I have several objects in my pockets that do stuff when I put them near things:

  1. A token to disable a house alarm
  2. A Transport for London Oyster Card
  3. A security pass

And in the not-too-distant-future, I wouldn't be surprised if my phone used NFC to, for example, pay for stuff.

What kind of hardware do I need to figure out what "protocol" these objects use to communicate? Is there any (affordable) hardware to read from a wide variety of RFID/NFC? The Oyster Card uses Mifare, I think, but I only know that because of a little reading around the web.

I know nearly nothing about wireless communications, so apologies if I'm using the wrong terminology.

Photo showing RFID tags

  • 2
    \$\begingroup\$ You could try experimenting with an RFID reader, with software like the RFIDIOt you can tell a lot. rfidiot.org/#What_can_it_read \$\endgroup\$ – Toby Jaffey Aug 14 '12 at 10:50
  • 1
    \$\begingroup\$ If something like RFID_IO_T does not elicit a response you could add a search coil and observe results on eg a pocket oscilloscope when in use. Or log the envelopes present (ie modulation signal) and compare them with characteristic patterns for various systems. Your site security people may or may not react to your peering at a pocket 'scope while you enter the plant. \$\endgroup\$ – Russell McMahon Aug 14 '12 at 11:12
  • 1
    \$\begingroup\$ If they mind someone peering at a pocket scope, then either a poor protocol was implemented which heavily relies on 'security by obscurity', or the security people watch too much TV and have an unstoppable urge to feel important. \$\endgroup\$ – jippie Aug 15 '12 at 7:01

http://www.adafruit.com/products/364 plus an Arduino is easy to get started with if you want hardware development.

Even easier though is getting a SCM SCL3711 USB NFC stick and running it with libNFC.

Those are just for NFC and 13.56 MHz though. The security thing could be an older HID key and use 125 kHz and for that you'd need other hardware like an HID reader off ebay, they can be cheap there. They usually put out Wiegand data that is easy to read.

It really all depends on who manufactured the thing you're trying to interact with. I don't think there is really one universal device for all this, but if there is, I'd love to know about it.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.