so ive been sitting on this idea for a while now and finally started messing around with it last weekend. basically i want to use an arduino mega to control my old Yaesu G-800 rotator instead of the stock controller, mostly because the stock controller died and a replacement is like $200+ and that seems insane when i have a pile of arduinos and a couple of stepper driver boards sitting in a drawer.

the rotator itself uses a simple potentiometer for position feedback which should be easy enough to read with the analog input on the arduino, and ive seen a few write-ups where people used an H-bridge or a relay board to actually drive the motor. what im not sure about is how to handle the calibration — like getting the pot reading to map cleanly to actual degrees without a ton of drift over time. also thinking about adding a small OLED display and maybe serial control so i can eventually tie it into my logging software or maybe hamlib.

anyone gone down this road? curious if theres a better approach or if someone already made a library for this kind of thing that i just havent found yet.

yeah i did something similar with an older rotor, different brand but same basic idea. the pot feedback is fine for this, just make sure you're averaging a bunch of analog reads before you do anything with the value, the noise on those things can be annoying especially if the motor is running at the same time. i ended up using a running average of like 10 samples and that cleaned it up a lot.

for the actual mapping i just did a two-point calibration at startup — point it north, hit a button, then point it to a known bearing, hit the button again, and from there it interpolates. works pretty well, ive been running it for about 8 months now and drift is minimal. i think the pot itself just has to be decent quality, the one in those yaesu units is usually fine.

hamlib has rotctld which can talk over serial so thats actually not that hard to implement, theres some example sketches floating around on github if you search for rotator controller arduino, dont remember the exact repo names but they exist.

tangentially related but if you end up wanting to do more automation stuff, a raspberry pi alongside the arduino is a nice combo — let the arduino handle the real-time motor control stuff where timing matters, and the pi handles the higher level logic, logging, maybe a web interface. i built a little antenna switch controller that way and its been solid. the pi runs a flask app so i can control it from my phone which is honestly the main reason i did it.