Over the last weeks I've been working together with Milosch and Brita from bitmanufaktur.de on OpenPCD, a Free Software and Free Hardware design of an RFID reader for popular 13.56MHz based protocols such as ISO 14443 and ISO 15693.
The hardware design will be released under a CC attribution share-alike license, the reader firmware and drivers (librfid glue code, plus some extras) will be released under GNU GPL.
We now have our first fully functional prototype, happily reading ePassport samples and the like.
In addition to being free (and being able to controlling the bare hardware because of the firmware source code) this reader gives an unique opportunity to study RFID signalling, since various analogue and digital test signals are available on headers or (currently BNC, later U.FL) receptacles.
Also, this device can be used to generate arbitrary modulation patterns, with full user control on frequency, modulation width, depth, etc.
We're currently too busy to release the code and docs in an appropriate way, but my hope is that you'll be able to check out a first release within the next two weeks.
The next goal is a similarly 100% free RFID PICC (transponder side) simulator. We're already working on this for some time, but I don't want to blow too much of the good news weeks before you will be able to actually check out the code and hw design. Stay tuned..
Oh, and not to cause misunderstandings: Some time ago I was mentioning that I'd be working on an incredibly cool Linux project in China. This RFID stuff is _not_ what I was talking about, even though I still think it is extremely cool ;)