MudPad

We present MudPad, a system that is capable of localized active haptic feedback on multitouch surfaces. An array of electromagnets locally actuates a tablet-sized overlay containing magnetorheological (MR) fluid. The reaction time of the fluid is fast enough for realtime feedback ranging from static levels of surface softness to a broad set of dynamically changeable textures. As each area can be addressed individually, the entire visual interface can be enriched with a multi-touch haptic layer that conveys semantic information as the appropriate counterpart to multi-touch input.