In the previous chapters, we built our first prototype equipped with an LED actuator to alter the surround environment, and then we enabled the Android application to control the LED behavior through the internal ADK communication. We have seen that sensors are really helpful to improve interactions of our prototypes and we may be tempted to add this new capability to the previous project. Indeed, because we're using a component capable of producing light, we may think about adding an external light sensor so that the microcontroller is capable of turning on and off the LED according to the environment light.

This is just an example of how we can use a light sensor. Indeed, we have to bear in mind that each sensor can be used in different ways and it's our job to find a correlation between detected values and the goal of our physical application. We should never stop to use sensors only for their main use, as we will see in the heartbeat monitor.