[oidar]

Is there a sensor like this that is open enough for tinkering at home? The radar sensor could be useful for home automation.

[shermozle]

I have four of these around my house and they're a massive improvement on plain PIR for human presence detection. I use them to turn lights and screens on and off and to notify when someone is at the front door.

https://www.athom.tech/blank-1/human-presence-sensor

[AugurCognito]

There are mmWave radar sensors available commercially.