Today, there exist many types of electronic devices such as mobile telephones, media players, palmtop computers etc. Such devices are often associated with a headset, i.e. a separate unit being arranged to be mounted on or close to a user's left or right ear. The headset normally comprises an earphone and a microphone for the output and input, respectively, of audio signals. Such audio signals are transmitted between the headset and the associated electronic device. Today, such a configuration is commonly used in the field of mobile telephones, in order to allow so-called “hands-free” operation of the mobile telephone.
In the case of mobile telephones, the headset is arranged so that the earphone is positioned close to a users ear and so that the microphone is positioned close to the users mouth. In order to position the headset in such a way, it normally comprises a so-called ear loop device, i.e. a generally annular element used in order to mount the headset on either the left or right ear of the user. According to known technology, a headset is normally provided with certain user interface (“man machine interface”) functions, for example in the form of input controls for receiving user commands or making selections related to the operation of the device. For example, a headset can be provided with control buttons for increasing or decreasing the volume of the audio signal being fed to the earphone.
More complicated headsets may be provided with compass sensor, accelerometer and/or gyro.
A headset is just an example of an external unit which may be provided with sensors for detecting position and motion.