The Arduino is able to output sound through a library that has been developed called the Tone Library.
By creating an interface and a program that can call certain values to be output to an audio out, the Arduino Synthesizer is a robust tool for making a rudimentary noise machine. It uses granular synthesis techniques to generate a distinctive sound that can be a whole lot of fun for musicians, artists, tinkerers, and hobbyists.
Step 1: How it works
The grain consists of two triangular waves of adjustable frequency, and adjustable decay rate.
The repetition rate is set by another control.