Rechargeable battery capacity tester   If you are like most
people, you likely have a mixed pile of rechargeable batteries
sitting around with no idea as to what kind of charge they can
hold. You could watch a voltmeter for a few hours while you
drain each and every battery, noting when it drops below its
stated voltage – but then again, you have a life.  Instead of
wasting away in front of his multimeter, [BrianH] decided he
would build an automated battery capacity tester to do the job
for him.  He created a simple circuit that drains any AA
battery, NiMh or NiCd, and records its useful capacity in
milliamp hours.  Since the ATMega168 microcontroller used has 6
analog/digital converters on board, he figured that he might as
well design his tester to measure the capacity of three
batteries simultaneously.  [BrianH] wired the meter up to an old
Nokia LCD, then moved his project to a perfboarded ATMega,
freeing up his Arduino for other tasks. Once he had things
reassembled, he packed it all into a handsome woo