Find file
Fetching contributors…
Cannot retrieve contributors at this time
108 lines (81 sloc) 3.8 KB


A p5.js library that more or less clones the Processing Serial Library API. As JavaScript in a browser can not interact directly with a serial port, it includes a simple Node.js based WebSocket server that performs the actual serial communication.

To Use:

Connect an Arduino or other serial device to your computuer.

Clone or download this repo and install the dependencies with: npm install and start the server with: node startserver.js

Alternatively, you can install the server globally via npm with sudo npm install -g p5.serialserver and then run it with p5serial or locally with npm install p5.serialserver and run it from the node_modules directory with node startserver.js

Another alternative is to download and run a release of p5.serialcontrol which incorporates p5.serialserver in a GUI application for MacOS and Windows.

Then load one of the examples/ in your browser to see it in action. (You'll likely have to change the name of the serial port that is opened.)

API documentation now available

The basics:

var serial;

function setup() {
  // Instantiate our SerialPort object
  serial = new p5.SerialPort();

  // Let's list the ports available
  var portlist = serial.list();

  // Assuming our Arduino is connected, let's open the connection to it
  // Change this to the name of your arduino's serial port"/dev/cu.usbmodem1421");

  // Register some callbacks

  // When we connect to the underlying server
  serial.on('connected', serverConnected);

  // When we get a list of serial ports that are available
  serial.on('list', gotList);

  // When we some data from the serial port
  serial.on('data', gotData);

  // When or if we get an error
  serial.on('error', gotError);

  // When our serial port is opened and ready for read/write
  serial.on('open', gotOpen);

// We are connected and ready to go
function serverConnected() {
    println("We are connected!");

// Got the list of ports
function gotList(thelist) {
  // theList is an array of their names
  for (var i = 0; i < thelist.length; i++) {
    // Display in the console
    println(i + " " + thelist[i]);

// Connected to our serial device
function gotOpen() {
  println("Serial Port is open!");

// Ut oh, here is an error, let's log it
function gotError(theerror) {

// There is data available to work with from the serial port
function gotData() {
  var currentString = serial.readStringUntil("\r\n");

// Methods available
// returns a single byte of data (first in the buffer)
// serial.readChar() returns a single char 'A', 'a'
// serial.readBytes() returns all of the data available as an array of bytes
// serial.readBytesUntil('\n') returns all of the data available until a '\n' (line break) is encountered
// serial.readString() retunrs all of the data available as a string
// serial.readStringUntil('\n') returns all of the data available as a tring until a (line break) is encountered
// serial.last() returns the last byte of data from the buffer
// serial.lastChar() returns the last byte of data from the buffer as a char
// serial.clear() clears the underlying serial buffer
// serial.available() returns the number of bytes available in the buffer

function draw() {
  // Polling method
  if (serial.available() > 0) {
    var data =;


To generate documentation, install yuidoc (npm install -g yuidocjs) and run yuidoc -c yuidoc.json ./lib