so i finally caved and ordered a couple pi zeros and an arduino mega a few weeks back after seeing someone at our club meeting show off their automated station setup. been messing with it on and off and honestly i went way deeper than i expected to

started simple, just wanted to pull frequency data from my IC-7300 via USB and have it auto-log to a spreadsheet or something. ended up writing a python script that reads CAT commands, pushes the data to a little sqlite database, and now i have a dashboard running on my local network showing me band conditions, what frequency im on, mode, all that. its actually pretty slick but im not gonna pretend the first two weeks werent a nightmare of broken dependencies and me googling error messages at midnight

now im thinking about hooking up an arduino to handle some physical stuff — like switching between antennas based on what band the rig selects automatically, maybe even triggering a bandpass filter bank if i ever build one. has anyone done relay control through an arduino that talks to a pi? im trying to figure out if i should do I2C between them or just have the pi handle the GPIO directly and skip the arduino altogether for the relay part. the arduino feels like overkill if i dont need the analog stuff but i have it sitting there so might as well use it

yeah i went down exactly this hole about 18 months ago and never really came back out lol. I2C between the pi and arduino works fine but honestly for relay switching you probably dont need it unless you want the arduino handling timing-critical stuff independently. if its just switching antenna relays based on a band command from the pi, just wire up a relay board directly to the GPIO and write a simple python function that maps band to relay state. way less complexity.

where the arduino actually earns its keep in my setup is handling the rotator interface — i needed faster loop timing than the pi could reliably give me with linux getting in the way, and the arduino handles that no problem while the pi just sends it target azimuth commands over serial. that separation of concerns made everything way more stable. the pi is terrible at anything that needs real-time response, just keep that in mind before you trust it with anything timing sensitive

im kind of in the same boat, been trying to get hamlib talking to my old ft-857 through a pi 4 and its been hit or miss. sometimes rigctld just drops the connection for no reason and i have to restart it. didnt think itd be this flakey honestly. your setup sounds more polished than mine, what are you using for the CAT stuff, hamlib or did you write your own serial parsing