Background Art Utility companies, who supplies utilities such as gas, water, electricity (hereinafter, generally referred to as"gas or the like"), generally collect a charge from subscribers according to the quantity of consumed gas or the like. The amount of consumed gas or the like, based on which the charge is imposed, is represented by an indicator value of a metering device. The metering device includes a rotation needle type metering device and a rotation number wheel type metering device, according to the meter-value indicating mode. These metering devices indicate the quantity of consumed gas or the like with a figure consisting of 6 digits including one digit below the decimal point, for example, using six rotation needles or number wheels.

In order to automatically and remotely reading the utility metering

device, various techniques have been developed. One of the automatic remote meter-reading systems is a digital metering device, which is constituted in a digital operation mode, not in a mechanical fashion. The quantity of consumed utility is output as a digital signal, and thus an automatic remote meter-reading system can be easily implemented thereto. However, the digital metering device is expensive and must replace the widely-spread existing mechanical metering devices, thereby failing to provide a good economical efficiency. Thus, the digital metering device has been used mainly for industrial purposes of high capacity, but practically can not be used for a house service meter.

As an alternative approach, the rotation frequency of the rotation needle of a mechanical metering device is counted and utilized for an automatic remote meter-reading system. A certain type of mechanical metering device houses a magnetic lead switch or a hall sensor and transmits an electrical pulse.

However, this method cannot be applied to the exiting mechanical metering devices without imposing a structural change thereto. In addition, a metering error is likely to occur due to the magnet.

As another alternative method, the indicator value of a metering device is photographed using a digital camera and then a character recognition technology is used to recognize the indicator value from the picture image.

Korean Patent Application No. 10-2000-0017058 discloses a meter-reading system using a digital camera and a character recognition program, in which the numbers of a number wheel are converted into a video signal through a charge coupled-device (CCD) and then are recognized using an image recognition technique, thereby obtaining the rotation frequency of the number wheels. In these approaches, however, the computing time becomes extended, which results in an increase in the power consumption and in the size of the computing and memory devices. In addition, due to the digital camera used, the fabrication cost thereof increases. Furthermore, in case where the numbers

are not completely exposed, an error may occur in the character recognition process.

As an attempt in order to solve the above problems in the previous techniques, an automatic remote meter-reading apparatus using an optical sensing has been proposed, which can perform an automatic remote meter- reading by a simple construction, while utilizing the existing mechanical metering devices of rotation number wheel type. For example, Korean Patent Registration No. 10-0287540 discloses an apparatus for generating a signal for the quantity of consumption of a metering device using an optical sensing, and Korean Laid-open Patent No. 2000-0066245 discloses a revolution counter for a number wheel in a metering device. In this method of counting the rotation frequency of a rotation number wheel, a portion of the rotation number wheel is coated with a reflecting film and a light emitting diode radiates a light towards the rotation number wheel. Therefore, the reflecting film reflects most of the light, but the remaining portion of the number wheel does not. A phototransistor senses the light reflected from the reflecting film to thereby detect the reflecting area and the non-reflecting area and consequently count the rotation frequency of the number wheel. That is, when the rotating number wheel passes a certain pre-selected point, i. e., below the light emitting diode, the number wheel is regarded as having carried out one cycle of rotation. In addition, Korean Utility Model Registration No. 20-0323744 discloses an improvement in the above optical sensing type automatic remote meter-reading system, in which a noise generation due to an external light in the optical sensing mode is cut off to thereby improve the accuracy of optical sensing.

In the above optical sensing mode, a light reflecting film or tape is to be coated or attached to the rotation number wheel. However, the already manufactured or installed metering devices do not have a light reflecting film or tape. In order to apply the optical sensing technique, therefore, the number

wheels of the metering devices must be disassembled and processed for coating a reflecting film or attaching a reflecting tape. Accordingly, the practical application of the optical sensing mode embraces various limitations and inconveniences associated therewith. The reflecting film coating itself needs many efforts and the already-installed metering device also cannot be easily and readily disassembled in order to provide a reflecting film or tape. That is, it is not practical that the already installed devices are to be disassembled only for the reflecting film coating. In some countries, for example, Korea, the metering devices in service must be tested for normal operation and re-certified every few years. This point is most opportune for implementing the above optical sensing technique into the existing metering devices. For re-certification of the metering devices, they are detached from each subscriber and sent to the re- certification authority, where the devices are tested for normal operation. While doing that, a reflecting film or tape can be applied thereto most practically.

Consequently, only the metering device to be re-certified can be implemented with the above optical sensing method. That is, there is a limitation in applying the optical sensing mode in a bulk and collective fashion. In the case where this optical method is applied to newly fabricated metering devices, an agreement between parties including the metering device manufacturers and the utility companies is required, for example, in terms of coating a reflecting film in a certain specific number wheel. In contrast, some countries such as the Unites States does not adopt a re-certification system for metering devices and thus the installed metering devices can be used for the life time thereof. In these countries, unavoidably, many limitations and inconveniences will be associated with the application of the automatic remote meter-reading system using a light reflecting film. Furthermore, in case of a rotation needle type metering device, the structure of the rotation needle is not appropriate for attaching a reflecting film, for example, owing to the small size of the rotation

needle. Thus, it is difficult in practice that the optical sensing mode is applied to the rotation needle type metering devices.

Disclosure of Invention Technical Problem Accordingly, the present invention has been made in order to solve the above problems in the prior art, and it is an object of the invention to provide an automatic remote meter-reading method and apparatus, which can be applied to both a rotation needle type metering device and a rotation number wheel type metering device, and also can be applied to existing metering devices, without necessity of changing or modifying the structure thereof.

