Frames of Reference for Portable Device Interaction Sile O'Modhrain Sonic Arts Research Centre Queens University, Belfast sile@qub.ac.uk

Position Statement Increasingly mobile devices are being enhanced by the addition of sensors These can provide feedback about their location, motion and orientation Applications for such devices are situated in real-world frames of reference Device-centred, body-centred, world-centred Our work seeks to to build on the users' pre-existing skills and expectations from the real world to support movement-based interactions that may transcend these multiple frames of reference.

Example Applications Tilting Maze Body Mnemonics

Example Applications Topographic Torch GPS and magnetic compass sensing are combined with inertial sensing to provide an egocentric reference for a city map.

Proposal As mobile devices become more powerful, the designer of applications for the mobile user is likely to have to negotiate a design space with multiple frames of reference for a user's actions. Here a better understanding of the senses of touch, of the body's motion and its sense of its own motion, may be the key to providing a meaningful bridge between multiple, interleaved and interdependent spaces.