goal: robot leaves charging station when battery full, returns when battery falls below threshold. need: battery monitor Answered
Naturally I want a battery-monitoring circuit/electronics that uses as little power as possible. I'd be surprised if such a circuit isn't available off-the-shelf, but I've never seen one advertised as a standalone component I could plug in to add it to my project. Speaking of "my project," it doesn't exist in physical form yet, only in my head, but I'm thinking of an R/C car body, big enough to carry a small video camera or 2; the charging station could be solar panels in a fixed sunny spot that it navigates to, or perhaps (a) panel(s) on board the car (so it could find a sunny spot anywhere during the day, e.g.).