A capacitive measurement system for gesture recognition

A prototype is presented to reliably recognize finger gestures contactlessly by tracking the time history of capacitance variations of an electrode array. It is demonstrated that given sufficient resolution along the time line even rather large noise figures of the read-out electronics can be circumvented. The mechanical constraints result in the assumption of a rather smooth finger movement in 3D along premeditated or intended trajectories out of a predefined set of gestures. Regarding optimal electrical processing of the capacitance variations a shielding strategy is presented and its powerful suppression of body to ground capacitances and its variations due to varying environmental conditions is demonstrated.