Let's Make Robots!

SM125-IC/M1 RFID reader/writer

Vendor's Description: 

There are a few models of this but the SM125-IC is an RFID Interigator with read/write capabilities and I2C connection capabilities. I have been looking for a chip to base my RFID interigator after for a while and this one in my humble opinion takes the cake.

  • Has internal small microcontroller for small tasks that the programmer can control
  • Has programmable IO pins
  • Has output pins for LCD screen
  • Has I2C compatability as a slave, up to 115200bps
  • Has all processors, drivers, and decoders internal.
  • Ugradable firmware
  • Can run at either 5 or 3.3 volts (3.3 with upgrade to firmware)
  • Supports Sleep Operation (not sure what this meens yet but I think it is like power save mode)
  • The example coding is in C++

The reason that I Like this one, besides the I2C connection and internal Drivers and decoders, is because of all the others I found (ex: MIFARE, TI, etc) this isn't built for a particular purpose or network of products. for example the MIFARE and TI RFID reader ICs, besides not having write capabilities, have extra tidbits in it like MIFARE's Payment system or TI's product tracking software integrated into the IC. these muck up and make things more difficult to work with. also I found onw that had 4 ground pins in a 30 pin Dip package and another with 38 pins in a square package that was oddly sized. Having too many grounds seems redundant and like the chip wasn't planed well and might not work well.

This is wonderfully designed with no extras exept small extras which we all would probably use like integrated LCD support or integrated reprogrammable uController with a few extra IO pins just for people like us who like programming robots and other random things like door locks. I haventfound the exact range yet or if that is antenna specific or programmable but I have found that the pin layout looks simple and well thought out.

here is the SM125 Datasheet (pdf)


The store (http://www.sonmicro.com/index.php)


I found a problem on the store. the store to get them requires 95USD minimum initial purchas. after you have made the first purchase, you may purchase as little or as much as you like. There is still the problem of 95$ to begin with. The proces are as follows:

  • IC (latest version) - 4.50 USD/unit for less then 100
  • Modual (latest with integrated RS232 drivers and other nameless things) - 10.90 US/unitfor less then 50
  • Evaluation Set - 189 USD
  • other tags, antenna, and stuffare available
I am setting a forum post in Electronics section of the forum to discuss maybe ganging up to tackle the 95$ limit. the node is 1419