​

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

​

let freshData = false;

​

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

}

​

​

function draw() {

  background(0); // black background

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

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

  if (freshData) { //set in serialEvent when data received

    serial.write('x');

    freshData = false;

  }

}

​

// 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.')

  // send a byte to prompt the microcontroller to send:

  serial.write('x');

}

​

function serialError(err) {

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

}

​

function portClose() {

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

}

​

function keyPressed() {

  serial.write('x');

}

​

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) {

    print(inString);

    if (inString !== 'hello') { // if you get hello, ignore it

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

    }

    //freshData=true; //does work

    // send a byte requesting more serial data

    serial.write('x'); //doesn't work

  }

}