int RED_LED = 2 ;
int YELLOW_LED = 4 ;
int GREEN_LED = 6 ;
int SENSOR = 8 ;
int Val1 = 0;
int Parking = 0 ;

void setup() {
  pinMode(RED_LED, OUTPUT);                // sets the pin as output
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(SENSOR, INPUT);                  // sets the pin as input
  Serial.begin(9600);
}

void loop() {
  Val1 = digitalRead(SENSOR);              // sets input as name
  Serial.print("ที่จอดรถ = ");
  if (Val1 == 1) {                         // sets RedLight open when car is parking
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    Serial.println("ที่จอดรถไม่ว่าง");
    Parking = 1;
  }
  else {
    digitalWrite(RED_LED, LOW);
    if (Parking == 1){                     // sets GreenLight open when no parking
      digitalWrite(YELLOW_LED, HIGH);
      Serial.println("รถกำลังออก");
      delay(1000);
      digitalWrite(YELLOW_LED, LOW);
      Parking = 0;
    }
    digitalWrite(GREEN_LED, HIGH);
    Serial.println("ที่จอดรถว่าง"); 
  }
  delay(200);
}