Published August 6, 2019

Breathing Circle on LED Matrix

By using MatrixLED_MAX7219 and HTML5 Canvas, draw a circle animation on an LED matrix.

BeginnerFull instructions provided1 hour565

Things used in this project

Hardware components

Cambrian Robotics obniz

Story

By using MatrixLED_MAX7219 and HTML5 Canvas, drawing circle animations on an LED matrix.

Untitled file

<!-- HTML Example -->
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <script src="https://unpkg.com/obniz@2.0.2/obniz.js"></script>
</head>

<body>
<div id="obniz-debug"></div>
<br>
<div class="text-center">
    <h1>DotMatrix Breath</h1>
</div>

<script>

/* This will be over written on obniz.io webapp page */
var obniz = new Obniz("OBNIZ_ID_HERE");

obniz.onconnect = async function () {
  const matrix = obniz.wired("MatrixLED_MAX7219", {vcc:0, gnd:1, din:2, cs:3, clk:4});
  matrix.init(8*4, 8);
  matrix.brightness(7);
  
  const ctx = obniz.util.createCanvasContext(matrix.width, matrix.height);
  
  var r = 0;
  obniz.repeat(async function() {
    ctx.fillStyle = "black";
    ctx.fillRect(0, 0, matrix.width, matrix.height);
    ctx.fillStyle = "white";
    ctx.strokeStyle = "white";
    ctx.beginPath();
    ctx.arc(8*2, 4, 2 + 3*(Math.sin(r/4)+1), 0, 2*Math.PI);
    ctx.stroke();
    r++;
    
    matrix.draw(ctx);
  }, 1000/30);
  
}
    
</script>
</body>
</html>