Interacting with the environment in a digital way is very practical, and you'll use it in a different number of situations. In fact, we are very accustomed to these kinds of interactions and they are nothing really new.

In this chapter, we will see a very different kind of interaction that not only supports an on and an off state but also a number of different states between them. We will deal with analog outputs.

We will begin by fading an LED to later see a new circuit that controls the speed of a motor through an analog output.