Hey everybody,

First of all I'd like to apologise for my english and say hello everybody here as I am new. I started playing with mbed just a week ago.

After playing for 1 week with mbed and an ID-12 RFID reader I encountered my first problem with my setup. I need no read a TAG ID and be able to say when this tag is removed. I found an example with arduino (http://blog.formatlos.de/2008/12/08/arduino-id-12/) but after having tried for hours I still haven't found the solution.

Can anyone give me a clue about this little (but huge for me) problem?

Thank you very much!

Just try reading the ID periodically (e.g. use a Ticker). When you can't read the ID anymore, this means the tag is gone.

I have an ID-12 and Igor's suggestion makes sense but is hard to do. I'm not sure but maybe toggling the reset pin of the ID-12 will cause it to retry reading the card, or maybe you have to power-off and then power-on the ID-12 to force it to re-read the card.

Hi again. Thank you both for your answers. I finally did it by pulling-down the reset pin and forcing the mbed to read again the ID-12 with the help of a ticker. I do it every two seconds, when no read is detected I assume the card is removed. At the moment it is working flawlessly.