so ive been messing around with an old antenna rotator for probably the last month or so and the controller on it is basically dead, the pot is shot and the original control box is just cooked. instead of buying a replacement i figured why not just roll my own with an arduino and a motor driver board. i've done some basic arduino stuff before like blinking LEDs and reading sensors so im not a complete newbie but this feels like a bigger step.

the rotator motor itself is a pretty standard DC type, i think its somewhere around 24v. my plan was to use an L298N motor driver to handle the actual switching and then just have the arduino read heading from a replacement pot i wired in. eventually i want it to talk to my logging software over serial so it can point the beam automatically when i work a new grid or something. has anyone gone down this road already? im mostly worried about the feedback loop being stable enough that it doesnt just hunt back and forth forever around the target bearing. seen some guys use a PI controller loop for this but i honestly havent messed with control theory since college and i barely remember it

also wondering if a raspberry pi would be a better choice here since it could just run a proper rotctld instance and integrate with stuff like gpredict without needing a separate computer in the loop. thoughts?

yeah ive done almost exactly this, took me a few weekends but it works really well now. i used an arduino mega just because i had one sitting in a drawer but an uno would probably be fine. the hunting problem is real and annoying — what worked for me was adding a small deadband, like i just ignore any error less than 2 or 3 degrees and that stops it from constantly twitching. you dont need a full PID for something this slow moving honestly, a simple proportional control with that deadband is usually good enough unless your bearings need to be super precise for like EME or something.

on the RPi question, i actually ended up running both — arduino does the low level motor stuff and pot reading, then it talks over USB serial to a pi zero that runs rotctld. that way the timing sensitive stuff stays on the microcontroller and the pi handles all the network stuff and integrates with gpredict. works great for satellite tracking. the pi zero is cheap enough that it wasnt really a hard decision

dont overlook the current sensing on that L298N, those boards can get surprisingly warm depending on your motor load and the onboard regulator is pretty weak. had one die on me mid contest which was annoying. nothing major just something to watch for. i ended up putting a little heatsink on mine and it's been fine since.