Introduction Wearable computing facilitates a new form of human-computer interaction comprising a small body-worn component that is always on and always ready and accessible. This new computational framework differs from that of hand held devices, laptop computers and personal digital assistants (PDAs). The “always ready'' capability leads to a new form of synergy between human and computer, characterized by long-term adaptation through constancy of user-interface. A wearable computer is a computer that is intertwined into the personal space of the user, controlled by the user, and is always on and always accessible. Most notably, it is