Bluetooth Home Automation

// Home Automation: Bluetooth Controlled Light
const int relayPin = 13;
char incomingData;

void setup() {
  pinMode(relayPin, OUTPUT);
  // Default state: Light OFF (Note: Most relays are Active Low)
  digitalWrite(relayPin, HIGH); 
  
  Serial.begin(9600); // Bluetooth default baud rate
}

void loop() {
  if (Serial.available() > 0) {
    incomingData = Serial.read();
    
    // Send '1' to turn ON, '0' to turn OFF
    if (incomingData == '1') {
      digitalWrite(relayPin, LOW); // Relay ON
      Serial.println("Light: ON");
    } 
    else if (incomingData == '0') {
      digitalWrite(relayPin, HIGH); // Relay OFF
      Serial.println("Light: OFF");
    }
  }
}