MEM3, MEM4 outside the first transponder 100a such that the temperature information TINF1 is associated with the first identifier F1 .

Location data LOCDATA may indicate the location of the first transponder 100a with respect to a location reference LOCREF. The temperature information TINF1 and the location data LOCDATA may be provided at an interface 500 such that the temperature information TINF1 is associated with the location data LOCDATA. The location data LOCDATA may be retrieved from a memory MEM7 according to identification data ID1 obtained from the first transponder 100a.

Referring back to Figs. 7a - 7h, the location data LOCDATA may be determined by:

- determining the location of a reader 200 with respect to a location reference LOCREF, and

- determining the location of the first transponder 100a with respect to the reader 200.

The location of the first transponder 100a with respect to the reader 200 may be determined e.g. by determining the location (x,y) of the first transponder 100a based on a time delay Δπ and/or amplitude A of a response signal RES obtained from the first transponder 100a. The location of the first transponder 100a with respect to the reader 200 may be determined e.g. by varying spatial distribution of interrogation signals RES sent from a reader 200. When using several transponders 100a, 1 00b, the method may comprise:

- determining an identifier F1 based on identification data ID1 obtained from a transponder 100a, and

- comparing the identifier F1 with a reference identifier R1 attached in the vicinity of the first transponder 100a in order to check whether the identification data ID1 is truly obtained from the first transponder 100a.

During the manufacturing and/or during the use in the system 700, a control unit CNT4 may be arranged to generate a control signal S _C NT based on temperature data TDATA1 obtained from the first transponder 100a. The control unit CNT4 may be arranged to perform an action based on temperature data TDATA1 obtained from the first transponder 100a. The control unit CNT4 may be arranged to provide an alarm signal and/or to initiate an emergency procedure based on temperature data TDATA1 obtained from the first transponder 100a.

The control unit CNT4 may be arranged to compare the temperature data TDATA1 obtained from the first transponder 100a with reference temperature data TREF. The reference temperature data may be stored e.g. in the memory MEM12 as reference data REFDATA.

The reference temperature data TREF may be obtained from the first transponder 1 00a or from a second transponder 100b attached to the first item 300a or from a second transponder 100b attached to a second item 300b. The control unit CNT4 may be arranged to compare the rate of change of temperature data TDATA1 obtained from the first transponder 1 00a with reference value TREF, and to display temperature information and/or to perform an action based on the comparison.

In certain embodiments, the identity of an item may be associated with a high financial value. For those applications, separating the transponder from the item should preferably be difficult or impossible. The first transponder 100a may be attached to the item 300a such that the item and/or the transponder will be damaged in an attempt to separate the transponder from the item. Unauthorized separation may also be detected e.g. by using a security seal.

The owner of the item and/or a responsible party may be determined based on identification data ID1 obtained from the first transponder 1 00a. Party data PARDATA may be retrieved from a memory MEM8 based on identification data ID1 obtained from the first transponder 1 00a. A transaction may be requested between the first party and a second party. The transaction may be e.g. payment of a price when the item is sold or a refund of a deposit fee when the item is recycled.

Sometimes the lifetime of the item may be reduced if it is manufactured and/or stored at a temperature, which is too high or too low. An estimate for a remaining lifetime of the first item 300a may be determined based on temperature data TDATA1 obtained from the first item 300a.

Sometimes the quality of the item may be degraded if it is manufactured and/or stored at a temperature, which is too high or too low. An estimate for a financial value of the first item 300a may be determined based on temperature data TDATA1 obtained from the first item 300a.

Referring to the examples discussed above, the first item 300a may be e.g. a building element, a wall, a pipe, a piece of thermal insulation, a laminated beam, a piece of plywood, a container, a pallet, a package, a piece of foodstuff, a refrigerator, an oven, a plant pot, a part of a machine, a part of a vehicle, a tire, a gas bottle, an explosive device, a battery, a garment, a diaper, a bed, a bed linen, a sleeping bag, a chair, a table, an incubator, an electric conductor, an electric connector, an electronic component, a hard disk drive, a solid state drive a high voltage component, solar panel a component containing resin, a component containing rubber, and an element containing concrete. Referring to the examples discussed above, a manufacturing system 900 or a subsequent system 700 may comprise a functional unit, which in turn may comprise at least one reader 200. The functional unit may be e.g. a storage, a cooled storage, a container, a pallet, a vehicle, a building, an apparatus for producing a building element, a refrigerator, an oven, a greenhouse, a sauna, a furniture, a bed, a chair, and a table.

In particular, the above-mentioned applications related to building elements, tires, and batteries may be examples of using a transponder in two or more different phases during a lifetime of an item.

Referring to Fig. 15a, one or more transponders 100a, 100b, 100c may be attached to material 31 1 or embedded in a material 31 1 .

The transponders may be e.g. laminated between material layers 31 1 , 312.

An item 300 may be manufactured from the material 31 1 so that the manufactured item 300 comprises the one or more transponders 100a, 100b, 100c. The item 300 may be e.g. a concrete element or a plywood element.

