DETECTOR AND ALARM SYSTEM AND POWER SUPPLY UNIT RELATED APPLICATION

This application claims priority and benefit from Swedish patent application No. 0101300-2, filed September 8, 2006, the entire teachings of which are incorporated herein by reference. TECHNICAL FIELD

The present invention relates to units, methods and systems for protecting and/or supervising objects, in particular wireless and computer based units, methods and systems for use in applications such as alarm systems and systems for automatization and/or control, particularly in, at and on buildings and other facilities. The invention also relates to a power supply unit for supplying power to detectors and other electric devices. BACKGROUND

Unfortunately, burglaries in houses, both in private homes, apartment houses and office facilities, are becoming more and more common. Then, it has become common to install some burglar alarms of some kind in the facilities and/or apartments. Burglar alarms of today are mainly based on magnetic switches, detectors of broken glass windows, vibration detectors, Doppler effect detectors, infrared (IR) detectors and combinations thereof. Also, camera supervision is used to some extent.

Magnetic components, e.g. two component magnetic circuit breakers/closing circuits, are used for detecting one of two positions, a closed position or an open position, and they cannot be used for detecting positions located between these two positions. In addition, magnetic detectors of various kinds can be easily interfered with by short and long variations of the local magnetic field and by drift of the field. Exterior magnetic fields can be applied by mistake or intentionally. Similarly, electric fields can interfere with magnetic detectors.

Broken glass detectors and vibration detectors can detect violent actions to glass and weak materials, but they have difficulties in detecting that a window or a door is cautiously and slowly removed.

Furthermore, the detectors described above cannot be active when e.g. doors and windows are being opened and being closed.

However, it is generally well-known to detect movements to give alarms. Thus, in the pub- lished U.S. patent application 2005/0151847 a monitoring system comprising event detectors is disclosed. An example of such a detector is a detector that senses its own movement, such as an accelerometer, see the published German patent application 44 20431. In the published U.S. patent application 2003/0071739 a system for sensing changes of the position of a monitored object is disclosed. The detectors in the described system can be designed to sense changes of the

earth magnetic field or of the gravitation field of the earth and output an alarm signal if a change is larger than a predetermined value, which means that the detectors have moved more than within an allowed range. Infrared detectors and Doppler effect detectors can also be used in alarm system but since they are activated by the presence of warm bodies or movements they cannot be active where people are staying. In the published U.S. patent application 2004/011378 an alarm system including movement detectors is disclosed, which detect the position of an object either by detecting that a string attached to the object is extended or is elastically retracted or using an inertia sensor or gyro device attached to the object, hi the British patent 1 279 451 automatic supervision using a television camera is disclosed. A problem associated with some of the solutions disclosed in the documents cited above is that an authorized person cannot freely move within the area which is monitored by the alarm system, e.g. a building or a part thereof, i.e. within a limited region thereof, without triggering the alarm.

Furthermore, in several of the prior art systems it is not possible to have windows open such as for airing or when the weather is hot.

Moreover, it is in other fields well-known to follow and measure positions of objects using light, optical devices, image detectors and photodetectors. This is used e.g. in CD/DVD players/burners, for scanning documents and in printers and copying machines. It is also used in systems and methods that are used in optical input/output means of computers, so called optical mice. A common feature of these appliances is the constant distance between light source and detector or between a considered surface and the detector.

Nowadays sensors and detectors in alarm systems are often supplied with energy from chemical cells so that they do not require connection to a power distribution network. Since they must work for long time periods it is advantageous if the replacing of the chemical cells is not too often required. The power supply unit for e.g. such detectors can include a plurality of different power sources, see e.g. the published U.S. patent application 2005/0127871 and U.S. patent 5,568,038, and the power sources can include solar cells, see thee published U.S. patent applications 2006/0197507 and 2006/0164040. Included in the power sources is at least one accumulator of electrochemical type, which by a control system is charged from some other power source and from which power is supplied to a consumer or load.

SUMMARY

It is an object of the invention to provide detectors suitable to sense movements of objects. It is another object of the invention to provide a detector that can be suited to be included as part of a supervision and/or alarm system or a supervision and/or alarm installation.

It is another object of the invention to provide a flexible supervision and/or alarm system or a flexible supervision and/or alarm installation.

It is another object of the invention to provide an energy supply unit that in an efficient way can supply power to electronic circuits, e.g. in a detector or sensor. In order to allow the detection of movements and/or to be capable of monitoring the position of an individual object, e.g. a door, a window, a wall picture or similar object, at least one suitable detector can be mounted to or close to the object. Using such a detector that includes a special sensor the current position and/or the current orientation of an object such as door, a window or a wall picture can be determined. The positions of the objects that are determined using such detectors, which positions thus can be of different kinds, i.e. can be indicated as distances from some reference or angular position or similar, can be used in alarm applications and/or to achieve buildings having automatized functions. An optical sensor can be used in the detector and can then work e.g. as a miniature imaging system. Also other sensor elements can be used when it is suitable or is required for different applications, e.g. simple photosensors, magnetic sensors or sensors that sense the gravitation or the earth magnetic field.

Thus, a detector for supervising a movable object can generally include a sensor mounted to or close to the movable, supervised object. The sensor continuously senses its position in relation to a segment of a surface of a geographically stationary object located close to the supervised movable object or on the supervised, movable object, respectively. The detector provides a signal or message only after it has determined that the sensor has been displaced or has moved in relation to said segment to a position outside limits that have been previously set. It is obviously equivalent to the fact that said segment has been displaced or has moved in relation to the sensor to a position outside limits that have been set in advance.

An advantage of a method and a system, that include a determination of positions during and primarily after movements and displacements, is that e.g. balcony doors, windows etc. can be left open in arbitrary positions or obviously also be kept closed without triggering an alarm.

Another advantage may be that persons can be staying within the shell protection which such a method and system give and there they can freely move.

Then, if the supervised object moves outside set limits, which can be dynamically set e.g. when activating an alarm system, the system can indicate that this has occurred, e.g. by activating an alarm or control signal.

Another advantage is that an alarm system including detection/supervision as has been described above, can always be active and that it can be easily reactivated to a new reference state that corresponds to the current states of the positions and orientations, i.e. angular positions,

of all objects.

Another advantage is that such a system can provide an alarm signal if a window or a door has been left open when all persons leave a building or a room.

An advantage of an optical sensor is that it is insensitive to exterior electrical and magnetic fields.

Electronic and optoelectronic components tend to become smaller and to have lower costs as well as radio circuits, microprocessors and memories suitable to be built into various systems ("embedded systems"). Hence, a complete sensor system including circuits and devices for wireless transmission and power supply and control be integrated on a very small area of a substrate, e.g. on a microelectronic chip, for example such as in SIM cards for mobile telephones, which today contain a complete microcomputer including a memory.

