A gesture detection system comprising a virtual button structure for mounting in an outer frame of a mobile device for detecting finger gestures by a user. First and second piezo-electric actuators are in contact with the virtual button structure, and configured to generate first and second varying electrical signals, respectively in response to a dynamic force application to the virtual button structure. A processor is configured to execute instructions stored in memory to i) determine a magnitude and a position of the dynamic force application on the virtual button structure over time, based on the first varying electrical signal and the second varying electrical signal, ii) determine a gesture corresponding to the magnitude and the position of the dynamic force application over time; and iii) provide a response signal based on the gesture.