PinChangeInterrupt for a lot of pins Rising, Falling or Change detection for every pin separately Usable on a lot Arduino compatible boards Implementation is fast, compact and resource friendly ...

[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… ...

The 4×4 keypad connects to the Arduino’s digital pins, with rows attached to pins D9, D8, D7, and D6, and columns to pins D5, D4, D3, and D2. A push button is wired to ground and connected to pin D10 ...