5.1. Accelerometer

Windows Phones contain an accelerometer—a small hardware device that essentially measures force, which elementary physics tells us is proportional to acceleration. When the phone is held still, the accelerometer responds to the force of gravity, so the accelerometer can tell your application the direction of the Earth relative to the phone.

A simulation of a bubble level is an archetypal application that makes use of an accelerometer, but the accelerometer can also provide a basis for interactive animations. For example, you might pilot a messenger bike through the streets of Manhattan by tilting the phone left or right to indicate steering.