Automatic Doors

[PurpleSplurp]

How do automatic doors work?

[BillyBB]

Many use microwave frequency to detect movement towards them, alot like police radar speed guns but much lower power.

[rccatnap]

BiilyBB is quite right, though the answer is strictly illustrating why they work. Automatic doors come in many guises. All of them require some form of sensor, be it motion, heat, proximity of a vehicle, to trigger the switch to provide the power to enable the opening mechanism to work. Once the doors have that 'trigger', they can be pulled up and over, rolled up, simply opened like a normal door, slid open, revolved, a barrier lifted or dropped, are just some of the main ways. The actual mechanisms used are many and varied, as are the safety features to prevent anyone (or thing) being trapped. Doors can be powered by a simple electric motor or hydraulic ram or, as in the case of lift sliding doors, a scissor mechanism. Hope this helps.