I'm having a bit of an issue running two ID12s.
They don't work if both are connected and enabled. They are around 10cm from each other, and if I pull the Reset connection (normally to +5v) on one, then the other works ok.
Is there a way around this? I have no means to try them further away at the moment, as I don't have another breadboard to hand.
limitations
There are a few limitations I wanted to point out quickly. Sadly, the ID-2 / 12 /20 , as with most readers, can only read one tag at a time. In fact, having 2 or more tags in the readers range will cause it to not read any tags at all. So, if you need to detect the presence of many tags, you will need to figure out another way, get a different sensor, or buy a bunch of these. But… more than one reader right next to each other can cause none of them to work due to interference. You can wrap the bottom and sides with foil to help cancel the interference (be careful not to short the reader with the foil). Lastly, the range, even on the ID-20 is less than 4in real world. That means you can’t easily use these for detecting finish times in a race or anything like that.
That's surprising on the ID-12 though. I have one of those and the detect range is really close. Probably within 1cm. I would think that you are far enough apart. The ID-20 has more power and a longer range which I could see causing interference.