US Patent 9924255 On/off head detection using magnetic field sensing

An on/off head detection system uses magnetic field intensity to determine a configuration, position and/or orientation of a headphone, including whether a headphone is on or off a wearer's head. The system includes a magnetic field sensor configured to detect a magnetic field emitted by a magnetic field source associated with an earpiece of the headphone. A control module determines an intensity of the magnetic field and whether the intensity of the magnetic field has reached a threshold. An operational mode associated with the headphone or an associated device is performed in response to the intensity of the magnetic field reaching the threshold.