Technical Solution In order to accomplish the above object, according to one aspect of the invention, there is provided an automatic remote meter-reading apparatus for a rotation needle type metering device where a plurality of rotation needles rotates in proportion to a quantity of consumed utilities such as gas, water, electricity, or the like and indicates a numeral value on a scale plate, and for a rotation number wheel type metering device where a plurality of rotation number wheel indicates a numeral value corresponding to a consumed amount of utilities. In the automatic remote meter-reading apparatus of the invention, a plurality of photoelectric elements converts a light reflected from the rotation area of a rotation needle into an electrical signal, and the level-changing pattern in the electrical signal is analyzed to determine whether the rotation needle has performed one rotation, thereby automatically reading the mechanical metering

device of rotation needle type, without attaching any additional device to the rotation needle type or rotation number wheel type mechanical metering devices.

The automatic remote meter-reading apparatus comprises preferably : a photosensor unit disposed in a rotation path of a rotation needle or a rotation number wheel, which indicates a number place lower than a significant number used for a charge imposition, the photosensor unit including a light emitting unit having at least one light emitting element for radiating a light into a desired detection area in the rotation path and a photoelectric element unit having a plurality of photoelectric elements for receiving a light reflected from the detection area and converting into an electrical signal corresponding to the received light ; a rotation frequency calculation unit for computing an accumulated rotation frequency of the rotation needle or the rotation number wheel, in such a manner as to extract a level-changing pattern of an electrical signal output from each photoelectric element of the photoelectric element unit as time passes, to compare the extracted level-changing pattern with a reference pattern, and to determine whether the rotation needle or the rotation number wheel has performed one rotation through the comparison, the reference level being a level-changing pattern of an electrical signal for each photoelectric element to be supposed to exhibit during one cycle of rotation of the rotation needle or the rotation number wheel ; and a power supply for supplying a required electric power to the light emitting unit, the photoelectric element unit, and the rotation frequency calculation unit, thereby counting a rotational frequency of the rotation needle or the rotation number wheel.

The photosensor unit may be further provided with a case. The case is made of an opaque material and provides a first space and a second space for accommodating respectively the light emitting element and the plurality of photoelectric elements. The first space and the second space are separated by a light barrier wall for preventing a light emitted by the light emitting element

from being incident directly on the photoelectric elements, and the first and second spaces are opened frontward such that a light reflected from the detection area can be applied to the photoelectric element.

Preferably, the automatic remote meter-reading apparatus of the invention may further comprise a housing capable of being assembled to the metering device, with the photosensor unit accommodated therein. The housing is provided with a transparent window at a position corresponding at least to the plurality of rotation needles or the plurality of rotation number wheels, which indicates the quantity of utilities consumed. The transparent window has an infrared cut-off function for preventing an infrared light from entering the housing.

The power supply may include a battery. Preferably, an electric power for driving the light emitting element includes a drive pulse having a period of no more than 250ms, the duration time of the drive pulse is longer than the response time of the photoelectric element, and the duty ratio thereof is determined as a value no more than 1/100.

The rotation frequency calculation unit may be constructed of a microcomputer. The microcomputer stores the reference pattern beforehand in a memory thereof and determines that the rotation needle or the rotation number wheel has finished one cycle of rotation, when the conformity between the extracted level-changing pattern and the reference pattern is above a desired percentage value. When calculating the conformity between the extracted level-changing pattern and the reference pattern, a weight may be applied, depending on the position of each photoelectric element. The reference pattern is an average value of level-changing patterns of electrical signals obtained from each photoelectric element during one cycle of rotation of the rotation needle or the rotation number wheel. Here, the electrical signals may be obtained through a trial operation of the metering device in which the

photosensor unit is installed. Alternatively, the electrical signals may be obtained through an experimental measurement to plural metering devices of a same type.

The photoelectric element may be formed of at least one of a photodiode, a phototransistor, a photoelectric tube and photomultiplier using a photoemissive surface, a photoelectric cell using an internal photoelectric effect, and a photovoltaic cell. The number of the photoelectric elements constituting the photoelectric element unit is preferred to be three or more, for reliability of counted rotation frequency. Furthermore, in order to enhance a pattern accuracy of the reflected light, preferably, a condenser lens is disposed in a path along which a reflected light from the detection area is incident to the photoelectric element unit. The plurality of photoelectric elements is arranged in one column or row, or in a crusade form, or in a closed packed form within a circular or polygonal area.

The automatic remote meter-reading apparatus of the invention may further comprise a transmitter unit for sending to a pre-established receiver an accumulated rotation frequency of the rotation needle or the rotation number wheel calculated by the rotation frequency calculation unit. The accumulated rotation frequency is transmitted through a wired and/or wireless communication system at a pre-set time or when requested.

According to another aspect of the invention, there is provided a method of automatically and remotely reading a metering device, including a rotation needle type metering device where a plurality of rotation needles rotates in proportion to a quantity of consumed utilities such as gas, water, electricity or the like and indicates a number value on a scale plate, and a rotation number wheel type metering device where a plurality of rotation number wheel indicates a number value corresponding to a consumed amount. The method of the invention comprises steps of: a) disposing a photosensor unit in a

rotation path of a rotation needle or a rotation number wheel, which indicates a number place lower than a significant number used for a charge imposition, the photosensor unit including a light emitting unit having at least one light emitting element for radiating a light into a desired detection area in the rotation path and a photoelectric element unit having a plurality of photoelectric elements for receiving a light reflected from the detection area and converting into an electrical signal corresponding to the received light, and converting a changing pattern in the reflected light according to rotation of the rotation needle or the rotation number wheel into an electrical signal through each photoelectric element of the photoelectric element unit; b) storing a reference pattern beforehand in a microcomputer, the reference pattern being a level changing pattern of an electrical signal output from each photoelectric element during one cycle of rotation of the rotation needle or the rotation number wheel ; and c) providing to the microcomputer an electrical signal output from each photoelectric element of the photoelectric element unit, and, in the microcomputer, comparing and analyzing an electrical signal output from each photoelectric element with the corresponding reference pattern, thereby calculating an accumulated rotation frequency of the rotation needle or the rotation number wheel.

