Karl, once again thanks for your great help!
The UNO is still running fine and sends the temp
I think we should make a small donation for Karl!
Next step: I also have a NodeMCU board (Lolin, it shows NodeMCU V3 on the rear side as well as 0.1 on the upper side, from eBay).
I think srkinard posted here also something about the board.
I had issues with the USB cable, the board is really sensitive (3 cables not working, the 4th is ok, board is recognized with the 340G driver)
Would like to add it too to Indigo, but I'm confused: I have to select NodeMCU 1.0 (ESP-12E) in the IDE but what to enter in the sketch?
There is only an entry for ESP1 and ESP16?
Yassi