(Really) Cheap RFID door opener

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.

Power supply case housing arduino and circuitry, along with door-pulling motor and ridiculously ugly tie-dye duct tape

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.

Touchscreen mounted to wall, password widget not shown. And no, I did not actually go to school in Munich, Germany 😀

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.

Ethan is a computer engineer and open source hardware/software developer from Michigan. He enjoys AVR and linux development, photography, mountain biking, and drinking significant amounts of home-roasted coffee. Find out more at ethanzonca.com.

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Posted in Arduino, Projects
3 comments on “(Really) Cheap RFID door opener
  1. Awesome! You should add facial-recognition so it opens automatically when you walk up (but only for certain people) combined with a spoken password. Hello Mr. Bond.

  2. Dan says:

    Hey, awesome! Im trying to do the same thing, but how were you able to mount it onto the door without drilling holes into it? I was thinking velcro. How did you do it? Any other ideas?

    • Mounting that crazy thing to the door was a bit challenging… I used a bunch of those velcro-ish removable wall adhesive things from wal-mart. They didn’t work out that great, but held everything together for the most part! I helped out a friend with another design this year using a motor on a bracket that hangs over the door (just a piece of bent aluminum). This design is much more robust! The motor pulls a metal wire that is attached to the door handle. His design doesn’t actually pull the door open, but it is extremely reliable. Good luck! Let me know how it goes.

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