If the detectors are provided with small solar cells and associated energy accumulators, e.g. an electrochemical microbattery or a capacitor built in the microelectronic circuit, they can work during very long operational periods, in principle during their whole lifetime, since they can be charged by the exterior daylight and also from interior illumination. They can also be provided with mirrors that reflect more light to the light-capturing surface. Thus, thin film solar cells can be integrated in a detector.

The charge regulating function can be built into the control circuit of a detector.

The detectors can be manufactured to be so small that they can be glued directly to objects of many kinds, such as windows, doors, and wall pictures, i.e. for a suitable design it can be very easy to install and mount the detectors. As they for a suitable design do not have to contain any movable components, they can have a very reliable operation.

Software in each detector system can for example be updated using wireless communication. A system, units and a method as described above can also be used by automatic control systems in so called intelligent buildings for controlling various devices, e.g. devices for ventilation, airing and protection against sun and rain

An optical sensor in a detector can as a main component include at least one light sensor or generally a light detector circuit such as for example an image sensor and it can also include at least one illumination element or light source and if required some optical system including at least one lens/prism/diaphragm for collecting/directing a suitable amount of light towards the light detector circuit. The detector can also include a microprocessor for processing information and a radio part for wireless transfer of information and means for power supply. Furthermore, in some cases a reflecting part or component designed in a special way can be used to simplify the

determination of distance or position.

The optical sensor can include or be connected to a power supply unit. Such a power supply unit, which generally can be used to supply electrical power to electronic and other electrical devices, can for example include a combined solar cell charger and energy accumulator, and can be designed to have small dimensions, which can be particularly suitable in the case where it is used to supply power to an optical sensor according to the description above or other alarm sensors and similar devices.

An advantage of such a power supply unit is obviously that it collects its energy from light, e.g. sun light or artificial light indoors or outdoors, and hence gives a low load on the environment of the power consumer to which it supplies power and that it can be placed in or directly connected to the power consumer, so that it does not require a connection through a separate wire or cable to some power source.

The lifetime of the power supply unit is mainly limited by the shortest lifetime of rechargeable accumulators, since at least one such accumulator is included in the unit. The lifetime can be in the magnitude of order of 5 - 8 years.

Fields of use for the power supply unit can be in actuators, detectors and sensors, in various application fields e.g. for automatizing, control, regulation and in alarm systems. A typical example is small wireless systems for short transmission ranges including radio transmitters and receivers that require a not too small amount of energy when they are operating. Furthermore, it can be used in toys, watches or other miniature electronic power consumers.

Generally, the power supply unit can advantageously be used where the need for power is larger than what can be provided using only primary batteries, i.e. not rechargeable electrochemical cells, in order to be operative for several years such as e.g. for supplying power to radio circuits for short range communication as mentioned above. Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the methods, processes, instrumentalities and combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

While the novel features of the invention are set forth with particularly in the appended claims, a complete understanding of the invention, both as to organization and content, and of the above and other features thereof may be gained from and the invention will be better appreciated from a consideration of the following detailed description of non-limiting

embodiments presented hereinbelow with reference to the accompanying drawings, in which:

- Fig. 1 is an overview of a detector system,

- Fig. 2 is a block diagram of a detector,

- Fig. 3 is a block diagram of a central unit for a detector system, - Fig. 4a - 4f are flow charts for various part processes performed in a detector system,

- Fig. 5a - 5d are pictures illustrating the mounting of a detector,

- Fig. 6a is a schematic picture from the side of a detector,

- Fig. 6b is a schematic perspective picture of the detector of Fig. 6a,

^• - Fig. 7a - 7h are pictures of different embodiments of a part having a surface designed specially for detection,

- Fig. 8 is a schematic picture illustrating how the width/length of the part according to Figs. 7a - 7h or a field arranged on the surface of this part changes its size when it its imaged in different directions,

- Fig. 9a - 9d are schematic pictures illustrating how a detector mounted at a hinge can sense the movement of a door or a window,

- Fig. 10 is a general block diagram of a power supply unit,

- Fig. 11 is a more detailed block diagram of a power supply unit,

- Fig. 12 and 13 are schematic pictures of connections inside an access network including a power supply unit, and - Fig. 14 is a block diagram of a power supply unit, in which a control circuit includes modules for fuzzy logic.

DETAILED DESCRIPTION

Here first detectors will be described, see the block diagram of Fig. 2, which are intended to be mounted to objects that are suited for supervision. Examples of the mounting of the detectors are shown in Figs. 5a - 5d and 9a - 9d. Such an object, such as a window, see Figs. 5a - 5b, a door, see Fig. 5c, or a wall picture, see Fig. 5d, is generally a body that can move, be displaced, i.e. change its geographical position, and/or change its orientation, its direction or its angular position. A change of position or orientation, respectively, can generally occur in one to three dimensions. From the change, which thus also detector attached to an object is submitted or in any case is sensed in some way, in a sensor 1 (A) included in a detector 3 (D), see Fig. 2, one or more output signals are produced. In Figs. 9a - 9d a detector 3 for optical detection is shown that is placed at a hinge 4 for a window or a door. The hinge is mounted between a casement of a window or a door leaf 4a and a door case/window frame 4b and the detector is attached to the movable part. The angular (curved) arrows show the rotation of the window/door leaf and the

straight double-way arrows symbolize the path of light in illuminating a geometrically stationary surface and after reflection against it towards the detector, respectively.

The detectors 3 can contain optical sensors 1. A surface 5 of some object 7 located close to such a sensor 1 can then be illuminated, see Figs. 6a and 6b, for example from a light source 9 included in the sensor, and be received by an optical sensor element 11 included in the sensor. The reflected light can pass an optical system, symbolically illustrated as the lens 13, to be projected and/or deflected towards the light sensitive surface of the sensor element. Hereby, a pattern derived from variations in the texture/structure of the surface 5, e.g. a small surface segment on a door case or window frame, wall, etc., is imaged on the light sensitive surface and is detected. The sensor 1, i.e. the very sensor element 11 and the light source 9, can be attached to the object to be supervised, favourably near the movement centre of this object if such a centre exists. The distance between the sensor and the reflecting surface 5 can advantageously be relatively small and should not vary too much when the object is displaced. Preferably, as has been said above, the sensor 1 can move together with the supervised object and the reflecting surface be stationary or geographically fixed, but also the inverted arrangement can be suitable in some cases, see Figs. 5a - 5d and 9a - 9d.

