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.
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: