RFID questions

Discussion in 'The Projects Forum' started by MorrillB, Mar 18, 2013.

  1. MorrillB

    Thread Starter New Member

    Mar 18, 2013

    Me and a few members from a class group are working on an measurement instrument and have a few questions about the workings of our idea. We would like to use an RFID tag and transponder to turn on/off an arduino board attached to an accelerometer. What would be the required tags/transponders and other equipment needed to do this. We want to be able to tap the RF tag on the transponder similar to door access(corporate security like). If there is any information out there for going about this efficiently please feel free to give us as much as possible.

    Thanks for your time. If you have questions or need clarifications please let me know.
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Arduino boards, such as the Uno, do not support soft power switching on board, you'll need to use an external supply, and switch that.

    Fundamentals, with a PIC (similar for AVR) are this:

    uC Sees RFID tag that matches data for shutdown.
    uC sets interrupt on serial data
    uC goes to sleep/low power mode
    When serial data is received from RFID reader, interrupt triggers wake up
    RFID in serial buffer compared to list for startup.
    if matches, continue running
    if no match, set interrupt and go back to sleep, (goto step 2)

    This is accomplished somewhat simpler with an external uC that does all of the I/O, and then switches a power MOSFET on/off to the entire Arduino board. Otherwise, the board itself will be using power for the regulator, programming IC, etc.