This is a wiring diagram that [Soranne] put together when developing a method of programming PIC microcontrollers using an Arduino board. You can see that he takes care of the 12V issue by connecting ...

[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 ...

Running out of GPIO pins? Learn how to connect multiple buttons to just one Arduino pin using clever wiring and resistor techniques. Perfect for compact projects, keyboards, or when using small boards ...