I'm about to start a project, where I'm sniffing data between remote controls and flight controllers on RC copters and doing stuff with that information. Do all (or most) flight controllers use the same protocol to communicate with the remote controls, or does it vary based on which one you buy? I would be testing on drones (DJI phantom and the like).
So, my real question is:
If I want to write something to read the data, will I need to buy a different flight controller for each protocol used, or do they all use the same protocol, and I can just buy one flight controller, and the info I can get out will be the same for all types of flight controllers?
Also, are the protocols only spoken by the ground remote control and the flight controller? Does the receiver care what protocol is being used, or is it just a middle man?