While I developed the Crunchtrack with the automotive field in mind, it became clear pretty soon that the board had a lot of potential in a lot of other applications. The very small board with a powerful MCU, a wide supply range, GSM, GPS and SD card is very flexible, so I bought it to the BattleHack Hackathon to see how far it could go. I pretty soon found three other members to form a team and we started working on an idea I had for a while: an anti-theft device for your notebook that could locate it anywhere and disable it.

Basics

Almost every modern (cheap) notebook has some spare space to install the Crunchtrack; even if you have the latest ultracompact, as long as there’s an optical unit you can swap it for a caddy with a second hard drive, freeing up some precious space.

The Crunchtrack can then be connected straight to the battery connector on the mainboard, to ensure that it will be always online, independently from the OS or any other variable.

Now you can find your PC anywhere in the world, and issue commands remotely.

Disabling the computer

So, they stole your notebook and when you tracked it you found it so far away that’s not worth the trip to recover it anymore. You will want to wipe and disable it. There are a few options for that, depending on your goals. If you want to destroy the data, there are a few ways to accomplish it, as you can see here:

…but that’s messy. A better way would be to have the [always encrypted!] data on an SSD drive and short the notebook battery to the flash chips in a way that would destroy them beyond recovery. That’s a very nice way to wipe data, as it only requires a mosfet and can be used to burn the motherboard too, flipping the finger to the thief that will not be able to resell your notebook anymore.

Building a detonator (don’t try this at home)

For our presentation, we went for a good show for our audience, and decided to use explosives.

Everyone who played with model rocketry will know this basic detonator design: we basically heat up a diode enough to light up a match taped to it, which in turn ignites something else (in our case a strip of firecrackers). I had to put a resistor in series to slow down the diode burning rate, as the LiPo battery I used in the demo was providing too much current and destroyed the diode immediately.

And here’s the final result during our demo at 3:30:

and we f***ing won!!!