A method and system for controlling actuators in a mechanical reproducing
piano or other instrument. In one implementation, a single finite state
machine is provided to control all the actuators. The finite state
machine may be or include a shift register or a toggle register, which
increases the operating speed. When a note is to be played, the desired
dynamic is mapped into a start vector and a stop vector. The actuator is
turned on when the state of the finite state machine is equal to the
start vector, and is turned off when the state of the finite state
machine is equal to the stop vector. Furthermore, the period of the
finite state machine is adjusted to be directly proportional to the
supply voltage. This allows notes to be played at the desired dynamics
even when the supply voltage fluctuates.