Arduino: Software FFT Color Organ, First Steps
I found a wonderful implementation of the Fast Fourier Transform that runs in Arduino code, and since it uses the ATmel’s native ADC commands it can work very fast, actually in realtime, to decompose an input audio signal. The program actually has 31 bands in the spectrum and combines those to actuate the LEDs in three groups, which would be RGB except that I ran out of everything except green ones.
I have to give credit to the programmers who originally wrote the FFT algorithm and ported it to Arduino:
Written by: Tom Roberts 11/8/89
Made portable: Malcolm Slaney 12/15/94 malcolm@interval.com
Enhanced: Dimitrios P. Bouras 14 Jun 2006 dbouras@ieee.org
Adapted for Arduino: Anatoly Kuzmenko 6 Feb 2011 k_anatoly@hotmail.com
http://fftarduino.blogspot.com/2011_02_01_archive.html
http://forum.arduino.cc/index.php/topic,51828.0.html
Thanks, guys! I was amazed when the code actually compiled and ran the very first time, without tweaking!
Further development will involve a board of driver transistors and some brighter RGB LEDs.
I hope Brother Nathaniel doesn’t mind that I used a short quotation from his excellent commentaries for my speech sample.