Code for Arduino Spectrrum Analyzer

Spectrum Analyzer

//#define LOG_OUT 1 // use the log output function
#define OCTAVE 1 // use the octave function
#define FFT_N 256 // set to 256 point fft
#define NBR_MTX 2 //Matrix
#include <FFT.h> // include the library
#include "LedControlMS.h"
int val[8];

LedControl lc=LedControl(7,6,5, NBR_MTX);//Configure pins for matrix // 12,11,10,NBR_MTX
void setup() {
    for (int i=0; i< NBR_MTX; i++){
    lc.shutdown(i,false);
    lc.setIntensity(0,0);
    lc.clearDisplay(i);
  }
  pinMode(A0,INPUT);
  Serial.begin(115200); // use the serial port
  TIMSK0 = 0; // turn off timer0 for lower jitter
  ADCSRA = 0xe5; // set the adc to free running mode
  ADMUX = 0x40; // use adc0
  DIDR0 = 0x01; // turn off the digital input for adc0
   lc.setLed(0,0,0,true);   
}

void loop() {
  while(1) { // reduces jitter
    cli();  // UDRE interrupt slows this way down on arduino1.0
    for (int i = 0 ; i < 512 ; i += 2) { // save 256 samples
      while(!(ADCSRA & 0x10)); // wait for adc to be ready
      ADCSRA = 0xf5; // restart adc
      byte m = ADCL; // fetch adc data
      byte j = ADCH;
      int k = (j << 8) | m; // form into an int
      k -= 0x0200; // form into a signed int
      k <<= 6; // form into a 16b signed int
      fft_input[i] = k; // put real data into even bins
      fft_input[i+1] = 0; // set odd bins to 0
    }
    fft_window(); // window the data for better frequency response
    fft_reorder(); // reorder the data before doing the fft
    fft_run(); // process the data in the fft
    //fft_mag_log(); // take the output of the fft
    fft_mag_octave();
    sei();
    //  lc.clearDisplay(0);


  for(int idx=0; idx < 8; idx++)
  {
  val[idx] = fft_oct_out[idx]/32;
  }
  
for(int idx=0; idx < 8; idx++)
  {
  for(int x = 0; x < 8; x++)
    {
      if(x <= val[idx])
        lc.setLed(0,x,7-idx,true);
      else  
        lc.setLed(0,x,7-idx,false);
    }
  }

//delay(5);
  }
}