Did you know that you can use Arduino to turn on an LED when you press a button? Well, it is true, you can do this! Leaving the joke aside, let me show how you can achieve this. You will need the ...

To program these chips, [Aaron] first had to wire up the microcontroller into a circuit. This was just a bit of perf board, a resistor, a few caps, and a USB A plug.

If you want to develop a program on Arduino with Raspberry Pi, then this tutorial has all the steps you need to take for it, in detail.