Sensor is the most important part in automatic doors and also an indispensible part in modern intelligent access control system. Along with the continuous development of automatic doors, their sensor is also improving constantly. Sensors of automatic doors can be divided into two categories: microwave sensor and infrared sensor.
Microwave sensor, also called microwave radar, can response to moving objects. It is applicable to places where people walk at a normal speed. Its disadvantage is that when people stay still near the door, radar will not response any more. Then the door will close and may clip people.
Infrared sensor can response to objects by recognizing objects' temperature. As long as the objects are in the scanning range of sensor, they can be detected no matter they are moving or not. The disadvantages of infrared sensor: reaction speed is slower than that of microwave sensor; it cannot response to human when the temperature of human body is close to the environment temperature in summer, or people wear to much clothes in winter.
