Unveiling Dynamic Finger–Key Interactions in Piano Performance Through 3D Force Measurements

Understanding haptic interactions between fingers and piano keys is essential for uncovering the sensorimotor mechanisms underlying piano performance. In the present study, we developed a sensor-integrated piano keyboard capable of monitoring three-dimensional (3D) forces applied to the keys, achieved by embedding MEMS sensor devices in both white and black keys spanning an entire octave (C4 to C5). The system captures both vertical (depressing) and horizontal (frictional) forces, offering novel insights into how pianists utilize friction to execute complex finger movements in playing note sequences and chords. We describe the system's design and functionality, and present representative results demonstrating its capabilities. Our findings reveal that the temporal profiles of both vertical and horizontal forces contain rich information about physical mechanisms underlying pianistic skills. Moreover, we report novel observations of the dynamic force interaction between the fingers and key surfaces. This system offers a valuable tool for analyzing the sensorimotor foundations of pianistic skills and for providing objective data to support piano pedagogy.