#define safe_led 10
#define hazard_led 9
#define hazard_buzzer 8
int incomingByte = 0; // for incoming serial data

void setup() {
  Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
  Serial.println("Start!");
  pinMode(safe_led, OUTPUT);
  pinMode(hazard_led, OUTPUT);
  pinMode(hazard_buzzer, OUTPUT);

}

void loop() {
  // send data only when you receive data:
  if (Serial.available() > 0) {
    // read the incoming byte:
    incomingByte = Serial.read()-'0';
    if (incomingByte == 1){
      digitalWrite(hazard_led, HIGH);
      //digitalWrite(hazard_buzzer, HIGH);
      tone(hazard_buzzer,550);
      digitalWrite(safe_led, LOW);
      Serial.println("Safe condition.");
    }
    else if (incomingByte == 0) {
      digitalWrite(safe_led, HIGH);
      digitalWrite(hazard_led, LOW);
      //digitalWrite(hazard_buzzer, LOW);
      noTone(hazard_buzzer);
      Serial.println("Hazard condition.");
    }
    delay(200);
  }
}