To provide a large enough pulse to drive the ceramic transducer , you need a lot of energy, so they pump up the 5v with an inductor/transformer to provide a high voltage pulse. This is 60v or more…
The more Energy you produce the farther the pulse will travel….
Everything thing else on the board run at 3.3 to 5V.
Add a large Capacitor of 100 µF are so between the 5v and ground on the device, this may clean up your problem.. Some CPU modules just can’t supply enough current quick enough that’s needed when the pulse is triggered.
These are very inexpensive device, we’re luck to see them work at 1/2 the spec range.
@kalina, Thanks. So it will not work for my configuration. Wall switch (push button) is already installed. No possibilities to draw more electrical wires.
Moreover, if i put the board near the light, i have just the Neutral and the return wire from the wall switch. No Live wire to power on the mysensors board.
I think in my ase the best way is to manage everything in my garage in the electrical main board where all the wires are mapped. I can get L + N for mysensors power supply. And i can continue to reuse the original wall switch independently of the Mysensors board.
You would use PID if you have a temperature feedback from the rooms, but in your case you are not interested so it doesn't matter much. Sure turning off pump when not needed is a good thing. I have colleague that also bought a few netatmo devices to control floor heating of some zones of his house and he is very happy.