so ive been messing around with this idea for a couple weeks now and im not sure if im overcomplicating things. basically i have an old CDE Ham IV rotator thats still mechanically solid but the controller box has seen better days, the pot is flaky and the meter is basically useless. instead of tracking down a replacement controller or paying for one of those aftermarket units i was thinking about just building something around an arduino mega i have sitting in a drawer.

the idea is pretty straightforward, read the pot voltage with the analog input, drive the rotator motor through a relay board, and then talk to the PC over serial so i can feed it into ham radio deluxe or whatever. ive seen a few projects online that do basically this but they all seem to have slightly different approaches and some of the code looks pretty old and probably written for earlier arduino IDE versions.

has anyone actually done this and used it for serious operating, like contesting or satellite work where you really need the heading to be accurate and responsive? im a little worried about the pot noise causing jitter in the position reading and whether simple averaging in software is good enough or if i need to do something more aggressive with filtering. also not sure if the mega is even the right board for this or if something like a pi zero with a proper ADC hat would be more accurate.

any experience here would be appreciated, even if its just "dont bother it was a nightmare"

yeah I did almost exactly this with a T2X about two years ago. used a nano originally but switched to a mega just for the extra pins when I added an LCD display and a manual control mode with a joystick. the pot noise thing is real, averaging helps but I ended up using a 10uf cap across the wiper and ground which cleaned it up a lot before it even got to the ADC. made a huge difference honestly.

for satellite work the latency over serial was fine for me, I was using Hamlib and it worked with Gpredict no problem. the heading accuracy ended up being within about 3-4 degrees which is more than good enough for anything I was doing. if you're doing EME with a narrow beam that might not cut it but for LEO satellites it was totally workable. just make sure whatever relay board you use has some kind of braking logic so you're not slamming the rotator to a stop, mine would occasionally overshoot before I added a slow-down zone near the target heading.

pi zero is overkill for just reading a pot and driving relays imo. the arduino approach is cleaner for something like this, fewer things to go wrong, no OS to hang on you in the middle of a contest. i tried a pi3 for a similar project and half my time was dealing with linux stuff that had nothing to do with ham radio. the arduino just does the one thing and does it reliably.

one thing i'd add — look up the AC2RC rotator interface project, theres a github for it and the code is reasonably well maintained. saved me from reinventing the wheel