This product adopts the principle of radar ranging, and the farthest ranging distance can reach 20m. Small size, easy installation, no influence on decoration, ultra-low power consumption, can set the distance of detection, in the set range, as long as there is an object will output relay action, can replace the traditional automatic door, improve the environment caused by misoperation or people have been in front of the door, can not open the door, must leave a distance close to open the door again, or through RS-485 interface output detection distance It is suitable for all kinds of applications that need to detect the distance.