A control circuit for an amusement device includes a sound detector, a
band-pass filter, a peak integrator and a controller. The sound detector
is configured to detect audible sound signals. The band-pass filter is
electrically coupled to the sound detector. The band-pass filter is
configured to extract sound signals in a predetermined audible frequency
range and to output a corresponding filtered signal. The peak integrator
is electrically coupled to the band-pass filter. The peak integrator is
configured to receive the filtered signal, to average peaks of the
filtered signal and to output a trigger signal based on a predetermined
range of the averaged filter signal. The controller is electrically
coupled to the peak integrator. The controller is configured to receive
the trigger signal and to provide a control output in response to the
trigger signal.