This is an Automatic Light Switch with mmWave Human Presence Sensor HLK-LD2412 (or HLK-LD2410).
It turns the light ON automatically when someone get into the room, and turns it OFF when no one is in the room.
Input voltage could be 110V or 220V AC.
Maximum load is 10A
Maximum distance for LD2410 is 6 meters and for LD2412 is 9 meters.
You need to preset the module with your smart phone via Bluetooth using this app (HLKRadarTool)
For Android :
https://play.google.com/store/apps/details?id=com.hlk.hlkradartool&pli=1
For IPhone :
https://apps.apple.com/us/app/hlkradartool/id1638651152
Parts list:
IC 7805
Presence Sensor module HLK-LD2412 (or HLK-LD2410)
Power Supply 12V 3W (Hi-Link PM12)
LED 5mm
Terminal connector HB-825 2P (2pcs)
Diode 1N4007
Resistor 1K (2pcs)
Capacitor 100nF (2pcs)
Capacitor 100uF 16V (2pcs)
Transistor 2N2222
Relay 12V 10A
Circuit:
You can download the Gerber file of this PCB from here:
https://drive.google.com/file/d/1HQf6qVNDbtGP12fqSohFyyrKTdG5Y4Cd/view?usp=sharing
Watch this video for more details: