Magnetic field sensing for tamper identification

• US 6,885,302 B2
• Filed: 07/31/2002
• Issued: 04/26/2005
• Est. Priority Date: 07/31/2002
• Status: Active Grant

• Current Assignee: Itron, Inc.
• Original Assignee: Itron Electricity Metering, Inc. (Itron, Inc.)
• Inventors: Seal, Brian Keith, Martin, Brent
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Previl, Daniel
• Application Number:
  US10/209,177
• Publication Number:
  US 20040021568A1
• Time in Patent Office: 1,000 Days
• Field of Search: 340/551, 340/552, 340/554, 340/561, 340/567, 340/310.01, 340/870.02, 340/870.03, 340/870.26, 340/825.22, 340/553
• US Class Current: 340/551
• CPC Class Codes: G01R 22/066 Arrangements for avoiding or indicating fraudulent use

Abstract

The present technology involves a method and apparatus for detecting and reporting magnetic fields in the proximity of a utility meter as an approach to determining tampering of such meter. The sensitivity level of the magnetic field sensors may be adjustable allowing either remote or local sensitivity adjustments to a magnetic field sensor to compensate for variations in the electromagnetic environments of different meter installation sites. Alternatively, the output of each magnetic field sensor may be connected to the input of an adjustable threshold circuit. When the output voltage of the magnetic field exceeds a predetermined threshold voltage, a magnetic event signal is generated. Threshold adjustments to the adjustable threshold circuit may be performed locally at the meter site or remotely from a station. The output of each magnetic field sensor may be monitored by a locally or remotely programmable magnetic sensor output monitor. Such magnetic sensor output monitor generates a magnetic event signal when a predetermined number of magnetic sensors have been activated.

Claims

1. An apparatus for detecting magnetic fields in the proximity of a utility meter, said apparatus comprising:

at least one magnetic field sensor with an adjustable sensitivity level, wherein said magnetic field sensor is activated when exposed to a given level of magnetic field strength; and

a processor associated with a memory, wherein said processor is connected to said magnetic field sensor device, wherein said processor stores, in said memory, sensor activation related data.

2. An apparatus for detecting magnetic fields as in claim 1, wherein said magnetic field sensor comprises a Hall cell device.

3. An apparatus for detecting magnetic fields as in claim 1, further comprising a utility meter including one of a solid state meter, electromechanical meter, and a solid state/electromechanical hybrid meter.

4. An apparatus for detecting magnetic fields as in claim 1, wherein a plurality of magnetic field sensors are oriented in a manner to enhance the ability to detect magnetic fields in three dimensions, and wherein said processor is connected to each of said plurality of magnetic field sensors.

5. An apparatus fur detecting magnetic fields as in claim 1, wherein said adjustable sensitivity level of said magnetic field sensor is manually adjustable.

6. An apparatus for detecting magnetic fields as in claim 1, wherein said adjustable sensitivity level of said magnetic field sensor is automatically adjustable by said processor.

7. An apparatus for detecting magnetic fields as in claim 1, further comprising a transmitter/receiver connected to said processor, wherein said transmitter/receiver is used to transfer selected sensor activation related data to a remote location.

8. An apparatus for detecting magnetic fields as in claim 7, wherein said sensor activation related data includes at least one of time, date, field strength, duration in time of magnetic field sensor activation, and the magnetic sensor sensitivity setting.

9. An apparatus for detecting magnetic fields in the proximity of a utility meter, to determine attempted tampering with the utility meter, said apparatus comprising:

at least one magnetic field sensor device having a sensor output wherein the magnitude of said output is a function of the strength of the magnetic field in the proximity of the magnetic field sensor device;

an adjustable threshold circuit connected to said magnetic field sensor, wherein said adjustable threshold circuit generates a magnetic event signal when said sensor output exceeds a threshold level; and

a processor associated with a memory, wherein said processor is connected to the adjustable threshold circuit, wherein the processor stores, in said memory, sensor activation related data when a magnetic event signal is detected.

10. An apparatus for detecting magnetic fields as in claim 9, further including a utility meter comprising one of a solid state, electromechanical, and solid state/electromechanical hybrid meters.

11. An apparatus for detecting magnetic fields as in claim 9, wherein said magnetic sensor device comprises Hail cell devices.

12. An apparatus for detecting magnetic fields as in claim 9, including a plurality of magnetic field sensor devices oriented in a manner to enhance their collective ability to detect magnetic fields in three dimensions.

13. An apparatus for detecting magnetic fields as in claim 9, wherein the threshold level of the adjustable threshold circuit is manually adjustable.

14. An apparatus for detecting magnetic fields as in claim 9, wherein the threshold level of the adjustable threshold circuit is adjusted automatically by the processor.

15. An apparatus for detecting magnetic fields as in claim 9, further comprising a transmitter/receiver connected to the processor, wherein the transmitter/receiver is used to transmit the sensor activation related data to a remote location.

