lol shield(14x9 led matrix) and arduino uno. code error fix_fft

I recently purchased the LOL shield by Jimmie p Rogers from and assembled it per instructions. The aim of this project is to make an audio spectrum analyzer vumeter . i had it setup and programmed as instructions given here ( with the code that reads;

FFT for LoL Shield v0.9
by Andy Doro

based on FFT library and code from the Arduino forums and
the Charlieplexing library for the LoL Shield.

#include <Charliplexing.h>
#include <fix_fft.h>

#define AUDIOPIN 5

char im[128], data[128];

char data_avgs[14];

int i=0,val;

void setup() {
LedSign::Init(); //Initilizes the LoL Shield

void loop() {

for (i=0; i < 128; i++){
val = analogRead(AUDIOPIN);
data[i] = val;
im[i] = 0;


for (i=0; i< 64;i++){
data[i] = sqrt(data[i] * data[i] + im[i] * im[i]); // this gets the absolute value of the values in the array, so we're only dealing with positive numbers

// average bars together
for (i=0; i<14; i++) {
data_avgs[i] = data[i*4] + data[i*4 + 1] + data[i*4 + 2] + data[i*4 + 3]; // average together
data_avgs[i] = map(data_avgs[i], 0, 30, 0, 9); // remap values for LoL

// set LoLShield

for (int x=0; x < 14; x++) {
for (int y=0; y < 9; y++) {
if (y < data_avgs[13-x]) { // 13-x reverses the bars so low to high frequences are represented from left to right.
LedSign::Set(x,y,1); // set the LED on
} else {
LedSign::Set(x,y,0); // set the LED off



but i keep getting the following error messages

“fft.ino: In function ‘void loop()’:
fft:37: error: ‘fix_fft’ was not declared in this scope”

i installed the charlieplexing file and fft file in my arduino library under my documents (which is the default location for windows OS). i’ve also attatched pics showing where i installed the files.
what am i doing wrong? please help


Posting code incorrectly. I am 100% certain that your code does NOT look like that.
Failing to read stuff you were supposed to read FIRST:

Shall I go on?

It looks like you failed to download and/or properly install the fix_fft library.

Hey einstein! did you see where i included the link with the code itself?? it seems like you sir is the one with the reading problem.
Firstly im pretty sure i installed everything i was supposed to install in the library except something is missing which i would like to know as i have included all the materials and links i'm working with. I am not a proffessional programmer or a programmer in any sense. i have basic electronics and programming knowledge and really i am just a diy guy just following simple instructions. most of the stuffs on the link you posted are hard for me to relate to. so if you can please break it down and stop trying to sound like a god. Thank you.

Calm down and look at the code you posted. Much of it is displayed in italics in your post but it is not like that in the IDE. If you had read which you could hardly miss as it is at the top of the forum page in bold red you would have seen the advice to use code tags when posting code here to avoid it being munged like yours.

As to the use of capitals. Please don’t do it. It is just plain rude.

Because your code is munged it is difficult to read an understand but as has been suggested faulty installation of the fix_fft library. I get the same error as you when compiling the code from the site you linked to without the library installed. Where do you have it installed exactly ?

i installed it in the arduino library under my documents folder (win OS). i don't know where else i'm going wrong. how i'm i supposed work this out. as for the code i gave the link to the original. i apologize if didn't post the code as required.

Hey einstein! did you see where i included the link with the code itself??

You are going to go a long way in life with that attitude.

If you go back and edit your first posting, both by correcting the capitals (most importantly in the subject line) and marking your code up with the code ([ # ]) icon above the edit window, you may get some more detailed help, quicker.