Multiple RC522 RFID Receivers

Hi Guys,

As per title,

I'm working on a project where I need to interface an arduino to several MC522 type RFID readers.

Hardware wise, this is possible, with each device having its own chip select line, but library wise, I havent been able to find anything like it.

Any experiences directly programming these? All I need to do is read the card serial number and compare it with one on the internal memory, but I need to read from several receivers (The same tag can perform different functions,depending on which receiver it is actually read from).

Thanks

You either have to hack the library so you can supply our own chip select line or feed the one chip select line through a multiplexer and have Arduino outputs set the multiplexer address.

Thanks Mike.

Do you know anything about changing the sensitivity of the receivers? I heard the tag can detect a card a few centimeters away, for my application I need to ensure this only happens within 3-5mm.

There is not much you can do with that reader. RFID will always work at zero range so the only way to get it not to work in the 0 to 3mm range is to physically stop the token getting that close. You could always add a distance sensor so you measure the card distance so you only take notice of the card when the distance is "correct" for you. Search for Time of flight distance sensor. They are quite accurate over 10cm.