First post here. I'm trying to make a simple MCU-based lamp which can be used without constantly plug in, so I want to have some rechargeable AA batteries (six of them so it should be about 7.2V) on the bottom. And since it's my very first project, I decided to use Uno Rev3's schematic as the major reference -- to build something similar but only contains what I actually need.
However, while I'm doing some research on posts, I found that power management may not work as I originally thought -- from what I read, Uno will always draw power from the batteries if it's higher than 6.6V, which I assume it will always ignored the external power supply until batteries are drained to that point.
What I'm planning are similar to laptops or any mobile device -- when external power supply plugged in, it will always draw power from there until you unplugged it. Therefore, I can maximized the battery life out of my lamp, and only using batteries when necessary.
So I wonder, if there's a way to achieve that, and do I also need some software to manage that well?
