so ive been messing around with this idea for a while now and finally started actually building it out. basically i want to use an arduino uno to handle automatic CW keying based on some sensor input — im setting up a little weather station and thought it would be cool if it could just beacon out the temp and pressure every few minutes on its own without me having to babysit it.

the keying part isnt too bad, i just have a transistor switching the key line on my IC-7300 and the arduino pulls the base low to key it. works fine on the bench. the issue im running into is timing — the dit/dah ratio gets a little weird at higher WPM and i think its because im using delay() which i know is bad practice but im still kind of learning this stuff. been looking at using millis() instead but havent fully wrapped my head around it yet.

the other thing i want to do eventually is swap in a raspberry pi zero so i can pull weather data off an API and format it automatically but that feels like overkill for now. anyone done something similar or have thoughts on the timing issue? does the iambic stuff get complicated to implement from scratch

yeah the delay() thing will absolutely kill you for CW timing, especially once you start getting above like 15 WPM. millis() is the right call and it clicks once you just sit down and really look at a few examples — basically you store the last time something happened in a variable and then check if enough time has passed instead of just blocking everything. there are some pretty clean CW libraries out there for arduino already too, morse.h or a couple others, might save you reinventing the wheel if the goal is just to get the beacon running.

the transistor keying approach is fine but double check you have a protection diode across whatever youre switching and that youre not pulling too much current through the arduino pin directly. some rigs are a little fussy about what they see on the key line.

i did almost exactly this a couple years ago with a uno and a bmp280 for pressure and temp. ended up going the pi zero route sooner than i thought because formatting the APRS-style string got annoying on the arduino side without proper string handling. the zero with python just made that part way easier and then i just had it talk to a small arduino nano over serial to handle the actual keying since i didnt want to deal with the pi gpio timing being messed up by the OS scheduler. works pretty reliably now, beacons every 10 minutes on 30m. the iambic stuff — honestly dont bother unless you really need it for a beacon, straight key timing is way simpler to code and nobody cares if a beacon isnt using iambic