Automatic player piano with magnetic velocity sensor shielded from solenoid-operated key actuators

摘要

A automatic player piano has an acoustic piano with black/white keys selectively fingered by a player, solenoid-operated key actuators selectively energized with driving signals for moving the black/white keys without the fingering, magnetic velocity sensors for detecting current velocities of the plungers of the solenoid-operated key actuators and a controller connected between the solenoid-operated key actuators and the magnetic velocity sensors and changing the magnitude of the driving signals for matching the current velocities to target velocities, and a magnetic shield structure is provided between the solenoid-operated key actuators and the magnetic velocity sensors so as to improve a signal-to-noise ratio of the detecting signals supplied to the controller.