How to do fast fourier transformation in arduino?

Hello! I've been looking on how to do a FFT on arduino but it seems impossible! Apparently I need to download a library and then design a code. I saw the examples on the arduino website but its useless because I can't download the library. Is there a library I can download and like pointers I can get in writing the code? What I'm trying to do is take a sound signal using a microphone, and split that noise in high and low frequencies to control LED lights.

Any advice?

Unless you write your own, you will have to use a library. OpenMusic labs has one.

The Arduino is limited to fairly low frequencies, anyway. You might want to look at the MSGEQ7: https://www.sparkfun.com/products/10468

http://apcmag.com/arduino-project-audio-spectrum-analyser.htm#null

KeithRB: Unless you write your own, you will have to use a library. OpenMusic labs has one.

The Arduino is limited to fairly low frequencies, anyway. You might want to look at the MSGEQ7: https://www.sparkfun.com/products/10468

Wait so with this will I not even need an arduino board?

Yes, because the MSGEQ7 just provides the spectrum analysis. The arduino needs to control the LED's. http://nuewire.com/info-archive/msgeq7-by-j-skoba/

Arduino Yun

opkg update
opkg install fftw3
opkg install fftw3f

fftw3 - 3.2.2-2 - FFTW is a collection of fast C routines for computing the Discrete Fourier Transform in one or more dimensions. It includes complex, real, and parallel transforms, and can handle arbitrary array sizes efficiently.

fftw3f - 3.2.2-2 - FFTW is a collection of fast C routines for computing the Discrete Fourier Transform in one or more dimensions. It includes complex, real, and parallel transforms, and can handle arbitrary array sizes efficiently. This package contains the single precision library.

@RogerClark, Cool link ! (I downloaded the waveform generator)

@raschemmel

Ta.

That magazine has started running an Arduino section almost every month for about a year, and most of the time its quite interesting stuff, so it may be worth looking to see what else they have done.

I'm going to wire up the FFT analog music input circuit this weekend and try out the waveform generator.