let serialActive = false;

​

async function getPort(baud = 9600) {

  let port = await navigator.serial.requestPort();

  await port.open({ baudRate: baud });

​

  // create read & write streams

  textDecoder = new TextDecoderStream();

  textEncoder = new TextEncoderStream();

  readableStreamClosed = port.readable.pipeTo(textDecoder.writable);

  writableStreamClosed = textEncoder.readable.pipeTo(port.writable);

​

  reader = textDecoder.readable

    .pipeThrough(new TransformStream(new LineBreakTransformer()))

    .getReader();

  writer = textEncoder.writable.getWriter();

​

  return { port, reader, writer };

}

​

class LineBreakTransformer {

  constructor() {

    this.chunks = "";

  }

​

  transform(chunk, controller) {

    this.chunks += chunk;

    const lines = this.chunks.split("\r\n");

    this.chunks = lines.pop();

    lines.forEach((line) => controller.enqueue(line));

  }

​

  flush(controller) {

    controller.enqueue(this.chunks);

  }

}

​

async function setUpSerial() {

  noLoop();

  ({ port, reader, writer } = await getPort());

  serialActive = true;

  runSerial();

  loop();

}

​

async function runSerial() {

  try {

    while (true) {

      const { value, done } = await reader.read();

      if (done) {

        reader.releaseLock();

        break;

      }

      readSerial(value);

    }

  } catch (e) {

    console.error(e);

  }

}

​

let rVal = 0; // Value from photoresistor

​

function setup() {

  createCanvas(640, 480);

  textSize(18);

}

​

function draw() {

  background(245, 245, 200);

  fill(0);

​

  if (!serialActive) {

    text("Press Space Bar to select Serial Port", 20, 30);

  } else {

    text("Connected", 20, 30);

    text('Photoresistor Value = ' + str(rVal), 20, 50);

​

    // Map the sensor value to the x-position of the ellipse

    let xPos = map(rVal, 0, 1023, 0, width);

    fill(100, 123, 158);

    ellipse(xPos, height / 2, 50, 50);

  }

}

​

function keyPressed() {

  if (key == " ") {

    setUpSerial();

  }

}

​

function readSerial(data) {

  if (data != null) {

    let fromArduino = trim(data); // Remove any whitespace

    rVal = int(fromArduino); // Convert the string to an integer

  }

}