Preferably, the above step c) includes steps of: i) sampling an electrical signal output from each photoelectric element of the photoelectric element unit and extracting a level-changing pattern with time; ii) comparing the extracted changing pattern with the reference pattern for the corresponding photoelectric element and determining whether the rotation needle or the rotation number wheel has completed one rotation; and iii) increasing an accumulated rotation frequency by one if determined that the rotation needle or the rotation number wheel has performed one cycle of rotation.

The level-changing pattern of an electrical signal extracted from each

photoelectric element and the reference pattern may be defined by a changing order and/or changing frequency in the value of signal level. It is determined that the rotation needle or the rotation number wheel has finished one cycle of rotation, when the conformity between the extracted level-changing pattern for each photoelectric element and the reference pattern for the corresponding photoelectric element exceeds a desired minimum limitation value.

The method of the invention may further comprise steps of: storing in a memory the accumulated rotation frequency of the rotation needle and the rotation number wheel ; and transmitting to a pre-established receiver the accumulated rotation frequency stored in the memory through a wired and/or wireless communication system, at a pre-set time or when requested.

Advantageous Effects As described above, the automatic remote meter-reading apparatus can be applied to the existing rotation needle type or rotation number wheel type metering device, without changing the structure thereof. Therefore, the invention can provide a wide range of applications including an ability of applying to pre-installed existing metering devices.

In addition, the photoelectric element unit is comprised of plural photoelectric elements, and all the level-changing patterns of electrical signals from the photoelectric elements are collectively considered. Also, a preventive measure against external optical noises is provided. Therefore, the rotation frequency of a rotation needle or rotation number wheel can be more accurately counted, as compared with the conventional case of using a single photoelectric element.

Furthermore, the meter-reading apparatus of the invention can perform a remote meter-reading in a complete automatic mode. That is, the remote

meter-reading apparatus is connected with a computer system of a utility company through a wired or wireless communication network. Therefore, the automatic meter-reading data can be provided to the computer system of the utility company, without any intervention by a meter-reading personnel.

Description of the Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 illustrates an automatic remote meter-reading apparatus according to a first embodiment of the invention, where the apparatus of the invention is applied to a water metering device which is one of the rotation needle type metering devices; FIG. 2 is a schematic diagram showing the whole structure of the automatic remote meter-reading apparatus according to the first embodiment of the invention; FIGS. 4 to 7 illustrate several embodiments of a photosensor unit according to the invention; FIGS. 8 and 9 illustrate electrical signals output from several photoelectric elements respectively when a rotation needle remains stopped and rotates with a constant speed; FIG. 10 is a flow chart showing the procedures of counting the rotation frequency through an especially prepared program; FIGS. 11 and 12 illustrate an automatic remote meter-reading apparatus according to a second embodiment of the invention, where the apparatus of the invention is applied to a gas metering device which is one of the rotation number wheel type metering devices;

FIG. 13 is a schematic diagram showing the whole structure of the automatic remote meter-reading apparatus according to the second embodiment of the invention; FIGS. 14 and 15 explain an operation of the automatic remote meter- reading apparatus according to the second embodiment; and FIG. 16 is a flow chart showing the procedures of counting the rotation frequency of a certain specific number wheel through an especially prepared program.

Best Mode for Invention The preferred embodiments of the invention will be hereafter described in detail with reference to the accompanying drawings.

As one of metering devices for measuring the quantity of utilities consumed such as gas, water, or electricity, a rotation needle type metering device indicates the amount of consumed utilities through a combination of numerals on a scale plate, which are pointed by plural rotation needles. FIG. 1 illustrates an automatic remote meter-reading apparatus according to a first embodiment of the invention, where the apparatus of the invention is applied to a water metering device 10, which is one of the rotation needle type metering devices. In FIG. 1, the automatic remote meter-reading apparatus of the invention is denoted generally at 100. In the meter-reading apparatus of FIG. 1, a photosensor unit 130 (or a meter cover 140) is opened. FIG. 2 is a schematic block diagram showing the whole structure of the automatic remote meter- reading apparatus 100 according to the first embodiment of the invention.

The water metering device 10 is provided with plural rotation needles 110,112 and a scale plate 30 corresponding to each rotation needle, which has a scale 40 for indicating a needle pointer value. The amount of consumed tap-

water (utilities) is indicated by a combination of scale values on the scale plate 30 pointed by the rotation needles 110 and 112. The respective rotation needles indicate different units of value. These scale values are combined to indicate the quantity of used utilities, being comprised generally of an integer part of 3 to 6 digits and decimal places of 1 to 3 digits. When a subscriber consumes tap-water, each rotation needle rotates in proportion to the quantity used and in inverse proportion to the place value therefor. In the invention, the rotation needle 112 to be counted is a rotation needle corresponding to a place lower than a significant digit, which is used for determining the amount of utilities used. For example, the meter reading of a water metering device is carried out above decimal places and thus it is preferred to select a rotation needle 110 indicating a place value lower than the decimal point.

The automatic remote meter-reading apparatus 100 of the invention includes a photosensor unit 130 for detecting the rotation of a certain pre- selected rotation needle 110 in the metering device 10, a microcomputer 153 programmed so as to calculate the rotation frequency using an electric signal output from the photosensor unit 130, and a power supply 156 for supplying an electric power required for driving each element of the apparatus 100. For the purpose of an automatic remote meter-reading, information on the calculated quantity of consumed water needs to be sent to a central computer 162 for administrating metering data in the water company. The information on the quantity consumed may be sent to the central computer 162 through a wired and/or wireless communication system. In order to employ a wireless communication mode, the automatic remote meter-reading apparatus 110 must be further provided with a wireless communication unit 154. When required, a local wireless repeater 160 may be provided in each unit district, where data transmitted from plural wireless communication units 153 is collected and sent to the central computer 162 for administrating metering data. In addition, the

local wireless repeaters 160 in the unit districts need to be connected to the data-administering central computer 162 in the water utility company, through a long distance wireless communication system (for example, a data communication using a mobile phone communication network) or a wired communication system. The photosensor unit 130 may be installed in the inner face of the cover of the metering device 10. Alternatively, preferably, the meter- reading apparatus 100 of the invention may be further provided with a housing 140, which can serve as a cover for the metering device 10 and at the same time function to accommodate the photosensor unit 130 therein and mount it to the metering device 10.

