You now have the basic tools to read and understand a real Arduino sketch. The famous “Blink” sketch is a perfect example that combines everything we’ve discussed. The comments below highlight how each building block is used.

// 1. VARIABLE: A global variable to hold the pin number for our LED.

// It’s an ‘int’ (integer) because pin numbers are whole numbers.

int ledPin = 13;

// 2. STRUCTURE: The setup() function runs once.

void setup() {

// We set the ledPin to be an output.

pinMode(ledPin, OUTPUT);

}

// 3. STRUCTURE: The loop() function runs forever.

void loop() {

// Turn the LED on

digitalWrite(ledPin, HIGH);

// Wait for 1 second (1000 milliseconds)

delay(1000);

// Turn the LED off

digitalWrite(ledPin, LOW);

// Wait for 1 second

delay(1000);

}

// NOTE: This sketch uses an ‘int’ variable for the pin number and the basic

// setup()/loop() structure. Inside loop(), we call the digitalWrite() function,

// passing it the pin number and a state (HIGH or LOW) to control the LED.

With these fundamental building blocks—setup() and loop(), variables and their data types, and operators—you have a solid foundation for your journey into the world of Arduino. You are now ready to start exploring, experimenting, and writing your own amazing sketches.