Spencer Russell created a “sleeve” for his upright bass to house electronic sensors which detect his position relative to the instrument. The sensors use an Arduino board to communicate with a computer running PD (PureData) to translate the sensor information into sound. He used Blender and QCad to make a 3D model of his bass in order to create a pattern for his fabric sleeve. He’ll be at October’s Dorkbot NYC if you want to see this in person. Link.