Today, I released gr-keyfob, a GNU Radio out of tree module to decode and re-encode some wireless key fobs from Hella. These keys are usually used in Audis, VWs, and Skodas, but not the brand new ones with a passive entry system.

I will give a short talk at the SDR Academy, co-located with HAM RADIO, where I describe the work flow and the tools I used to build a receiver.

To see what’s inside, I bought one on ebay and cracked it. Here are some photos at different stages of the disassembly process.

I will add some more information about the frame format soon. Hope you give it a try!