Update: A Google Group has been created to discuss ideas. http://groups.google.com/group/dojo-maglock
I've had a project running for a while to make an automatic sensor for a cat door that reads the RFID chip implanted in the pet and allows access only to the designated cats. I've got most of the hardware ready for prototyping and the project is stalling due to some (hopefully) approaching commitments. It could serve as a very nice access sensor and bookkeeping input device for the Dojo, though. What it needs is some Atmel programming - I can provide the hardware debugging and advice.
This can serve both as a learning project and as my first master project (which means I learn how to teach). The RFID chips (or "transponders") use the TIRIS technology from Texas Instruments. The basic device is a 23 mm long glass rod with the circuitry embedded - for the same price (about $8 each in 25 quantities from DigiKey) you can get them in key-fob forms - complete with its own key ring (481-1135-ND). Each is programmed with a unique 64-bit number.
I have the reader chip and have built a sense coil according to the specs. I stopped as I was abuot to assign pins from the Atmel microcontroller I have (AT Mega16). I've got documentation - not all too clear but clear enough) and I have made a flow chart for the basic reading routine. The Atmel chips are those used in the Arduino, so providing it can run compiled code (i.e., in real time) we could use them as controllers or development systems. I have an Atmel AVR development system that would be available for this project.
We could prototype the reader and have something that would interface with the outside world on a serial port. Readers could be used for access and to log someone's ID when they made use of some scarce resource like food, drink or copier/printer use. There's a system level of design and implementation necessary above the sensor, and there would have to be security considerations brought to bear, since this is a den of hackers after all and nothing quite whets the appetite for adventure like the challenge of security. The challenge runs both ways.
I'm willing to make the time available to help a crew get this running. Let me know if you're interested.
Lee Felsenstein
Comments (4)
Martin Williams said
at 9:09 pm on Aug 17, 2009
I'd be interested in helping out with this. I've got a fair bit of experience programming AVRs (ATMEGA 48/88/168) with avr-gcc, as well as a programmer (AVRISP mkII) and a few spare chips looking for a project.
Dean Mao said
at 3:34 pm on Aug 29, 2009
I just bought a 1200 lbs magnetic lock. Lets make this happen. We don't necessarily have to use RFID initially, we can just use a simple computerized entry, like dialing a phone number and entering a code.
Charles Merriam said
at 12:16 am on Aug 30, 2009
Could be fun. Also, once lock is in place, we could use the same infrastructure for unlock via cell phone call.
Lee Felsenstein said
at 10:56 pm on Sep 15, 2009
I've written up a discussion of the possible house control bus. See it here: <https://hackerdojo.pbworks.com/House-Bus-System-Design>. The main pointis that we have to get a discussion going within a knowledgable group to work out the architecture of whatever we're going to use for access, identification, bookkeeping and control. Let's not just let it grow.
Lee
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