Patent ID: 8326569

Claim:
An acclerometer system for determining if a device has been tapped, the system comprising: accelerometer circuitry outputting a temporal acceleration signal; an input for receiving a jerk select signal; a register for storing the temporal acceleration signal at time N−1; a subtraction circuit receiving from the register the temporal acceleration signal at time N−1 and subtracting the temporal acceleration signal at time N−1 from the temporal acceleration signal at time N producing a jerk signal; a multiplexor for receiving the jerk select signal from the input, the temporal acceleration signal from the accelerometer circuitry, and the jerk signal from the subtraction circuit and for outputting a multiplexor output signal of either the temporal acceleration signal or the jerk signal dependent on the jerk select signal; and a computation module receiving the multiplexor output signal and comparing the multiplexor output signal to at least one threshold to determine if the device has been tapped.