Trying to figure out the capacity left in a battery based on only its voltage is difficult. The equivalent-series-resistance (ESR) of the battery makes the cell’s voltage a function of the current ...

The hardware tinkerers and prototype mavens out there will invariably have stumbled across the Arduino platform. Completely open source and always pushing the limits for collaboration, there are a ton ...

[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 ...

Last year, the Raspberry Pi Foundation surprised the hobbyist world with its RPi Zero, the smallest incarnation of its popular single-board computer. However, that has nothing on this even smaller ...

Denis Hennessy recently encountered a problem we've all faced: he needed some AAs for a battery-eating gizmo, and he was overwhelmed by the choices available. Ignoring the shiny packaging and its ...

One of the great things about the Arduino is that it’s totally open source so you can make your own variations on it. Case in point, DIYer Johan Kanflo’s AAduino, which comes in at the size of a AA ...