The keys to my front door kept breaking off, so, just like everyone would, i built a bluetooth door lock opener :)
Ok, first 2 more video's. One of the first breadboard setup, and one of the inside of the intercom device.
Ok, so i took an MSP430 microcontroller (sampled), and soldered that onto a small piece of protoboard i cut out(less than a dollar). Then added a Relay (from an old device), a HC-06 Bluetooth module ($6.60 incl. shipping on DealExtreme), status led, protection diode, and some resistors (less than a dollar total)
So below $10, this is a pretty low budget hardware solution :)
On the Android side, I'm using BT_Serial_Tester for the first tests (just check the market) The free version can only send numerical values and cannot receive, but thats enough for a raw test of my implementation. For the final app i also want a response like "wrong code" or " code accepted" signalling the results.
Connecting is really easy with the HC-06 bluetooth module. You just have to power it with 3 volts, and connect the RX/TX to launchpad/msp430 TX/RX. Then pair with the Bluetooth module from your phone like you would with any device and you are done!
The code is still very rough, but functional: bluetoothdoorlockCRUDE.txt
And basic schematic - Im not really used to drawing them yet, but it should be clear: