so ive been messing around with a raspberry pi 4 for a few weeks now trying to get it to handle my antenna switching automatically based on band changes from my IC-7300. the radio puts out band data on the ACC port and i figured i could read that with the pi and then fire relays accordingly. got the basic GPIO stuff working fine, the relays click when i tell them to from the terminal, but im having a weird issue where sometimes when the pi boots it toggles all the outputs before the script loads and that has me a little nervous about what its doing to my antennas and the amp.

i know i could just use a commercial band decoder but where's the fun in that honestly. plus i want to eventually tie in spotting data from a cloudlog instance i have running on the same machine and have it automatically suggest which antenna is best for a given path. probably way overcomplicated but thats half the point

anyone gone down this rabbit hole already? curious what you used for the relay board, im currently using one of those cheap 8-channel 5v boards from amazon and im not 100% sure i trust it for the amp keying side of things

yeah the GPIO floating issue on boot is a real thing and it bit me too on a similar project. what i ended up doing was adding a small RC delay circuit on the enable line of the relay board so it doesnt activate until the pi has been up for like 3-4 seconds. works well enough. you can also set the GPIO pins to output low in /boot/config.txt using the gpio= directive but i always forget the exact syntax and have to look it up every time.

the cheap relay boards are fine for antenna switching honestly but i wouldnt use them for amp keying without at least putting an opto isolator between the pi and whatever goes to the amp. the ones with the opto already built in are better, look for the ones labeled active low - they behave a bit more predictably on startup too which kind of solves your problem at the same time. JBE makes some decent ones, also seen people use the Sequencer boards from US amateur suppliers specifically for this reason.

the cloudlog integration idea is cool, i did something similar pulling cluster spots via telnet and running a little python script to light up band LEDs on a panel i built. never got as far as antenna suggestions but the data is definitely there to do it

not gonna lie i tried something almost exactly like this about two years ago and gave up after like a month lol. not because it didnt work but because i kept getting distracted adding features and never actually finished it. i think the pi is still sitting in my shack with half a python script on it

one thing i'll say is look into using an Arduino for the actual relay switching part and just have the pi talk to it over USB serial. that way the arduino handles the hardware stuff and keeps outputs in a known state on startup, and the pi does all the logic and network stuff. separating those two jobs made my head hurt a lot less