How Automatic Doors Work

In this article "How automatic doors work, and 3 automatic door facts you probably didn’t know" we’ll answer all the above questions and more, as well as giving you 3 facts about automatic doors to ‘astound’ your colleagues (or not).

How do automatic doors work?

Automatic doors work using sensors. This basically means, a piece of technology that recognises when a person or object is near, and activates a mechanism that opens then closes the door.

The types of sensors used for automatic doors vary, and include –

Pressure Sensors

From the 1960s onwards, pressure sensors, whether installed in the floor or in mats at entrances and exits, have been used to register the weight of a person when they approach an automatic door. Although a great invention, nowadays, in many modern automatic door systems, pressure sensors tend to be used as backup devices, in case more advanced sensors fail.

Motion detection sensors

Motion detection sensors are used in most modern automatic door systems, and work either using:

• Microwave pulses – Don’t worry, microwave pulses at this level aren’t designed to cook you as you walk through the door, but as with a microwave oven, the microwave pulses the sensor emits, reflect off objects they encounter, before giving the signal to the opening mechanism to activate the door.
• Passive Infrared (PIR) – Far more common than microwave pulse sensors are passive infrared (PIR) motion sensors. Simply put, these sensors detect energy, including heat, as you approach and walk through the door. Amazingly, a PIR motion sensor can even tell how much you weigh – but don’t panic, as far as we know, they keep it a secret.

Access Control Systems

An access control system does away with sensors, and instead relies on the signal to open, coming from key cards, key fobs, smartphones or smart video intercoms. These systems are generally used in private offices or other workplaces, and whilst improving security, they also give authorised users more autonomy to move about properties more freely.

3 Automatic Door Facts You Probably Didn’t Know

1. Automatic Doors Were Invented in Ancient Greece

Strange as it sounds, the first prototype of an automatic door came into existence about 2000 years ago, in Ancient Greece. Apparently, a mathematician named Heron of Alexandria, used a type of hydraulic system powered by atmospheric pressure, generated from a fire. This system was then used to pump water into containers that acted as weights, that in turn, activated pulleys and ropes to open or close the door.

2. Automatic Doors Were Invented to Help Waiters

Well, we’re sure there were more general reasons behind the invention of automatic doors, but one of the earliest recorded uses of a crude type of automatic door, was in 1931, at Wilcox’s Pier Restaurant in Connecticut USA. The doors were installed to help waiting staff open doors whilst balancing numerous plates about their person.

3. H.G Wells Predicted Automatic Doors

In his 1910 novel, ‘When the Sleeper Wakes’, prolific science fiction author, H.G Wells predicts the use of automatic doors when he mentions that "an apparently solid wall rolled up with a snap, to allow them access before it closed again". OK, maybe that one is a bit tenuous.

Contact us

If you’re looking to install power assisted doors in your commercial property, contact Reactive Doors today. As automatic door specialists, we install, maintain and repair all types of automatic doors and pedestrian door systems.