​

// HTML button object:

let portButton;

let inData;                   // for incoming serial data

let outByte = 0;              // for outgoing data

​

function setup() {

  if (!navigator.serial) {

    alert("WebSerial is not supported in this browser. Try Chrome or MS Edge.");

  } 

  navigator.serial.addEventListener("connect", portConnect);

  navigator.serial.addEventListener("disconnect", portDisconnect);

  serial.getPorts();  // check for any ports that are available

  serial.on("noport", makePortButton);  // if there's no port chosen, choose one

  serial.on("portavailable", openPort); // open whatever port is available

  serial.on("requesterror", portError); // handle serial errors

  serial.on("data", serialEvent);       // handle any incoming serial data

  serial.on("close", makePortButton);

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

}

​

// if there's no port selected, make a port select button appear:

function makePortButton() {

  print("Making button");

  // create and position a port chooser button:

  portButton = createButton("choose port");

  portButton.position(10, 10);

  portButton.mousePressed(choosePort);  // button mousepressed handler

}

// make the port selector window appear:

function choosePort() {

  print("In choosePort");

  if (portButton) portButton.show();

  serial.requestPort();

}

// open the selected port, and make the port button invisible:

function openPort() {

  // wait for the serial.open promise to return, then call the initiateSerial function

  print("Opening port");

  serial.open().then(initiateSerial);

  // once the port opens, let the user know:

  function initiateSerial() {

    console.log("port open");

  }

  // hide the port button once a port is chosen:

  if (portButton) {

    portButton.hide();

    print("Hiding button");

  }

}

// pop up an alert if there's a port error:

function portError(err) {

  alert("Serial port error: " + err);

}

​

// read any incoming data as a string

function serialEvent() {

  //inData = Number(serial.read());

  inData = Number(serial.read());

  console.log(inData);

}

// try to connect if a new serial port gets added (i.e. plugged in via USB):

function portConnect() {

  console.log("Port connected");

  serial.getPorts();

}

// if a port is disconnected:

function portDisconnect() {

  serial.close();

  console.log("Port disconnected");

}

function closePort() {

  serial.close();

}