function setup() {

  createCanvas(640, 480);

  textSize(18);

}

​

function draw() {

  background(190);

  stroke(0);

  fill("purple");

  circle(map(circleX,0, 1023, 0, width), height/2, 50);

  if (!serialActive) {

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

  } else {

    text("Connected", 20, 30);

  }

}

​

function keyPressed() {

  if (key == " ") {

    // important to have in order to start the serial connection!!

    setUpSerial();

  }

}

​

// This function will be called by the web-serial library

// with each new *line* of data. The serial library reads

// the data until the newline and then gives it to us through

// this callback function

function readSerial(data) {

  ////////////////////////////////////

  //READ FROM ARDUINO HERE

  ////////////////////////////////////

​

  if (data != null) {

    circleX = int(trim(data));

  }

  print(circleX);

}