Arduino LED Blink Project – First Step Into Arduino Programming

Arduino LED Blink Project - The Perfect First Arduino Project

If you're new to Arduino, the LED Blink project is the best place to start. Although it's simple, this project teaches the basic concepts of Arduino programming, digital outputs, circuit wiring, and uploading code.

In this tutorial, you'll learn how to connect an LED to an Arduino Uno, write a simple program, and make the LED blink every second.

After completing this project, you'll have the knowledge needed to move on to more advanced Arduino projects involving sensors, displays, motors, and IoT devices.

Supplies

1 × Arduino Uno (or Nano, Mega, ESP32 with minor code changes)

1 × LED (any color)

1 × 220Ω resistor (330Ω also works)

1 × Breadboard

2 × Jumper wires

Computer with Arduino IDE installed

If You Live in Bangladesh, You might consider buying products directly from our store.

Product links are given below.

Arduino Uno - https://www.electronics.com.bd/arduino-uno-r3-board

Arduino Nano - https://www.electronics.com.bd/arduino-nano-atmega328p-ch340

Arduino Uno (SMD) - https://www.electronics.com.bd/arduino-uno-r3

5mm LED Diode (RED) - https://www.electronics.com.bd/led-basic-red-5mm

5mm LED Diode (Yellow) - https://www.electronics.com.bd/led-basic-yellow-5mm

5mm LED Diode (Blue) - https://www.electronics.com.bd/led-basic-blue-5mm

5mm LED Diode (Green) - https://www.electronics.com.bd/led-basic-green-5mm

Breadboard Half - https://www.electronics.com.bd/led-basic-green-5mm

USB 2.0 Male USB A to Male USB B Cable - https://www.electronics.com.bd/usb-2-0-male-usb-a-to-male-usb-b-cable-for-arduino-uno-1-5-meter

How It Works

Step 1: Understanding the Project

An LED (Light Emitting Diode) lights up whenever electrical current flows through it.

The Arduino controls the LED by changing the voltage of one of its digital output pins.

HIGH = 5V Output = LED ON
LOW = 0V Output = LED OFF

By repeatedly switching between HIGH and LOW with a delay, the LED continuously blinks.

Circuit Connection

Opera Snapshot_2026-08-02_195958_app.cirkitdesigner.com.png

Step 2: Circuit Connection

Arduino D13 → 220Ω Resistor
220Ω Resistor → LED Positive (Anode)
LED Negative (Cathode) → Arduino GND

Tip: The longer leg of the LED is the positive terminal (Anode).

Install Arduino IDE

Step 3: Install Arduino IDE

Download the Arduino IDE from the official Arduino website.
Install the software.
Connect the Arduino using a USB cable.
Select the correct Board from the Tools → Board menu.
Select the correct COM Port from the Tools → Port menu.

Arduino Code

Step 4: Upload the Code

Copy the following code into the Arduino IDE.

const int ledPin = 13;

void setup()

{

pinMode(ledPin, OUTPUT);

}

void loop()

{

digitalWrite(ledPin, HIGH);

delay(1000);

digitalWrite(ledPin, LOW);

delay(1000);

}

Click the Upload button. After uploading, the LED should begin blinking every second.

Code Explanation

Step 5: Understanding the Code

Define the LED Pin

const int ledPin = 13;

This line tells the Arduino which digital pin is connected to the LED.

Setup Function

void setup()

{

pinMode(ledPin, OUTPUT);

}

The setup() function runs only once after the Arduino powers on. Here, pin 13 is configured as an output.

Loop Function

void loop()

{

}

The loop() function repeats forever while the Arduino is powered.

Turn LED ON

digitalWrite(ledPin, HIGH);

This supplies 5V to the LED, turning it on.

Delay

delay(1000);

The Arduino waits for 1000 milliseconds (1 second).

Turn LED OFF

digitalWrite(ledPin, LOW);

This removes the voltage from the LED, turning it off.

Experiment

Step 6: Try Different Blink Speeds

You can change the blinking speed by modifying the delay values.

Fast Blink


delay(200);

Slow Blink


delay(2000);

Custom Blink Pattern


digitalWrite(ledPin, HIGH);
delay(100);

digitalWrite(ledPin, LOW);
delay(900);

Experiment with different values to create your own blinking patterns.