[szczepano]

esp32-cam microcontroller costs around $6 and you have face detection build in. It have bluetooth and wifi and most of it's drivers code if not everything is on github. Only problem is you need to program it using arduino or other microcontroller hardware.

[ed25519FUUU]

Face detection is nice but body/person detection is much more useful in these setups.

[szczepano]

You mean esp-who ? It uses mobilenetv2 so it's quite possible to train it to detect person instead of face. Didn't tried myself, just started playing with it.