Arduino MusicVisualizer

A Neopixel Arduino-Based Music Visualizer

A brief Introduction

MusicVisualizer takes as input music, specifically its sine wave, and processes it giving as output the amplitude of the various frequencies.

Hardware

• Arduino Nano
• WS2812B RGB LEDS (x300) laid down as a serpentine vector (zig-zag).

Data from music is fetched connecting one of the leads of the 3.5mm jack to an analogPin set to INPUT. This way the Arduino keeps reading the different voltage levels, which are the values of the sine wave. Then an FFT is performed and the output is pushed to the matrix.

External Libraries

<FastLED.h>

Easy to use library to work with neopixel leds (and similar chipsets, in my case WS2812B).

<LedMatrix.h>

This library works in conjunction with FastLED.h. It builds the array used by FastLED.h and draws the graphics.

<fix_fft.h>

This library is used to perform a Fast Fourier Transform, which transposes the sine wave from the time domain to the frequency domain. It is given as input an array containing the values read from analogRead(). The output of the FFT is a sequence of complex numbers. To graph the power spectral density of the audio, which is what most people want from the FFT, you only need to use the first N/2 values of the output array.