One aspect that distinguishes an interactive prototype is the capability to react to any action made by users. As we've seen in the previous chapter, sensors are one of the most important building blocks to achieve this important goal. However, sometimes, we want to provide a physical interaction where users are capable of altering the application's behavior with their hands, despite the presence of sensors. These parts that are still largely diffused, are simple mechanic or electronic components that convert analog movements into digital values that our microcontroller can use to alter the program flow. There are a lot of components that we may use to interact with our device: push buttons, switch buttons, joysticks, knobs, pedals, and levers, are just examples of these kind of components.

Knobs are components that we can use to alter some prototype configurations. Indeed, we may create a maintenance console that alters some device constants to prevent the recompilation...