var portName = '/dev/cu.usbmodem14121';  // fill in your serial port name here

var locH, locV;                         // location of the circle

var circleColor = 255;                  // color of the circle

​

function setup() {

  smooth();                           // antialias drawing lines

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

  serial.on('list', printList);       // set a callback function for the serialport list event

  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 draw() {

  background(0);                // black background

  fill(circleColor);            // fill depends on the button

  ellipse(locH, locV, 50, 50);  // draw the circle

}

// get the list of ports:

function printList(portList) {

  // portList is an array of serial port names

  for (var i = 0; i < portList.length; i++) {

    // Display the list the console:

    console.log(i + " " + portList[i]);

  }

}

​

function serverConnected() {

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

}

​

function portOpen() {

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

}

​

function serialEvent() {

  // read a string from the serial port

  // until you get carriage return and newline:

  var inString = serial.readStringUntil('\r\n');

  //check to see that there's actually a string there:

  if (inString.length > 0 ) {

    var sensors = split(inString, ',');             // split the string on the commas

    if (sensors.length > 2) {                       // if there are three elements

      locH = map(sensors[0], 250, 410, 0,width);    // element 0 is the locH

      locV = map(sensors[1], 250, 410, 0, height);  // element 1 is the locV

      circleColor = 255 - (sensors[2] * 255);       // element 2 is the button

    }

  }

}

​

function serialError(err) {

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

}

​

function portClose() {

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

}