Squeezy is a low-cost, tangible input device that adds multi-dimensional input to capacitive multi-touch tablet devices. Force input is implemented through force sensing resistors mounted on a rubber ball, which also provides passive haptic feedback. A microcontroller samples and transmits the measured pressure information. Conductive fabric attached to the finger contact area translates the touch to the bottom of the ball which allows the touchscreen to detect the position and orientation. The addition of a tangible, pressure-sensitive input to a portable multimedia device opens up new possibilities for expressive musical interfaces and Squeezy is used as a controller for real-time gesture-controlled voice synthesis research.
Johnty Wang, Nicolas d’Alessandro, Sidney S. Fels, and Bob Pritchard. 2011. SQUEEZY : Extending a Multi-touch Screen with Force Sensing Objects for Controlling Articulatory Synthesis. Proceedings of the International Conference on New Interfaces for Musical Expression, pp. 531–532 [pdf]