Tracking Mobile Phones on Interactive Tabletops

The number of ”interactive surface” systems, especially tabletop interfaces, in public is increasing. As more and more casual users interact with such systems, they may wish to use existing computing infrastructure, such as their mobile phone, in conjunction with the new interface. In this paper, we present a method to reliably detect and track unmodified mobile phones that are placed upon an interactive tabletop. Range detection and data exchange is done via Bluetooth, while the location of the phone is tracked through its shadow on the surface.