Mosquino rev2, micropower / energy harvesting Arduino variant - feedback wanted!

Yeah, everything apart from a basic LDO/UVLO is on a small interchangeable daughterboard.

That's the way to go! We used to have everything in a single board (ala Micaz and TMotesky era) and they give you less flexibility and sometimes you won't even know were the leaking uA goes to.

Sounds very interesting; I'm very curious to know about your WSN projects. It's something I want to experiment with in this project...when I get time But why would your networks have both a SLA and Li-Ion batteries? or is the 12V battery more of a charging station that is not consistently present?

I was working with mostly geo-technical and structural health monitoring sensors. And a lot of these sensors are powered up using 12V still. And in the network, when we were forced to use a router, the SLA usually comes into the picture together with a solar panel.

Yeah, that will still be the hard part... especially for me as a relative c++/Arduino noob (still digging out of this PIC assembler hole). Help/advice in this area too is appreciated Hard to say where the right balance between performance and usability will be struck - something as simple as providing wrappers for some peripheral functions that will set up the PRR correctly before use, keep track of the current clock divider setting (switch back for timing-critical functions, e.g. Serial.print...) and encourage the user to use the RTC instead of delay loops would probably go a long way for the time being. I have a feeling those who are already familiar with more advanced power managed modes know what they're in for (and probably don't think of Arduino as their first platform choice for such applications...)

There are also certain things that the Arduino core powers them up and uses which needs careful attention too.