int Forward = 2;
int Backward = 3;
int Left = 4;
int Right = 5;

int Low_Limit = 88;
int High_Limit = 168;

void setup()
{
  // begin the serial communication
  Serial.begin(38400);
  
  // Set Output pins
  pinMode(Forward, OUTPUT);
  pinMode(Backward, OUTPUT);
  pinMode(Left, OUTPUT);
  pinMode(Right, OUTPUT);
}

void loop()
{
  byte x,y;
  while (!Serial.available());
  if (Serial.available() >0 ) {
    x = Serial.read();
     Serial.print(x, BYTE);
  }
  while (!Serial.available());
  if (Serial.available() >0 ) {
    y = Serial.read();
     Serial.print(y,BYTE);
  }
  
  // Back and forward
  
  if ( x > High_Limit)
    {
      digitalWrite(Forward, HIGH);
      digitalWrite(Backward, LOW);
    }
  else if( x < Low_Limit)
    {
     digitalWrite(Forward, LOW);
     digitalWrite(Backward, HIGH);   
    }
    else 
    {
     digitalWrite(Forward, LOW);
     digitalWrite(Backward, LOW);   
    }
   
  //Left and Right 
  if ( y > High_Limit)
    {
      digitalWrite(Right, HIGH);
      digitalWrite(Left, LOW);
    }
  else if( y < Low_Limit)
    {
     digitalWrite(Right, LOW);
     digitalWrite(Left, HIGH);   
    }
    else 
    {
     digitalWrite(Right, LOW);
     digitalWrite(Left, LOW);   
    }    
}