Referring to Fig. 15b, the item 300 may be manufactured by using apparatus 900. The apparatus 900 may comprise e.g. a heater element 910, which is controlled by using a control signal S _C NT provided by a control unit.

Operation of the manufacturing apparatus may be monitored based on temperature data obtained from the one or more transponders 100a, 100b, 100c. Preliminary temperature data TDATA0 may be obtained from the transponder 100a in order to monitor/control the manufacturing system 900. A control unit CNT2/CNT4 may be arranged to provide a control signal S _C NT to a heater/cooler/ventilation unit 91 0. A heater unit 910 may emit e.g. infrared radiation IR1 . Operation of the manufacturing apparatus may be controlled based on temperature data obtained from the one or more transponders 100a, 100b, 1 00c. Referring to Fig. 15c, the manufactured item 300 may be subsequently used as a part of a system 700. The system 700 may be e.g. a building, which comprises a heating (and/or cooling) element 71 0 and/or a ventilation unit 720. Operation of the heating element 710 and/or a ventilation unit 720 may be controlled by control signals S _C NT provided by a control unit 400, based on temperature data obtained from the transponders 100a, 100b, 1 00c. The apparatus 700 may be arranged to store temperature history data associated with the transponder 100. The temperature history data may be stored e.g. in the memory MEM2, MEM3 and/or MEM6 (Fig. 6b). Referring to Fig. 15d, the antenna 205 of the reader 200 may also be a leaky waveguide antenna arranged to distribute the electromagnetic radio frequency interrogation signal ROG to a larger area. A leaky waveguide antenna may also be arranged to obtain electromagnetic radio frequency response signals RES from said larger area. In particular, the leaky waveguide antenna 205 may comprise a microstrip waveguide. The use of a leaky waveguide antenna has been described e.g. in a patent publication WO200700371 1 A1 .

In general, the reader 200 and the transponder 100 may be arranged to communicate e.g. according to the EPC Gen2 protocol. EPC Gen2 is a abbreviation for "EPCglobal UHF Class 1 Generation 2". The protocol has been incorporated e.g. in the standard ISO 18000-6C (frequency band 860-960MHz). (Reference is made to the latest versions of the protocol and standard as in force on 12 January 201 1 ). The reader 200 and the transponder 100 may be arranged to communicate e.g. according to one or more of the following standards:

ISO/IEC 18000-2A (frequency band 125/134.2 kHz, interrogation range e.g. up to 2 m)

ISO/IEC 18000-2B (frequency band 125/134.2 kHz)

ISO 18000-3 (frequency band 13.56 MHz, interrogation range e.g. up to 3 m)

ISO 18000-7 (frequency band 433 MHz)

ISO 18000-6A (frequency band 860-960MHz, interrogation range e.g. up to 3 m)

ISO 18000-6B (frequency band 860-960MHz)

ISO 18000-6C (frequency band 860-960MHz)

EPCglobal Class 0 (frequency band 860-960MHz)

EPCglobal Class 1 (frequency band 860-960MHz)

EPCglobal Class 1 Gen 2 (frequency band 860-960MHz)

ISO 18000-4 (frequency band 2.45 GHz, reading range e.g. up to 12 meters)

Proximity cards: ISO/IEC 14443 (frequency band 13.56 MHz, interrogation range e.g. up to 12.5 cm)

Vicinity cards: ISO/IEC 15693 (frequency band 13.56 MHz, interrogation range e.g. up to 1 .5 m)

(Reference is made to the latest versions of the protocols and standards as in force on 12 January 201 1 ).

The transponders 1 00a, 100b, 1 00c may be energetically passive so that they can be permanently embedded within the building structures. Referring back to Fig. 1 a, temperature data may be provided based on temperature-induced variations in the frequency of a local oscillator of an RFID transponder. Thus, the temperature measurement capability may inherent in a (standard) RFID integrated circuit 1 10. However, instead of utilizing the frequency f _C i_K of the local oscillator 52 for temperature monitoring or in addition to utilizing the frequency f _C i_K of the local oscillator 52 of the integrated circuit, the transponder 100 may comprise a temperature sensor 57. The temperature sensor 57 may be integrated in the RFID circuit 1 10 (Fig. 1 d), or the temperature sensor 57 may be connected to the RFID circuit 1 10 via terminals T3, T4 (Fig. 1 c).

The transponder 100 may comprise a temperature monitoring unit 55 arranged to convert an analog signal provided by the temperature sensor 57 into a digital signal, which may be stored in the memory MEM1 of the transponder and/or into a digital signal which may be sent via the radio frequency unit RXTX1 . Thus, the temperature monitoring unit 55 may be an analog-to-digital converter.

The transponder 100a may be arranged to store temperature data TDATA1 in a memory MEM1 located in the transponder 100a. The (digital) temperature data TDATA1 may be stored in a register located in the transponder 100a such that the value of the temperature data TDATA1 may be accessed and read by sending a predetermined interrogation signal ROG to the transponder 100a.

