emonTx not sending CT data

I think you need to reflash the EmonTX. I’d be concerned about the serial output that is shown here as ?.

I did this successfully via the PIO method on a PiZero (I updated the docs), but you need the RTS line connected and change the pin number, else Robert’s way with a programmer and Arduino IDE.

[edit]
Also note if you use the PIO method, you need to install the library first. The docs were written with this line in the platformio.ini file

lib_deps_external =
  https://github.com/openenergymonitor/EmonLibCM.git

But @glyn.hudson changed it back to just EmonLibCM @2.4.1, but this means you need to install it manually rather than have the PIO package manager do it for you.

@haffle
Did it go through the startup twice or more (“POST…wait 10s” … etc) after you reset it? If it did, that must have been the watchdog firing, in which case Brian’s assumption that the sketch is corrupted is all but proven.

I’d go along with that. But if you use platformio, I can’t help you with that - as I’ve written here so many times, it destroyed my system so I won’t touch it ever again.