Interfacing NeoPixel RGB LEDs with Arduino Uno (Hardware & Wokwi Simulation)

Abstract

In this article, we will learn how to interface a 16-bit NeoPixel RGB LED ring (WS2812B) with an Arduino Uno. NeoPixels are smart RGB LEDs that allow us to control each LED’s color and brightness individually using just one data pin.

We will explore the hardware connections, understand how NeoPixel communication works, write the Arduino program, and test the project using both real hardware and Wokwi simulation.

Pre-Request

• OS : Windows / Linux / Mac / Chrome
• Arduino IDE

Hardware Required

• Arduino Uno.
• NeoPixel RGB LED (WS2812B)
• BreadBoard.
• Mini USB Cable.
• Connecting wires.
• 5V DC power supply (Optional)

Understanding NeoPixel RGB LEDs

NeoPixels (WS2812B) are addressable RGB LEDs with a built-in controller. Unlike normal RGB LEDs, NeoPixels require only one digital data wire to control all LEDs in a chain.

Each LED can display millions of colors by mixing Red, Green, and Blue values.

Advantages of NeoPixels

• Only one control pin
• Each LED is individually addressable
• Supports animations, gradients, and effects
• Ideal for college projects, wearables, IoT, and decorations

Connection Table

NeoPixel → Arduino Uno

Code

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#include <Adafruit_NeoPixel.h>

#define LED_PIN 6
#define NUM_LEDS 16

Adafruit_NeoPixel pixels(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

// Define the colors (R, G, B)
uint8_t colors[][3] = {
  {255, 0, 0},    // Red
  {0, 255, 0},    // Green
  {0, 0, 255},    // Blue
  {255, 169, 0},  // Orange
  {255, 255, 255} // White
};

const int numColors = sizeof(colors) / sizeof(colors[0]);

void setup() {
  pixels.begin();
}

void loop() {

  // Display Yellow first
  for (int i = 0; i < NUM_LEDS; i++) {
    pixels.setPixelColor(i, pixels.Color(255, 255, 0));
  }
  pixels.show();
  delay(2000);

  // Cycle through colors
  for (int c = 0; c < numColors; c++) {
    for (int i = 0; i < NUM_LEDS; i++) {
      pixels.setPixelColor(i, pixels.Color(colors[c][0], colors[c][1], colors[c][2]));
      delay(50);
      pixels.show();
    }
    pixels.show();
    delay(1000);
  }
}

Code Explanation

Include the NeoPixel Library

#include <Adafruit_NeoPixel.h>

• This library enables Arduino to control WS2812B (NeoPixel) RGB LEDs.
• It manages precise timing required for NeoPixel communication and provides easy functions for color control.

Define the Data Pin and Number of LEDs

#define LED_PIN 6
#define NUM_LEDS 16

• LED_PIN specifies that the NeoPixel data line is connected to Arduino Uno pin D6.
• NUM_LEDS indicates that 16 NeoPixels are connected in series (ring or strip).

Create the NeoPixel Object

Adafruit_NeoPixel pixels(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

This initializes a NeoPixel object with:

• 16 LEDs
• GRB color order (used by most WS2812B LEDs)
• 800 kHz communication frequency

Define the Color List

uint8_t colors[][3] = {
  {255, 0, 0},    // Red
  {0, 255, 0},    // Green
  {0, 0, 255},    // Blue
  {255, 169, 0},  // Orange
  {255, 255, 255} // White
};

This array stores multiple RGB colors:

• Each color is defined using Red, Green, and Blue intensity values (0–255).
• These colors will be displayed sequentially on the NeoPixel LEDs.

Calculate the Number of Colors

const int numColors = sizeof(colors) / sizeof(colors[0]);

• This automatically calculates how many colors are stored in the array, making the code flexible if more colors are added later.

Initialize NeoPixels in setup()

void setup() {
  pixels.begin();
}

• The pixels.begin() function prepares the NeoPixel strip for operation.
• This step is mandatory before controlling the LEDs.

Display Yellow Color First

for (int i = 0; i < NUM_LEDS; i++) {
  pixels.setPixelColor(i, pixels.Color(255, 255, 0));
}
pixels.show();
delay(2000);

• All 16 LEDs are set to yellow.
• pixels.show() sends the data to the LEDs.
• The yellow color stays ON for 2 seconds.

Start Cycling Through Defined Colors

for (int c = 0; c < numColors; c++) {
    for (int i = 0; i < NUM_LEDS; i++) {
        pixels.setPixelColor(i, pixels.Color(colors[c][0], colors[c][1], colors[c][2]));
        delay(50);
        pixels.show();
    }
    pixels.show();
    delay(1000);
}

• This outer loop iterates through each color stored in the colors array.
• Each LED lights up one after another using the current color.
• delay(50) creates a smooth running-light animation effect.
• pixels.show() updates the LEDs in real time.
• After all LEDs are lit with the same color, the color remains visible for 1 second.
• The loop then moves to the next color.

--

Simulation

Extras

Components details

• Arduino Uno Data Sheet

Modules / Libraries Used

• Adafruit NeoPixel (Adafruit_NeoPixel.h)
  • Arduino library for controlling single-wire-based LED pixels and strip such as the Adafruit 60 LED/meter Digital LED strip, WS2812B, the Adafruit FLORA RGB Smart Pixel, the Adafruit Breadboard-friendly RGB Smart Pixel, the Adafruit NeoPixel Stick, and the Adafruit NeoPixel Shield.
  • More info
  • Github Source Code

Conclusion

Interfacing a 16-NeoPixel RGB LED with Arduino Uno allows you to create stunning light effects with minimal wiring. With only one control pin, you can build animations, indicators, and artistic displays for STEAM, IoT, and creative electronics projects.

Using Wokwi simulation, students and developers can test designs before building physical circuits, making this project perfect for learning and prototyping.