How to Use LED Matrix on Arduino UNO R4 WIFI to Display Text

The Arduino UNO R4 WIFI board has a built-in 12x8 LED Matrix ready to use. You can program it to display text, numbers, or custom images.

Required Components

• Arduino UNO R4 WIFI
• MB-102 Breadboard (830 Point)
• Power Adapter 9V 2A with 5.5x2.5mm jack
• Jumper wires: Male-to-Male, Male-to-Female, Female-to-Female, 20cm each, 40 pieces per type
• USB Type-C to USB 2.0 cable for code upload
• USB Type-C cable rated over 3A for power

Installing the Board Package

1. Connect Arduino UNO R4 WIFI to your computer via USB Type-C
2. Open Arduino IDE
3. Go to Tools > Boards Manager…
4. Type “arduino r4” in the search box
5. Wait for Arduino UNO R4 Boards to appear, then click Install
6. Wait until INSTALLED appears, then click Close

Uploading Sample Code to LED Matrix

After installing the Board Package, try uploading sample code to test the LED Matrix on your board

1. Download the sample code files and extract them
2. Open the code file in Arduino IDE
3. Go to Tools > Port and select the port your board is connected to
4. Go to Tools > Board and select Arduino UNO R4 WIFI
5. Click the Upload button (right arrow)
6. Wait for Done uploading message

When upload completes, the LED Matrix on the board will display the text or image defined in the code

Creating Custom Images and Text with Arduino LED Matrix Editor

To define your own images or text, use the Arduino LED Matrix Editor web tool

Accessing LED Matrix Editor

Go to https://ledmatrix-editor.arduino.cc

Drawing Your Image or Text

1. Select the Brush tool and click on grid cells to light up pixels
2. If you make a mistake, use the Eraser tool to remove pixels
3. Draw your desired shape or text pattern

Saving Your Work

Click Save button with two options

• Save as file - Save the file for later editing
• Export for Arduino - Export code to use in Arduino IDE

For creating animations or scrolling text - Create each frame individually by clicking the add frame button and drawing the next position

Importing Code from LED Matrix Editor to Arduino IDE

After exporting code from the website, follow these steps

Creating a New Tab in Arduino IDE

1. Open Arduino IDE
2. Click the arrow icon on the right side and select New Tab

[image: Screenshot showing the top section of Arduino IDE with the New Tab button highlighted as a down arrow icon]

3. Name the file matching your image name, appending .h at the end, for example mylogo.h
4. A new empty Tab will appear

Adding Code to the New Tab

1. Open the exported .h file from the website
2. Copy all the code and paste it into the new Tab
3. Press Ctrl+S to save

Editing Code in the Main Tab

Return to the first Tab and modify the #include "...h" line to match your filename

#include "mylogo.h"  // Change name to match your file

// Example code to display on LED Matrix
#include "Arduino_LED_Matrix.h"

ArduinoLEDMatrix matrix;

void setup() {
  Serial.begin(115200);
  matrix.begin();
}

void loop() {
  // Display frame 1
  matrix.loadFrame(0);
  delay(500);
  
  // Display frame 2
  matrix.loadFrame(1);
  delay(500);
}

Uploading the Code

1. Select the correct Port and Board type
2. Click Upload button
3. Wait for Done uploading message

When upload completes, the LED Matrix on the board will display your custom image or text

Reference Video

Arduino UNO R4 WIFI LED Matrix Demo

Summary

The Arduino UNO R4 WIFI has a built-in 12x8 LED Matrix on the board. It can display text, numbers, or images using the Arduino LED Matrix Editor tool to create patterns, then import the code into Arduino IDE by creating a new tab and including the correct header file.