Inputs, whether they are digital or analog, are the way through which Arduino can sense what is happening around it. In some cases, they are used as an interface with the user, such as when we connect buttons and switches. In other cases, we use inputs to measure a physical variable that will make our project react in some way or other.

Nowadays, we can find almost a different sensor for every physical variable we want to measure and an endless number of devices that allow humans to interact with electronic devices. So, the first thing we will have to consider is the type of sensor we will need for our project and, most importantly, from the point of view of connection and programming, the type of signal it generates, digital or analog. This is because it will affect the way in which we have to connect it to our Arduino board, by way of a digital or analog input, and program our sketch accordingly.

Digital sensors usually give us a 0V or 5V voltage or any way to obtain...