A reader 200 may obtain temperature data from the transponder so that the temperature data is not determined from variations of the modulation frequency f I_F of a response RES. The transponder 100a may be arranged to send a response RES such that the temperature data TDATA is included in the response e.g. by using pulse code modulation (PCM), by using pulse interval encoding PIE, and /or by using Manchester encoding. The transponder 100a may be arranged to send a response RES, which contains the temperature data TDATA in pulse code modulated format PCM and/or in a pulse interval encoded format PIE and/or in a Manchester encoded format.

Advantageously, the temperature monitoring unit 55 may be integrated in the RFID chip 1 10. However, also a separate temperature monitoring unit 55 of a transponder 100 may be connected to terminals of the chip 1 10. The temperature monitoring unit 55 may be implemented on a second semiconductor chip which is separate from a first chip 1 10, wherein the first chip 1 10 may comprise the radio frequency unit RXTX1 used for transmitting the response RES. The digital signal provided by the temperature monitoring unit 55 may be coupled to the chip 1 10 via the terminals.

The temperature sensor 57 and the temperature monitoring unit 55 may provide temperature data e.g. based on resistance of a resistive temperature sensor 57. The resistive temperature-dependent sensor 57 may be e.g. a NTC or PTC thermistor. (NTC denotes negative temperature coefficient, PTC denotes positive temperature coefficient). The resistive temperature sensor may be e.g. a platinum temperature sensor The temperature sensor unit may provide temperature data e.g. based on voltage of a P-N junction. The temperature sensor unit may provide temperature data e.g. based on voltage of a thermocouple. In such embodiment, the RFID transponder 100 may operate as a passive or semi-passive communication channel so that an external RFID reader 200 may interrogate temperature data TDATA1 from the transponder 100. In particular, the data may be communicated by using reflected power (in particular by using back scattering).

The analog to digital conversion in the transponder 100 (by the temperature monitoring unit 55) may be carried out by using energy extracted from a radio frequency field coupled to the antenna 140 of the transponder 100. In particular, the analog-to-digital conversion may be carried out by using energy extracted from an interrogation signal ROG coupled to the antenna 140 of the transponder 1 00.

The transponder may comprise a temperature monitoring unit (52, 55) arranged to generate the temperature-dependent digital signal (f _C i_K, N _c , TDATA) by using operating energy extracted from a radio frequency field (ROG).

The temperature monitoring unit (52, 55) may be arranged

- to obtain a temperature-dependent analog signal (S _T ) from a temperature sensor (57), and - to convert the temperature-dependent analog signal (S _T ) into the temperature-dependent digital signal (TDATA) by using operating energy extracted from the radio frequency field (ROG). According to preferred embodiments of the invention, the transponder 1 00 may be substantially energetically passive. This may provide a small size and a substantially infinite operating life.

However, in principle, the transponder 1 00 could also be an active device or a battery assisted device.

In case of a battery-assisted device, the response RES may be transmitted by using reflected power of the interrogation signal ROG (by using passive reflected power), but power provided by a battery may be used for processing information and/or storing information. This set-up may provide a long lifetime without a need to change the battery. However, if it is not possible to change the battery, the operating life of the battery still sets an upper limit for the operating life and size of the transponder. In practice the maximum operating life of a battery may be e.g. 1 year, 5 years, or 1 0 years.

In case of an active device, the battery provides operating power for the radio frequency unit RXTX1 . In this case, the operating life of the battery sets an upper limit for the operating life and size of the transponder.

In an embodiment, the second information INF2 (See Fig. 1 a) may be stored in a memory area, which is reserved for storing a "kill password". If the transponder receives an interrogation signal ROG, which contains the kill password, this may permanently and irrevocably disable operation of the transponder, i.e. it will "kill" the transponder. However, information INF2 may be read from the kill password area without disabling operation of the transponder (i.e. without killing the transponder). The present application has been filed together with the applications titled "Data storage on a remote-access apparatus", "A method for measuring environment using a calibration database", "A method for determining an environment dependent usability of an item", "Temperature monitoring system", "Temperature managed chain", all on the same date, and by the applicant of the present application.

For the purposes of storing and using application data in a password, the application "Data storage on a remote-access apparatus" is referred to.

For the purposes of forming and using calibration data related to temperature determination, the application "A method for measuring environment using a calibration database" is referred to.

For the purposes of determining usability of an item, using thresholds and ranges for the same, and for statistical determination of usability, the application "A method for determining an environment dependent usability of an item" is referred to.

For the purposes of determining temperature information in various systems, the application "Temperature monitoring system" is referred to. For the purposes of monitoring temperature of in a temperature- managed chain, the application "Temperature managed chain" is referred to.

For the person skilled in the art, it will be clear that modifications and variations of the devices and the methods according to the present invention are perceivable. The drawings are schematic. The particular embodiments described above with reference to the accompanying drawings are illustrative only and not meant to limit the scope of the invention, which is defined by the appended claims.