so ive been messing around with a pi zero W for a few weeks now trying to get it to pull WSPR spot data from wsprnet and log it locally whenever my rig is running. the idea is pretty simple, just a python script that polls the API every few minutes and dumps it into a sqlite database with timestamps and band info. i also want it to trigger a relay when conditions on 10 or 12 meters look good based on spot density from like DX stations, kind of a poor mans band condition indicator.

the relay part is where i started running into weirdness. im using one of those cheap 4-channel relay boards from amazon and the logic levels are all over the place — the pi zero GPIO is 3.3v but the relay board wants 5v to trigger reliably. i threw in a transistor to level shift it but honestly im not sure i did it right because one of the channels fires when it shouldnt. might just be floating inputs, havent totally figured it out yet.

has anyone done something similar or have a cleaner way to handle the relay triggering from a 3.3v GPIO? and also curious if anyone has played with wsjtx remote or similar to actually see what mode the rig is in and only log when its in WSPR mode specifically.

yeah the relay board thing is a super common headache with the pi. those cheap boards usually have active-low inputs which trips people up constantly — the relay fires when the pin goes LOW not high, so if your GPIO is floating at boot it can trigger randomly. easiest fix honestly is just pull the input pins high with a 10k resistor to 3.3v and then drive them low to activate. or just buy a relay board thats explicitly designed for 3.3v logic, they exist and they're like $3 more.

on the wsjtx side there's actually a UDP broadcast wsjtx puts out on port 2237 by default that you can listen to with python. it sends status packets including the current mode, so you can absolutely only log when the mode field says WSPR. there's a library called wsjtx-assistant or something similar, cant remember the exact name but googling wsjtx udp python should get you there pretty fast. i did something close to this for FT8 logging a while back and it works well once you wrap your head around the packet format.

not exactly the same project but i built something on a pi 3 that watches band conditions and keys a little LED panel i have on my desk. used the DXcluster feed instead of wspr though. the relay floating input problem you're describing, i had that exact thing happen, drove me nuts for like two days before someone on here told me about the active-low thing.

one thing i'd say is the pi zero W can get a little flaky with wifi under load if you're doing anything timing-sensitive, just something to watch out for. i ended up switching to a wired connection on mine but obviously the zero W doesnt have ethernet so thats a bit of a project in itself with a USB adapter. might just be easier to use a regular pi 3 or 4 if you have one sitting around