Here’s a nice option for art installations and sound projects that need to detect sound and/or measure sound amplitude.
The SparkFun Sound Detector is a small and relatively easy to use audio sensing board with three different outputs. The Sound Detector not only provides an audio output, but also a binary indication of the presence of sound, and an analog representation of its amplitude. The 3 outputs are simultaneous and independent, so you can use as many or as few as you want at once.
This first demo that includes and arduino and the sound detector board, starts with simple “claps” in order to demonstrate the binary indication of sound. Note that that the LED changes color and an indication light goes on and off on the sound detector board.
The next demo uses a horn sound, the horn sound is more complex and an anolog representation of the sound is shown through the changing colors of the idea. As the amplitude of the sound changes so does the color.
The third demo creates feedback using the sound detectors audio out and generating feedback with the use of the mini amp.