On which technology does Automatic Doors work?

[Kross]

Automatic doors are those doors that open by itself as someone approaches it. Automatic doors are being widely used in malls, eateries and corporate organizations.

I am wondering the technology that powers automatic doors. What kind of technology is being used to power automatic doors?

 

[Fidelia]

Automatic doors mostly use infra red sensors to detect people that approach it. Some use Radar sensors too. They are sensitive to movements.

 

[King Belieal]

There are some that use the change of pressure on the floor around it as the person is approaching to detect humans approaching to open the doors automatically.