Copying my garage remote control code

Hi

I'm working on a project where I need to open my garage door from my arduino. There are two different ways of doing this: 1.) open the existing remote and then try to wire it to the arduino 2.) determine the code of remote and then use a transmitter to send this code using the arduino. I've opted for 2.

I've used a SDR and Audacity to copy the code emitted by the remote. Please see the attached two images below:


(the full code)


(zoomed in on one of the large blocks)

Are these smaller blocks essentially defined units of time during which the remote is either on or off (e.g. a long block is 4 units and a short one is 1 block)? Do I just have to manually go through each block to discover the code?

Any ideas much welcome (including as to whether this is a feasible project).

Thanks

You probably won't be able to discover the code. Garage remotes are very effectively encrypted, so the only feasible approach is to have the Arduino "push" the buttons of the control.

jremington:
You probably won’t be able to discover the code. Garage remotes are very effectively encrypted, so the only feasible approach is to have the Arduino “push” the buttons of the control.

Ah does the code change each time then? Also, I know I can buy another remote and use the existing one to copy the code to the new device - how do you think this works?

Many or most garage remotes use a rolling code in order to defeat a "replay attack".

With two remotes, there is probably an internal ID, so that the receiver can keep track of the last code emitted by each one.

Actually there is a THIRD way. Use the Arduino to push the inside door-open switch. Use a relay because the control wiring is probably AC.

Paul