Handheld data capture system with power and safety monitor and method therefore

1. A motion detection circuit for a handheld item detection system, the motion detection circuit comprising:

an accelerometer, the accelerometer outputting at least one signal corresponding to a measured acceleration;

a differentiator, the differentiator differentiating the at least one signal corresponding to the measured acceleration; and

a motion detection device, the motion detection device evaluating a discriminated version of the acceleration and a discriminated version of the differentiated acceleration to determine whether the handheld item detection system is in motion.

2. The motion detection circuit of claim 1 , wherein the accelerometer outputs a plurality of signals corresponding to measured accelerations along a plurality of axes of motion.

3. The motion detection circuit of claim 2 , wherein the differentiator differentiates the plurality of signals corresponding to the measured accelerations along the plurality of axes of motion.

4. The motion detection circuit of claim 1 , wherein at least one of the accelerometer output signal and the differentiator output is analog.

5. The motion detection circuit of claim 4 , further comprising an analog-to-digital conversion circuit providing a digital signal to the motion detection device based on the analog signal from at least one of the accelerometer and differentiator.

6. The motion detection circuit of claim 5 , wherein the analog-to-digital conversion circuit provides a first digital output corresponding to a first acceleration force and a second digital output corresponding to a second acceleration force opposite the first acceleration force.

7. The motion detection circuit of claim 1 , further comprising a low power input, wherein the low power input selectively controls a signal input to the motion detection device from at least one of the accelerometer and the differentiator.

8. The motion detection circuit of claim 7 , further comprising a processor coupled to the low power input.

9. The motion detection circuit of claim 8 , wherein the processor exits a low power mode upon receipt of a measured acceleration signal from the accelerometer.

10. A handheld item detection system, comprising:

a motion detection circuit, the motion detection circuit including:

an accelerometer, the accelerometer outputting at least one signal corresponding to a measured acceleration;

a differentiator, the differentiator differentiating the acceleration; and

a motion detection device, the motion detection device evaluating a discriminated version of the acceleration and a discriminated version of the differentiated acceleration to determine whether the handheld item detection system is in motion.

11. The handheld item detection system of claim 10 , further comprising a processor in electrical communication with the accelerometer, the processor exits a low power mode upon receipt of a signal indicating that the handheld system item detection system is in motion.

12. The handheld item detection system of claim 11 , wherein the process further:

evaluates the signal corresponding to the measured acceleration; and

determines whether the motion correlates to a predetermined abnormal motion criteria.

13. The handheld item detection system of claim 11 , wherein if the motion correlates to the predetermined abnormal motion criteria, the processor:

prohibits item detection; and

requires user input relating to the integrity of the handheld system prior to re-allowing use for item detection.

14. The handheld item detection system of claim 11 , wherein if the motion correlates to the predetermined abnormal motion criteria, the processor causes at least one stored system charge having a corresponding voltage in excess of a predetermined voltage to be discharged.

15. The handheld item detection system of claim 14 , wherein the predetermined voltage is greater than approximately 50 volts.

16. A method for detecting motion of a handheld item detection system, the method comprising:

measuring acceleration;

generating at least one signal corresponding to the measured acceleration;

generating at least one differentiated signal corresponding to a rate of change of the measured acceleration;

evaluating the measured acceleration and at least one differentiated signal to determine whether the handheld item detection system is in motion;

exiting a low power mode if the handheld system item detection system is determined as being in motion;

evaluating the at least one signal corresponding to acceleration; and

using a processor for determining whether the motion correlates to predetermined abnormal motion criteria.

17. The method of claim 16 , wherein the predetermined motion criteria includes a g force measurement along one or more axes.

18. The method of claim 16 , further comprising the step of prohibiting item detection based on the determination of whether the motion correlates to predetermined abnormal motion criteria.

19. The method of claim 18 , further comprising the step of requiring a user input relating to the integrity of the handheld system prior to re-allowing use for item detection.

20. The method of claim 16 , further comprising the step of discharging at least one stored system charge having a corresponding voltage in excess of a predetermined voltage.