[Trent M. Wyatt]’s CPUVolt library provides a fast way to measure voltage using no external components, and no I/O pin. It only applies to certain microcontrollers, but he provides example Arduino ...
Identify a fake Lithium-Ion/Lithium-Polymer/NiCd/NiMH battery Adjustable constant current load (can also be modified by the user) Capable of measuring the capacity of ...