SM125 125Khz RFID Read/Write Library

I've recently been working on a project that utilizes the SM125 RFID module from SonMicro. As part of that project I made this library that implements all of the publicly described functions in the SM125 datasheet. There is some functionally mentioned in the datasheet that unfortunately isn't described well enough for me to implement it yet.

The library allows reading EM4102 cards and reading/writing Q5 and Atmel T55x7 125khz cards. I have done quite a bit of testing, but as this is my first Arduino library, its very possible I missed something.

The code is available at GitHub:

I hope it is useful to someone, somewhere.


I am hoping I can get hold of the author of this thread. I have a project that uses the SM125 RFID Module from Cooking Hacks. I will be using multiple antennae which is connected by way of a matrix of optorelays. Each relay will connect an antenna to the SM125. Upon connection, I would like to issue a command to read the tag, if present, which is sitting on the antenna. The pseudo-code is as follows:

  1. Activate next optorelay (connect the antenna) activate SM125
  2. Is there a tag? issue read command
  3. if found, read, record, and report the tag otherwise go to 1

I hope I have explained my request. thanks,