Microwave motion sensor is combined with microwave detection and light sensing function. It can sense daylight, LED light source and adopts a photosensor that removes IR interference. With high sensitivity and anti-interference capacity, sensors are widely used in the motion activated light control. It adopts zero-crossing detection technology. Through software calculation and control, current flowing through the relay contacts is close to zero at the moment when the relay is turned on or off, effectively improving the lifetime of a relay. This compact motion sensor supports surface mounting and recessed mounting.