Context-Aware Computing with Sound

We propose audio networking: using ubiquitously available sound hardware (i.e. speakers, sound-cards and microphones) for low-bandwidth, wireless networking. A variety of location- and context-aware applications that use audio networking are presented including a location system, a pick-and-drop interface and a framework for embedding digital attachments in voice notes or telephone conversations. Audio networking has a number of interesting characteristics that differentiate it from existing wireless networking technologies: (i) it offers fine-grained control over the range of transmission (since audio APIs allow fine-grained volume adjustment); (ii) walls of buildings are typically designed specifically to attenuate sound waves so one can easily contain transmission to a single room; (iii) it allows existing devices that record or play audio to be "brought into the user interface"; and (iv) it offers the potential to unify device-to-device and device-to-human communication.