There are three primary technologies: PIR (Passive Infrared), Microwave (Radar), and Dusk-to-Dawn (Photocell). PIR sensors detect heat signatures and are best for indoor use or direct line-of-sight paths. Microwave sensors are more sensitive, can detect motion through thin walls/glass, and are ideal for large warehouses or security lighting. Dusk-to-Dawn sensors respond only to ambient light levels. For B2B sourcing, ensure the detection range (usually 5-8 meters) and delay time (30-60 seconds) align with your specific application.