Ok, so I read that whole thing you sent me, laadams85. I understand it more so than I did, still not 100%, but I'll reread it again. Also I got the library that you linked, Steen. In the example that was provided, it says the A0 pin receives the analog input but I dont see A0 defined anywhere or referenced in the code, unless thats what #define IR_AUDIO 0 is, which im fairly certain it is ( I'm new to all this though, could easily be wrong). The way this example is set up, it appears to me to be doing the first method you mentioned laadams85, wherein it fills an array, performs the FFT, then gets the new array. It also appears to spit it out over serial. I guess next on the list is how to hook a microphone up. Could anyone point me in the right direction?
Oh and Sembazuru, I had looked at the lilypad, but i ended up just getting the mega 2560, I want to do other projects after this one, and I dont know how powerful the lilypad is in comparison.
Here is the example that came with the library that I have been referencing.
/*
This Example acquire analog signal from A0 of Arduino, and Serial out to Processing application to visualize.
Tested with preamplified audio data. Take a look at http://www.youtube.com/watch?v=drYWullBWcI
Analog signal is captured at 9.6 KHz, 64 spectrum bands each 150Hz which can be change from adcInit()
Load the this file to Arduio, run Processing application.
Original Fixed point FFT library is from ELM Chan, http://elm-chan.org/works/akilcd/report_e.html
A way to port it to the Arduino library and most demo codes are from AMurchick http://arduino.cc/forum/index.php/topic,37751.0.html
Processing app is based on codes from boolscott http://boolscott.wordpress.com/2010/02/04/arduino-processing-analogue-bar-graph-2/
*/
#include <stdint.h>
#include <ffft.h>
#define IR_AUDIO 0 // ADC channel to capture
volatile byte position = 0;
volatile long zero = 0;
int16_t capture[FFT_N]; /* Wave captureing buffer */
complex_t bfly_buff[FFT_N]; /* FFT buffer */
uint16_t spektrum[FFT_N/2]; /* Spectrum output buffer */
void setup()
{
Serial.begin(57600);
adcInit();
adcCalb();
establishContact(); // send a byte to establish contact until Processing respon
}
void loop()
{
if (position == FFT_N)
{
fft_input(capture, bfly_buff);
fft_execute(bfly_buff);
fft_output(bfly_buff, spektrum);
for (byte i = 0; i < 64; i++){
Serial.write(spektrum[i]);
}
position = 0;
}
}
void establishContact() {
while (Serial.available() <= 0) {
Serial.write('A'); // send a capital A
delay(300);
}
}
// free running ADC fills capture buffer
ISR(ADC_vect)
{
if (position >= FFT_N)
return;
capture[position] = ADC + zero;
if (capture[position] == -1 || capture[position] == 1)
capture[position] = 0;
position++;
}
void adcInit(){
/* REFS0 : VCC use as a ref, IR_AUDIO : channel selection, ADEN : ADC Enable, ADSC : ADC Start, ADATE : ADC Auto Trigger Enable, ADIE : ADC Interrupt Enable, ADPS : ADC Prescaler */
// free running ADC mode, f = ( 16MHz / prescaler ) / 13 cycles per conversion
ADMUX = _BV(REFS0) | IR_AUDIO; // | _BV(ADLAR);
// ADCSRA = _BV(ADSC) | _BV(ADEN) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1) //prescaler 64 : 19231 Hz - 300Hz per 64 divisions
ADCSRA = _BV(ADSC) | _BV(ADEN) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0); // prescaler 128 : 9615 Hz - 150 Hz per 64 divisions, better for most music
sei();
}
void adcCalb(){
Serial.println("Start to calc zero");
long midl = 0;
// get 2 meashurment at 2 sec
// on ADC input must be NO SIGNAL!!!
for (byte i = 0; i < 2; i++)
{
position = 0;
delay(100);
midl += capture[0];
delay(900);
}
zero = -midl/2;
Serial.println("Done.");
}
Again, thank you for your time.
