const byte Red = 12;      //Red on GPIO_12
    const byte Yellow  = 13;  //Yellow on GPIO_13
    const byte Green = 14;    //Green on GPIO_14
    
    const byte Relay1 = 0;    //Relay1 on GPIO_0
    const byte Relay2 = 2;    //Relay2 on GPIO_2
    
    void setup() {
      pinMode(Red, OUTPUT);   //Setup pin as Output
      pinMode(Yellow, OUTPUT);
      pinMode(Green, OUTPUT);
    
      pinMode(Relay1, OUTPUT);
      pinMode(Relay2, OUTPUT);
      
      Serial.begin(9600);
    }
    
    void loop() {
      // read the input on analog pin 0:
      int sensorValue = analogRead(A0);
      Serial.print("sensorValue: ");Serial.println(sensorValue);
    
      if (sensorValue > 600) {
        digitalWrite(Red, HIGH);
        digitalWrite(Yellow, LOW);
        digitalWrite(Green, LOW);
        digitalWrite(Relay1, LOW);  //Relay1 ON
        digitalWrite(Relay2, LOW);  //Relay2 ON
        
      } else if (sensorValue > 300) {
        digitalWrite(Red, LOW);
   digitalWrite(Yellow, HIGH);
        digitalWrite(Green, LOW);
        digitalWrite(Relay1, LOW);  //Relay1 ON
        digitalWrite(Relay2, HIGH); //Relay2 OFF    
      } else {
        digitalWrite(Red, LOW);
        digitalWrite(Yellow, LOW);
        digitalWrite(Green, HIGH);
        digitalWrite(Relay1, HIGH); //Relay1 OFF 
        digitalWrite(Relay2, HIGH); //Relay2 OFF 
      }
      delay(500);        // delay in between reads for stability
    }