var portSelector; // a select menu for the port list

var locH = 0;

var locV = 0;        // location of the circle

var circleColor = 255; // color of the circle

function setup() {

  createCanvas(640, 480);          // make canvas

  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

}

​

// get the list of ports:

function printList(portList) {

  // make a select menu and position it:

  portSelector = createSelect();

  portSelector.position(10,10);

  // 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]);

    // add item to the select menu:

    portSelector.option(portList[i]);

  }

  // set a handler for when a port is selected from the menu:

  portSelector.changed(openPort);

}

​

function openPort() {

  var thisPort = portSelector.value();

  if (thisPort != null) {

    serial.open(thisPort);

  }

}

​

function serverConnected() {

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

}

function portOpen() {

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

}

function serialError(err) {

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

}

function portClose() {

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

}

​

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], 0, 1024, 0, width);   // element 0 is the locH

      locV = map(sensors[1], 0, 1024, 0, height); // element 1 is the locV

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

    }

  }

}

​

function draw() {

  background(0);               // black background

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

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

}

​

​