Wiring up buttons

We're going to add buttons to the project from the previous chapter, to allow users to change the way the RGB LED works by pressing buttons. When you look at a button, you see four prongs. While there are four prongs, there are only two input/outputs to a button—one where electricity goes in, and one where it goes out when the button is pressed. This is because a button essentially controls the flow of electricity. When the button is not pressed, the contacts are not connected and electricity cannot flow, and when pressed, a conductor bridges the two sides and electricity flows. This is how we will use the button as an input device: a high signal means the button is pressed, a low signal means it isn't.

Putting a button on a breadboard

Take your button and observe the metal prongs on the bottom. Usually, the two pairs curve towards the inside of the button. There is one in and out on each side, and each pair with the same curve has one of each. Keep this in mind when placing...