Thanks, that's exactly what I have been doing over the last day or two. I think I've found the issue. The key for me was that going through my code by typing it in "live" to the python interpreter worked, even without using screen first, so I figured this must be some kind of timing issue. This is w...

I understood from the docs that timeout=0 means non-blocking mode? https://pyserial.readthedocs.io/en/latest/pyserial_api.html Anyway, the code does work, albeit after I've had to run the screen command. My question is, what could the screen command be doing regarding the serial port that then makes...

Sorry, here's the rest of the code in my main(), up until it blocks in the sendCommand function.

I've got a strange problem that took a while to figure out, but I don't understand what is going on. I have an arduino gathering some data, and it also waits for very simple commands (a single character) on the serial port, and replies back on the serial port with some numbers sandwiched between the...