For example, the sensor 1 for a door can be advantageously placed close to the hinges of the door taken radially from the rotation axis of the door, i.e. near the centre of the rotation movement, and close to a surface, e.g. the floor, taken axially in relation to the same rotation axis. Such a place could be said to be adapted to a supervision of the hinge itself and the movement of the rotatable part thereof. The mounting can be facilitated by the use of mounting wedges and distance elements, not shown, for the sensor 1, so that the reflecting surface 5 is located within the depth of field of the image on the active surface of the sensor element 11. Corners and other edges can be good candidates as portions of a reflecting surface. The characteristic pattern in the sensed image is analyzed by a sensor processor 15 (C) in the detector, see Fig. 2, (in the subsystem for illumination-optics-imaging) and therefrom the position of the surface 5 can be determined. The positions then determined are analyzed and if they are found to be outside allowed limits it can be signalled to the rest of a supervision or alarm system in which the detector is included as will be described below. The illumination device 9 can advantageously assist in making the intensity of the light that is reflected against the surface 5 and thereafter hits the sensor element 11 constant and in any case independent of exterior light conditions and can in one embodiment e.g. be a light emitting diode (LED). It is favourable to the pattern recognition if the illumination causes a pattern having a good contrast, e.g. patterns on floors, wall papers etc., and is also facilitated if

the light is incident in an angle different from 90 degrees to the reflecting surface 5. hi another embodiment, in such cases where the contrast can be supposed to be low, a laser diode can be used as the light source 9, particularly if the surface 5 that is illuminated has a fine or small texture, i.e. if the texture has a characteristic dimension that is relatively small, say in the magnitude of order of 1 - 10 μm, such as for example single colour surfaces, and/or if the distance to the surface is relatively large, e.g. of the magnitude of order of 1 cm instead of the magnitude of order of 1 mm, where the latter can bee the normal or desired case, or if the light source emits light perpendicularly to the surface, over substantially the whole movement that is detected, i.e. when not sufficiently good shadows are formed so that it will be possible to image and detect the pattern of the surface 5 considering the resolution in the sensor element 11. The coherent light from a laser, which has the same phase and has a narrow wavelength distribution, results in the fact that a very small unevenness can form detectable patterns for different distances between the surface and the sensor element.

The light emitted by the light source 9 can have wavelengths within the visible spectrum but also infrared (IR) or ultraviolet (UV) light can be used.

The detector 3 can be designed to perform dynamic following or tracking similar to that used in optical mice for computers. The sensor element 11 can in this case capture images at regularly repeated times and analyze each captured image in comparison to previously captured images to determine whether a change of position has occurred and to give, in such a case, some indication of the new position in relation to the reflecting surface, which can described as the sequence of captured images being analyzed in regard of its "optical flow". The determination of constant optical flow from an image sensor can be performed, in order to allow the following of movements from an image sensor, according to Berthold K. P. Horn, "Determining Constant Optical Flow". Generally, a first image or reference image can be correlated with a new image or new images.

Also, it is possible that the reflecting surface 5 is the surface of a part or component 7 is designed and arranged specially for this purpose. Such a component can be a strip or plate, that can be flexible and is suited to be applied at the desired place. It can for example be a piece of self-adhesive tape or a stick-on label. The component 7 can then have a pattern or structure on its surface, that can be easily sensed by the optical sensor 1 and then also advantageously directly can code for different positions of the supervised object in relation to the sensor element 11, see Figs. 7a - 7h and 8. hi Fig. 8 the angle v denotes the imaging direction in relation to the normal of the reflecting surface of the component 7. The pattern or structure can then suitably be three- dimensional. The surface structure must obviously be capable of reflecting the light emitted by

the light source 9, such as that it e.g. is sensitive to IR-light.

When using such a specially designed pattern/structure or surface structure it can be easier for the sensor 1 to sense a position, because it then can be obtained directly by a static instantaneous photograph or snapshot. If using such a pattern or structure it can be achieved that a dynamic following or tracking of movements according to the description above of the movement does not have to be performed, since a portion of the pattern/structure that is proportional to the size of the movement of the object, is directly imaged on the image sensor, and by means of suitable algorithm for image analysis it can be directly decoded and calculated how large the portion of the pattern/structure is or which portion of the pattern/structure that is detected by the image sensor and therefrom the position of the object can be easily obtained.

In Fig. 7a a special component 7 is shown that on it surface has a field 51 that has a colour or pattern different from that of a background 53. The field can have the shape of a wedge as illustrated. Then, if the imaging system 13 is set so that only a limited region 55 is imaged on the sensor element 11 , this region only covering a portion of the wedge-shaped field and for a movement the region is displaced in the longitudinal direction of the wedge, the width/length of the imaged part of the wedge can be obtained in a simple way and then gives a measurement of the position. This may presuppose that the region 55 has a width that is small compared the length of the wedge. The wedge-shape field can be curved as illustrated in Fig. 7c.

A plurality of fields having deviating colour or pattern can also be used as shown in Figs. 7b and 7d - 7h. A variable number of dots or fields having the shape of typographical periods can be detected using the structures of Figs. 7b and 7f. Straight or curved lines having different lengths can be detected using the structures of Figs. 7d, 7e, 7g and 7f. The detected number or the detected length can in these cases directly provide information about the position of the supervised object. The special component 7 can in another embodiment, not shown, have a substantially uniform reflecting capability over its surface, i.e. have a completely smooth and single colour surface, but instead have an exterior shape that can be used for distance determination or determination of the position at and after a movement of the supervised object. Such an exterior shape can for example be like a wedge. In a simple case it can also be sufficient that the special component 7 as described above is strip-shaped or rectangular and generally has a constant width but has reflecting properties, such as a colour or a structure, on its surface 5 that deviates from that of the substrate or base part to which the component 7 is intended to be attached. For a suitable mounting the component 7 is imaged with varying widths depending on the angle in which it is imaged on the sensor element

11, see Fig. 8. This width can directly provide information about the position of the sensor element in relation to the component 7 and thereby about the position of the supervised object.

The system can learn allowed limits for movements and return movements and the limits can be variable. E.g. an artificial neural network can be modelled to perform the pattern 5 recognition.

The sensor element 11, which in this embodiment is an image detector, can e.g. be a CMOS or CCD detector but it can be considerably smaller and in particular have a considerably lower resolution than that of such image detectors which for example in ordinary cameras are used capturing photographs. It can e.g. have such a low resolution as 30x30 pixels (picture 10 elements). The resolution must always be chosen so that it is sufficient to distinguish the variations and unevenness which will be visible when the reflecting surface 5 is illuminated or for distinguishing between the lengths of fields having different reflecting characteristics, such as colour, structure or pattern.

E.g. some parts of the architecture of the integrated components Avago (Agilent) ADNS- 15 2610, ADNB-7051-EV or PixArt PANlOlB CMOS Navigation Sensor can be used as the sensor element 11. Also such miniature cameras that are used in mobile units such as mobile telephones can be employed.

In the simplest embodiment the sensor element 11 is a photosensor that is used only to measure the intensity of or the amount of received reflected light without forming any image on

20 an image sensor. Changes of the signature of the intensity/amount can correspond to position changes. A special pattern according to the description above can be used to facilitate a controlled reflection.

