probleem uitlezen twee opto sensors met arduino

//for printf
#include <stdio.h>

const int S0Distance = 8; //pin attached to sensor that measures one complete turn 
const int S1Distance = 11; //pin attached to sensor that measures one complete turn 

//for printf
int my_putc( char c, FILE *t) {
  Serial.write( c );
} 

void setup()
{	
	pinMode(S0Distance,INPUT);
	pinMode(S1Distance,INPUT);
	       
        Serial.begin(9600);

        fdevopen( &my_putc, 0); 
        printf("test %i",10);
}

void loop()
{
    bool done = false; 
    while (!done) 
    {
                ....
          	if (digitalRead(S0Distance) == HIGH)
		{
		      printf("S0Distance high");
		}
 
                //a small delay didn't work out (1 to 10) 
	       //delay(1);
		
		if (digitalRead(S1Distance) == HIGH)
		{
			printf("S1Distance high");	
		}
    }
}