Author Keywords Bio-acoustics, finger input, buttons, gestures, on-body interaction, projected displays, audio interfaces.
INTRODUCTION
Devices with significant computational power and capabilities can now be easily carried on our bodies. However, their small size typically leads to limited interaction space (e.g.,diminutive screens, buttons, and jog wheels) and consequently diminishes their usability and functionality. Since we cannot simply make buttons and screens larger without losing the primary benefit of small size, we consider alter-native approaches that enhance interactions with small mobile system. One option is to opportunistically appropriate surface are a from the environment for interactive purposes. For example, [10] describes a technique that allows a small mobile device to turn tables on which it rests into a gestural finger input canvas. However, tables are not always present, and in a mobile context, users are unlikely to want to carry appropriated surfaces with them (at this point, one might a swell just have a larger device). However, there is one surface that has been previous overlooked as an input canvas , and one that happens to always travel with us: our skin. Appropriating the human