so ive been messing around with this for a few weeks now and im at the point where i either need help or need to just accept i dont know enough python to make this work properly. basically the idea is to have a raspberry pi zero w sitting between my logging software and the rotator controller, parsing the AZ commands from ham radio deluxe and then sending the right voltage signals out through a little MCP4725 DAC board to the rotator's analog input.

the hardware side actually went smoother than i expected, i got the i2c talking to the DAC no problem and i can move the antenna manually by just writing values to the register from the terminal. the issue is the software side — when HRD sends a new azimuth command the pi sometimes just misses it entirely or processes it late and the antenna ends up like 15 degrees off where it should be. i think its a threading issue in my script but honestly im not sure. also running this over wifi feels kinda sketchy, wondering if i should just hardwire it with ethernet or use a small pi 3 instead of the zero.

anyone done something similar? doesnt have to be rotator specific, just curious if theres a better way to handle serial parsing on these things without it getting flakey.

yeah the zero w wifi is honestly not great for anything where timing matters, ive had similar headaches using one as a remote audio bridge and it would just randomly hiccup. if you can swing a pi 3A+ you get the same small-ish form factor but actual ethernet and a proper processor so the serial parsing doesnt fall behind. that said if you want to stick with the zero, look into using a hardware UART instead of relying on the USB CDC serial — the zero has two UARTs and if you disable bluetooth you can get a clean dedicated serial port that doesnt have the same latency weirdness.

for the threading thing, are you using a queue between your serial listener and the DAC write function? if youre just calling the DAC write directly from inside the serial read loop that could absolutely cause you to drop commands under load. stick the incoming commands in a queue.Queue and have a separate thread drain it, its like 10 extra lines and it fixes that whole class of problem.

not exactly the same setup but i did something with an arduino mega controlling an old hygain rotator and it was way simpler than i expected once i stopped overthinking it. arduino just polls the serial port in the main loop, parses the GS232 commands, and drives a motor controller board. no threading, no wifi, no linux, just runs forever without issues. might be worth considering if the pi zero is giving you grief — sometimes the simpler tool is the right one for a job like this where reliability matters more than flexibility.