Servo myservo; 
int pos = 90;   // initial position
int sens1 = A1; // photoresistor 1 pin
int sens2 = A0; //photoresistor 2 pin
int tolerance = 2;
 
void setup() 
{ 
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object 
  pinMode(sens1, INPUT);
  pinMode(sens2, INPUT);
  myservo.write(pos);
  delay(2000); // a 2 seconds delay while we position the solar panel
}  
 
void loop() 
{ 
  int val1 = analogRead(sens1); // read the value of sensor 1
  int val2 = analogRead(sens2); // read the value of sensor 2
 
  if((abs(val1 - val2) <= tolerance) || (abs(val2 - val1) <= tolerance)) {
    //do nothing if the difference between values is within the tolerance limit
  } else {    
    if(val1 > val2)
    {
      pos = --pos;
    }
    if(val1 < val2) 
    {
      pos = ++pos;
    }
  }
 
  if(pos > 170) { pos = 170; } // reset to 180 if it goes higher
  if(pos < 0) { pos = 0; } // reset to 0 if it goes lower
  
  myservo.write(pos); // write the position to servo
  delay(50);
}