Garage door opener
November 14, 2010 1 Comment
Here’s a quick description of a project that’s a few years old now. My parents have an automatic garage door, and it has some lights that come on when the door is operated. One of the lightbulbs had blown while I was visiting, so I was up a ladder sorting it out.
As evidence that I’ll never be a professional electrician, while doing this I managed to accidently short a section of the control board to earth with a screwdriver. While I didn’t die or cause any damage, I did make the door start to close.
As evidence that I’ll never be a professional electrician because I am a too much of a physicist, my next move was to do it again to see if it was reproducible. And yes, here was a way to open and close the garage door – touch these two points with a screwdriver.
And so within about a week I had some wires attached to those two points, running along the rafters and down through the wall to a microcontroller circuit mounted on the external wall of the garage. If the correct code is entered, a relay does the work of my screwdriver and opens or closes the door. This is a useful function for my parents, saving them from walking the long way around the house if they need to get into the garage but don’t have the wireless remote on them.
(And yes, if you were clever you could just rip the box off the wall and short the relay, bypassing the key-code. But there are other ways into the garage anyway, so I don’t think you could really call it a security risk.)
The schematics are long gone, but the source is here. I think it was for an ATMega8 (?). I wrote in it about an hour, it just handles a keypad, a relay and plays some super cool tunes on a piezo buzzer. It’s a boring read, but hey whatever floats your boat.
I can however show you a video of the thing in action: