Tuesday, 7 July 2015

MIRRORCROCODILE - a tool that helps to mess around with 433Mhz devices

I think the coolest thing to do with computers is to interact with the real world. Computers used to have parallel ports. Parallel ports made it super easy for tinkerers to interface with the real world. I have seen a lot of projects around parallel port but they are the thing of the past. New computers do not ship with parallel ports – nobody uses them – only people, who want to flash LEDs, when they receive a new email etc.

What is the next best thing? What is the thing that every computer has? USB is hard mess around because it is too advanced for simple projects. You need to use controllers and it gets complicated fast - at least for me.

So then, inspired from that triggertrap post I realized – SOUNDCARD. Every computer/phone has a headphone jack. But what happens if you want to listen to music and flash LEDs? Then you buy a cheap USB soundcard from eBay and use that as a platform (You do not want to fry your onboard soundcard, I think).

Soundcard is basically an ADC and a DAC (microphone and headphone jack).

So I had an idea to strap a 433 MHz transmitter and a receiver to the soundcard. In my head it played out like this :

  • You can record devices that use simple modulations (AM/OOK).

  • You can send signals from the computer(GNURadio).

  • You can use replay (transmit, what was received).


So this project needed a cool codename, NSA has l33t codenames so I came up with MIRRORCROCODILE courtesy of nsanamegenerator.com

 

2015-07-02_16-39-21


2015-07-02 21.25.50

Mirror attack is the simplest, you only have to record and press play.

Here is a video, where I mimic my wireless doorbell signal. Technically it should work most of the 433 MHz devices that do not use rolling code or not use some other signal modulation.
[youtube http://www.youtube.com/watch?v=BpOdoevWoJY]

Or if you want to edit/analyze the data more or even send out completely new stuff - GNURadio should be useful enough.

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