Let's take a look at using some basic input devices first. We'll start with a button and a potentiometer—two of the easiest input devices to use with Johnny-Five, and a good way to get acquainted with both specialized input objects, such as buttons, and general Sensor objects, which we'll use for the potentiometer.
First, we're going to wire up a button and write some code to measure whether it is pressed or not, using an LED as our indicator. The wiring of the project will look like this:
Wiring diagram for a button and an LED
Make sure that if you're using the four-prong button, it crosses over the center trough of your breadboard as shown in the diagram. If it does not, the button will not work properly. If you are using a two-prong button, the wiring is very similar, and it does not have to cross over.