If you want to get started with motion sensors and the like, ESPHome makes it incredibly easy to build your own sensors.

I've just come across a no-name non-contact, high-precision 80 GHz mmWave radar sensor for liquid level detection with a 40m ...

Built your very own parking sensors for the car using nothing more than an Arduino board and cheap components you can find online ...

SJEC-AICTE IDEA lab in collaboration with Department of Electronics and Communication Engineering (ECE) at St Joseph ...