p5-wallplotter/
├── lib/
│   ├── WallPlotter.js   # library
│   └── README.md        # public API
└── examples/
    └── zickzack/        # example sketch
        ├── index.html
        └── sketch.js

Run the example

Chrome or Edge. Serve over localhost (Web Serial does not work from file://).

cd p5-wallplotter
python -m http.server 8080

Open http://localhost:8080/examples/zickzack/

Press C to connect, H to set home, then Test (preview) or Plot (send G-code).

Use in a sketch

<script src="https://cdn.jsdelivr.net/npm/p5@1.11.3/lib/p5.min.js"></script>
<script src="../../lib/WallPlotter.js"></script>
<script src="sketch.js"></script>

let wp;

function setup() {
  createCanvas(windowWidth, windowHeight).parent('sketch-host');
  wp = new WallPlotter();
  wp.setSpeed(3000, 1500);
  wp.enableKeyInputs();
  wp.enablePlotButtons();
}

function draw() {
  background(28, 28, 32);
  wp.showInfos();
}

async function plot() {
  await drawArt(false);
}

async function test() {
  await drawArt(true);
}

async function drawArt(testOnly) {
  wp.startPath();
  wp.move(-200, -200);
  wp.draw(200, -200);
  await wp.runPath(testOnly);
}

Full API: lib/README.md.

Baud 115200. Pen servo: M280 P0 S90 up, M280 P0 S50 down. Coordinates in mm, origin at home (G92).