[jofzar]

You can probably just use a cheap motion sensor instead of the webcam if you wanted to. There so many now

[hipjiveguy]

If you have some to suggest, I'd love to hear it... TIA!

[bayesianbot]

Something like LD2410 [0]. IIRC there's newer ones that report accurate position and even heart beat rate, but I've forgotten the names of those..

[0] https://dronebotworkshop.com/ld2410c-human-sensor/

[dimitri-vs]

What's your budget? https://en.tokyodevices.com/items/128

But seriously you can probably DIY something a lot cheaper.

[danielheath]

Found a few aliexpress sellers offering LD2410C's, but all cost 30% more than the webcam I used.