Using an image sensor, it can for the alarm application be sufficient to detect changes of positions and then, in the simplest case, changes in two successive images can be used. The

25 sensitivity can e.g. be adjusted by allowing a certain number of pixels to vary without providing an alarm. Another method is to compare the distribution of light intensities in all pixels in two successive images and to provide an alarm signal, when some predetermined threshold has been passed. Such a threshold can include that the light intensity distribution does not too much differ from, as measured using some suitable algorithm, a predetermined distribution or a distribution

30 that has been initially determined in a calibration procedure. For applications in the field of automation preferably some method is used by means of which movements of objects can be followed since in this case usually movements and positions are of interest.

The optical system 13, that can include one or more lenses/prisms, diaphragm devices etc., is advantageously configured to give a large depth of field when imaging the reflecting surface 5

on the image sensor 11, so that captured images have a sufficient sharpness for varying distances from the surface. The distance between the sensor element 11 and the reflecting surface also influences the size of the image on the image sensor for a given optical system 13. A good sharpness/a good contrast in the image on the active surface of the image sensor can be aimed at for all positions of the supervised object.

The optical system 13 can be adjusted in regard of magnification - size reduction, focal distances/lengths, so that the best performance for detecting patterns on the image sensor 11 are obtained. The light and reflections can also be split and made to change direction by mirrors, prisms and other optical element, not shown, in order to keep the distance between image sensor and reflecting surface 5 within reasonable limits.

In the optical part 13 of the sensor 1, as has been mentioned above, a plurality of optical elements such as lenses, prisms, light splitters and mirrors can be used. They can be arranged in the traditional way in series with each such as in a camera/field glass. Alternatively or additionally also a plurality of parallel optical elements, for example lenses having different focal distances, can be used, so that several simultaneous images are imaged on different portions of the image sensor 11.

Alternatively, the optical part 13 can in a simple way be replaceable to provide different focal distances/focal lengths/deflections etc. in order to adapt the distance between the detector 3 and the illuminated, reflecting surface 5 and the size of the image and the image angle. The field of depth is also affected by the size of the aperture, i.e. by the amount of light that is allowed to reach the active surface of the sensor element 11, and by the angles in which light beams are allowed to be incident to the active surface, i.e. the space angle of the light aperture.

Furthermore, the field of depth is also affected by the intensity of the illumination and the exposure time, these being parameters that can be adjusted, such as automatically, by suitable software in the microprocessor 15 of the detector.

In the case where laser light is used, the Philips PLN2020 twin-eye laser sensor can be an example of a suitable light source.

Also new technology exists that can be used to increase the field of depth in an optical system with about 5 - 10 times, so called Wavefront Coding, see E. R. Dowski, W. T. Cathey, "Extended Depth of Field Through Wavefront Coding". Then, a non-spherical optical element is used to refract the light rays in a controlled manner, which generates a blurred, "spread-out" image on the active surface of the image sensor 11. By digital postprocessing, e.g. in the control unit 15 of the detector, of such a spread-out image a sharp image having a wide field of depth

can be obtained.

In order to obtain a good sharpness also "autofocus" such as in miniature cameras can be used. Such autofocusing can be performed using piezo-ceramic miniature motors. This solution is e.g. used in cameras for mobile telephones. The whole detector 3 is advantageously encapsulated in/protected by a housing, see Fig.

6b.

In Fig. 2 a possible embodiment of the detector 3 is shown. The detector can as shown contain a sensor part 17 (S), which contains the very sensor 1. The sensor can generally output one or more output signals. The signal or signals is/are received by an interface 19 (I) in the control unit or processor 15 in the sensor part 17, is processed and evaluated therein and possibly then, depending on the result of the processing and evaluation, a signal or message is provided from the detector 3, which signal or message generally indicates that set limits for the movement have been passed. Therefor the detector 3 can contain a radio unit 21 (Tx) together with an associated antenna that is coupled to the control unit 15 and is included in the sensor part and that can be arranged only for transmission or for both transmission and reception. A temperature sensor 23 (T) can be provided in the sensor part S and is then suitably connected to the control unit to output to it a signal representing the current temperature.

Furthermore, the detector 3 contains in the embodiment shown a power supply unit 25 (E), which as shown in turn can contain a solar cell 27 (PV), a battery (B) such as an electrochemical cell or accumulator 29 and a regulator circuit or unit 31 (R), connected to both the solar cell and the battery/accumulator for regulating the charging of the accumulator 29. In the mounting process the detector is placed, so that sufficient light, exterior or interior, can hit the active surface of the solar cell 27 to supply energy for supplying power to the electric circuits of the detector. The power supply unit 25 can alternatively be constructed in a particularly efficient way including two different energy accumulators as will be described hereinafter.

AU the electronic and optical components included in the detector 3 can be integrated on one or more silicon chips, so called "System on chip" (SoC).

The signal/signals from the sensor 1 has/have as been discussed above generally special signatures, i.e. they have different special shapes and different special characteristics dependent on the sensed positions. The signal or the signals, respectively, are submitted to calculations and analysis in the control unit 15, that for example can be a miniature microcomputer including a processor integrated with a memory. The result of the calculations and the analysis can as been described above be used to output a signal or message of some suitable form that indicates that

certain set limit values or limit characteristics have been passed, i.e. that corresponding quantities have been found to be larger or smaller than said limit values or limit characteristics, or that indicates a measure of the sensed position which can for example be obtained in a proportional decoding process and when using reflecting surfaces of the type shown in Figs. 7a - 7h.

Thus, each output signal including its characteristic signatures can be analysed using statistical methods or so called signature analysis which is a form of pattern recognition. An artificial neural network can thus be modelled to perform such a pattern recognition.

The system can in a calibration state learn allowed limits for movements and the limits can furthermore be variable.

If desired, a temperature control of the housing or encapsulating casing of the detector can be easily implemented using the temperature sensor 23.

The electronic and optical components included in the detector 3 are in the embodiment illustrated in the figure powered by the solar cell 27 that charges an energy buffer, the accumulator 29, that e.g. is a microbattery or alternatively can be a so called super capacitor and that is intended to supply the necessary electric current when the solar cell is not capable of supplying sufficient electrical current, such as when it is too dark in the environment of the detector. In a suitable electronic circuit such as a regulator circuit 31 the charging process can be controlled, hi particular, the charging current at different times on the day and night can be evaluated so that it can determined whether the charging processes are normal and that hence no component of the power supply part 25, in particular not the active surface of the solar cell, has been exposed to attempted sabotage. The regulator circuit 31 can also control the charging processes using different charging characteristics at different times of the year, i.e. for different light and temperature conditions in the environment. The components of the detector 3 can alternatively be powered only by an ordinary electrochemical battery or an ordinary electrochemical cell 29 designed to supply small electrical current during a relatively long time.

Another alternative is to supply energy to the detector 3 by means of electromagnetic radio frequency waves and/or by microwaves. hi order to further save energy the control circuit 15 included in the detector 3 can be designed or programmed to operate as efficient as possible as to the energy consumption, for example by replacing function calls in the program code with copies of code, so called inlining.

The detector 3 and particularly its control unit 15 can be constructed so that most of the components in the detector most of the time are in a rest state in which they consume very little

power or no power at all. The lengths of the activity intervals during which the detector is fully operating can be adapted as required such as when detecting events.

The control unit 15 in the detector 3 can be arranged so that it at periodically repeated times, "cyclically", requests an image from the optical sensor 1 in order to the perform an analysis of the sensed image using a limit value/limit values that are narrower set than it/they for which an alarm is to be produced. Possibly also, the analysis itself can be performed, using a lower accuracy. Between these times, most of the detector 3 can be in a rest state. If the narrower limit values have been passed, the whole detector is awakened to perform a possibly more complete analysis and to analyze more images. Obviously, the detector 3 can be sensitive to drift phenomena of various kinds, primarily drift with time, i.e. aging of components comprised in the detector, and temperature variations. However, the drift of components can be calibrated away.

The temperature drift can substantially be an offset/bias (DC) component, as in the case including an optical sensor of the simplest type, but it can also be a sensitivity component. These signal components are relatively linear and can be easily compensated for in the detector control unit 15 using table-lookup operations and the signal from the temperature sensor 23.

The drift with time can be calibrated regularly, e.g. each time when the detector 3 is reactivated to a new reference state.

For the case including an optical sensor of the simplest type comprising only sensing the amount/intensity of received light, the bandwidth of the signal output from the sensor can be adjusted using bandpass filtering, so that the noise contribution is reduced to give a favourable signal-to-noise ratio for a sufficient accuracy, and so that immunity to rapid movements, e.g. wind movements, can be obtained. By means of e.g. continuous or running averaging the performance of the detector can be further increased in such a case. Slow variations can depend on temperature drift and hence too slow variations can be filtered away. Also, too rapid movements can filtered away.

The operational steps and methods mentioned above will now be described with reference to the flow charts of Figs. 4a - 4f.

Each detector 3 is started from the very first beginning, see step 101 in Fig. 4a, e.g. by removing a polymer protection from the battery 29 in the same way as for small battery driven toys, which results in that electric power is supplied to the other components of the detector and in particular to the control unit 15, which starts to execute the instructions in a program that is stored in the memory thereof and is designed in a suitable way. Thereafter the detector proceeds to a calibration state in which the components in the detector run through a sequence of initiation

and configuration steps, the following steps then being performed:

- The detector 3 is being wirelessly connected to a central unit 33 (CE) in the alarm system of which it is a part, see Figs. 1 and 3, by activating the radio unit 21, see step 103. The radio unit thus is given a command to transmit a suitable identifying signal. When receiving this signal the

5 monitoring of the connection with the detector is started in the central unit 33. As long as the detector 3 is active, then, with equal intervals a suitable message is sent from the radio unit 21 thereof, for example a message of the same type as the first sent identifying message. The central unit 33 can give a system alarm if the message is not received from the detector at the expected times.

10 - The control unit 15 activates the regulator circuit 31 to start the regulating of the charging of the battery, see step 105. The regulating will then continue during the whole lifetime of the detector. The energy regulating state can be active relative infrequently in order to save energy, say every fifth minute, i.e. the regulator 31 is awakened only at periodically repeated times to then perform a setting of suitable parameters for charging the battery.

15 - The control unit 15 performs, through the radio unit 21 cooperating with the user interface of the central unit 33, i.e. the terminal 35 (TE ₁ ) and its display and keyboard, see Fig. 3, a "movement calibration" in step 107, in which the object that is supervised by the detector 3, is moved to its end or limit positions. This can be performed using different velocities and a plurality of times in order to allow that characteristic signatures are provided that define how the

20. object can move and in order to allow a determination of the maximum limits of the movement of the object. These limit values are then stored in the memory of the control unit 15.

- The control unit 15 exchanges, through the radio unit 21, information with the central unit 33 and other detectors included in the supervision system, i.e. detectors connected to the same central unit, about routing for forwarding messages, etc. and stores addresses and other necessary

25 data in its memory, see step 109. Routing and multihop algorithms from some suitable operative system, for example the sensor operative system TinyOS, can be used.

- The control unit 15 brings in a step 111 the detector 3 into a calibration step, in which limit values for the signals from sensor 1 are determined depending on drift in temperature and time, i.e. aging.

30 After these initiation and configuration steps the detector 3 continues to take its normal function, its reference state, for supervision and control of the position of the supervised object, see step 113, by the procedure that the detector receives a suitable command from the central unit 33, as can be input using the user interface thereof, or from a remote control unit 37 (F) provided for this purpose, see Fig. 1.

Temporary devactivations/reactivations of the supervision and control function of the detector 3 which are required when a supervised object must be displaced, e.g. in order to make it possible to open a window, can be performed using the wireless remote control unit 37. Other alternatives include that this is made from the central unit 33 or from the detector itself, which can make it practical and simple to open/displace to supervised object. An authorized person can confirm his authorization in some simple way. In addition to the use of a remote control unit 37 it can be done e.g. using a PIN code/signature entered on a simple set of keys, not shown, integrated with the detector 3.

It can also be conceived that an authorized person carries a radio transmitter, "ID-code beacon" 39 (B), see Fig. 1, for short range transmission/communication, that can be a separate unit or arranged e.g. in the remote control unit 37 and that when the authorized person is sufficiently close to the detector 3, without any special command or input, can verify that the person is authorized to change the position of the supervised object.

The detector 3 can also be configured, so that in the case where the object that is supervised by the detector, is a window, a door or similar device, the closing of the object is always permitted, i.e. so that deactivation and reactivation of the detector only have to be performed when opening such a supervised object.

When one of the supervised objects, e.g. a window, is to be displaced, the detector 3 supervising this object can be blocked so that the sensor function of the detector and hence transmission of an alarm signal or a alarm message, is inhibited for some time period, or when an

"ID-code beacon" 39 is located in the vicinity of the detector. After the blocking period the detector is reactivated and comes into a new reference state.

The sensor 1 in the detector 3 can as has been indicated above be active during only a fraction of the total supervised time. How often it is to be active and during how long a time period it is to be active at each supervising occasion is determined in dependence of how rapid movements of the supervised object that one wishes will be detected. It can be configurable in each detector.

The detectors 3 that have access to only limited amounts of energy are as mentioned above most of the total time in a rest state. The unit which is always operative is a time circuit, not shown, in the sensor computer 15, that consumes very little energy, and at a predetermined but configurable time limit, i.e. after each sampling interval, a time triggering event is performed in which a check is made whether any movement has occurred. The detectors can as mentioned above be event controlled, see Fig. 4b. An event of a first kind is that a detector is deactivated, see step 115, to permit an authorized person to change the position of the supervised object.

When the detector 3 then is reactivated, it can return to the calibration state mentioned above for performing the initiation and configuration steps, see Fig. 4a.

