PC unlocking with an xNT

edited December 2015 in RFID/NFC
Hi. I've had my xNT about a year now and have finally got round to making something other than an Ezon lock work with it. My current (almost finished) project is to unlock my PC with the implant.

It basically a NFC reader that will type "Ctrl-Alt-Del [password] enter" when it detects my implant's ID. It acts as a USB keyboard so that I could use it at work without having to install any software that might not be approved by the infrastructure guys.

The core of it is a MSP430F5510 microcontroller and a TRF7970A NFC transceiver. The antenna is a custom inductor antenna that works reasonably well with the xNT. Not an amazing range, but less fussy on opsition than a PCB antenna. I can't take the credit for the antenna design as that was the work of Mathieu Stephan.

It can also be done with some off-the-shelf development boards which was version 1.0.

Anyway, if anyone's interested, let me know. I'm not trying to sell these. I'm happy to share the design (hardware and software) with anyone who wants it. I might be able make a few and sell them at cost, but don't really have the time.


  • how much is the cost per unit?
  • Good question. I must admit I hadn't really thought about it as it's just a personal project. Maybe about £15 or $20 just to cover costs and postage.
  • Interesting - so will the password be hardcoded somewhere?
  • The password is stored in the flash memory of the microcontroller. It's not encrypted right now, but it could be. The device appears as a USB keyboard and also a USB serial port. You can use this serial port to change but not read the password.

    The current state of the project is that I have a working PCB with a mistake that needed some ugly soldering to fix. (The IC just to the right of centre in the photo.) I'll be ordering a corrected version soon. Whilst waiting for that I'll tweak the software.

    I was really just wondering whether it's worth making a few or not.
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