The photosensor unit 130 emits a light on the surface of a detection area 60 and senses the reflected light therefrom to convert it into an electrical signal. The detection area 60 may be selected from the rotation path or region of a rotation needle 110 to be sensed. For this purpose, the photosensor unit 130 includes a light emitting unit having at least one light emitting element 132a, 132b, and a photoelectric element unit 134 having a plurality of photoelectric elements A1, A2,... E4, E5. The light emitting element 132a, 132b functions to radiate a light on the detection area 60 in the scale plate 30, above which the rotation needle 110 rotates. The photoelectric element receives a light reflected from the rotation needle 110 and the detection area 60 and converts it into an electrical signal. The light emitted from the light emitting element 132a, 132b must be configured so as not to be incident directly on the photoelectric element unit 134, but to be incident on the surface of the detection area 60 on which the rotation needle 110 rotates, and then be reflected from the surface of the detection area 60 and incident on the photoelectric element unit 134. The photoelectric element unit 134 includes at least three photoelectric elements and the number thereof can be selected appropriately, not exceeding one hundred. If the number of the photoelectric elements is too low, the rotation

frequency of the rotation needle 110 can not be precisely measured. On the contrary, if the number of the photoelectric elements is overly high, the electric power consumption is increased, together with increase in the manufacturing cost. The light emitting element is typically exemplified by a light emitting diode (LED). The photoelectric element must sense the light radiated from the light emitting, and need to have the same peak wavelength and spectrum band width as that of the light emitting element. For example, in case of employing a light emitting diode emitting an infrared light, the photoelectric element must be an element capable of sensing the infrared light. A typical photoelectric element includes a photodiode or a phototransistor. Other examples for the ) photoelectric element include a photovoltaic cell, a photoelectric cell, a photoelectric tube, or the like. In this case, an appropriate light emitting element needs to be selected.

It is preferable that the light emitting unit 132 and the photoelectric element unit 134 are housed in a case to thereby form an integral photosensor unit, for the convenience of installation and for the safety of sensor operation.

FIGS. 4 to 7 illustrate several embodiments of a photosensor unit according to the invention, where the photosensor units are denoted by reference numerals 130,130-1, 130-2,130-3. In the photosensor unit 130 of FIG. 4, twenty-five photoelectric elements A1, A2,..., E4, E5 are arranged in a 5x5 matrix pattern to thereby form a photoelectric element unit 134, and a light emitting element is disposed in the left and right side of the photoelectric element unit 134 respectively to thereby form a light emitting unit 132a, 132b. As shown in FIG. 4, the photosensor unit 130 is provided with a case 136 made of a nontransparent material and providing two spaces 136a and 136b, and 136c for housing the two light emitting elements 132a, 132b and the plurality of photoelectric elements A1, A2,..., E4, E5. The first room 136a, 136b and the second room 136c are partitioned by a light barrier wall 136d, 136e and thus the light from the

light emitting elements 132a, 132b is prevented from being incident directly on the photoelectric elements A1, A2,..., E4, E5. The first room and second room is opened frontward thereof such that the reflected light from the detection area 60 is received by the photoelectric elements A1, A2,...., E4, E5. In order to improve a light receiving efficiency, the light emitting element 132a, 132b may be slightly inclined towards of the photoelectric element unit 134, or the outer wall of the first room 136a, 136b may be slightly inclined such that the light of the light emitting element can be directed towards the photoelectric element, or the inner wall of the first room 136a, 136b and the inner wall of the second room 136c may be treated with a light reflecting film (not shown) to thereby reduce a light transmission loss. Furthermore, in case where the photoelectric element is far away from the scale plate, the light receiving sensitivity may be lowered. In this case, a condenser lens (not shown) may be disposed in the path, along which a light reflected from the rotation needle 110 and the detection area 60 travels towards the photoelectric element unit 134, thereby enabling to improve the accuracy of light pattern. The condenser lends is exemplified by a rod lens array. Alternatively, a photoelectric element each having a condenser lens attached thereto may be employed. As a further alternative, a light filter (not shown) may be disposed in the entrance of the second room 136c so as to selectively pass only the light emitted from the light emitting element 132a, 132b, thereby effectively cutting off a noise caused by an external light.

Preferably, the plurality of photoelectric element constituting the photoelectric element unit 134 is arranged on a same plane. The arrangement of the plurality of the photoelectric elements is not limited to a particular pattern.

However, it is preferable that the photoelectric elements are arranged so as to accurately detect the light reflected from the whole surface area of the rotation needle 110, which is positioned right below the light emitting unit 132a, 132b.

For example, the plurality of photoelectric elements may be arranged in one

column (as shown in FIG. 7), or in a crusade pattern, or in the form of a circle or a polygon within a certain desired area such that the photoelectric element unit 134 has a certain area, as shown in FIGS. 4 to 6. FIG. 5 illustrates another arrangement of the photosensor unit. The photosensor unit 130-1 in FIG. 5 is constructed such that twenty-three photoelectric elements A1, A2,..., E4, E5 are arranged within a rectangular room 136c in a 5x5 matrix pattern to thereby form the photoelectric element unit 134, and at the same time two light emitting elements 132a, 132b are placed in an appropriate position within the photoelectric element unit 134. Similar to the structure of FIG. 4, the case 136' is structured such that a partition wall 136d', 136e'is disposed around the place where the light emitting element 132a, 132b is installed, thereby light-separating the light emitting element 132a, 132b and the photoelectric element unit 134 from each other. FIG. 6 illustrates a photosensor unit 130-2 constructed in a hexagon pattern using a hexagon case 136". In case of a circular detection area 60, thirty photoelectric elements A1, A2,..., G1, G2 are arranged in a hexagon room 136c"in a close-packed fashion to thereby form a photo electric unit 134 having a shape similar to a circle. Then, two light emitting elements 132a, 132b are disposed in an upper and lower space 136a", 136b"respectively, which are separately prepared in the upper and lower side of the photoelectric element unit 134. In this case, also the photoelectric element unit 134 and the two light emitting elements 132a, 132b are partitioned by a partition wall 136d", 136e". In the photosensor unit 130-3 shown in FIG. 7, ten photoelectric elements AO, A2,..., A8, A9 are arranged in one straight column to constitute a photoelectric element unit 134 and a light emitting element 132a, 132b is disposed within the photoelectric element unit 134 or outside thereof. Many other configurations for the photosensor unit may occurs to those skilled in the art within the scope of the invention.

