Calibrating the Accelerometer
Accelerometer does not provide calibration support out of the box. Moreover, there is no systemwide calibration setting that your app can update. It is up to your app to have the user place the phone in a level position, calculate an offset value, and save the offset value in isolated storage.
EnhancedAccelerometer provides support for calibrating a device placed on a level surface. It includes the following two calibration related methods: