When people approach the door, the sensor recognizes the body's infrared microwave transmitted to the drive system to open the door, the door automatically closed when people leave. The sensor is the eyes of the automatic door control system, which should be the antenna to pedestrians or moving objects through the sensor. This signal is converted into passive dry contact short circuit signal transmission to the automatic door controller, in order to achieve automatic door open. Sensors with accurate, sensitive, durable features, to achieve automatic detection and control of the most important part of the automatic door, which is widely used in automatic doors.