In FIG. 1, the housing 140 serves as a cover for the metering device

and the photosensor unit 130 is fixed inside the housing 140. The housing 140 is structured so as to be detachably attached to the metering device 10. The housing 140 is mounted in the metering device 10 with the photosensor unit 130 fixed inside thereof, and at this time the photosensor unit 130 is positioned above the detection area 60, in which the rotation needle 110 is placed.

The housing 140 is preferred to have a transparent window at a position corresponding to the rotation needle so as to read a needle value pointed by the rotation needle 112, even in the state where the housing 140 is mounted in the metering device. Depending on the design of metering device, a meter-reading unit 70 constituted of plural rotating number wheels may be further provided, in addition to the rotation needles. In this case, the housing 140 is preferred to have a transparent window 144 at a position corresponding at least to the meter-reading unit 70. The remaining area except for the transparent window is preferred to be opaque. However, a natural light can be introduced into the inside of the housing 140 from outside through the transparent window 144.

The sunlight has a broad range of wavelength including ultraviolet, visual lights and infrared, and thus is considered to have light rays having the same wavelength as in the photosensor unit 130. Therefore, if the introduction of the sunlight through the transparent window 144 is not shut off, a sensing error may occur in the photoelectric element unit 134. Thus, an infrared cut-off function needs to be provided in the transparent window 144 so as not to pass an infrared light having a wavelength range used in the photosensor unit 130. In order to provide the infrared cut-off function to the housing 140, at least the transparent window may be coated with an infrared cut-off film or vapor- deposited with an infrared cut-off material, or an infrared cut-off material may be mixed with the material which is used for the injection molding of the housing 140. Alternatively, using two polarizing films having a 90-degree difference in their polarization angles, one of the films is attached to the transparent window

144 and the other is attached to the front face of the photoelectric element unit 134.

FIG. 2 is a schematic diagram showing the whole structure of the automatic remote meter-reading apparatus according to the invention. The photoelectric elements of the photoelectric element unit 134 in the photosensor unit 130 is connected with the microcomputer 152, and thus an electrical signal output from the photoelectric elements is input to the microcomputer 152. The output port of the microcomputer 152 is coupled to a wireless communication unit 154. The microcomputer 152, the wireless communication unit 154, and the power supply 156 may be preferably integrated into a printed circuit board (not shown) to thereby form a computation/wireless communication module 150.

The automatic remote meter-reading apparatus 100 of the invention having the above described construction is to be installed in each metering device. The meter-reading data read by the remote meter-reading apparatus 100 is sent to the central computer 162 in the utility company through a communication network. For the saving of communication charge and for the efficiency of administration, the control area of a utility company may be divided into plural sub-areas, in each of which a local wireless repeater 160 is installed. Then, the respective local wireless repeater 160 collects the meter-reading data in the corresponding sub-area and sends the collected data to the central computer 162 in the utility company. The local wireless repeater 160 is connected with the automatic remote meter-reading apparatus 100 and the central computer of the utility company respectively through a wireless and/or wired communication network.

When the meter-reading apparatus 100 is installed in a metering device 10, the photosensor unit 130 is positioned right above the detection area 60 including a scale 40 to be pointed by the rotation needle 110. While the rotation needle 110 rotates or stops, the light emitted from the light emitting elements

132a, 132b is reflected by the rotation needle 110 and the detection area 60. A certain portion of the reflected light is incident on the photoelectric elements A1, A2,..., E4, E5 of the photoelectric element unit 134. In the case where a condenser lens is further installed, each photoelectric element A1, A2,..., E4, E5 receives a larger quantity of light and thus can detect more accurate pattern of reflected light.

The intensity of the light, i. e. , the spatial distribution pattern of the reflected light, which is incident on each photoelectric element of the photoelectric element unit 134, is determined by the portion on which the light of the light emitting element is incident, i. e., light-reflecting elements. The light- reflecting element may include the rotation needle 110 and the surface of the detection area 60. Here, the rotation needle 110 is rotated when the utility (water, gas, electricity, etc. ) is consumed. Therefore, the light-reflecting element constituted of a combination of the rotation needle 110 and the surface of the detection area 60 is regarded as a variable light-reflection element, of which reflectivity varies with the consumption of utilities. The intensity of light reflected to the photoelectric element unit 134 will be changed, depending on a rotation angle of the rotation needle 110 (i. e. , the position thereof). From the viewpoint of each respective photoelectric element, the intensity of light incident to itself varies with time during one cycle of rotation of the rotation needle 110, and thus, the level of electric signal output from the corresponding photoelectric varies correspondingly. In addition, from the viewpoint of the entire photoelectric elements, during one cycle of rotation of the rotation needle 110, the intensity of light incident on each respective photoelectric element is not necessarily the same. Here, it should be noted that, while the rotation needle 110 rotates, the changing pattern in the electrical signal of a certain particular photoelectric element is repeated regularly every time of rotation. Using this phenomenon, the present invention counts the rotation frequency of the rotation needle 110.

FIGS. 8 and 9 illustrate electrical signals output from several photoelectric elements B3, D2, D3, D4, D5 respectively when the rotation needle 110 remains stopped and rotates with a constant speed. When water is not consumed, the rotation needle 110 stops. Therefore, the electrical signal output from each photoelectric element in the photoelectric element unit 134 maintains a constant level for each photoelectric element, as shown in FIG. 8.

