A microcontroller is needed to interpret the data from the sensor and then do something with that data. Examples of actions to be taken are to present the data to the user, deploy the airbag or to control an object in a game. The microcontroller often uses data fusion in order to give meaningful feedback to the user application. This implies taking data from more than one sensor type. The algorithm commonly used in a digital compass takes data from both the magnetometer and the acceleometer to tell where the user is heading.