rpi-fft-led

This is a Raspberry Pi Projekt for the German Jugend Forscht competition. This Code controlls WS2812B LEDs using the SPI port of the Raspberry Pi by calculating a Fast Fourier Transform. The code I wrote makes use of the GPU_FFT library (http://www.aholme.co.uk/GPU_FFT/Main.htm) and code to steer the WS2812b LEDs (https://github.com/penfold42/stuff/blob/master/ws2812_spi.c).

fft.c is the main file and requires 1 to 3 arguments, the

• 1st is a mono .wav file to play or "mic" if you want to use an external microphone
• 2nd is the mode 1-4 to for displaying the sound
• 3nd is optional. If set to "log" displays Bins logarythmically on LED-Strip. If set as something else the frequency spectrum of each time frame should be scaled to 1 for the highest FFT amplitude.

The Modes are in the led_modes.c file

• Mode 1 maps each LED a number of bins and displays a color spectrum and the brightness is the amplitude(has to be optimized).
• Mode 2 maps each LED a number of bins and the color is the amplitude.
• Mode 3 is the same as mode 2 but the base is additional brightness.
• Mode 4 displays a snake that always adds the frequency with the highest amplitude to the beginning.
• Mode 5 displays the current volume using the number of LEDs. The color is represented by the most domiante frequency

Install and build

#Update system
sudo apt-get update && sudo apt-get upgrade

#Install missing librarys
sudo apt-get install libsndfile1 libsndfile1-dev

#Clone Project
git clone https://github.com/mariusdkm/rpi-fft-led

cd rpi-fft-led

#Build Project
make fft.bin

An example call would be:

sudo ./fft.bin example.wav 4

or

sudo ./fft.bin mic 2

Run the code using sudo since the GPU_FFT code makes use of the GPU, which requires root permissions.

The Langfassung.pdf is the Document I wrote for the Jugend Forscht Contest. It is in German but goes a bit deeper into how and why I've built this Project.

In developing this, I made use of the following information: http://www.aholme.co.uk/GPU_FFT/Main.htm https://stackoverflow.com/questions/3407942/rgb-values-of-visible-spectrum https://github.com/penfold42/stuff/blob/master/ws2812_spi.c https://www.linuxjournal.com/article/6735 https://ubuntuforums.org/showthread.php?t=968690

For the spi interface Copyright (c) 2016 penfold42

For the GPU_FFT Copyright (c) 2014 Andrew Holme.

Copyright (c) 2018 mariusdkm

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Softare Foundation, version 2.