so you don’t have to set the rate if you want 9600bps*/

// change the data rate to whatever you wish

// var options = { baudrate: 9600}; 

​

var serial; // variable to hold an instance of the serialport library

var portName = '/dev/cu.usbmodem1451'; // fill in your serial port name here

var inData; // for incoming serial data

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

​

function setup() {

  createCanvas(400, 300);

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

  serial.on('connected', serverConnected); // callback for connecting to the server

  serial.on('open', portOpen); // callback for the port opening

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

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

  serial.on('close', portClose); // callback for the port closing

​

  serial.list(); // list the serial ports

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

}

​

function serverConnected() {

  console.log('connected to server.');

}

​

function portOpen() {

  console.log('the serial port opened.')

}

​

function serialEvent() { 

  var inString = serial.readLine();  //receiving data as a string value (0-1023);

  if (inString.length > 0 ){  // check to see that there's actually a string there

  inData = Number(inString);  // convert it to a number

  }

}

​

function serialError(err) {

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

}

​

function portClose() {

  console.log('The serial port closed.');

}

​

function draw() {

  background(0);

  drawDots(inData);

}

​

function drawDots(newData) {

  fill(255);

  noStroke();

  // map the range of the input to number of dots :

  var num = map(newData, 0, 1023, 500, 0);

  // draw the dots:

  for(i=0;i<num;i++){

    ellipse(random(0,width),random(0,height),10,10);

  }

}