D202X is 2 elements PIR sensor, with small detection angle. Mainly used for toys and other small angle requirement products. PIR sensor sense the motion object, always used to detet the human. There is a detect rang for the PIR sensor. When a people move in or out of the detect rang, the PIR sensor will be triggered. PIR sensor are low-power, small, easy to used. For this reason it can be used for the alarm system and lighting control. PIR sensor also named passive infrared, Pyroelectric or IR motion sensor.