Pyroelectric IR motion sensor

1. A motion sensing device, comprising:

an array of pyroelectric IR (PIR) sensors; and

a Fresnel lens including a plurality of lenslets, wherein two or more lenslets are each configured to direct received IR (IR) radiation to at least two of the PIR sensors in the array of PIR sensors.

2. The motion sensing device of claim 1 , wherein the plurality of lenslets are configured in an asymmetric pattern.

3. The motion sensing device of claim 1 , wherein the focal point of the Fresnel lens is behind the array of PIR sensors.

4. The motion sensing device of claim 1 , wherein the array of PIR sensors has at least a pair of PIR sensors separated from a third PIR sensor by a substantially similar distance.

5. The motion sensing device of claim 1 , wherein the array of PIR sensors includes at least two PIR sensors mounted such that the array of PIR sensors has a wider field of detection than the field of detection of a single constituent PIR sensor.

6. The motion sensing device of claim 1 , further comprising a security system coupled to the array of PIR sensors.

7. A non-transitory computer-readable medium, comprising:

instructions stored by the non-transitory computer-readable medium, wherein the instructions are configured to cause a processor to:

initiate receiving pyroelectric IR (PIR) sensor array data;

initiate extracting angular position features from the PIR sensor array data; and

initiate identifying the relative angular position by applying a pattern matching algorithm to the angular position features.

8. The non-transitory computer-readable medium of claim 7 , wherein the PIR sensor array data is a time series of data.

9. The non-transitory computer-readable medium of claim 7 , wherein the angular position features include one or more of a peak position, an amplitude, or a polarity.

10. The non-transitory computer-readable medium of claim 7 , wherein the instructions are configured to cause the processor to initiate training the pattern matching algorithm with training data.

11. The non-transitory computer-readable medium of claim 7 , wherein the instructions are configured to cause the processor to:

initiate determining, from the PIR sensor array data, a normalized output magnitude across all PIR sensors;

initiate comparing the relative angular position to a proximity lookup table to identify a proximity threshold; and

initiate comparing the normalized output magnitude to the proximity threshold to determine if the target is within a threshold distance, beyond a threshold distance, or at a threshold distance.

12. The non-transitory computer-readable medium of claim 11 , wherein the instructions are configured to cause the processor to initiate training the proximity lookup table with training data.

13. The non-transitory computer-readable medium of claim 11 , wherein the instructions are configured to cause the processor to initiate, in response to identifying the target is within the threshold distance, initiating turning on one or more of a camera, a light, an alarm, or a combination thereof.

14. An apparatus, comprising:

a processor; and

a memory coupled to the processor and configured to cause the processor to:

initiate receiving pyroelectric IR (PIR) sensor array data;

initiate extracting angular position features from the PIR sensor array data; and

initiate identifying the relative angular position by applying a pattern matching algorithm to the angular position features.

15. The apparatus of claim 14 , wherein the PIR sensor array data is a time series of data.

16. The apparatus of claim 14 , wherein the angular position features include one or more of a peak position, an amplitude, or a polarity.

17. The apparatus of claim 14 , wherein the memory is further configured to cause the processor to initiate training the pattern matching algorithm with training data.

18. The apparatus of claim 14 , wherein the memory is further configured to cause the processor to:

initiate determining, from the PIR sensor array data, a normalized output magnitude across all PIR sensors;

initiate comparing the relative angular position to a proximity lookup table to identify a proximity threshold; and

initiate comparing the normalized output magnitude to the proximity threshold to determine if the target is within a threshold distance, beyond a threshold distance, or at a threshold distance.

19. The apparatus of claim 18 , wherein the memory is further configured to cause the processor to initiate training the proximity lookup table with training data.

20. The apparatus of claim 18 , wherein the memory is further configured to cause the processor to initiate, in response to identifying the target is within the threshold distance, turning on one or more of a camera, a light, an alarm, or a combination thereof.

21. The apparatus of claim 14 , further comprising a security system coupled to the processor.

22. The apparatus of claim 14 , wherein the processor is a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, a programmable logic device, an application-specific integrated circuit, a controller, a non-generic special-purpose processor, a state machine, a gated logic device, a discrete hardware component, a dedicated hardware finite state machine, or a combination thereof.

23. A method for determining a relative angular position of a target of a motion sensor, comprising:

receiving pyroelectric IR (PIR) sensor array data;

extracting angular position features from the PIR sensor array data; and

identifying the relative angular position by applying a pattern matching algorithm to the angular position features.

24. The method of claim 23 , wherein the PIR sensor array data is a time series of data.

25. The method of claim 23 , wherein the angular position features include one or more of a peak position, an amplitude, or a polarity.

26. The method of claim 23 , further comprising training the pattern matching algorithm with training data.

27. The method of claim 23 , further comprising:

determining, from the PIR sensor array data, a normalized output magnitude across all PIR sensors;

comparing the relative angular position to a proximity lookup table to identify a proximity threshold; and

comparing the normalized output magnitude to the proximity threshold to determine if the target is within a threshold distance, beyond a threshold distance, or at a threshold distance.

28. The method of claim 27 , further comprising training the proximity lookup table with training data.

29. The method of claim 27 , further comprising, in response to identifying the target is within the threshold distance, initiating turning on one or more of a camera, a light, an alarm, or a combination thereof.