A music tempo calculation system uses a microphone to input ambient music; the input is then processed in real time to display beats per minute (BPM). Input from the microphone is decomposed by a detector into a plurality of digital signals ranging from a most sensitive signal to a least sensitive signal. A software-implemented algorithm is applied to the time between peak music values to determine tempo. BPM is then output to a display to provide feedback to performing musicians regarding tempo. The sensitivity of the detector adjusts automatically to compensate for changes in music volume. In another embodiment, the calculated tempo is used to control motors used to animate toys. Once BPM is known, the moment of an upcoming beat can be anticipated. It then becomes possible to start, stop, and reverse directions of a motor in anticipation of an upcoming beat thereby providing the appearance the animated toy is responding to music beat.