Buffer sensor Buffer sensor includes rubber pad and aluminum grille pad, both of which are installed on the ground in front of the automatic door. Its working principle is: when people or things press on the mat, the mat is mechanically deformed and sends a signal. This sensor is characterized by clear detection range, accurate signal and stable operation, but its durability makes the life of the cushion slightly worse. When using, it is necessary to prevent overweight and fire prevention. The sensor belongs to static detection type. Active infrared sensors Active infrared sensors can emit invisible infrared beams. When the light beam hits the human body and other moving objects, the light beam generates a variable signal, which is amplified, shaped and instructed to drive the motor to work. Its main characteristics are accurate detection, strong anti-interference ability, good durability, and little influence by temperature change, but it should be protected from rain and snow. The sensor belongs to static detection type. Passive infrared sensor The new Heng Chang external sensor is a kind of thermal sensor, and its basic principle is to use the temperature difference photoresistor effect. When there is a target in the detection area, the infrared detection element can receive the far infrared ray with a fixed wavelength emitted by the target thermal object, and then output an electrical signal to instruct the door leaf of the automatic door to open and close. Its main features are clear detection range, large detection area and durability, but it is only suitable for detecting objects with temperature and has no effect on objects without temperature. There are several types of acoustic sensors, such as ultrasonic, radar and microwave. They can emit ultrasonic or microwave models. When the signal encounters an obstacle, the wavelength or frequency of the sound wave changes, generating a signal to control the motor switch. Its main characteristics are little influence by ambient temperature and good durability, but its anti-interference ability is poor, and its detection range is not very clear, so it has a certain application range. The electric eye is a sensor that uses people or things to enter the detection area to block the light, so that the receiver can't receive the light, and detects and sends a signal through the change of the light. It is mainly used to smooth the gap between the two movable doors of the automatic door and carry out anti-pinch safety protection. Nowadays, modern buildings are equipped with automatic doors, and the automatic door system relies on reliable sensor systems to ensure its work and safe operation. There are many kinds of sensors, ranging from photoelectric sensors that can identify the direction and distinguish between people and vehicles to sensors that provide position and prevent extrusion and collision. Therefore, when selecting the automatic door sensor, we should pay attention to the installation location and use requirements of the automatic door.