Accelerometer Overview for Windows Phone
An accelerometer is a sensor that measures acceleration forces such as gravity or the forces caused by moving the sensor. All Windows Phones have at least one accelerometer sensor that, when accessed by the managed Accelerometer API, can be used to provide input to Windows Phone applications including both Silverlight for Windows Phone and XNA for Windows Phone applications.
The accelerometer API is a managed library that is included with Windows Phone Developer Tools. It is built on top of a more general sensor framework so other sensors that may be supported by Windows Phones in the future will be accessed in a similar way.
The accelerometer data is delivered to the application using the AccelerometerReadingEventArgs class. This class exposes properties for the X, Y, and Z axis that are double values between -2 and 2 indicating the direction of acceleration for each axis in gravitational units.