Intercepting RF signals from car alarm

I recently bought one of these for my motorcycle, which has two way communication to tell me what happened.. if it was tapped, tilted, etc. It comes with a keychain/LED display that beeps when something happens, and that's okay, but I want to improve upon it.

The keychain beeps and displays messages of what happened, but I worry that it wont wake me up if I'm sleeping or it's in another room. My goal is to make a simple device that listens for the same signal (if it was tilted or shocked) and then handle that from my home server. I'd setup maybe SMS notifications, or turn on my Sonos alarm to a particular MP3 or something.

The part I need help with is a course of action for getting the signal. My first thought was to modify the keychain itself since it's all hooked up.. but I'm worried about possibly damaging it and then having nothing.

My ideal scenario would be scanning to figure out the frequency after pressing buttons perhaps and creating a simple device that'll catch it if it matches the one that my keychain catches.

Anyone have any thoughts or direction for me?


You need to know at least the signal frequency, and hopefully will have captured some transmissions before anyone can guess how difficult the task might be.

The easiest approach is to buy a spare keychain receiver and modify that.

You could try the RCSwitch library.
I am using the receive demo code to read 433MHz signals.