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.
@berkseo
Yes, it's available here. The documentation is a little bit scarce I admit but if you understand Apache MyNewt and its build system it should be pretty straightforward theoretically.
I will add more details when I have the time. The code was tested and it's in production. Works without a glitch so far.
@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.
@sundberg84
I also on my last work removed the LG33, it's faster
Well this most likely have been provided as info, but else it's here:
Remember to burn new OPTIBOOT 8MHz into the Arduino Pro Mini
and then I also use avrdude with a usbtinyISP to set the fuse to not check battery voltage monitoring, this is done after I have flashed this with Arduino IDE
avrdude -c usbtiny -p m328p -U efuse:w:0x07:m```
Thanks again, learned a lot... I decide to give a try there, I also had a look on some components' datasheet and seems to be what I need... Let's see, if end up getting the boards I'll publish a review here later.
