Multi-point vibrotactile feedback for an expressive musical interface

This paper describes the design of a hardware/software system for rendering multi-point, localized vibrotactile feedback in a multi-touch musical interface. A prototype was developed, based on the Madrona Labs Soundplane, which was chosen for it provides easy access to multi-touch data, including force, and its easily expandable layered construction. The proposed solution makes use of several piezo actuator discs, densely arranged in a honeycomb pattern on a thin PCB layer. Based on off-the-shelf components, custom amplifying and routing electronics were designed to drive each piezo element with standard audio signals. Features, as well as electronic and mechanical issues of the current prototype are discussed.