I have a line 6 fm4 pedal that takes its own special expression pedal 0-10k linear I think. I am new to this and want to make a special control from my guitars pick guard and or a light control for hand use. complicated maybe but simple parts to put together. ive seen these new midi syhth controls but light and or theremin, which I have one of. I want to get into diy mods and think this will be a simple thing to some people. anyone help ?