A mobile device includes a magnetometer. The mobile device is calibrated during application usage by sampling magnetic information received from the magnetometer, recognizing an initial controller orientation signal derived from a first sample of a plurality of samples of the magnetic information and from directional offset data, calculating updated directional offset data based on the plurality of samples of the magnetic information and on the directional offset data, and deriving a calibrated controller orientation signal from a second sample of the plurality of samples of the magnetic information and the updated directional offset data.