After it has been decided that a movement beyond some predetermined base level has occurred, as has been described above, the control unit 15 of the detector can be awakened to sense or record more of the movements. Calculation and analysis of the movement is then made in a step 117 and in another step 119 it is compared how much the position taken after the movement is allowed to deviate from set limit values. If the deviation is within the set limits, the detector 3 continues to a power regulation state, see Fig. 4e. If the deviation is outside the limits, such as when an unauthorized person moves the supervised object too much, the detector proceeds to a sharp alarm state L ₅ , see fig. 4d, activating in a step 121 an audible or visual sharp alarm signal, such as by informing the central unit 33, which immediately, when receiving the corresponding message, activates its alarm devices, see Fig. 3. The alarm signal can thus generally activate an audio and/or visual alarm or alerting devices, but it can also be forwarded, see step 123, so that the message in respect of the alarm reaches other systems and terminals, e.g. electronic mail clients, computers, mobile telephones and other alarm systems.

Thereupon, the system continues to a wait state, in which only an authorized person can reset the alarm.

Another event that can occur is that the area supervised by the detectors 3 _ls 3 ₂ , ... is left unattended, e.g. that a house becomes emptied of people and is locked. A signal is then provided to the system, e.g. from the central unit 33 or a wireless remote control unit 37.

If some supervised object then is outside its initial reference state, that can be set in configuring the system in the central unit 33, e.g. that all windows and doors are closed, the system will give a reminder alarm, i.e. an alarm of a different kind that can be distinguished from the alarm described above , using another audible or visual signal, so that a suitable measure can be performed, e.g. to close the window or door or to accept the current position.

In Fig. 1 a system of detectors 3 _1? 3 ₂ , ... is illustrated that wirelessly communicate with each other and with a central unit 33 and if desired, can wirelessly receive information from a remote control unit 37 and also from a beacon-unit 39. The communication can for example be performed by using a so called peer-to-peer network/meshed network, in which all nodes, i.e. mainly the detectors 3, participate in the delivery of a message between an individual detector and the central unit 33, i.e. a "multi-hop" process can be used for forwarding messages. This can also assist in reducing the energy consumption in the detectors. The messages can also be made to take any of a plurality of alternative paths ("routes") between a detector and the central unit.

The wireless standard IEEE 802.15.4 and/or ZigBee can e.g. be used to forward the

information in a so called "Wireless Sensor Network" (WSN). These standards are intended for small data amounts and the detectors/nodes work in a power saving way.

The standard Ultra Wide Band (UWB) can also be used for the radio communication.

In the system also ports, "Gate Ways", not shown, to other systems can be arranged to make it possible to integrate the detector system with other existing systems in a simple way.

In the system a node, the central unit 33, is provided as mentioned above that has central functionality for connection to other systems.

In the system, in the simplest embodiment thereof, messages can be transmitted only from the detectors 3 _ls 3 ₂ , ... to the central unit 33. In another embodiment all units can send and receive messages, i.e. the can all have transceiver functionality. The radio connections between each detector and central unit can, as mentioned above, be regularly supervised and an alarm can be triggered if not all detectors 3i, 3 ₂ , ... transmit messages with regular intervals, a so called watch-dog function. The system and particularly the detectors 3j, 3 ₂ , ... can also be controlled, at least in regard of some functions, by the wireless remote control unit 37 as described above, e.g. in an activation/reactivation procedure. It can also be possible to interact with the system using a wireless remote control unit 37, e.g. in an activation/reactivation procedure.

The central unit 33 can be supplied with power from the public electrical distribution network and can moreover suitably have a reserve power supply using a battery, not shown, for safety reasons. When the central unit is being installed and activated/started it can perform an initiation procedure and thereupon it is ready waiting for detectors to connect to it.

The central unit 33 can have or be connected to or when desired be connected to a user interface, including e.g. a set of keys/a keyboard and/or a display and suitable graphical information shown thereon, see Fig. 3. The interface devices can be integrated in the central unit 33 or directly coupled thereto. The central unit 33 can alternatively be connected to a personal computer or terminal 35 (TEi), the interface means being the keyboard and monitor of the computer. Information can be shown on the monitor using e.g. a web browser. In particular, the central unit 33 can also comprise a so called web server, not shown, e.g. Apache, from which said information being shown using the web browser is retrieved. The central unit 33 can also be connected to a local area network (LAN), that in turn can be connected to the Internet. Hereby, the information can be shown on a terminal 41 (TE ₂ ) connected to the Internet and the system be controlled from it.

By means of the user interface the state of the current system installation can be graphically presented in a simple way. The system installation can also be initiated and configured from the user interface to be adapted to the supervised area/the supervised building or

similar facilities/the supervised object.

In the central unit 33 also, as mentioned above, ports "GateWays", not shown, to other systems can be provided in order to easily allow an integration of the sensor system with other systems, e.g. mobile data networks such as GSM. Typical application examples:

Detectors as described above can be used in alarm systems for shell protection, i.e. burglary/intrusion protection for houses and facilities. The detectors are then suitably mounted to or close to windows and doors, see Figs. 5a - 5c and 9a - 9d, in the building or facilities. The detectors are interconnected and configured to form a system/network according to Fig. 1, having a central unit 33, using the user interface of the system.

For detectors 3 powered by solar cells the active surface of the solar cell can if possible be turned towards the exterior, away from the building, if the object supervised by the detector is a window and more light comes into the building from the outside than from the interior illumination. For objects such as solid doors and dark/reflecting windows the active surface of the solar cell can be turned towards the interior to collect energy from the interior illumination. The detector 3 together with its solar cell 27 can also be placed outdoors if desired or suitable.

When an unauthorized person moves (opens) one (or more) supervised object(s) beyond the set limits an alarm is signalled as described above.

A detector/detectors 3 according to the description above can also be used in alarm systems for anti-theft purposes. The detectors can be mounted to computers, objects of art, e.g. pictures, and other valuable objects, see Fig. 5d. In museums e.g. it is common to provide a strong illumination of the object and for a detector powered by a solar cell 27 the solar cell can then receive energy from the illuminating, artificial light.

The detector system works in principle in the same way as the shell protection described above, i.e. when an unauthorized person moves a supervised object beyond the given limits an alarm is triggered.

The detector system described herein can furthermore be used to supervise poles and similar objects for electricity cables, telephone cables and illumination. For hard weather, accidences, etc. loads on, displacements of, orientation of such poles and similar devices are supervised. The detectors can then transmit, by forwarding messages using a multi-hop algorithm as described above, status information over very long distances in a very energy- saving way. As the detectors are self-supporting in regard of energy and communication channel (radio) they can signal, also in the case where e.g. a cable stops working e.g. due to a break, an alarm.

The detector system described herein can also be used by automatic control systems in so called intelligent buildings to e.g. control and check ventilation, airing and devices for protecting against sunlight and rain. Then, more of the functions of the detector can be used, such as the temperature sensor that indicates the temperature and the charging level of the solar cell which can give a measure of for example the light intensity.

