so ive been messing around with this idea for a few weeks now and finally got something working but im not sure its the right approach. basically i have an old prop pitch motor setup for my yagi and the controller that came with it is pretty much dead, just a basic analog pot and some relays. figured why not replace the whole thing with an arduino and a proper feedback loop.

what i ended up doing was using an uno with a motor shield to drive the relays and im reading the az feedback pot with one of the analog pins. works okay but the dead band tuning is driving me nuts - it either overshoots like crazy or hunts forever trying to settle. ive messed with the delay values but i feel like i need an actual PID library or something instead of the dumb bang-bang control im doing now.

also thinking about adding a raspberry pi so i can tie it into hamlib and have rotctld actually talk to it over serial, that way it would show up in my logging software automatically. has anyone done that bridge before, like arduino handles the hardware side and the pi sits in between as the interface layer? seems like the right split but maybe im overcomplicating it.

yeah the PID thing is definitely the move for rotator control, bang-bang is gonna make you crazy. Brett VE3something posted a whole writeup on the arduino-rotator project a while back, worth searching for. the arduino PID library by Brett Beauregard is dead simple to drop in and tune. you'll want to spend some time with the Kp Ki Kd values but once it settles its rock solid, my old prop pitch hasn't hunted in over a year.

the pi as a hamlib bridge works great, thats pretty much exactly how mine is set up. arduino does the hardware, pi runs rotctld with a custom backend, and everything in N1MM just sees it as a normal rotator. the only weird thing is you gotta make sure the serial baud rates match and sometimes the pi sleeps the serial port if nothing is talking to it for a while, had to add a keepalive thing in the script to stop that.

dont overcomplicate it with the pi if you dont need logging integration right now. i ran just an arduino mega directly to the pc via usb for like two years, wrote a little python script that presented it as a hamlib compatible rotator over a virtual com port. worked fine. the pi adds another thing that can crash at 2am during a contest lol