JP2002507036A - Electronic sensor to identify objects to prevent loss, theft or movement - Google Patents

Abstract

The invention concerns an electronic sensor in particular for detecting theft or loss of objects comprising a central electronic unit (1) exchanging coded data by radio frequency with at least a transponder (11), associated with an object to be monitored to verify its presence in a located volume (12) and emitting an alarm (13) when said transponder (11) is no longer present in the monitored volume (12). The invention is characterised in that said transponder (11) is automatically set in stand-by mode outside the transponder active phases (11) and the central unit (1) selectively corresponds with said transponder.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to an electronic sensor that detects theft, loss, or movement of an object.

[0002] Currently, several devices are known that can monitor the presence of an object in a given area, such as, for example, the device described in US Patent No. 5,396,218. Comprises a master card and at least one slave card or transponder designed to be placed in the object to be monitored, between which information can be exchanged by radio frequency and a central The master card forming the control system includes an alarm circuit which is activated when the slave card leaves the protected area.

[0003] German Patent No. 3618416 also relates to an electronic device for monitoring luggage or other objects, which device can be placed in or integrated with the object to be monitored. A central electronic unit for exchanging coding information with a second unit or transponder, which is programmable according to the number of second units, the level of reception or other parameters and A paging signal is sent to a second unit responding to the unit and an alarm is triggered according to the received signal.

[0004] However, in these devices, the electronics of the second unit are constantly turned on, causing power consumption and independence problems, especially when the small second unit or transponder is approximately 400 MHz. When used to transmit signals at high frequencies, considerable power consumption is required to cover transmission / reception uniformly within a spherical or delta shaped spatial range of several meters. On the other hand, these devices have an integrated power supply, which cannot be recharged or replaced. Further, these devices require that all transponders be activated or deactivated if the user does not want to stop or restart the system at the user's workplace, home, or other location that does not need to protect the object. This is inconvenient, since such a procedure must be performed several times a day.

On the other hand, these devices do not transmit signals even if an extra unit is introduced with the same coding into the protection range of the device in order to maliciously replace the protected second unit.

[0006] Accordingly, one of the problems to be solved is to effectively cover a predetermined spatial range by exchanging information in a high frequency band between the transponder and the central unit. The object is to provide a device for detecting an object using the obtained small transponder.

The present invention addresses these disadvantages by providing a small transponder that provides considerable independence in use, facilitates calibration and operation of the device, and ensures security features. Suggest a device to detect.

Means for Solving the Problems An electronic sensor for an object according to the present invention uses at least one transponder integrated with the object to be monitored to check for its presence in a specified space range via a radio frequency. An electronic sensor of the type comprising a central electronic unit for exchanging coded information and issuing an alarm when said transponder is no longer present in said monitored space, said transponder being automatically operated outside of the activation phase of said transponder. The central unit is selectively set in a standby mode, and the central unit selectively communicates with the transponder.

[0009] The activation stage corresponds to an activation state in which the signal transmitted by the central unit is received and processed, and consequently, an activation state in which a message is transmitted in response to the signal. The signal transmitted from the central unit may be a signal confirming the presence, and the response signal transmitted by the transponder may be a coded message for confirming the presence from the transponder in the space to be monitored.

[0010] The relationship between the duration of the start-up phase and the duration of the operating cycle should be very small in order to provide a large power independence for each transponder, preferably 10
%. The central unit relates to a transmitting / receiving circuit, an interface comprising a buffer memory enabling a radio frequency connection between the central unit and several transponders, a microcontroller, and various modes of operation of the sensor. A memory containing an algorithm in the form of a computer program.

In a first embodiment, each transponder includes a microcontroller and a memory, a transmitting / receiving circuit, and an interface with a buffer memory that allows connection to several controllers. In the second embodiment, each transponder receives the impulse transmitted by the transmitting / receiving circuit and the central unit, and simultaneously transmits the coded information contained in its own memory via the transmitting / receiving circuit to the central unit. And an intelligent memory that can be transmitted to

According to the present invention, there is provided the electronic sensor, wherein: (1) the central unit detects a transponder arranged in a space range monitored by the central unit, and stores the transponder in a memory of the central unit. A calibration mode for identifying in the memory transponders detected among the enumerated transponders; (2) the central unit loops continuously querying the transponders enumerated and identified in its memory; And, if one of the transponders does not respond, raises an alarm, a protection mode, and (3) the central unit continuously queries each listed transponder in a loop, and one of the transponders responds Sometimes, for example, trigger an alarm until user intervention or the central unit detects all of the transponders And a detection mode.

[0013] The sensor according to the invention may additionally include an initialization mode for modifying the memory that references each transponder from introducing a new transponder. This mode uses the time provided at the beginning of the inquiry frame for each transponder, initializes a new transponder to identify and monitor it, and enumerates it in the memory, Other transponders enumerated and identified are in the initialization mode and during the time interval.

