i'm looking into a battery powered arduino setup (AA, Ni, Li... don't know yet, still in paper design phase). Any guidelines to hw/sw for monitoring the available charge, just like in a cell phone where you have xx % battery available?
thank you
As the analogue to digital converter normally has it's reference voltage the same as the arduino's power.
So you need a reference voltage that is independent of the supply. Look up how to use the internal 1V reference and use potential divider resistors to get the supply voltage down to that range.
Then look at the discharge characteristics of your chosen battery and remember it is only ever going to be approximate.
ok, I'll research a little more, still in early learning phase... I'll be happy not to get x% exactly or even approximate but just a simple warning of low battery/"replace me".
tks for the pointers