You are walking towards the door, just then you are wondering how you are going to open the door. Whether you'll need to drop some bags down, or you'll beckon on someone to help you with the door. As the thoughts run through your mind as you approach the door, "Swoosh!" The door opens itself as if by magic. Oh! What a relief you must have thought. At a moment you wonder, is there a ghost lurking around nearby opening the door for people leaving the shopping mall? Nope!
Would you believe it's pure science and technology?
Automatic doors are one of the best modern inventions. They open and close with the help of simple technology. All you have to do is just walk towards the door and it magically opens for you. All automatic doors, regardless of their design, consists of sensors that help trigger the opening/closing of doors when the need arises. Sensors just like they sound; they sense things.
There are various kinds of sensors used in automatic doors.
Most automatic doors use Motion detection or Optical sensors to activate the opening and closing mechanisms. These sensors are installed on the side of the door our at the top of the frame of the automatic doors. These sensors detect motion in front of the door with the aid of microwave beam(10.5 GHz) that is produced by an antenna installed on the door header and points in the downward and outward direction.
Whenever the optic or motion sensor sense motion nearby, they activate the automatic doors to open and then close. That is why, when you walk towards an automatic door, it will open as soon as you get close enough to trigger the sensors.
Another type of sensor is the Pressure sensor. It senses weight. These weight/pressure sensor are designed in a rubber mat on a specific area of the ground in front and back of the door. If the weight that the rubber mat experiences is more than the set limit, the sensor sends a signal to the automatic door then the door would open.
Other automatic doors require a human interface remote control to open and close the door. When the door receives the signal from the remote control, then it will open.
Automatic doors are usually found in commercial and industrial buildings making it easier and convenient for people to get into and out of buildings. They are especially helpful for those who are handicapped.
Automatic doors are time savers, it reduces the number of times doors are open to persons. Automatic doors become handy when you have shopped till your hands are filled with bags.
Having automatic doors is a step further into the future. And work is always being done to discover better and smarter designs.
Personally, I would love a door that opens with a simple spoken command. What about You? Well, that's the kind of future I'm looking forward to!
I am still that humble dude 
