#include <avr/io.h>
#include <avr/interrupt.h>
#include<util/delay.h>
#include<stdlib.h>

char result[5];

void init_ADC()
{
ADMUX |= 1<<REFS0;
ADMUX |= 1<<ADLAR;
ADCSRA |= 1<<ADEN;
ADCSRA |= 1<<ADIE;

//ADCSRA |= 1<<ADFR;

ADCSRA |= 1<<ADPS2; //prescalar factor of 16
}

int ReadADC(uint8_t ch)
{
//Select ADC Channel ch must be 0-7
ch=ch&0b00000111;
ADMUX|=ch;

//Start Single conversion
ADCSRA |= (1<<ADSC);

//Wait for conversion to complete
while(!(ADCSRA&(1<<ADIF)));

ADCSRA|=(1<<ADIF);

return(ADC);
}

int main()
{
DDRC = 0×00;

//sei();
init_ADC();
int x1,x2,x3,x4;

DDRB = 0xFF;
DDRD = 0xFF;
PORTB= 0x00;
_delay_ms(100);
while(1)

{

x1=ReadADC(2);      //forward   PINC2
x2=ReadADC(3);      //right     PINC3
x3=ReadADC(4);      //left      PINC4
x4=ReadADC(5);      //BACK      PINC5

if(x1<512)
{
    PORTB = 0X0F;
    PORTD = 0b00010100;
}
if(x2<512)
{
    PORTB = 0X0F;
    PORTD = 0b00100100;
}
if(x3<512)
{
    PORTB = 0X0F;
    PORTD = 0b00011000;
}
if(x4<512)
{
    PORTB = 0X0F;
    PORTD = 0b00101000;
}
}

return 0;
}