let portName = '/dev/tty.usbmodem14201';  // fill in your serial port name here

let inData;                               // for incoming serial data

let xPos = 0;                           // x position of the graph

​

function setup() {

  createCanvas(400, 300);          // make the canvas

  serial = new p5.SerialPort();    // make a new instance of the serialport library

  serial.on('data', serialEvent);  // callback for when new data arrives

  serial.on('error', serialError); // callback for errors

  serial.open(portName);           // open a serial port

}

​

function draw() {

  // black background, white text:

  background(0);

  fill(255);

  // display the incoming serial data as a string:

  text("incoming value: " + inData, 30, 30);

}

​

function mouseDragged() {

  // map the mouseY to a range from 0 to 255:

  outByte = int(map(mouseY, 0, height, 0, 255));

  // send it out the serial port:

  serial.write(outByte);

}

​

function keyPressed() {

  if (key >=0 && key <=9) {   // if the user presses 0 through 9

    outByte = byte(key * 25); // map the key to a range from 0 to 225

  }

  serial.write(outByte);      // send it out the serial port

}

​

function serialEvent() {

  // read a byte from the serial port:

  var inByte = serial.read();

  // store it in a global variable:

  inData = inByte;

}

​

function serialError(err) {

  console.log('Something went wrong with the serial port. ' + err);

}