What Type of Sensors are Used in Automatic Doors?

Published on
April 14, 2021 4:28:09 PM PDT April 14, 2021 4:28:09 PM PDTth, April 14, 2021 4:28:09 PM PDT

We use automatic doors in our everyday lives. From grocery stores, to airports, the mall, and even within our own homes. You walk up to them, the sensors open the door, and you go about your day. What may have amazed people 70 years ago, we find commonplace. But have you ever wondered how automatic sliding doors work? Learn more about the three different types of sensors used in automatic doors that make our lives so much easier.


Optical Sensors

Most doors use optical sensors, also called motion sensors. These detectors are installed on the door frame, and detects anyone that approaches. The detector sends out a microwave beam (10.5 GHz), which points downward to see anyone or anything approaching. The only downfall with this type of door sensor is if you stand completely still, or are moving very slow, it may close on you or before you get to the door. 


Presence Sensor

Another type of automatic door is a presence sensor. This is a sensor designed by using a mat on the ground, and when someone steps on it, the door opens. It remains open until the person, or object, such as a shopping cart, has left the mat. If someone else steps on the mat while you are still on it, the door will not close, because it still feels the presence. Most of these doors have mats on either side of the door, for easy use. That is, unless it is a one way-door, as sometimes seen in automated swing doors.


Infrared Sensors

The final kind of sensor is an infrared sensor. These mounted active infrared safety detectors scan the air around the door to see when someone enters. It looks for the individual’s heat signature and movement, and when it detects a change, it will open. The owner of said door can change the door's ability to detect, by changing the height, width, and more, of the area it scans. This way, someone walking 10 feet away will not open and close the door, but someone walking up to it within 5 feet will trigger the door.


All Together Now

Often, these different sensors will be used together, combining two or three of them to complete a door opening system. This changes the detection pattern. If the door uses an optical sensor and a presence motion sensor, it will open when someone gets near the door, but will also remain open if someone is taking longer than anticipated, as they are standing on the mat leading up to the door. This will prevent the door from closing on someone prematurely. 


Next time you use an automated door, try to guess which sensor, or sensors, it uses as its door operator.