Accelerometer based removal and inversion tamper detection and tap switch feature

1. A method for providing tamper and tap detection in an electric meter, comprising:

providing an electric meter including at least a register;

associating a three-axes accelerometer with the register, the accelerometer being capable of providing signals representative of acceleration in X, Y, and Z planes relative to a front view of the electric meter;

monitoring for acceleration in the X plane to detect inversion tamper;

monitoring for change in acceleration in the Y plane to detect tap; and

monitoring for change in acceleration in the X and Z planes to detect removal tamper.

2. The method of claim 1 , further comprising;

establishing steady state acceleration values for each of the X, Y, and Z planes; and

comparing current X, Y, and Z plane acceleration values to their respective steady state acceleration values.

3. The method of claim 2 , wherein the step of establishing comprises:

sampling and saving a predetermined number of acceleration values for each of the X, Y, and Z planes;

discarding the saved values if the predetermined number of acceleration values for each of the individual planes are not within predetermined values of each other, and repeating the sampling step;

averaging the samples for each of the X, Y, and Z planes individually; and

setting the averages for each of the X, Y, and Z planes as the steady state values.

4. The method of claim 2 , further comprising establishing steady state values upon power up of the electric meter and periodically thereafter.

5. The method of claim 1 , further comprising:

reading signals from the accelerometer representative of the X and Z planes;

determining whether the signals exceed a predetermined threshold;

determining whether the electric meter is powered down; and

generating a removal tamper alarm.

6. A method for determining the occurrence of a meter tap, comprising:

providing an electric meter including at least a register;

associating an accelerometer with the register, where the accelerometer is capable of providing signals representative of acceleration in the Y plane relative to a front view of the electric meter;

reading signals representative of acceleration in the Y plane from the accelerometer;

averaging the signals representative of acceleration in the Y plane for a predetermined time period;

comparing the average to a predetermined threshold value;

identifying occurrence of a potential tap if the average exceeds the predetermined threshold; and

identifying occurrence of a tap if the average drops below the predetermined threshold value within a predetermined time.

7. The method of claim 6 , further comprising:

associating a display with the electric meter;

starting a first timer upon identification of a first tap;

monitoring signals representative of acceleration in the Y plane to determine the occurrence of another tap; and

activating a countdown display timer upon timing out of the first timer if a second tap is not detected prior to the first timer timing out.

8. The method of claim 7 , further comprising:

starting a second timer concurrently with activation of the countdown display timer;

identifying a potential double-tap if a tap is determined to have occurred after the second timer times out and before the countdown display timer times out; and

identifying occurrence of a double-tap if no further tap is determined to have occurred within a predetermined time period following identification of the potential double-tap.

9. The method of claim 8 , further comprising:

starting a third timer concurrently with identifying occurrence of a double-tap;

identifying a potential triple-tap if a tap is determined to have occurred after the third timer times out and before the countdown display timer times out; and

identifying occurrence of a triple-tap if no further tap is determined to have occurred within a predetermined time period following identification of the potential triple-tap.

10. The method of claim 6 , further comprising:

sampling and saving a predetermined number of acceleration values for the Y plane;

discarding the saved values if the predetermined number of acceleration values is not within predetermined values of each other and repeating the sampling step;

averaging the samples for the Y plane; and

setting the average as the predetermined threshold value.

11. The method of claim 10 , further comprising:

setting the average as the predetermined threshold value upon power up of the electric meter; and

periodically re-sampling, discarding, averaging, and re-setting the predetermined threshold value.

12. An electric meter, comprising:

a housing;

a register;

a display; and

a three-axes accelerometer,

wherein the accelerometer is associated with the register, mounted in the housing, and configured to providing signals representative of acceleration in X, Y, and Z planes relative to a front view of the electric meter; and

wherein the register is configured to monitor for change in acceleration in the X plane to detect inversion tamper, monitor for change in acceleration in the Y plane to detect tap, and monitor for change in acceleration in the X and Z planes to detect removal tamper.

13. The electric meter of claim 12 , wherein the register is configured to establish steady state acceleration values for each of the X, Y, and Z planes and to compare current X, Y, and Z plane acceleration values to their respective steady state acceleration values.

14. The electric meter of claim 12 , wherein the register is configured to activate a display function upon detection of a valid double-tap on the meter housing.

15. The electric meter of claim 14 , wherein the register is configured to activate an alternate display function upon detection of a valid triple-tap on the meter housing.