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Built-in project · Arduino Uno R4 WiFi

Uno R4 WiFi heart

A heart beating on the Uno R4 WiFi’s 12 x 8 LED matrix, drawn through Arduino_LED_Matrix.h with no parts to wire. The whole build, an Arduino Uno R4 WiFi, runs here in your browser on the firmware below; open it in the editor to change the wiring or the code and run it again.

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Uno R4 WiFi heart · Arduino Uno R4 WiFilive0.000 s 0.00x
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The circuit itself, running here on the simulator. Press what can be pressed; click anything else to open it in the editor.

The code

The firmware exactly as the editor opens it. Change a line there and press Run: it compiles in the browser.

sketch.ino · Arduino Uno R4 WiFi
// Matrix: a heart on the Uno R4 WiFi's 12 x 8 LED matrix, beating.
//
// The picture is eight rows of twelve, written the way it looks: a 1 is a lit
// LED. renderBitmap() hands it to the library, and the library does the hard
// part in the background: the matrix is ninety-six LEDs on only eleven pins,
// so it lights one pin's worth at a time, a millisecond each, faster than an
// eye can follow. Nothing on the board remembers the picture; the sketch just
// changes it.
//
// The LED on pin 13 blinks with the beat, so the two lamps show the same
// thing: one on its own pin, one ninety-sixth of a charlieplexed panel.

#include "Arduino_LED_Matrix.h"

ArduinoLEDMatrix matrix;

const uint8_t BIG[8][12] = {
  {0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0},
  {0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0},
  {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
  {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
  {0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0},
  {0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0},
  {0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0},
  {0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0},
};

const uint8_t SMALL[8][12] = {
  {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
  {0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0},
  {0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0},
  {0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0},
  {0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0},
  {0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0},
  {0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0},
  {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
};

void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  matrix.begin();
  Serial.println("a heart on the LED matrix");
}

void loop() {
  matrix.renderBitmap(BIG, 8, 12);
  digitalWrite(LED_BUILTIN, HIGH);
  delay(400);
  matrix.renderBitmap(SMALL, 8, 12);
  digitalWrite(LED_BUILTIN, LOW);
  delay(600);
}

Parts list

1 part, plus the jumper wires. Every one is in the editor's parts bin.

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