Really cool bit of kit. The Violet Mirror is an RFID reader shaped as a circular disc. It reads 13.56MHz RFID chips based on the ISO14443 protocol .

They are sold out nearly everywhere but you can still get them at planete domotique

These chips are built in to the Ztamps violet sold and also the Nabaztag bunnies. You can also use standard chips complying with this protocol. ISO/IEC 14443 consists of four parts and describes two types of cards: Type A and Type B, both of which communicate wirelessly at 13.56 MHz. Typically, a ISO 14443 tag has a range of 10cm. The 13.56MHz RFIDs have a broad range of applications across the world.

Tags:  Violet tags,  MiFare,  FeliCa
Readers:  ACR122 (Touchtag) and Violet mirror
Application:  Oyster card (transport payment) @london

I have developed an arduino reader which uses the USB host shield from circuitsonline. Nothing fancy just a reader for which the program reads out the tag number. The code can be downloaded here. It is unfortunate that the reader seems not to be sold any longer. Its a long story but the company Violet was taken over a couple of times. At the moment the owners are aldebaran but they do not have it on their website.

There is still a website selling everything except the mir:ror from the Nabaztag stuff on the website from when it was all called Karotz. Hope you can still follow.  The two links below give some support still.

There are a couple of alternatives for the original software. These can be found in the links below:

Maybe the best thing to do is to rewrite the software for the Touchatag reader (also called ACR122) which is quite similar. Personally i like the mir:ror better because it looks more attractive, but then the touchatag is cheaper. You can download the software Violet Mir:ror software

Here you can find my other arduino projects.