I'm using this device for that exact purpose and it has been working, almost too well. I live in a condo and it was picking up a neighbor through the wall. I thought I was getting false positives before I figured it out. I had to move it about 5 feet away from the wall. It was picking them up from the "back" of the device.
I'm using this driver [BETA] Tuya Zigbee mmWave Sensors with the "Sonoff SNZB-06P Radar" profile. I had to turn the sensitivity to it's lowest. Our distance from the device ranges from 2 to 6 feet. I'm using Rule machine and similar logic to what's above.
