Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using it's URL and the proper URL extention.

+ add another resource


Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.


Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.


                <h1>Prototyping IoT Demo UI</h1>

<button class="on">Blink LED</button>

<script src="//"></script>


                button {
  font-size: 2em;
  padding: 10px 20px;


                // Use the same keys that you are going to use for Arduino code with Johnny-Five

var pubnub = PUBNUB.init({
  publish_key: 'pub-c-0b43969b-341d-41f5-a85e-0bd9d30404b8',
  subscribe_key: 'sub-c-cb24903e-c9f4-11e5-b684-02ee2ddab7fe'

// Use the same channel name
var channel = 'led';

var button = document.querySelector('button.on');

Setting a state to lable the button.
This example is simplified for the tutorail, however,
in reality, you need to subscribe the channel to set the state, 
rather than toggling the boolian variable.
Why? because multiple people may be accessing this UI to control 
your LED on Arduino! So we need to listen all data coming from the
subscribers of the channel!

for the completed code

var blinkState = true;

Upon a button click, publish the data.
Arduino will subscribe it and blink LED
button.addEventListener('click', function(e) {
    channel: channel, 
    message: {blink: blinkState},
    callback: function(m) {
      blinkState = !blinkState;
      button.textContent = (blinkState) ? 'Blink LED' : 'Stop LED';