@epierre You can use a Peltier element to power this board. Like this one:
http://www.ebay.com/itm/TEC1-12706-12V-60W-Heatsink-Thermoelectric-Cooler-Cooling-Peltier-Plate-Module-/121349774916?hash=item1c41029e44:g:mukAAOSwDNdVrg-U
@GLAB No worries, was in a similar situation.. My perspective was on what the Node could be made to provide, not what could be done within Domoticz to address the requirement - eg Had heard of Dummy counters but had no experience nor understood their purpose, nor had ever used scripts.
I had been sending a logical ON/OFF as well as a cumulative total from the Node and hit the same hair-pulling scenario as yourself.
Now only the ON/OFF is sent and the short script makes the transposition within Domoticz to a dummy meter (I think kWhr) using the internal clock in Domoticz.
Have fun
@nono8223 I think it will be a good idea as long as there are people actively developing & supporting the platform now and in the future.
Recently the Raspberry Pi port (or Linux, in general) has been updated and included in the core library, so MySensors is no longer Arduino-only.
It might be possible to power the Arduino off the output pin. Since they are dirt cheap I would just test it.
But like the others I would suggest to use the interrupts of pin 2 and 3.
For my battery powered 3.3v pro mini I use 3.3v pir sensors without the voltage regulator. The standard 5v pir needs at least 4.5v just to step it down internally to 3.3V. On these I had problems with voltage stability because I stepped it up to 5V. Also the battery lifetime was poor.
With the 3.3v pir version this thing runs for months. With the solar panel on top maybe forever.