In Chapter 6, Working with Analog Inputs and Local Storage, we used a photoresistor that is included in a voltage divider and we connected it to an analog input pin. We were able to measure the ambient light and we determined different darkness levels and change the brightness levels of an RGB LED. The photoresistor, also known as LDR (short for Light-Dependent Resistor) or photocell, is a sensor. We just needed to include it in a voltage divider to make the changes in the resistance value of the photoresistor via the ambient light. These variations in the resistance value will generate changes in the voltage value in our analog pin. Thus, we worked with a configuration of electronic components that generated an analog sensor, capable of transforming changes in the environment light into voltage values.
There are a huge number of sensors that allow us to retrieve data from the real world and convert it into analog or digital values that we...