16. An apparatus for detecting magnetic fields as in claim 15, wherein the sensor activation related data includes at least one of time, date, field strength, duration in time of magnetic field sensor activation, and the threshold level setting.

17. A method for detecting magnetic fields within the proximity of a utility meter, comprising the steps of:

positioning at least one magnetic field sensor with an adjustable sensitivity level within said utility meter, wherein said magnetic field sensor is activated when exposed to a magnetic field having a given level of magnetic field strength;

providing a processor, wherein said processor is connected to said magnetic field sensor to detect magnetic field sensor activation;

storing magnetic event related data when said magnetic field sensor activation is detected;

(d) establishing a communications link between said processor and a remote computing device;

(e) transferring said magnetic event related data to said remote computing device; and

(f) automatically adjusting said adjustable sensitivity level according to magnetic field sensor sensitivity level adjustment commends received from said remote computing device.

18. A method for detecting magnetic fields as in claim 17. further comprising the step of providing a plurality of magnetic field sensor devices oriented in a manner to enhance their collective ability to detect magnetic fields in three dimensions.

19. A method for detecting magnetic fields as in claim 17, wherein said magnetic field sensor comprises a Hall cell device.

20. A method for detecting magnetic fields as in claim 17, wherein said utility meter comprises one of a solid state meter, an electromechanical, and a solid state/electromechanical hybrid meter.

21. A method for detecting magnetic fields as in claim 17, further comprising the step of manually adjusting the sensitivity level of said magnetic field sensor.

22. A method for detecting magnetic fields as in claim 17, wherein said magnetic event related data includes at least one of time, date, field strength, duration in time of magnetic field sensor activation, and the magnetic sensor sensitivity setting.

23. An apparatus for detecting magnetic fields in the proximity of a utility meter, said apparatus comprising:

at least one magnetic field sensor with an adjustable sensitivity level, wherein said magnetic field sensor is activated when exposed to a magnetic field having a given level of magnetic field strength;

a processor connected to said magnetic field sensor, wherein said processor stores sensor activation related data in a memory associated with said processor

a transmitter/receiver associated with said processor for transferring data to and receiving data from a remote computing device; and

wherein said processor is configured to adjust the sensitivity level of said magnetic field sensor consistent with magnetic field sensor adjustment data received from said remote computing device.

24. An apparatus for detecting magnetic fields as in claim 23, wherein said sensor activation related data includes at least one of time, date, field strength, duration in time of magnetic field sensor activation, and the magnetic sensor sensitivity setting.

25. An apparatus for detecting magnetic fields as in claim 23, wherein said magnetic field sensor comprises a Hall cell device.

26. An apparatus for detecting magnetic fields as in claim 23, further comprising a utility meter wherein said utility meter is one of a solid state meter, electromechanical meter, and a solid state/electromechanical hybrid meter.

27. An apparatus for detecting magnetic fields in the proximity of a utility meter, to determine attempted tampering with the utility meter, said apparatus comprising:

at least one magnetic field sensor device having a sensor output;

an threshold circuit having an adjustable threshold level, wherein said threshold circuit is connected to said magnetic field sensor, wherein said threshold circuit generates a magnetic event signal when said sensor output exceeds said adjustable threshold level;

a processor associated with a memory wherein mid processor is connected to the threshold circuit and wherein the processor stores sensor activation related data in said memory when a magnetic event signal is detected

a transmitter/receiver associated with said processor wherein said processor is configured to use said transmitter/receiver to transmit data to and receive data from a remote computing device;

wherein said processor is further configured to transmit at least part of said sensor activation related data to a remote computing device; and

wherein said processor is further configured to adjust said adjustable threshold level to a level specified by a remote computing device.

28. An apparatus for detecting magnetic fields as in claim 27, further including a utility meter comprising one of a solid state, electromechanical, and solid state/electromechanical hybrid meters.

29. An apparatus for detecting magnetic fields as in claim 27, including a plurality of magnetic field sensor devices oriented in a mariner to enhance their collective ability to detect magnetic fields in three dimensions.

30. An apparatus for detecting magnetic fields as in claim 27, wherein said adjustable threshold level is manually adjustable.

31. An apparatus for detecting magnetic fields as in claim 27, wherein said adjustable threshold level is adjusted automatically by the processor.

32. An apparatus for detecting magnetic fields as in claim 27, wherein

the sensor activation related data includes at least one of (a) time of sensor activation, (b) date of sensor activation, (c) field strength of the magnetic field sensed by said magnetic field sensor, (d) duration in time of magnetic field sensor activation, and (e) the adjustable threshold level value.

33. An apparatus for detecting magnetic fields as in claim 27, wherein the magnitude of said output of said at least one magnetic field sensor device is a function of the corresponding magnetic field strength in the proximity of the at least one magnetic field sensor.

34. An apparatus for detecting magnetic fields as in claim 33, wherein said magnetic field sensor device comprises at least one Hall cell device.