Are MIFARE smart cards programmable in sense I could write a program they could execute?

Variations of MIFARE Ultralight cards are becoming quite widespread. For example, huge transport companies employ them as payment cards开发者_C百科.

As I get from MIFARE site and Wikipedia there's a full-blown microcomputer inside the card - with a processor, memory, etc. When I move the card close to the reader its field induces current in the card antenna, the card computer turns on and runs some complicated protocol to communicate with the reader.

That's all cool but could I write my own program that would run on such a card and do something useful a card doesn't do by default? What are simple examples of what such program could do?

The microprocessor based contactless cards are easy to work with, our company has had good success with the the NXP JCOP product line with wireless capability (this wireless capability is provided via MIFARE technology, but these are microprocessor cards and not MIFARE Ultralight cards.) The JCOP cards let you install your own Global Platform or Javacard cardlet apps on the card and commmunicate with them wirelessly using the ISO 14443 A protocol.

MIFARE Ultralight cards just store data - you can't write a program to run on the card. The MIFARe Classic and Plus variants are similar. MIFARE ProX, SmartMX & DESFire Cards are all microprocessor based cards.

The memory only cards are easy to work with - readers and cheap & easy to obtain via eBay or similar. I'm not sure how you develop with the microprocessor based cards because we've never used them.

I think you need to talk to MIFARE about that. My guess is that have some sort of software development kit as well as a special programmer for the card for potential developers. I haven't fully perused their site, so they may not allow individual developers to work on it, but do the work themselves as a service.