Tamper detection mechanism for electronic lock device

Patent metadata

Field	Value
Publication number	US-9624694-B2
Application number	US-201414269008-A
Country	US
Kind code	B2
Filing date	May 2, 2014
Priority date	May 2, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

An apparatus and method for tamper detection of an electronic lock device using a capacitive proximity sensor. The capacitive proximity sensor is positioned on a printed circuit board that is positioned in an inner region of a housing of the electronic lock device. An electronic signal is transmitted to a conductive element, such as, for example, an area of a copper layer(s) or trace(s) on the printed circuit board. The transmitted electronic signal is monitored to determine a capacitance value. The capacitance value is evaluated to determine whether the capacitance value corresponds to known or predetermined capacitance values that are associated with a cover plate covering an opening of the inner region. In the event the capacitance value is determined to be outside of predetermined capacitance values, and signal may be generated to a reporting authority indicating the removal of the cover plate from the housing.

First claim

The invention claimed is:

1. A method for detecting tampering of an electronic lock device, the method comprising:
establishing one or more capacitance values that correspond to a cover plate being positioned to operably cover an opening to an inner region of a housing of the electronic lock device;
transmitting an electric signal to a conductive element contained within the housing;
determining a monitored capacitance value using the transmitted electric signal; and
evaluating the monitored capacitance value with respect to the established one or more capacitance values to determine whether the cover plate remains positioned to operably cover the inner region.

2. The method of claim 1 , wherein the step of determining the monitored capacitance value includes obtaining a charge time measurement of the transmitted electric signal.

3. The method of claim 2 , wherein the step of evaluating the monitored capacitance value includes applying an algorithm using the monitored capacitance value to determine whether the monitored capacitance value is within a predetermined range of the established one or more capacitance values.

4. The method of claim 3 , wherein the step of establishing one or more capacitance values includes:
positioning the cover plate about the opening to operably cover to the inner region;
transmitting, when the cover plate is positioned about the opening, one or more calibration electric signals to the conductive element;
monitoring the one or more calibration electric signals;
determining one or more calibrated capacitance values using the monitored one or more calibration electric signals; and
recording the one or more calibrated capacitance values, the recorded one or more calibrated capacitance values providing the established one or more capacitance values.

5. The method of claim 4 , wherein the predetermined range of capacitance values are at least in part based on an anticipated variation in the determined one or more calibrated capacitance values.

6. The method of claim 4 , further including the step of engaging a user interface of the electronic lock device to initiate the transmission of the one or more calibration electric signals.

7. The method of claim 2 , further including the step of transmitting, if the monitored capacitance value indicates the cover plate does not remain positioned to operably cover the inner region, a signal indicative of the removal of the cover plate from the housing.

8. The method of claim 7 , further including the step of initiating, if the monitored capacitance value indicates the cover plate remains positioned to operably cover the inner region, a timer to set the timing of a subsequent transmission of an electric signal to the conductive element.

9. A method for detecting tampering of an electronic lock device, the method comprising:
transmitting an electric signal from a capacitance proximity sensor to a conductive element contained within an inner region of a housing of the electronic lock device;
monitoring by the capacitance proximity sensor the transmitted electric signal to the conductive element;
determining a capacitance value based at least in part from information obtained from monitoring the transmitted electric signal;
transmitting the capacitance value to an evaluator module;
evaluating the transmitted capacitance value using an algorithm of the evaluator module; and
determining whether the evaluated capacitance value corresponds to one or more established capacitance values that are associated with a cover plate being operably positioned about an opening of the inner region.

10. The method of claim 9 , wherein the step of determining the capacitance value includes obtaining a decay rate of the transmitted electric signal.

11. The method of claim 10 , further including the steps of:
securing the cover plate to the housing;
transmitting, when the cover plate is secured to the housing, one or more electric calibration signals;
monitoring the transmitted one or more electric calibration signals; and
determining one or more calibrated capacitance values using information obtained from monitoring the transmitted one or more electric calibration signals; and
wherein the one or more calibrated capacitance values provide the one or more established capacitance values.

12. The method of claim 11 , further including the steps of:
transmitting to a reporting authority a signal indicative of the cover plate being removed from the housing when the evaluated capacitance value does not correspond to the one or more established capacitance values; and
initiating, if the evaluated capacitance value corresponds to the one or more established capacitance values, a timer for timing a subsequent transmission of an electric signal to the conductive element.

13. The method of claim 12 , wherein the one or more established capacitance values is a range of the one or more calibrated capacitance values.

14. The method of claim 12 , wherein the one or more established capacitance values is a range of capacitance values that is at least in part based on expected variation in the one or more calibrated capacitance values.

15. A tamper detection mechanism for an electronic lock comprising:
a housing assembly having a cover plate, a printed circuit board, and a housing, the cover plate configured for removable attachment to the housing, the housing having one or more sidewalls that generally define an inner region, the inner region configured to receive insertion of the printed circuit board;
a capacitance proximity sensor operably connected to the printed circuit board;
a conductive element positioned on the printed circuit board and operably connected to the capacitance proximity sensor, the capacitance proximity sensor adapted to monitor an electric signal that is transmitted to the conductive element to obtain a capacitance value; and
an evaluator module operably connected to the capacitance proximity sensor, the evaluator module being adapted to determine whether the capacitance value is outside a predetermined range of capacitance values that correspond to the cover plate being positioned to operably cover an opening to the inner region.

16. The tamper detection mechanism of claim 15 , further including a microcontroller positioned on the printed circuit board, the microcontroller including the evaluator module.

17. The tamper detection mechanism of claim 16 , wherein the microcontroller further includes the capacitance proximity sensor.

18. The tamper detection mechanism of claim 15 , wherein the conductive element is a copper pad area of the printed circuit board.

19. The tamper detection mechanism of claim 15 , wherein the conductive element is a trace of the printed circuit board.

20. The tamper detection mechanism of claim 15 , wherein the capacitance proximity sensor is a high resolution timer that is configured to monitor a decay rate of the electric signal that is transmitted to the conductive element.

Assignees

• Schlage Lock Co Llc

Inventors

• Kincaid Ryan C

Classifications

• E05B45/06 Primary

  Electric alarm locks {(E05B45/005 takes precedence)} · CPC title

• E05B39/00

  Locks giving indication of {authorised} or unauthorised unlocking {(with key identification means E05B35/001; alarm locks E05B45/00)} · CPC title