The detector system can also be used to supervise oscillations and vibrations in buildings and bridges.

Also, in all these cases the detectors can transmit, due to the fact that they forward the message using a multi-hop algorithm, status information, e.g. control information, not using electrical cables, e.g. in houses and similar facilities. A redundancy obtained by means of a plurality of neighbouring detectors gives an increased security as well as the fact that the detectors are self-supporting in regard of energy and communication channel (radio), and the system can signal information also in the case of a breakdown.

The power supply unit 25 briefly described above can alternatively be constructed in another way which can be advantageous at least in some contexts. In the alternative design schematically shown in Figs. 10 - 14 the power supply unit includes two different batteries or accumulators for storing energy obtained from the solar cell 27.

The alternative power supply unit 25' can be used, in addition to being a power source for sensors or to power sensors, integrated or separate in other devices, for example devices of small dimensions or of a miniature format, e.g. actuators, small electrical motors, watches and toys.

The power supply unit 25' shown in Fig. 10 generally includes substantially the following components:

- at least one solar cell 27 (PV) for converting light to electrical energy, wherein, in the case where more than one solar cell is provided, they can be connected in series or parallel with each other or if a large number of solar cells are used, they can be interconnected in a combination of connections of serial and parallel types,

- at least one first energy accumulator 20I ₁ (A ₁ ) and at least one second energy accumulator 20I ₂ , (A ₂ ), at least the second energy accumulator being of "secondary type", i.e. of the type electrochemical accumulator, and - at least one regulator 31 (R) for checking, controlling, converting and regulating the energy flow to and from the energy accumulators. The regulator can include a control circuit such as a microcomputer 203 (μC) and a memory 205 (D) and electrical current to power an electronic circuit 207, for example a sensor part 17 (F) according to Fig. 1.

More possible components that can be included in or be connected to the power supply

unit 25' and in particular to the regulator 31 appear from Fig. 11. Thus, there may be provided

- at least one temperature sensor 23' (T), that possibly can be common to the power supply unit and the electronic circuit 207, compare Fig. 1, that in any case can sense the temperature of the energy accumulators 201 ₁ , 20I ₂ , - possibly an access network 209 (AN), and

- possibly a DC/DC-converter 211 (DC).

The access network and the DC/DC-converter can be included in the regulator 31.

Generally, the power supply unit 25' can include a plurality of energy accumulators 20I ₁ ,

- 20I ₂ , ..., 20I _n (Ai, ..., A _n ). The function of the regulator 31 is such that mainly the solar cell supplies energy to the first energy accumulator 20I ₁ whereas the second energy accumulator 20I ₂ is charged from the first energy accumulator.

Furthermore, Fig. 11 shows that the components included in the power supply unit 25' can be interconnected using an access network 209 that allows different possible paths for the power. The access network can be seen as a graph having nodes 210, to which the components are connected, and edges between the nodes, which can be switched on and off. In the shown embodiment a total connectivity between all possible nodes is provided. Other embodiments in which the access network 209 does not necessarily have to have a total connectivity with all nodes 210 are obviously possible but they give a lower flexibility. The control unit 207 can according to a control program, that e.g. is stored in the memory

205, perform the regulator function, i.e. the very regulating function of the regulator 31.

The fact that at least two accumulators 20I ₁ , ..., 20I _n are used allows the inflow and outflow of energy to and from the energy accumulators of the power supply unit 25' to be controlled in a suitable way and be buffered. The fact that at least two accumulators are used also makes it possible to choose properties of different types for the at least two accumulators. Thereby, the power supply unit can be configured and programmed in different ways, so that different power requirement profiles can be provided dependent on the area of use. Thus, e.g. time of year, climate and geographical position (the equator/the poles) and different activity intervals for the consumer 207 during day and night can be taken into account. Furthermore, the use of accumulators 20I ₁ , ..., 20I _n of at least two types together with a programmable regulator implies that it is very easy to tailor and minimize the exterior dimensions of the power supply unit for different types of applications, power demands and considering various characteristics. Thereby, the chemistry of the different batteries can be adapted and optimized and the different characteristics of the different types of secondary

batteries, i.e. rechargeable batteries, can be utilized.

The use of primary and secondary accumulators of different types can among other things mean that the different charging characteristics, discharging characteristics, lifetimes, charging velocities, numbers of charging cycles etc. can be adapted according to the application. Due to the fact that a number of different properties of the power supply unit are combined with each other - connection in series and/or in parallel of solar cells 27, that batteries of at least two different chemical designs are used and possibly a voltage conversion by the DC/DC- converter 211 a number of different configurations are obtained that can be tailored according the needs of the consumer/load 207 (L). The task of the regulator 31 in the embodiment as described above is to arrange that so much energy from the solar cell 27 as possible will be used and at the same time the energy accumulators 20I ₁ , 20I ₂ , ... are charged in the best way and to allow the specified power to be supplied to the consumer 207.

The first accumulator 20I ₁ can e.g. be a "secondary battery", i.e. a rechargeable electro- chemical battery, or be a super capacitor that typically can have a very large capacitance, in the magnitude of order Farad, the energy storing capacity being somewhere between the energy storing capacity of an electrolyte capacitor, that generally is in the magnitude of order microFarad, and rechargeable electrochemical batteries. Example 1 , In a first example the first energy accumulator 201 ₁ is a nickel metal hydride battery or a nickel-cadmium-battery and the second energy accumulator 20I ₂ is a lithium-ion battery. A first energy accumulator of this kind can easily be charged for compensation/maintenance which in this case is not necessary for the second energy accumulator. However, a second energy accumulator of this kind can be charged and discharged as controlled by the regulator 31, so that all of its charging cycles are optimally used during all of its lifetime. A first energy accumulator 20I ₁ of said kind can sustain approximately twice the number of charging cycles of the second energy accumulator 20I ₂ that however has a higher cell voltage and therefore can directly, without any conversion system, supply power to electronic circuits. Example 2 In a second example the first energy accumulator 201 _\ is a super capacitor and the second energy accumulator 20I ₂ is as in example 1 a lithium-ion battery. Hereby, a rapid charging and a long lifetime of the first energy accumulator are achieved among other things.

The regulating functions of the regulator 31 can be a so called embedded microprocessor application and the regulator can then include or be included in the microcomputer 203 having

analog and digital input ports and output ports 213, 215 (I, O). The energy regulating algorithms and functions are then implemented in software. In the regulator also a continuous supervision of the whole power supply unit 25' is performed e.g. that no critical limes are being passed so that safety, functions and lifetimes of the energy accumulators are not jeopardized. The program code for the system and regulator 31 can e.g. be written in the programming language nesC and can be executed regularly with a desired time interval controlled by an operative system, such as a real time operative system, e.g. TinyOS.

By the at least one temperature sensor 23' the temperatures of the energy accumulators 20I ₁ , 201 ₂ , ... can be supervised which can be necessary in many cases to give a completely secure function.

