Anyone implemented a coloumb counting algorithm on a uP before for estimating LiPo battery SOC? I'm powering an 8 bit AVR and a few external widgets off a small 3.7 volt single-cell LiPo battery, about the size of a stick of gum, and would like to give it a rough estimate of the battery's SOC without using more hardware. I have at least one 10 bit ADC channel available for sensing.
For this application it doesn't have to super-accurate; could get away with putting the SOC into say 5 "bins" with nouns like "Great, OK, fair, weak, bad."