First, thanks for sharing your project. Regarding the question “Any ideas where to init the sensors” — can you be more specific? Did you mean where in the firmware code to init the sensors? Generally initialization code can go to OpenSprinkler.cpp, look for the
OpenSprinkler::begin()
function. But if your code requires network to be ready, then it should go to main.cpp, look for the
do_setup()
function. There you will see mqtt.init.