After a steep learning curve I found out that one of my UNO clones was not able to receive messages in any way. I have now made a sensor based on a pro mini which works fine with a serial gateway. The only problems I still encounter is that the node-ID is not assigned automatically but I solved it by defining it in the sketch. @sundberg84 : I saw a different post of you for the Easy/Newbie PCB for MySensors. It looks very tempting to start using them !