@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
@fets So far, I have only built the 5x5 board (but the others should be schematically identical). The only issue I have found so far is that I cannot get the ISP port to work. But I have checked and I have an identical setup on the 1.0 board and that worked, so I suspect the programmer is too weak to drive the net on this one. So it is not a board-issue per se, and might only be an issue on the 5x5 board as routing is the most complex on that one due to the size.
@Puneit-Thukral
Could you post your full working sketch please?
I'm revisiting some of my 51822 nodes that have sat collecting dust for a long time and thought i might try to get them working again.
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.