The transistor serves as a current sink, and its base is connected to Arduino pin 3 (D3) to apply pulse width modulation control. The wiring diagram and sketch for a simple experiment is shown below. ...

Looking for practical Arduino projects? This guide shows how to control a relay from your smartphone using an Arduino Uno — ...

[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 Ar… ...