(This level is determined by the rotation phase angle of the rotation needle 110 at that time.) While water is being consumed, the rotation speed of the rotation needle 110 will vary with the quantity of water consumed. Accordingly, the level of electrical signal output from each photoelectric element exhibits a particular changing pattern, as illustrated in FIG. 9 with respect to some photoelectric elements only. Regardless of the rotation speed of the rotation needle 110, while the rotation needle 110 performs one cycle of rotation, the changing pattern in the level of electrical signal output from each individual photoelectric element, i. e. , the ascending and descending pattern of level is the same, from the viewpoint of the corresponding individual photoelectric element. Therefore, the each individual photoelectric element has its own inherent changing pattern, which is hereinafter referred to as a"reference pattern"for each photoelectric element. The reference pattern for each photoelectric element is obtained and pre-established in the microcomputer 152. Thus, when the consumer uses water or gas, whether the rotation needle 110 has finished its one cycle of rotation can be determined in such a way that the obtained changing pattern in the electrical signal level output from each photoelectric element is compared with the pre-established reference pattern for the corresponding photoelectric element.

In determining whether the rotation needle 110 has completed its one cycle of rotation, it is of importance how the level is changed, not how long a certain level is lasted. That is, whatever speed the rotation needle 110 rotates

with, the electrical signal level exhibits the same changing pattern with time with respect to each photoelectric element. This point bases a determination as to whether the rotation needle 110 has completed one rotation. The level changing pattern of electrical signal output from each photoelectric element and the reference pattern all may be defined by a changing order and changing frequency of level value. In addition, a further information as to whether a first level is"low"or"high"can define the changing pattern and the reference pattern more completely. For example, as illustrated in FIG. 9, in case of a photoelectric element D2, during one cycle of rotation, two times of level descending and two times of level ascending are exhibited. This changing pattern of level can be pre-established in the microcomputer 152 as a reference pattern for the photoelectric element D2. When water is consumed, the level changing pattern in the actual electrical signal output form the photoelectric element D2 can be compared with the pre-established reference pattern, thereby enabling the determination as to whether the rotation needle 110 has carried out one cycle of rotation. The same is for other photoelectric elements.

The changing pattern with time in an electrical signal output from each photoelectric element contains information capable of determining whether a certain specific rotation needle 110 rotates or not. Thus, the microcomputer 152 samples periodically the electrical signal output from each photoelectric element and extracts from the electrical signal a changing pattern with time for each individual photoelectric element. Then, the extracted changing pattern is compared with the pre-established reference pattern, thereby counting the rotation frequency of the rotation needle 110. The microcomputer 152 carries out the counting of the rotation frequency of the rotation needle 110 using an especially prepared program, which is stored in the microcomputer 152. FIG.

10 is a flow chart showing the procedures of counting the rotation frequency through the above program.

First, when a certain specific rotation needle 110 performs one cycle of rotation, the level changing pattern with time in the electrical signal obtained from each photoelectric element is stored beforehand in a memory (not shown) as a reference pattern (S10). One method of obtaining a reference pattern utilizes an electrical signal output from each photoelectric element, which can be obtained through a measurement experiment for a certain period of time, using plural water metering devices of same type. That is, while the rotation needle 110 repeats its rotation, an electrical signal output from a certain single photoelectric element is sampled and an average changing pattern for one cycle of rotation is computed from the sampled electrical signals. The computed average changing pattern is determined as a reference pattern for the concerned photoelectric element. This operation is carried out for all photoelectric elements to thereby obtain a reference pattern for each individual photoelectric element. As an alternative method of obtaining a reference pattern, a pre-trial operation is performed for a water metering device 10 having the automatic remote meter-reading apparatus 100 installed therein. An electrical signal output from each photoelectric element through the pre-trial operation can be utilized for obtaining a reference pattern. That is, while the water is actually consumed, the rotation needle 110 will rotates in the metering device 10 having the remote meter-reading apparatus 100 of the invention, and at this time, an electrical signal for each photoelectric element will be obtained.

This electrical signal can be used for calculating an average changing pattern, which will be determined as a reference pattern for the concerned photoelectric element. The reference pattern for each photoelectric element as described above is stored beforehand in a memory of the microcomputer 152.

In this way, if the determination of a reference pattern is completed, then the rotation frequency of the rotation needle 110 can be counted. For this purpose, first, a variable for storing a level changing pattern in the electrical

signal output actually from each photoelectric element is initialized (S12).

Thereafter, an electrical signal output from each photoelectric element of the photoelectric element unit 134 is sampled. Then, a level changing pattern in the electrical signal output from each photoelectric element is extracted from the above sampled signal. The extracted level changing pattern value is stored in the corresponding variable (S14). In this way, a level changing pattern value stored in the previous period is replaced by a new level changing pattern value of the current period.

Next, for each photoelectric element, the extracted level changing pattern value is compared with the pre-established reference pattern value in order to determine whether they conform to each other. If the conformity between both values is more than a minimum limitation value (a reference value), the rotation needle 110 is regarded as having finished one cycle of rotation. Otherwise, it is determined that one cycle of rotation has not finished yet, and return to the step S14 (S16). Here, in the case where the rotation needle 110 has performed one cycle of rotation, the conformity between the extracted level-changing pattern value and the pre-established reference pattern value must be 100% theoretically. In practice, however, the reference value needs to be slightly alleviated, for example, to 90%, considering an error or disturbance in the measurement, an operational error or deviation in the light emitting element 132a, 132b and the photoelectric element unit 134.

If it is determined that the rotation needle 110 has finished one rotation, the accumulated rotation frequency is increased by one (S18) and return to the step S12, where the variable for storing a level-changing pattern value is initialized. Then, the steps S14 to S18 are repeated again. By repeating the above procedures, the microcomputer 152 can count an accumulated rotation frequency for a certain specific rotation needle 110. In addition, the accumulated rotation frequency is stored in the microcomputer 152, which

controls such that the stored rotation frequency is sent to the local wireless repeater through the wireless communication unit 154, periodically or when requested. A program for performing this is stored in the microcomputer 152.