The sensor according to the present invention may also include an erasing mode that allows the user to erase from memory the transponders that he does not want to maintain. The central unit preferably includes means such as signal lights or alphanumeric displays to inform the user of the respective operating modes of the sensor, for example when introducing a new transponder, so that a new transponder May be confirmed to be monitored after being listed in the above memory.

According to the invention, furthermore, the transponders can each be provided in the form of electronic labels, which can each be integrated or integrated with the monitored object, and each transponder can be self-contained. Alternatively, power is supplied by the central unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The advantages and features of the present invention will become more apparent from the following description, taken in conjunction with the accompanying drawings, illustrating some non-limiting embodiments of the present invention. Referring to FIG. 1, a device for detecting an object according to the present invention includes a transponder 11 coupled to an object (not shown) and controlling the presence of each transponder 11 placed within a defined space area 12. And a central unit 1 for exchanging information 10.

The central unit 1 therefore controls the communication confirming the presence of each transponder 11 in the monitored space 12 and triggers an audible alarm 13 if one of them is absent. As shown in FIG. 2, the central unit 1 includes an antenna 21 and several transponders.
A transmission / reception circuit 20 connected to an interface 20 'and an antenna 21 enabling connection to the transmission / reception circuit 20, and one is connected to the transmission / reception circuit 20 and the other is connected to the transmission / reception circuit 20 (FIGS. 4a to 4e). (Shown) A microcontroller 22 connected to a read-only memory 23 containing a computer program integrating the algorithms of the various modes of operation of the device, and a random access memory 23 'containing parameters specific to each transponder 11. And a buzzer 24 to emit an audible alarm 13
And one or more LEDs 25 that emit a light alarm signal that can provide information to the user about the function of the device.

Each transponder 11 is connected to a transmitting / receiving circuit 31 connected to an antenna 32 and contains the characteristics of the transponder 11, in particular the particular coding information to be transmitted on request from said central unit. It comprises a microcontroller 30 connected to a memory 33 and two timer counters 34, 34 '. Although not shown, the transmitters of the transmitting / receiving circuits 20, 31 have a digital data input and a distance of about 400M at a distance in the range of a few meters, especially 1 to about 120 meters.
A transmission circuit for transmitting digital information preferably in a frequency range of Hz or more. The receiver may use a super-heterodyne type structure with two mixers to be able to recover the information coming from the central unit in either analog or digital form. The receiver may also be adapted to transmit a carrier detection signal indicating that reception is occurring.

The sensor according to the invention has three main operating modes (calibration mode, protection mode, detection mode) selected using the central unit 1 and two parameter setting modes, an initialization mode and a memory. Operate in erase mode. [Calibration mode] In the calibration mode, the central unit continuously queries all the transponders 11 listed in its own memory 23 at predetermined time intervals, and determines whether the transponders 11 exist in the monitored space range 12. For example, to show FIG.
The information in the form of activity bits set to "1" as shown in Table 1 is queried and stored for each of the enumerated transponders. In this figure,
Only the transponders TR1, TR2, TR4 and TR7 have an activity bit of “
It will be understood that it is set to 1 ". The user can confirm the good function and the result of the calibration by means of the LED 25. The selected transponder 11 remains in the memory until a further calibration mode is performed. .

[Protection Mode] In the protection mode, the central unit 1 continuously queries the transponders 11 in the order in which the transponders 11 listed in its memory 23 are stored and at predetermined time intervals. In the transponders TR1, TR2, TR4 and TR7 listed as shown in FIG. 3a, the activity bit is "1".
, Only the transponders TR1, TR2, TR4 and TR7 set to the central unit 1 are queried, and any of the transponders whose activity bits are set to "1" are Triggers an alarm 13 when it does not respond via transmission with a predetermined code indicating that it has disappeared.

[Detection Mode] In the detection mode, the central unit 1 queries all of the listed transponders and triggers an alarm 13 for each transponder's response according to the same principle as described above, and the user is involved. The triggering transponder is excluded from the inquiry loop until or until detection of all listed transponders is achieved.

Thus, according to the detection mode, the missing object can be located and an extra transponder 11 is introduced with the same coding in order to maliciously replace or plunder the enumerated and calibrated transponders. Any risks can be prevented. Referring to FIG. 3b, the operating cycle of the device in the protection mode is shown, but the time is divided into seconds and 1/10 seconds for simplicity and to aid understanding.

