let distance = 0; // variable to store distance measured by the ultrasonic sensor

​

function setup() {

  createCanvas(400, 400);

  serial = new p5.SerialPort(); // create new serial port object

  serial.open("/dev/tty.usbmodem11301"); // replace with the serial port number of your Arduino board

  serial.on("data", getData); // call getData function when data is received from the serial port

}

​

function getData() {

  let data = serial.readStringUntil('\n'); // read data from serial port until newline character

  if (data) { // if data is not empty

    distance = parseInt(data); // convert data to integer and store in distance variable

  }

}

​

function draw() {

  background(220);

  let size = map(distance, 0, 100, 50, 200); // map distance values to ellipse size

  ellipse(width/2, height/2, size, size); // draw ellipse in the center of the canvas

}

​