ArduinoMatrixScroller – Scrolling Text Library for Arduino UNO R4 LED Matrix

Arduino® UNO R4 WiFi

Arduino IDE

<html><body>ArduinoMatrixScroller is a lightweight Arduino library that enables smooth horizontal scrolling text on the built-in 12×8 LED matrix of the Arduino UNO R4 (WiFi and Minima). The library abstracts low-level LED matrix handling and provides a simple API to display scrolling alphanumeric text without manually managing frame buffers, timing, or display orientation. Motivation: The Arduino UNO R4 includes an onboard LED matrix, but official support is limited to static frame rendering. Implementing scrolling text requires repetitive low-level code for column shifting, timing control, and orientation correction. ArduinoMatrixScroller was created to provide a reusable and reliable solution for scrolling text on the UNO R4 platform. Features: <ol><li>Smooth horizontal scrolling text </li><li>Simple API with three methods </li><li>Supports ASCII characters (A–Z, a–z, 0–9, space) </li><li>Real-time text updates via Serial Monitor </li><li>Correct LED orientation (no mirroring issues) </li><li>Optimized scroll speed (80 ms per frame) </li></ol>Hardware Required: <ol><li>Arduino UNO R4 WiFi or Arduino UNO R4 Minima </li><li>Built-in 12×8 LED matrix (onboard) </li></ol>Software Required <ol><li>Arduino IDE </li><li>Arduino UNO R4 board package </li><li>Arduino_LED_Matrix (included with board package) </li></ol>How It Works <ol><li>The library uses a custom 5×7 pixel font. </li><li>Each character is rendered column-by-column and shifted across the 12-column LED matrix buffer. </li><li>The display is refreshed at a fixed interval to maintain smooth and readable scrolling. </li></ol>All matrix orientation mapping and timing control are handled internally by the library. Example Code: <pre>#include &lt;MatrixScroller.h&gt; </pre><pre>MatrixScroller scroller; </pre><pre>void setup() { </pre><pre>	 scroller.begin(); </pre><pre>	 scroller.setText("HELLO WORLD"); </pre><pre>} </pre><pre>void loop() { </pre><pre>	 scroller.update(); </pre><pre>} </pre><pre>Serial Input Example </pre><pre>#include &lt;MatrixScroller.h&gt; </pre><pre>MatrixScroller scroller; </pre><pre>void setup() { </pre><pre>	 Serial.begin(115200); </pre><pre>	 scroller.begin(); </pre><pre>	 scroller.setText("HELLO UNO R4"); </pre><pre>} </pre><pre>void loop() { </pre><pre>	 scroller.update(); </pre><pre>	 if (Serial.available()) { </pre><pre>	 String text = Serial.readStringUntil('\n'); </pre><pre>	 text.trim(); </pre><pre>	 if (text.length() &gt; 0) { </pre><pre>	 scroller.setText(text); </pre><pre>	 } </pre><pre>	 } </pre><pre>} </pre>Supported Characters: <ol><li>Uppercase letters: A–Z </li><li>Lowercase letters: a–z </li><li>Numbers: 0–9 </li><li>Space </li></ol>Unsupported characters are rendered as blank spaces. Applications: <ol><li>Status and notification displays </li><li>Debug output visualization </li><li>Educational LED matrix demonstrations </li><li>Simple embedded UI elements </li></ol>Notes: <ol><li>Scroll speed is fixed at 80 ms per frame and can be adjusted in the library header if required. </li><li>Servos or external hardware are not required. </li></ol></body></html>