so ive been messing around with an arduino uno for the past couple weeks trying to build a simple antenna switch controller. the idea is pretty straightforward — i have 4 antennas and i want the arduino to read which band the radio is on via the band data output on the back of the IC-7300 and then automatically key the right relay to connect that antenna. in theory super simple right.

the problem is im not sure if im overthinking the whole thing. right now ive got a relay board hooked up and it works fine when i manually send commands over serial but getting the band data lines decoded reliably is being a pain. the 7300 outputs like a 4 bit BCD signal i think and im reading it fine but theres occasional glitching where it'll briefly show the wrong band during a QSY and the relay fires for a half second before correcting. nothing is damaged but i could see that being an issue with an amp in line eventually.

has anyone done something similar and figured out a decent debounce or delay approach that doesnt cause a noticeable lag when you actually switch bands? i tried just putting a 200ms delay before acting on a new band reading but that feels sloppy. also wondering if a pi would be better for this just because i could run some logging on the side too but seems like overkill for what is basically a relay controller

yeah i did almost exactly this about a year ago with a 7300 and a 4 antenna setup. the BCD glitching is totally normal, what worked for me was reading the band data line like 3-4 times over maybe 50ms and only acting on it if all readings agree. not elegant but it completely eliminated the false trips. the 200ms flat delay is worse because youre always waiting even when theres no glitch, the consensus approach only adds delay when something is actually unstable which is rare.

as for pi vs arduino — for just switching relays the pi is genuinely overkill and honestly kinda worse because youre dealing with linux boot times and if power glitches you might come back to a corrupted SD card. arduino just wakes up and does its thing instantly. i do run a pi zero separately for logging and CAT control stuff but kept the antenna switching on a nano because i wanted it bulletproof. you can always have them talk to each other over serial if you want the logging piece.

the glitching thing you're describing is pretty common with that kind of setup, ive seen guys use a small RC filter on the input lines too before the arduino reads them, smooths out the transients a bit. might be worth trying alongside the software debounce.

also not to derail but if youre going to have an amp in line at any point i'd seriously look at adding some logic to inhibit the relay switching unless ptt is unkeyed. had a buddy who fried a relay doing hot switching under power, wasnt pretty. just a thought