// 🛠 Third Arduino Program: Control LED using Serial Monitor
// 👉 Concepts introduced: Serial.available(), Serial.read(), conditional statements

int ledPin = 13;  // LED connected to pin 13

void setup() {
  pinMode(ledPin, OUTPUT);  
  Serial.begin(9600);  // Initialize Serial Communication
  Serial.println("Send '1' to turn ON LED, '0' to turn OFF LED");
}

void loop() {
  if (Serial.available() > 0) { // 1️⃣ Check if data is available
    char data = Serial.read();  // 2️⃣ Read the received character

    if (data == '1') {  
      digitalWrite(ledPin, HIGH);
      Serial.println("LED is ON");
    } 
    else if (data == '0') {
      digitalWrite(ledPin, LOW);
      Serial.println("LED is OFF");
    }
  }
}