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Your first Arduino.
Let’s make it blink.

From a board on your desk to your first blinking light. A little code. A real-world result.

Let’s get startedNeed a hand?
Beginner friendlyYour first win is one blink away.
01 / Meet your Arduino

A little board.
A world of possibilities.

Arduino connects your code to the physical world. Its microcontroller reads inputs, runs your sketch, and controls outputs—from a small light to the next thing you invent.

Make something respond

Turn an LED on, sound a buzzer, or move a small servo.

Listen to the world

Read a button or sensor and decide what happens next.

Learn one small step at a time

Write a sketch, upload it, then change something and try again.

An Arduino runs your sketch. It does not need a desktop operating system or microSD card for this guide.

02 / Find your starting point

Choose your board.

Already have an Arduino? Start there. Match the USB cable and IDE board package to the exact model on your desk.

Our starting point
Illustration of an Arduino UNO board

Arduino UNO R3

A familiar starting point for learning inputs, outputs, and your first sketches. Uses a USB-B cable.

Shop this setup
Room for connected ideas

UNO R4 WiFi

For projects with wireless connections and an onboard LED matrix. Uses USB-C and its own board package.

Meet the R4 WiFi
When small matters

Arduino Nano

A compact family for smaller builds. Connectors, board packages, and logic voltages vary by model.

Explore the classic Nano

This guide starts with an UNO R3. The built-in Blink example also works on many other Arduino boards when you select the correct board in the IDE.

03 / A few things before you begin

Gather the essentials.

Use what you already have. For your first blink, three things are enough.

An Arduino board

An UNO R3 is a straightforward place to begin.

A data USB cable

USB-B for UNO R3. Match the other end to your computer.

A computer + Arduino IDE

Use a supported Windows, macOS, or Linux computer.

Prefer everything in one box?

Choose one UNO R3 kit
Basic Starter KitArduino UNO R3 included

Basic Starter Kit

An UNO R3, USB cable, breadboard, holder, jumper wires, and a battery connector. A simple starting point.

Ultimate Starter KitArduino UNO R3 included

Ultimate Starter Kit

An UNO R3, USB cable, a printed guide, and components including LEDs, resistors, sensors, and motors for your next projects.

No extra circuit for Blink. The UNO’s built-in LED and USB power are all you need. Breadboards, jumper wires, LEDs, and resistors come later.

04 / Give your board its instructions

One app. Your ideas, in code.

Arduino IDE is where you write, check, and upload a sketch. Install it on your computer before connecting your first project.

  1. 1

    Get Arduino IDE

    Download the current Arduino IDE for your operating system and follow the installer.

    Download Arduino IDE
  2. 2

    Open a fresh sketch

    A sketch is the program your board runs. Start with an example rather than a blank page.

  3. 3

    Learn the two main parts

    setup() runs once after startup. loop() repeats while the board is powered.

Arduino IDEBlink.ino
Arduino UNO
void setup() {
  // Run once
}

void loop() {
  // Run again and again
}
Editor illustration. Labels may vary by version.
05 / Make the connection

Plug in. Select. You’re ready.

The IDE needs to know both the board model and the USB port it is connected to.

  1. 1

    Connect with a data USB cable

    Connect the board directly to your computer. USB supplies power and transfers your sketch.

  2. 2

    Install the matching board package

    Accept the IDE’s install prompt, or use Boards Manager. UNO R3 uses Arduino AVR Boards; UNO R4 uses Arduino UNO R4 Boards.

  3. 3

    Choose your board and port

    Use the board selector at the top of IDE 2, or Tools → Board and Tools → Port. Choose the port that appears when you connect your Arduino.

    Board and port guide

A power light does not prove the cable carries data. If no port appears, try a known data cable before changing your sketch.

06 / Your first little milestone

Start with the board’s built-in LED. No breadboard or loose wires—just your Arduino, your cable, and a sketch.

  1. 1

    Open the Blink example

    In Arduino IDE, choose File → Examples → 01.Basics → Blink. Or paste the sketch below into a new sketch.

  2. 2

    Verify, then upload

    The checkmark verifies your code. The right-arrow Upload button sends it to your board. Wait for the upload to finish.

  3. 3

    Watch the LED marked L

    It turns on for one second, then off for one second. Change both delay(1000) values to delay(500), upload again, and watch it blink faster.

Blink.ino
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
}

That first blink is yours.

A small signal that your code and your board are talking.

Browser preview. Upload the sketch to run it on your board.

LED_BUILTIN uses the LED pin defined for the selected board. On UNO R3, it is connected to digital pin 13.

07 / A little help along the way

Hit a bump? Start here.

Check one thing at a time. Most first-upload problems begin with the cable, board selection, or port.

My board does not appear in the port list.

Try a known data USB cable and a direct USB port on your computer. A charge-only cable can power the board without transferring data. Reconnect the board, then open the board selector again.

The sketch verifies, but will not upload.

Check the exact board and port. Close other programs using the port, including another Serial Monitor, and disconnect external circuits while trying Blink. Use the full error message to find the matching Arduino support article.

Which board package should I install?

UNO R3 uses Arduino AVR Boards. UNO R4 Minima or WiFi uses Arduino UNO R4 Boards. Nano models use different packages: match the full model name printed on your board.

The LED was already blinking when I plugged it in.

A sketch may already be stored on the board. Upload Blink, then change both delay values from 1000 to 500 and upload again. A faster blink shows that your new sketch is running.

Do I need a breadboard, LED, or battery for Blink?

No. This exercise uses the board's built-in LED and USB power. Save the breadboard and other components for your next project.

UNO R3 pinoutKnow your pins before wiringStarter codeKeep experimenting

Before wiring your next circuit, disconnect power and use the pinout for your exact board. Use a resistor with an external LED and a suitable driver for a motor.

Your next chapter

One blink is just the beginning.

Try a button, a sensor, or a small project you can make your own.

Find your first project

In this guide

In this guide7 chapters