So, I need to figure out what ir protocol a controller board uses. I know how to do it with a remote, but how would I do it with the board? Can I reverse engineer the ir reciver to find it's protocol?

I wouldn't try reverse engineering in this case but rather trial and error.. Find a protocol, try to apply it to the ir, if it works you've found the protocol; if not, find another one

@ananaszjoe there are so many fucking protocols.

@ananaszjoe found aflaw with that. It's not the recover that parses which ir channels it used. The microcontroller on the board makes sure that the ir frequencys are correct.

@ananaszjoe could I JTAG it and rip the firmware, see what's going on and what the controller is doing to the ir sensor? I have no clue how id do it but...

@hyperlisk That's beyond my realm, that's why I wouldn't do that. It might be more fruitful though

@hyperlisk: If debuggin ports aren't disabled, you can extract the firmware and disassemble it (if they are, you can probably resort to glitching to get the firmware image). Then you could look around what happens in interrupts that might be triggered from the pin the IR receiver is connected to (EXTI, timer, serial interface, etc.). Maybe you'd find something useful there.

Depending on the device, it might be easier to brute-force it: Throw some random protocol or data at it via IR and check if something happens. If you can automate this, that is.

@7400 so I do have a usb port, can I steal the firmware from there or do I connect a computer to it and use a special tool?

@7400 I'm gonna be honest I am pretty fucking clueless on most of this.

@hyperlisk: Step 1 of reverse engineering is always research. The time finding out what is documented about your device or what somebody else has found out already is well spent pretty much always. Any small piece of information helps.

If you want to reverse engineer the firmware and don't have a debug port available and can't desolder some external memory to retrieve its contents, here's a nice summary on glitching to get it via USB: https://youtube.com/watch/... (sorry for the video, I don't have a writeup at hand right now). This will of course be different if you have an embedded Linux system or something else in your device.

When you obtained the firmware image, you'll have to start analysing it. How hard that will be is difficult to estimate in advance.

@7400 thank you very much 🤠