During the activation of the protection mode, when the central unit 11 sends an impulse at 40, the impulse triggers the timer counter 34 of each transponder TR1, TR2, TR4, TR7 simultaneously, and then differs from transponder to transponder. After the specified time interval, each timer
The counter activates at 41 to receive the presence inquiry signal sent by the central unit 1, and if queried by said central unit during awakening, the corresponding transponder TR1, TR2, TR4 or TR7 responds. Then, a coded message 42 indicating its presence in the monitored space range is transmitted to the central unit.
The transponder is then automatically set to sleep mode for a predetermined time interval 43 by its second timer counter 34 '. At the end of the sleep period, the transponder restarts its own counter 34 when it receives an impulse 44 from the central unit 1 and wakes up at the end of the count of that counter, and during the wake-up period the impulse 46 , The transponder returns a coded message 42 indicating its presence to the central unit 1. Thus, as can be seen in FIG. 3b, the transponder TR9 is awakened last after all the transponders TR1, TR2, TR4 and TR7 are awakened simultaneously by the impulse 40 transmitted from the central unit 1, 1 first, then the transponder TR9 sends an identification code 42 in response to the central unit 1. After that, in order to confirm the existence of the transponder TR4,
4 is the turn referred to by the central unit, after which it becomes the transponder TR2 and the transponder TR1 successively.

As can be further understood in FIG. 3 b, at the beginning of the frame there is an initialization mode 47, and since all transponders listed are in standby during said initialization mode 47, the central unit 1 It becomes possible to introduce a new transponder in the memory 23 '. Each of the above transponders can be integrated into an object to be protected, such as a banking chip card, which satisfies the surface and thickness requirements, or in the form of a separate electronic label, which can be integrated with the object to be protected, for example by means of an adhesive. It can be called.

To increase the security of the device, the communication between the central unit and the transponder is encrypted. It should be understood that the absence counter can be used so that the central unit triggers the alarm only after n absences to avoid an untimely alarm.

Since the central unit can be integrated into a device such as a mobile phone, power can be supplied from the battery of such a device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a device according to the present invention.

FIG. 2 is a functional diagram of a central unit and a transponder.

FIG. 3a shows the state of the registers of the memory of the central unit for a particular case of the operation of the device according to the invention.

FIG. 3b is a time chart in the protection mode of the device according to the invention.

FIG. 4a is a diagram illustrating an algorithm of an initialization mode.

FIG. 4b is a diagram illustrating an algorithm of a protection mode.

FIG. 4c is a diagram showing an algorithm of a detection mode.

FIG. 4D is a diagram showing an algorithm of a memory erase mode.

FIG. 4e illustrates the algorithm for the calibration mode.

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Claims (9)

[Claims] To check for the presence of an object in a defined spatial area (12), encoded information is transmitted via radio frequency with at least one transponder (11) integrated with the object to be monitored. A central electronic unit (1) that replaces and issues an alarm (13) when the transponder (11) is no longer within the monitored space area (12).
An electronic sensor for detecting theft or loss of an object, wherein the transponder (11) is automatically set to a standby mode other than the activation stage of the transponder (11), and An electronic sensor, wherein the central unit (1) selectively communicates with the transponder. 2. The central unit (1) detects transponders (TR1, TR2, TR4, TR7) arranged in a spatial area (12) monitored by the central unit (1), and A calibration mode for identifying in the memory the transponders (11) detected among the transponders (11) listed in the memory of the unit (1), the central unit (1) having its own memory (23) ') The transponders (TR1, TR2, TR4, TR7) listed and identified in () are continually queried in a loop, and if one of said transponders (11) does not respond, issue an alarm (13), protection A detection mode in which the central unit (1) continuously queries the enumerated transponders (11) in a loop and triggers an alarm (13) when one of the transponders responds. The electronic device according to claim 1, Sensor. 3. At the beginning of a query frame for the new transponder (11), to initialize the new transponder and enumerate it in the memory to identify and monitor the new transponder. An initialization mode that introduces the new transponder using a given time, wherein the other transponders enumerated and identified are standby during the initialization mode and during the time interval; The electronic sensor according to claim 2, wherein: 4. The electronic sensor according to claim 1, further comprising means (25) for notifying a user in each operation mode of the sensor. 5. The transponder (11) comprises a microcontroller (22), memories (23, 23 ′) and a transmitting / receiving circuit (20). An electronic sensor according to the item. 6. The transponder (11) comprises a transmission / reception circuit (20) and a random memory, which store the coded information contained in the memory of the transponder (11). Upon receipt of the impulse transmitted by the central unit (1), the central unit
The electronic sensor according to any one of claims 1 to 4, wherein the electronic sensor can be transmitted through the transmission / reception circuit to (1). 7. The transponders (11) may each be provided in the form of an electronic label, each of which may be integrated within the monitored object, or which may be integrated with the object.
7. The electronic sensor according to claim 1, wherein power is supplied to each transponder independently or by the central unit. 8. 8. Electronic sensor according to claim 1, wherein the communication between the central unit (1) and the transponder (11) is encrypted. 9. The method according to claim 1, wherein the central unit includes an absence counter to trigger its own alarm only after n absences. Electronic sensor.