#define leftSensor A2
#define rightSensor A3
 
void setup() 
{
  Serial.begin(9600);
  pinMode(4, OUTPUT); 
}
 
void loop() 
{
  int leftRead = analogRead(leftSensor);
  int rightRead = analogRead(rightSensor);
 
  if (leftRead > 500)
  {
    digitalWrite(4, LOW); 
  }
  else if (rightRead > 500)
  {
    digitalWrite(4, LOW); 
  }
  else
  {
    digitalWrite(4, HIGH);  
  }
}
