with two contacts, switches or sensor triggering levels along the key kinematic path

Full Title

Input/output interfacing specifically adapted for electrophonic musical tools or instruments > User input interfaces for electrophonic musical instruments > Key design details; Special characteristics of individual keys of a keyboard; Key-like musical input devices, e.g. finger sensors, pedals, potentiometers, selectors > Switching mechanism or sensor details of individual keys, e.g. details of key contacts, hall effect or piezoelectric sensors used for key position or movement sensing purposes; Mounting thereof > with two contacts, switches or sensor triggering levels along the key kinematic path