{"id":159,"date":"2012-06-19T19:49:46","date_gmt":"2012-06-19T17:49:46","guid":{"rendered":"http:\/\/jcoder.me\/blog\/?p=159"},"modified":"2013-02-14T21:16:52","modified_gmt":"2013-02-14T20:16:52","slug":"reading-rfid-tags-with-arduino-and-id12","status":"publish","type":"post","link":"https:\/\/jcoder.me\/blog\/2012\/06\/19\/reading-rfid-tags-with-arduino-and-id12\/","title":{"rendered":"Reading RFID tags with Arduino and ID12"},"content":{"rendered":"

The mission: getting started with RFID<\/h1>\n

With my recent gadget<\/a> order I also bought an ID-12 RFID reader<\/a> with a corresponding breakout board<\/a>. The breakout board is needed because the ID12 chip contacts have a 2mm grid while the breadboards have a 2.54mm grid.<\/p>\n

Step 1 – setting up the circuits<\/h1>\n

Yesterday I soldered the reader and connectors to the breakout board (not a very easy task for a non-soldering-expert like me), and today I tried to get it working. And guess what: it didn’t work :(<\/p>\n

After each step of soldering I checked the connections with a multimeter and everything seems to work fine (except that I got confused, because on the breakout board the pins 3 and 4 both connect to the antenna somehow and are then connected which I did not expect).<\/p>\n

But when trying to get some data out of the assembled circuit nothing happened, and after some checks I found the error: the pin 2 did not connect correctly to the pin on the ID-12 chip. I wasn’t expecting this, so I tried to fix the soldering at that connection, but still no success, so finally I had to solder a testing wire to the pin, and then the contact worked.<\/p>\n

Conclusion up to this point:<\/em> check the soldering connections after each step, even if they look<\/em> good.<\/p>\n

This is how the connections are made:<\/p>\n

\"\"<\/a><\/p>\n

Actually the ID-12 is soldered to a breakout board so this is how everything looks in reality (notice the white wire on the left side of the chip – this is the one that I soldered directly to the chip):<\/p>\n

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(A big thanks goes out to HC Gilje for the good explaination on how to connect the ID-12 chip<\/a>.)<\/p>\n

Step 2 – coding to get some results<\/h1>\n

There is some great example code for reading RFID tag data on the Arduino website<\/a>.<\/p>\n

It works quite well, but…<\/strong> the ID-12 chip uses a serial connection and the Arduino just has one serial port (input: pin 0, labeled RX), and internally the flashing and PC connection also uses a serial connection. So you cannot have both connections set up at the same time (therefore it is suggested to disconnect the ID-12 chip when uploading a new software version).<\/p>\n

But there is a great solution provided by the Arduino IDE: it comes with a SoftwareSerial library (see “File”, “Examples”, “SoftwareSerial”) which turns two normal pins into a serial port. I guess there are some limitations on this, but for me it works quite well.
\nIf you take a close look at the photo and schematics you’ll see that the blue wire (serial) is connected to pin 2 instead of pin 0. This is because I configured the SoftwareSerial lib to use pins 2 (RX) and 3 (TX) to provide a serial port.<\/p>\n

By changing the example code to work with two serial ports and opening a PuTTY on port COM3 I was finally able to see the tag IDs showing up!<\/p>\n

On request (please leave a comment below) I’ll share my code – it is currently not proper formatted and commented ;)<\/p>\n

What’s next?<\/h1>\n

I’m very excited that this worked so well, but I’ll continue building upon the code and circuit layout:<\/p>\n