so ive been messing around with this idea for a few weeks now and i think im finally ready to actually try building it but wanted to see if anyone here has gone down this road before. basically i have an old ham-iv rotator that still works fine mechanically but the controller is kind of shot, the meter is flaky and sometimes it just doesnt stop where it's supposed to. instead of buying a replacement controller which honestly arent cheap, i figured why not build something around an arduino and just do it properly.

the plan is to use a arduino mega since i need the extra pins, read the pot position from the rotator, drive the motor through a relay board, and then either control it from the shack PC over serial or maybe eventually hook a raspberry pi in there so i could do web-based azimuth control. ive seen the yaesu GS-232 command set mentioned a lot for this kind of thing and i think making it speak that protocol would let it work with most logging software automatically.

main thing im not sure about is the motor control side — the ham-iv uses a 24vac motor if i remember right and i dont want to fry anything figuring that out. anyone dealt with this specifically or have a schematic they found useful? also curious if people think the pi is overkill for just the web interface part or if its actually worth having linux running there.

yeah ive done almost exactly this, took me a few weekends but it works really well now. the 24vac motor side is actually not that bad once you get your head around it — you basically just need a couple of relays to switch the two legs and make sure you have some logic in the code to never energize both directions at once or you'll have a bad time. i used a solid state relay board i got off amazon for like eight bucks and it handles it fine. the brake line on the ham-iv needs a little extra attention too, there's a delay you need to build in or it'll jerk.

for the GS-232 stuff there's actually a library on github that handles most of the parsing already, cant remember who wrote it but search arduino GS-232 rotator and you'll find it. saved me a ton of time. as for the pi vs just a cheap esp8266 — honestly the esp8266 or esp32 can do a simple web interface no problem and its way simpler than running a whole linux box for that one job. pi is nice if you want to do more with it later i guess.

the pot reading part can be tricky depending on how worn the pot is in your rotator. mine was reading all over the place and i spent like two hours thinking my code was wrong before i realized the pot itself had dead spots. worth checking the raw ADC values in serial monitor before you build any logic around it. a little filtering in software helps too, i just average the last 8 or so readings and it smooths right out.