Step 4: Electronics

Picture of Electronics
For the electronics, a simple on/off switch would have worked.  But I wanted to get a little fancier and control the timing of the doors opening and closing.  I made the circuitry from components that are readily available at Radio Shack and Sparkfun.com.   The circuitry just waits for the button to be pushed then switches the air valve on so the door will open.  After a few seconds, the valve switches back off and the door closes.

I mounted a DIP socket, a relay, and a few other components on a Radio Shack perf board, and placed the whole thing inside a plastic junction box.  I also wired in two AC power switches, one supplying AC power to the wall adapter for the circuitry, and the other supplying power to the compressor in the attic. I wanted the whole system to be enabled and disabled from this "control panel", including the air supply.
rhino214 years ago
you could also put a motion sensor near the door so that it opens automatically like the doors at the mall
Plasanator4 years ago
Great job
falcon50524 years ago
an easier yet maybe less geeky way of doing the timing would to use a timer relay rather than a standard relay and a micro-controller, although there is nothing wrong with your set up, it might have saved some time and money.

-Live Long and Prosper
with a µC he can easily add things or change the delay or something like that, personally I'm always using µC for projects because it's so easy to programm and upgrade!
And 2€ for a µC (like the Atmega168) isn't much money :p
thats true... i didn't think about that. you could do more with a micro controller like that. lights and sounds later on if you want to. more options!!!! love them! thats what makes us nerds!
or like a steam machine behind the doorframe so when it opens the steam comes out :D
or maybe a rfid chipcard you have to hold against the door with a little display that indicates you if you're allowed to pass or not ^^
so much possibilities! :D
jj.inc4 years ago
do you have a better description of the wiring, I truthfully don't have any idea how to do it. Great instructable