Thank you for excellent concept.

[happytm]

I have tried your code and it shows excellent result. I wanted to bring to your attention similar approach to count people in certain area. Following is link to paper published and they have mathematical formula to count people.

https://web.ece.ucsb.edu/~ymostofi/papers/Mobisys21_KoranyMostofi.pdf

Thanks.

[happytm]

I have taken liberty to modify your code to make it work with web interface instead of serial so that device can be mobile.
https://github.com/happytm/MotionDetector

Thanks.