#include <Servo.h>

Servo myservodx;
Servo myservosx;


void setup()
{
   Serial.begin(9600); 
   myservodx.attach(9);  
   myservosx.attach(10);  
}

void loop()
 {  
   int val;
   val=analogRead(0);      //connect grayscale sensor to Analog 0
   Serial.println(val,DEC);//print the value to serial        
   delay(100);             // wait 0.1 s
   
   if (val > 850) {
     // in this case the light is large enough: we abandoned 
     // the black line
     myservodx.write(86);
     myservosx.write(100);
   } else {
     // go forward (the two values differs depending on the
     // friction between the wheel and the floor. The two motors
     // must move in opposite directions because they are mounted 
     // back to back.
     myservodx.write(100);
     myservosx.write(86);
     // wait 5 s
     delay(5000);
     // stop (writing 90 to servomotors they stop)
     myservodx.write(90);
     myservosx.write(90);  
   }
 }