MatrixScroller

A scrolling text library for the Arduino UNO R4 WiFi/Minima LED Matrix display. Display smooth, readable scrolling text with support for ASCII characters (A-Z, 0-9), serial input, and correct LED orientation.

Features

Easy to Use - Simple API with just three methods: begin(), setText(), and update()
ASCII Support - Displays uppercase/lowercase letters (A-Z) and numbers (0-9)
Smooth Scrolling - Optimized scroll speed (80ms delay) for readable text
Serial Input - Update scrolling text in real-time via Serial Monitor
Correct Orientation - Fixed mirroring issue for proper text display

Installation

Method 1: Arduino IDE (ZIP)

1. Download this repository as a ZIP file (Code → Download ZIP)
2. In Arduino IDE: Sketch → Include Library → Add .ZIP Library...
3. Select the downloaded ZIP file
4. Restart Arduino IDE

Method 2: Git Clone

Clone the repository directly into your Arduino libraries folder:

Windows:

cd Documents\Arduino\libraries
git clone https://github.com/bharanidharanrangaraj/ArduinoMatrixScroller.git

macOS/Linux:

cd ~/Documents/Arduino/libraries
git clone https://github.com/bharanidharanrangaraj/ArduinoMatrixScroller.git

Then restart Arduino IDE.

Method 3: Manual Installation

1. Download this repository
2. Copy the MatrixScroller folder to your Arduino libraries directory:
   • Windows: Documents\Arduino\libraries\
   • macOS: ~/Documents/Arduino/libraries/
   • Linux: ~/Arduino/libraries/
3. Restart Arduino IDE

Hardware Requirements

• Arduino UNO R4 WiFi or Arduino UNO R4 Minima
• The built-in 12×8 LED Matrix display

Dependencies

• Arduino_LED_Matrix (included with Arduino UNO R4 board package)

Usage

Basic Example

#include <MatrixScroller.h>

MatrixScroller scroller;

void setup() {
    scroller.begin();
    scroller.setText("HELLO WORLD");
}

void loop() {
    scroller.update();
}

Serial Input Example

#include <MatrixScroller.h>

MatrixScroller scroller;

void setup() {
    Serial.begin(115200);
    scroller.begin();
    scroller.setText("HELLO UNO R4");
}

void loop() {
    scroller.update();

    if (Serial.available()) {
        String text = Serial.readStringUntil('\n');
        text.trim();
        if (text.length() > 0) {
            scroller.setText(text);
        }
    }
}

To use:

1. Upload the sketch to your Arduino UNO R4
2. Open Serial Monitor (115200 baud)
3. Type your message and press Enter
4. Watch it scroll on the LED matrix!

API Reference

MatrixScroller()

Constructor - creates a new MatrixScroller instance.

MatrixScroller scroller;

void begin()

Initializes the LED matrix. Call this once in setup().

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

void setText(const String &text)

Sets the text to scroll. Automatically adds spacing after the text.

Parameters:

• text - String to display (supports A-Z, a-z, 0-9, and spaces)

scroller.setText("ARDUINO R4");

void update()

Updates the scrolling animation. Call this repeatedly in loop(). The scroll speed is automatically managed (80ms between frames).

void loop() {
    scroller.update();
}

Supported Characters

• Letters: A-Z (uppercase and lowercase)
• Numbers: 0-9
• Spaces: Supported
• Other characters: Displayed as spaces

How It Works

The library uses a custom 5×7 pixel font stored in the FONT array. Each character is rendered column by column as the text scrolls horizontally across the 12×8 LED matrix. The scrolling speed is optimized at 80ms per frame for smooth, readable text.

Technical Details

• Display Resolution: 12 columns × 8 rows
• Font Size: 5 columns × 7 rows per character
• Character Spacing: 1 pixel between characters (6 total stride)
• Scroll Delay: 80ms between frames
• Orientation: Correctly mapped to prevent mirroring

Troubleshooting

Text appears mirrored or upside down

This issue has been fixed in the library. The text should display correctly with the proper orientation.

Text scrolls too fast or too slow

The scroll speed is set to 80ms (SCROLL_DELAY constant in MatrixScroller.h). You can modify this value and recompile if needed.

Characters don't display

Make sure you're using supported characters (A-Z, a-z, 0-9, spaces). Other characters will render as spaces.

LED Matrix doesn't initialize

Ensure you have:

• Arduino UNO R4 WiFi or Minima
• Latest Arduino UNO R4 board package installed
• Arduino_LED_Matrix library available

Examples

The examples folder contains:

• SerialScroll - Interactive serial input demo

Access examples in Arduino IDE: File → Examples → MatrixScroller

License

This library is open source. Feel free to use, modify, and distribute.

Version History

• v1.0.0 - Initial release
  • Scrolling text support for A-Z, a-z, 0-9
  • Serial input functionality
  • Fixed LED orientation/mirroring
  • Optimized scroll speed

Contributing

Contributions are welcome! If you find bugs or have feature suggestions, please open an issue.

Acknowledgments

Built for the Arduino UNO R4's innovative 12×8 LED Matrix display. Special thanks to the Arduino community.

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Enjoy scrolling!