Garage Door Circuit - notkevinjohn/PiGarageDoor GitHub Wiki

Lets start by understanding how a garage door works. We have some kind of button, usually right on the wall by the door. When this button is pressed, it causes a circuit to be completed and the motor engages, either to open or close the garage door.

In this project, we want to be able to have a second way of controlling the garage door (we don't want to lose the ability to open and close it from the switch). You could imagine adding a second switch, just like the first, by wiring it in parallel with the first. If either of these two switches are pressed, the circuit is complete and the motor engages.

Of course, that's not what we're really going to do, we are really going to insert an embedded device in place of a switch. It will be able to accomplish the same function, but instead of controlling it with a finger press, we control it with code. Since we can execute that code remotely, this gives us a lot of options of how we control this garage door.