so ive been sitting on this idea for a while now and finally starting to poke at it. i have a 4-port coax switch out in the shack and honestly im just tired of walking over to flip it manually every time i change bands. figured an arduino nano with a relay board would do the trick but im not sure if i should just go that route or use a pi zero for the whole thing.

the main thing i want is for the radio to send some kind of signal when it changes bands and have the switch follow it automatically. my ic-7300 has the acc port and i know it spits out band data but i havent really dug into the ci-v stuff yet. anyone tied ci-v reads to gpio pins on an arduino before? feels like this should be a solved problem but i cant find a clean writeup anywhere that isnt for a completely different radio.

also not sure if a nano has enough horsepower for this or if i should just use a pi from the start. dont really need a screen or anything fancy, just reliable switching. open to suggestions

yeah done something pretty similar with a 7300 and an arduino mega actually. the ci-v stuff isnt that bad once you get your head around it — its just serial at 9600 baud by default and the radio sends band change packets automatically if you enable it in the menu. i wrote a little state machine that listens for the frequency data and then fires the appropriate relay. took maybe a weekend to get working reliably.

one thing ill say though — use an optocoupler between the arduino outputs and your relay board if youre switching anything with real RF nearby. had some really weird resets early on that turned out to be RF getting back into the arduino through the relay coils. common ground issue mostly but the optocouplers just killed the problem entirely. also put a flyback diode across each relay coil if your relay board doesnt already have them, some of the cheap ones from amazon dont bother.

for your use case a nano is totally fine honestly. a pi would be overkill unless you want a web interface or logging or something. the nano boots in like 2 seconds and just works, no waiting for linux to come up.

i did this exact thing but used a pi zero w instead because i wanted to control it from my phone when im not in the shack. flask server, couple of gpio pins, done. works fine but honestly the boot time is kinda annoying if power goes out and comes back, takes like 40 seconds before its responsive again. probably shouldve just used an arduino for the actual switching logic and kept the pi just for the network piece if i did it over.