8.0 Note playback in RPiSparkModule (PWM TONE)
PWM (Pulse Width Modulation) is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off. for more detailed Pulse-width modulation (PWM).
The RPi-Spark can play back PWM tones of a specified frequency, and the output is through a mono headphone jack or a mono speaker. In this section we using it play collision sound for BallBox.