In the regulator 31 also discrete components, not shown, can be included for a complete function, among other things a switch, for example of FET or MOSFET type, and some energy storage device such as a capacitor and/or an inductor.

The solar cell 27 can as indicated above include a plurality of elements which are connected in series or parallel with each other in order to fulfil different requirements for voltages and/or currents.

A plurality of controllable switches 234 (Sy), which e.g. can be semiconductor type such as

FET or MOSFET, can be provided in the access network 209 and allows that all components in the power supply unit 25' can be interconnected in different ways, so that different paths for transferring energy within the unit can be established according to the need, see also Figs. 2 and

3.

Fig. 12 shows how each node 210 (Ni, N _j ) in the access network 209 can be connected to an analog measurement point such as an AD-port of the control unit, i.e. to the analog input terminal 213 (I), possibly through a multiplexer, not shown. Thereby each node, i.e. connected component, can be seen as a sensor and the voltage in the node can be measured and thereby indirectly - using a known (small) resistor - also the electrical current flowing between two nodes.

Fig. 13 shows a portion of the access network 209 and how edges between the nodes 210 can be connected by controllable electronic switches 234 (Sy). hi this manner the nodes can be controlled to be interconnected as desired due to the fact that they can be connected to (digital) output ports (O) from the control unit 203. FETs/MOSFETs only consume electric current when they are switched and can be obtained having a very small channel resistance. Thereby, the influence on the energy consumption can be minimized, i.e. be maintained on a relatively very low level.

The large number of possible configurations according to the description above can result in an optimization problem with the target function of maximizing energy retrieving/storing and lifetime of the system that is difficult to solve.

A large number of variables and dependencies (secondary conditions) appear here including among other things:

- conditions of the energy accumulators, e.g. temperature, voltage (which indirectly over a known resistance gives the electrical current) that are supervised (measured)

- parameters of the energy accumulators, e.g. lifetimes, numbers of charging cycles, maximum and minimum voltages and currents, charging velocities, etc. These parameters are given by the type (chemistry) of the energy accumulators. It is also very important that critical limits, e.g. highest and lowest voltages, are never passed in a lithium-ion battery .

- time and date, as the solar cell 27 supplies different amounts of energy depending on exterior conditions such as altitude of the sun, weather and time of the year.

- energy requirement profile of the consumer 207 that varies also depending on application and exterior conditions.

- the DC/DC-converter 211, preferably of switched type, can work in different modes, step-up or step down, and it can include a capacitor and/or inductor, not shown, as an energy storage. Its function and parameters can be controlled by the control unit 203 as well as its switching frequency. - exterior dimensions that generally should.be kept as small as possible.

- the solar cells 27 can be connected in series and/or parallel with each other and different number of solar cells may be provided.

In addition to the fact there exists, as is apparent from the list above, many variables and dependencies and hence a large number of combinations, several of these variables, relations and restrictions are also nonlinear and/or stochastic. This complexity results in the fact that a simple regulator will not generate a particularly good performance in regard of the target function.

Moreover, if not charging the energy accumulators according to requirements given by their chemical characteristics, it can generally shorten their lifetime and energy storing capacities to a considerable extent. To solve these problems a so called expert system can be used in which experience and expert knowledge, e.g. with respect to battery charging, are introduced. The knowledge can be codified in the regulator 31 which here can be a microcomputer/-controller or be included in such a device, usually as rules and facts given in natural language, i.e. in linguistic form. By furthermore using fuzzy logic, vague concepts and impreciseness can also be introduced, as

experiences and expert knowledge most often exist in an imprecise form, e.g. as rules of thumb. Expert systems and fuzzy logic are well-known technology, se e.g. Earl Cox, "The Fuzzy Systems Handbook", Academic Press 1994.

Additionally, a fuzzy expert system can be said to make its conclusions, i.e. perform inference from data and rules, in a parallel form, i.e. all rules are considered before a decision is made, which is different from a traditional expert system, in which the rules are sequentially executed, compare a decision tree. Thus, fuzzy rules can be easily weighted and taken into combined account, such as by inference and "defuzzyfication" which is different from discrete decision rules. How it can be done is described e.g. in the book mentioned above. An example of a rule including a fuzzy linguistic, a so called Fuzzy Set (in italics bold type, upper-case letters below) is as follows:

"If the charge level of the first battery is HIGH and the charge level of the second battery is LOW charge until the charge of the first battery is LOW" A fuzzy model results in that the regulating is continuously, i.e. with relatively short time intervals, and automatically improved towards an optimized inflow and outflow of energy in accordance with the fuzzy rules that have been entered. A fuzzy expert system implies that the model complexity is reduced, and it can thus be implemented in a small embedded microcomputer and be executed using the limited resources which exist therein. Moreover, the rules can be _. easily changed by configuration operations and it is not necessary to reprogram the power supply unit 257regulator 31.

Fig. 14 illustrates how this fuzzy control unit/regulator can be designed in a microcomputer for this system. In a knowledge base 221 (KB) modules (R, D, FS) containing rules, data and fuzzy amounts are stored at memory places 223, 224, 225. Further, means 227 (PL) for processing logic, ports 229, 231 (I, O) for input data and output data - analog and digital, a real time clock 233 (RTC) for time and date and means/functions 235, 237 (DF, F) to give sharpened results - "defuzzify" - and to give unsharpened results - "fuzzify" - , see e.g. the book mentioned above for known methods, are provided.

Rules, data and fuzzy variables ("Fuzzy Sets") in the knowledge base 221 and also configuration data can affect the regulator function (RF) and the system.

Configuration data (KD) stored on a memory place 239 can e.g. include:

- the chemical structure and chemical characteristics of the energy accumulators,

- lifetimes of the energy accumulators,

- numbers of possible charging cycles for the energy accumulators,

- maximum and minimum voltages, in particular for the energy accumulators,

- maximum and minimum currents, in particular for the energy accumulators and some semiconductor components,

- maximum and minimum temperatures, in particular for the energy accumulators, - charging velocities for the energy accumulators,

- discharge levels for the energy accumulators,

- geographical position - place (constant),

- energy profile,

- requirement, and - activity interval.

Thus, Fig. 14 shows how the regulator function performed by the control circuit 31 forms a control system having feedback for collecting energy using the solar cell or cells 27, storing energy in the accumulators 20I ₁ , 20I ₂ , ... and supply of power to the load/consumer 207.

The power supply unit 25' becomes, due to the fact that is controlled by a fuzzy logic expert system, a so called Fuzzy Logic Controller (FLC), an autonomous system having very good performance to which new knowledge can be added in a simple way by using linguistic rules.

While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous other embodiments may be envisaged and that numerous additional advantages, modifications and changes will readily occur to those skilled in the art without departing from the spirit and scope of the invention. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within a true spirit and scope of the invention. Numerous other embodiments may be envisaged without departing from the spirit and scope of the invention.