Well, the school year is over, so I thought I’d post up some information about my (extremely cheap and junky-looking but functional) door opener.
The door handle is turned by one 24v globe motor (which have encoders that I’m sadly not using at the moment), and is pulled open by another identical motor. A very affordable ($30) SparkFun RFID reader is attached to the back the door so cards can be scanned from the outside. An arduino controls the process, and drives motors and a cooling fan with 3 darlington transistors.
The arduino was attached to an old Dell laptop, which ran the Apache webserver. A small password-protected php web interface was created to allow door opening from anywhere on campus. KDE4 widgets allowed door opening from computers inside the room, letting my roommate and I avoid walking less than 8 feet (or less) away to open the door for someone.
I also put a password-protected KDE4 widget on our touchscreen mounted on the wall outside of our room, so if one of us forgot our RFID card, we could type in a password on the touchscreen, and the door would open. Fun stuff.
Unfortunately I don’t have too many pictures, and the entire thing is disassembled now. Hopefully next year I’ll improve it (encoders and PID for motion control?) and post some more information.