Ball-shaped sensor and audio directional propagation method and system employing same

The invention provides a ball-shaped sensor including a driving module used for receiving movement instructions sent by a mobile terminal and driving the ball-shaped sensor to move to a target area; a target detecting module used for receiving a target detecting instruction sent by a control terminal, locking a target object and acquiring the information of distance between the target object and the ball-shaped sensor; an ultrasonic wave generating module used for generating ultrasonic waves of corresponding power according to the distance information; an audio processing module used for receiving audio signals sent by the control terminal and utilizing the audio signals for modulating the ultrasonic wave signals so as to generate audio modulation signals and to further send the audio modulating signals to the target object. Besides, the invention also provides an audio directional propagation method and system employing the ball-shaped sensor which can realize the directional propagation of the audio signals.