I want to start with the RFID by building up a simple lock which can be unlocked with another RFID transponder.

The device which has unlocks the lock and has one RFID transponder will be a BeagleBone Black. I would like to have the key as some static RFID transponder (sends only its key).

To achieve this I have following questions:

  1. Is it possible to connect a RFID antenna and control it just with GPIO and PWM or does it necessarily require an own micro controller
  2. What protocol is used for data communication between the RFID transponders
  3. Where or how do I set a key on a static RFID transponder
  4. Are there any resources I should read additionally?

1 Answer 1


1) An RFID antenna is a piece of analog circuitry and requires its own analog recieve/transmit circuitry. You can generally get modules that do this all for you and speak I2C/SPI/serial to your controller. That's by far the simplest way of doing this.

If you limit yourself to the 125kHz cards you can do it with just a GPIO pin (provided your controller is fast enough to PWM at that speed) and a bit of analog wiring: http://scanlime.org/2008/08/simplest-rfid-reader/ (note: requires good understanding and osciliscope)

2) Protocols, there's a lot: http://rfid.net/basics/186-iso-rfid-standards-a-complete-list-

3) The simplest transponders (cards, tags) just respond with their serial number, and you use that to decide whether to open the door. If you want cryptographic security, research MIFARE.


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