Arduino Basics

Your first Arduino program — blinking an LED

An Arduino program is like a drummer in a band. setup() is the drummer counting in — "1, 2, 3, 4" — it runs once before the music begins. loop() is the beat that repeats for the entire song. The drummer does not stop until the music ends. Your Arduino does not stop until you pull the plug.

Variables and timing — controlling blink speed

A variable is like the volume knob on a radio. The knob has a name ("volume"), it holds a value (say, 7), and you can turn it up or down. Your code is the same — the variable has a name, holds a number, and you can increase or decrease it whenever you want.

Multiple LEDs — patterns and sequences

An array is like a row of numbered mailboxes in an apartment building. Instead of remembering each tenant by name, you just say "mailbox 0, mailbox 1, mailbox 2." A for loop is the mail carrier walking down the row, dropping a letter in each box one at a time.

Reading input — buttons and decisions

digitalRead is like checking your mailbox. You walk out, open the box, and look inside. Either there is mail (1) or there is not (0). You do not control whether mail arrives — you just check and react. Your Arduino checks the pin and reacts to whatever state it finds.

Analog output — fading and brightness

PWM is like a ceiling fan. The fan motor is either spinning or not — there is no "half speed" switch. Instead, the fan clicks on and off rapidly. Mostly on? The fan spins fast. Mostly off? It spins slowly. Your eyes blur the flickering into smooth motion, just as they blur PWM into smooth brightness.

Serial communication — talking to the computer

Serial communication is like a walkie-talkie. The Arduino holds down the button and talks: "Temperature is 24 degrees." Your computer listens and writes it down. The Arduino cannot hear back in our simulator, but the one-way reports are enough to monitor everything happening on the board.

Making sound — tone(), frequency, and the buzzer

Think of a guitar string. A thick, loose string vibrates slowly — low frequency, deep sound. A thin, tight string vibrates fast — high frequency, high pitch. tone() tells the Arduino how fast to vibrate the buzzer. 262 vibrations per second = middle C. 880 vibrations per second = a high A. You are programming the string tension with a number.