fft_led/main.c

#include<avr/power.h>
#include<util/delay.h>
#include<avr/io.h>
#include"fix_fft.h"
#include"avr_adc.h"
#include"light_ws2812_AVR/Light_WS2812/ws2812_config.h"
#include"light_ws2812_AVR/Light_WS2812/light_ws2812.h"
#include"main.h"

#define STARTADC ADCSRA |= (1<<ADSC)
#define PB_mic PB0
#define NOISE 100
#define SCALE_FACTOR 10
//resolution fft calc: 
//https://3roam.com/fft-resolution-bandwidth-calculator/
//128 samples , 1kSPS  = 7.8Hz
//interested in 0-10000 Hz
// 
//128 bins a 7.8hz = 0...1000Hz
//
//we have 8 leds:
//bands 125hz/band -> 16 bins
//
//1-7.8 - ca 130hz
//2-	255hz
//3-	380
//4-	505
//5-	630
//6-	755
//7-	880
//8-	1kHz
//

const float log_scale = 64./log(64./SCALE_FACTOR + 1.); 


int msec;

ISR(TIMER1_OVF_vect)
{
if(msec<100)
{
	msec++;
}
else msec=0;
}

int main (void)
{
		int i,i2;
		//int colorb;
		//int colora;
		int sum,avg;
		char sample[64];
		char im[64];
		char buff[64];

		float fac_r=0;
		float fac_g=0.5;
		float fac_b=1;
		msec=0;
		struct cRGB led_bar1[8];
		//DDRB = (1<<mic);//would be setting output, default is input so no need for setting
		setupADC();
		setupTimer();

		//OSCCAL = 250;//overclock!!! to 30MHz
		for(i=0;i<8;i++)
		{
				led_bar1[i].r=0;
				led_bar1[i].g=0;
				led_bar1[i].b=0;
		}
		for(i=0;i<64;i++)
		{
				buff[i]=0;
		}

		sei();
		while(1)
		{
//######RECORD SAMPLES######
				sum = 0;
				for(i=0;i<64;i++)
				{	
				msec=0;
						STARTADC; 
						sample[i] = (ADCH-128); //read Analog value register 8bit center -128
						//sample[i] = (sample[i] <= NOISE) ? 0 : (sample[i] - NOISE);						  //noise reduction
						im[i]=0;		//pseudo data for funciton
										//
						sum+=sample[i];//dc-bias
				
						//while(msec<=1);
				}
				avg = sum/64;//calculate bias
				for(i=0;i<64;i++)
				{
						sample[i]-=avg;//remove bias
				}				
				fix_fftr(sample,6,0);//im[i] is alwa§§ys zero
//####Averaging Data####
//
				for(i=0;i<64;i++)
				{	
						if(sample[i]<0) sample[i] = 0;
						if(sample[i]>64) sample[i]=64;
						sample[i] = sample[i] *SCALE_FACTOR;
						sample[i] = (sample[i]*0.7 + buff[i]*0.3);
						buff[i] = sample[i];	

				}
				for(i=0;i<8;i++)
				{
						for(i2=1;i2<=4;i2++)
						{
								sample[i] = ((sample[i] + sample[i*8+i2])/2);
						}
						//avg written to sample[0..7]

						if(sample[i]<20)
						{
								led_bar1[i].r=(char)sample[i]*fac_r;
								led_bar1[i].g=(char)sample[i]*fac_g;
								led_bar1[i].b=(char)sample[i]*fac_b;
						}
						else if(sample[i]<30)
						{
								led_bar1[i].r=0;
								led_bar1[i].g=sample[i];
								led_bar1[i].b=sample[i]/2;
						}
						else if(sample[i]<50)
						{
								led_bar1[i].r=sample[i];
								led_bar1[i].g=0;
								led_bar1[i].b=sample[i]/2;
						}
				}				
				ws2812_setleds(led_bar1,8);
		}
return 0;                 
}

int map(int value, int old_min, int old_max,int new_min, int new_max)
{
		return (new_max/old_max*value);
}

void setupTimer(void)
{
		clock_prescale_set(0);
		TCCR1 = (1<<CS10);//(1<<CS13)|(1<<CS10)|(1<<CTC1);										//clear timer on compare match
		GTCCR = 0;												//default values should be ok
		//OCR1C =	117;											//Compare value of timer / overflow , sets OCF1A
		//OCR1A = 117;
		TIMSK |= (1<<TOIE1);//|(1<<TOIE1);			//timer0 ovf 
		TIFR |=	(1<<TOV1); 			//flag register "aka when to interrupt
}
/*
 * 1/(30Mhz/16384) *255 = 0.139264s  Time for one overflow
 * 			1024		= 0.008704s 
 *			2024		= 0.017204s
 * 						255/0.017204*0.001=15 counts = 1ms
 *			256 gives 1ms
 */

void wait_period(void)
{
	//	TIFR |=(1<<TOV1);			//clear overflow flag
}