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Awesome Open Source


A p5.js library that enables communication between your p5 sketch and Arduino (or another serial enabled device).

What Does it Do?

p5.serialport more or less clones the Processing Serial Library API. As JavaScript in a browser can not interact directly with a serial port, this library solves this. p5.serialport comes in two flavors; one is a simple app, this is good for all skill levels and is the easiest to use; second is Node.js based WebSocket server, this is for more skilled advanced users or someone who needs heavy customization.

p5.serial App

To begin download and run a release of p5.serialcontrol. This application incorporates p5.serialserver in a GUI application for MacOS and Windows.

Once you have the application launched 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 in the examples to the one your Arduino is using.

p5.serial Node.js

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

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 in the examples to the one your Arduino is using.

Getting Started

After running either the p5.serialcontrol application or p5.serialserver, you need to include the client side library in your html file. You can download the p5.serialport.js client library and include this as a script tag as below:

<script language="javascript" type="text/javascript" src="p5.serialport.js">

or, you can use a CDN link available via jsdelivr:

<script language="javascript" type="text/javascript" src="[email protected]/lib/p5.serialport.js"></script>



Basic Example

let serial;

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

  // Let's list the ports available
  let 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() {
    print("We are connected!");

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

// Connected to our serial device
function gotOpen() {
  print("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() {
  let 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) {
    let data =;


To generate documentation, install jsdoc (npm install -g jsdoc) and run npm run doc

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