Monday, August 29, 2011

RFID tag cloned using an ATtiny85 and a 1mh inductor

Following http://svn.navi.cx/misc/trunk/avrfid/avrfid.S I was able to clone my company parking lot's RFID card to an ATtiny85 microcontroller with an inductor connected to it's external clock pins.

This was made possible thanks to the advice (and code) from a nice guy from #avr channel on Freenode nicknamed 'RikusW'.

Thanks to him, I was able to use another ATtiny85 chip I had as the clock source to reprogram what I thought was a "bricked" ATtiny85 after programming it's LFUSE byte to use external clock.

The Attiny85 on the right is programmed to provide external clock for the Attiny85 on the left
I've also added an on/off switch for RFID skimmer:

Unfortunately I must place the tag _really_ close to the reader. But it does work:


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3 comments:

  1. UnknownSeptember 1, 2015 at 3:53 AM

    Hi Avri,
    Can you please point out how to use another ATTINY 85 to reprogram a bricked ATTINY85.

    ReplyDelete
  2. AvriSeptember 1, 2015 at 11:18 AM

    Hi Ankit,

    Sorry. I couldn't find the source code that 'RikusW' gave me back then. But I guess you could use something like this:
    Generate high frequency square wave

    ReplyDelete
    Replies
    1. UnknownSeptember 4, 2015 at 9:40 PM

      Hi Avri,
      Just to be sure I will need a freq of 125Khz correct. I tried with 125Khz but still getting
      C:\>avrdude -c usbasp
      -p attiny85 -U flash:w:PortB.hex

      avrdude: warning: cannot set sck period. please check for usbasp firmware update
      .
      avrdude: error: programm enable: target doesn't answer. 1
      avrdude: initialization failed, rc=-1
      Double check connections and try again, or use -F to override
      this check.


      avrdude done. Thank you.

      Any help will be appreciated.

      Delete

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