Furthermore, information collected in each local wireless repeater 160 is transmitted to the data-administrating central computer 162 of the utility company (water company) through a long distance wireless or wired communication network, thereby enabling a complete automation for the remote meter-reading of metering devices.

On the other hand, the power supply 156 includes a battery (not shown) and a supply circuit (not shown) for supplying an electric power from the battery to each element such as the photosensor unit 130, the microcomputer 152, and the wireless communication unit 154. In particular, the electric power for the light emitting element 132 is preferred to be supplied in a pulse form, in terms of energy saving. For this purpose, using an oscillator and a counter for demultiplying a signal from the oscillator and converting into a pulse signal having a desired period and duty ratio, the battery power is made into a pulse form, which then is sent to the light emitting element 132. The circuit can be configured such that the microcomputer 152 controls the period and duty ratio of the pulse signal. The period T of the pulse signal is appropriately selected, not exceeding 250ms. The pulse duration Td is selected as short as possible, but longer than the response time of the photoelectric element 134. Therefore, the duty ratio Td/T of the pulse signal of the light emitting element 132 is to be made less than about 1/100. The light emitting element 132 emits lights intermittently, in response to the duration time of a pulse signal. For the purpose of stable operation, the amplitude of the pulse signal is preferred to be made larger than 2mA, and in this case, the duty ratio is to be reduced proportionally.

FIGS. 11 and 12 illustrate an automatic remote meter-reading apparatus

200 according to a second embodiment of the invention, where the apparatus of the invention is applied to a gas metering device 300 which is one of the rotation frequency wheel type metering devices. FIGS. 11 and 12 show respectively before and after a housing with a photosensor unit 130 mounted thereon is installed in the gas metering device 300.

In a rotation number wheel type gas metering device 300, a meter- reading unit 210 is constructed of plural number wheels arranged one after another and configured so as to represent an integer part of 4 to 5 digits and decimal places of 1 to 3 digits. Each number wheel has a drum shape and digits of 0 to 9 are indicated along the outer circumferential surface thereof.

When the gas is consumed, a number wheel of lowest level is rotated with highest speed in proportion to the quantity of gas consumed. At this time, the rotation speed of a certain number wheel is ten times of that of the adjacent lower number wheel, or tenth times of that of the adjacent higher level number wheel. In general, the gas charge is calculated, based on the number value above the decimal point (i. e. , the integer part). Therefore, the present invention is designed, preferably, such that a certain number wheel below the decimal point (i. e. , a number wheel in the decimal place) is selected in order to count the rotation frequency.

FIG. 13 is a schematic block diagram showing the whole structure of the automatic remote meter-reading apparatus 200 according to the second embodiment of the invention. The structure of the apparatus 200 is the same as in FIG. 2, except that a rotation number wheel 210a is illustrated instead of the rotation needle 110 in FIG. 2. In FIG. 13, the photosensor unit is represented as a cross-section taken along the line A-A'in FIG. 12 and the remainder is illustrated as a block diagram. Similar to the previous embodiment 100, the automatic remote meter-reading apparatus 200 of this embodiment includes a photosensor unit 130 for sensing rotation of a certain number wheel in the

metering device 300, a microcomputer 152 programmed so as to computer the rotation frequency of the certain number wheel using an electrical signal output from the photosensor unit 130, a power supply for supplying an electric power to each element of the apparatus 200, and a wireless communication unit 154 for transmitting a meter-reading value corresponding to the computed rotation frequency to a receiver, for example, a local wireless repeater 160. When compared with the previous apparatus 100 applied to a rotation needle type metering device 10, the meter-reading apparatus 200 of this embodiment has several differences in measuring the rotation frequency of a rotation number wheel, not a rotation needle. For example, the structure of the housing 240 is different, and the determination as to whether the rotation number wheel has finished one cycle of rotation is made differently. The remainder has almost the same construction, and the constitutional elements including the photosensor unit 130 have substantially the same functions.

The photosensor unit 130, which is installed above a certain specific number wheel 210a, radiates a light on the surface of the specific number wheel 210a and senses the reflected light therefrom, and then convert it into an electrical signal. For the above configuration of the photosensor unit 130, preferably, a housing 240 may be employed. The photosensor unit 130 is fixed inside the housing 240. The housing 240 is structured so as to be detachably assembled to the metering device 300, as shown in the figures. Preferably, the housing 240 with the photosensor unit 130 fixed thereinside is detachably assembled to a flange 212 in such a way to cover the meter-reading unit 210 of the metering device. For this purpose, in the entrance rim of the housing 240 is formed a plurality of locking members 246 for allowing the housing 240 to be detachably attached to the flange 212. The housing 240 has a portion 242a for fixing the photosensor unit 130 and a portion 242b for covering the meter- reading unit 210 of the metering device, where the two portions have a stepped-

structure. In the inner face of the portion 242a for fixing the photosensor unit 130, a fixing member 248 is formed in order to insert and fix the photosensor unit 130. When the housing with the photosensor unit 130 fixed thereinside is mounted to the metering device 300, the photosensor unit 130 is made to be positioned above the rotation path of the specific number wheel 210a, as shown in FIG. 12.

It is preferable that the housing 240 is structured so as to be able to read a numerical value of the meter-reading unit 210, even in the state where it is mounted in the metering device. Therefore, the housing 240 needs to make it transparent the entire structure or at least a portion corresponding to the meter- reading unit 210. In the later case, the remaining area except for a transparent window 244 covering the meter-reading unit 210 is preferred to be completely opaque so as not to transmit light. In case of providing the transparent window 24, as described in the first embodiment, an infrared cut-off function needs to be provided to the transparent window 244 so as not to pass an infrared light.

FIGS. 14 and 15 explain an operation of the automatic remote meter- reading apparatus 200 according to the second embodiment. As illustrated in FIGS. 14 and 15, while the specific number wheel 210a rotates or remains stopped, the light radiated from the light emitting element 132a, 132b is incident mostly on the surface of the specific number wheel 210a, and the incident light is reflected from the surface of the number wheel 210a. The reflected light is incident on each photoelectric element A1, A2,..., E4, E5) of the photoelectric element unit 134. The intensity of the reflected light, the reflection angle, and the like will vary with the reflection condition such as the reflectivity of the incident surface, the surface profile, or the like. In general, the surface of the number wheel 210a is made of a blackish material having a good optical absorptiveness, and the number 0-9 thereon is made of a color well- contrasted with the black color, i. e. , a whitish material having a good optical

reflectivity. For example, the numbers may be engraved in the surface thereof and a white paint may be applied to the engraved numbers. In addition, the areas engraved with each number have different surface profiles. In this way, each number area exhibits a different optical reflection pattern, due to a difference in the color distribution and the surface profile. For example, the number "1" area is distinguished from that of the number "2" area, in terms of their surface profiles and distribution pattern of optical reflectivity. Similarly, each number areas of 0-9 has its own inherent surface profile and reflectivity distribution pattern. Due to these characteristics, the spatial distribution pattern of the reflected light (such as the quantity and intensity of the light), which is incident on each photoelectric element A1, A2,..., E4, E5 of the photoelectric element unit 134, differs from number area to number area. Here, it is of importance that the level of an electrical signal output from a certain single photoelectric element is exhibited differently with respect to each individual number area. That is, while the number wheel 210a rotates with a certain speed, the level of an electrical signal output from a certain single photoelectric element varies with time. Also, the level changing pattern of electrical signal output from each photoelectric element A1, A2,..., E4, E5 is different from one another. In the invention, the rotation frequency of a certain specific number wheel 210a is counted, based on the above-described characteristics. In other words, when the gas is not consumed, the number wheel 21 Oa remains stopped.

Thus, as shown in FIG. 8, the electrical signal from each photoelectric element of the photoelectric element unit 134 maintains a constant level. In contrast, while the gas is being consumed, the rotation speed of the number wheel 21 Oa will vary with the quantity of gas consumed. Accordingly, the level of an electrical signal output from each photoelectric element exhibits a respective characteristic pattern, as illustrated in FIG. 9 for several photoelectric elements.

In addition, regardless of the rotation speed of the number wheel 210a, during

one cycle of rotation, the electrical signal has a same level changing pattern for a same photoelectric element. Therefore, the inherent changing pattern for each photoelectric element can be obtained and stored beforehand in the microcomputer 152 as a"reference pattern"for each concerned photoelectric element. Then, a level changing pattern of an electrical signal, which is obtained while consuming gas, can be compared with the stored reference pattern, in order to determine whether the number wheel 210a has performed one cycle of rotation. In determining whether the number wheel 210a has finished its one cycle of rotation, it is of importance how the level of an electrical signal is changed, not how long a certain level is lasted. Whatever speed the number wheel 210a rotates with, the electrical signal level exhibits the same changing pattern with time with respect to each photoelectric element. This characteristic bases how to count the rotation frequency of the number wheel 210a, similar to the counting principles of the rotation needle 110 in the first embodiment. That is, the method of determining whether the number wheel 210a has completed one rotation is the same as that of the rotation needle 110 in the previous embodiment.

FIG. 16 is a flow chart showing the procedures of counting the rotation frequency of a certain specific number wheel through an especially prepared program. As shown in FIG. 16, in order to count the rotation frequency of the specific number wheel 210a, a program for performing the counting process is prepared and stored in the microcomputer 152. The microcomputer 152 executes the program to thereby count the rotation frequency of the number wheel 210a. The general procedures from step S110 to step S118 are substantially the same as those in FIG. 10 and thus details thereon will not be repeated here. However, the level changing pattern with time of an electrical signal, which is obtained from each photoelectric element during one cycle of rotation, is different from that of FIG. 10. That is, the reference pattern of FIG.

16 is different from that of FIG. 10. The procedures for obtaining the reference patterns, and the post-treating process of an accumulated rotation frequency of the number wheel 210a are the same as those in the first embodiment.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. For example, in the above embodiments, the present invention is applied to a rotation needle type water metering device and a rotation number wheel type gas metering device. The present invention may be applied to other metering devices, such as an electricity or gas metering devices, as long as they employ a rotation needle or a rotation number wheel.

As another embodiment, in determining whether a rotation needle 110 or a rotation number wheel 110a has performed one cycle of rotation, a weight may be applied to each photoelectric element, depending on its position. That is, considering the analysis result for the level-changing pattern of electrical signals obtained from all the photoelectric elements of the photoelectric element unit 134, a weight may be provided to the analysis result of one or more photoelectric elements placed at certain specific positions. In applying a weight, the weight may be input to the program beforehand, or the program may be configured so as to determine a weight.

As a further embodiment, the case 136 of the photosensor unit 130 may not be separately formed, but the light emitting elements 132a, 132b and the photoelectric element unit 134 may be fixed directly to the housing 140. That is, the case 136 may be integrated with the housing 140.

Furthermore, the reference pattern may be applied in different manners.

The reference pattern for counting the rotation frequency of the rotation needle 110 or the rotation number wheel 110a does not need to be obtained from their

one cycle of rotation. For example, the reference pattern may be prepared with respect to every 1/2 rotation or 1/3 rotation, and, using these prepared reference patterns, the rotation frequency may be counted and computed. In this case, the counting accuracy will be improved, but the computing time will increase.

Industrial Applicability As apparent from the above description, the present invention can be applied to any type of metering devices for measuring the quantity of utilities consumed (gas, water, electricity, or the like), as long as they employ a rotation needle or a rotation number wheel in order to exhibit the consumed amount.

The structure or shape of a metering device will be able to be modified so as to apply the present invention, by changing appropriately the structure of the housing. In particular, the automatic remote meter-reading apparatus of the invention can be installed in the existing metering devices, without necessity of changing the structure thereof.