This instrument started as a January term project and eventually provided the motivation for my thesis project at MIT. It's an acoustic drum outfitted with a system of electromagnets and control electronics which are used to induce pushing and pulling forces on a drumstick (with a permanent magnet embedded in its tip), moving it through a desired path in space. There are two states (attract or repel) which are controlled using the MIDI protocol (noteon messages attract the drumstick while noteoff messages repel it). Although the system works very well (it's a pretty bizzare experience to be holding a drumstick and have it move by itself!), my real interest was in experimenting with "kinesthetic preview" as a means for teaching complex gestures. This required an experimental tool with actuation and measurement fidelity beyond what was easily doable with electromagnetics. So, I eventually moved on to a motorized design which formed the basis of the HAptic GUidance System (aka. HAGUS), the experimental device used in my thesis project at MIT. You can read more about that project here