so ive been messing around with an arduino mega for a few weeks now trying to get it to automatically switch between my vertical and my dipole based on what band i dial in on the radio. the idea is to have it read the band data output from my IC-7300 (it outputs band info on the USB serial port) and then fire the appropriate relay to route the feedline. sounds simple enough in theory but im running into issues with the relay coil voltage — the arduino 5v logic isnt driving the relay directly without a transistor buffer and i keep frying things apparently

anyway before i go further down this rabbit hole wondering if anyone has done something similar or has a better approach. ive seen some folks use raspberry pi instead but honestly seems like overkill for just switching relays. also not sure if i should be looking at a proper relay shield or just rolling my own with discrete transistors and some flyback diodes. my soldering is decent but im not an EE by any stretch

any pointers welcome, been at this hobby about 3 years now mostly HF digital modes and this is my first real electronics project beyond kit building

yeah done almost exactly this with a nano and an IC-7300 a couple years back. the band data stuff works great once you get the baud rate sorted, i think mine was 9600 but double check that in the radio menu. for the relays just grab one of those 8-channel relay boards off amazon, they run like $8 and they already have the optocouplers and transistors built in so you dont have to worry about frying anything. they take a logic low to trigger which threw me off at first but once i figured that out it was smooth sailing. i used a SainSmart board but honestly any of them should work the same. the flyback diode thing is real important if youre doing discrete relays, i learned that the hard way with a dead nano before i switched to the prebuilt board

pi is definitely overkill for relay switching but I will say if you ever want to expand it into something more ambitious — logging, cluster spotting, maybe a web interface to control stuff remotely — then it starts to make more sense. I run a pi 4 that handles my rotator controller, does automatic band switching for my amp, and serves up a little webpage I can hit from my phone. took a while to get it all stable but now it just runs. that said for what youre describing the arduino approach is totally fine and honestly easier to debug. just watch your ground loops if youre mixing the radio's USB ground with the relay circuit, had some weird noise issues early on until i isolated things properly