[Frank Herrmann] had an interesting idea to turn a geared DC motor into a servo motor assembly, but with a stepper motor-like interface. By stacking some small PCBs behind the motor body, it was ...

An Arduino can be used to test the life of any battery with less than 5 volts, Boxall says. So, for a quick way to see how much juice your AAA, AA, C, or D batteries have left, build this ...