Bluetooth LE and If This Then That

If This Then That has a Maker Applet that allows you to trigger things easily from the internet.

If you were using an Espruino device connected straight to the Internet then all you'd have to do is to call the special URL (you'll see how to get this later on).

However when using Puck.js you need a 'bridge' - something that will take messages over Bluetooth LE and turn them into webpage requests on the internet.

Getting an IFTTT URL

  • Create an account on If This Then That
  • In the top right, click New Applet
  • Click on +this, search for Webhooks, and click it
  • Click Receive a web request
  • Enter puck_pressed as the event name
  • Click on +that and choose a task to perform - maybe Email to send yourself an email
  • Click through the remaining pages and click Finish
  • Now, to find the URL, go to the Maker Applet
  • In the top right click Settings
  • It'll say something like URL:
  • Copy that URL and paste it into your browser's address bar
  • At the top it'll show you a URL like:{event}/with/key/jghfJHGFhjkgHJKGjhgJHgkHfRDhgfKJtfrjgh
  • Replace {event} with puck_pressed (which we entered earlier) so you get a URL like this:

This is what you need to copy in below (or access if you're using an Internet-connected Espruino board)


Create a Webpage with the following code in - it'll need to be hosted on HTTPS.

For an example of how to do this, see the Web Bluetooth tutorial

   <title>IFTTT Web Bluetooth Example</title>
  <pre id="log"></pre>
  <button>Click here to start</button><br/>
  <iframe id="ifttt" style="width:640px;height:32px"></iframe>
  <script src=""></script>
  <script type="text/javascript">
    // ------------------------------------- REPLACE ME
    var URL = "";
    // ------------------------------------- REPLACE ME
    var button = document.getElementsByTagName('button')[0];
    var logelement = document.getElementById('log');
    var iftttRequests = 0;
    function log(txt) {
      logelement.innerHTML += txt+"\n";

    function ifttt() {
      document.getElementById('ifttt').src = URL+"?"+iftttRequests;

    // Called when we get a line of data
    function onLine(v) {
      log("Received: "+JSON.stringify(v));
      if (v.indexOf("Pressed")>=0) {
        log("Calling IFTTT");

    // When clicked, connect or disconnect
    var connection;
    button.addEventListener("click", function() {
      if (connection) {
        log("Closing connection");
        connection = undefined;
      log("Opening connection");
      Puck.connect(function(c) {
        if (!c) {
          log("Couldn't connect!");
        connection = c;
        // Handle the data we get back, and call 'onLine'
        // whenever we get a line
        var buf = "";
        connection.on("data", function(d) {
          buf += d;
          var i = buf.indexOf("\n");
          while (i>=0) {
            buf = buf.substr(i+1);
            i = buf.indexOf("\n");
        // First, reset Puck.js
        connection.write("\x10reset();\n", function() {
          // Wait for it to reset itself
          setTimeout(function() {
            // Now tell it to write data on the current light level to Bluetooth 10 times a second
              function() { log("Ready!"); });
          }, 1500);

Now just click Click here to start - when you press the button on the Puck, IFTTT will now be called!

Note: If you're a web developer you'll want to make the code above use an AJAX request - however sadly IFTTT don't set the Access-Control-Allow-Origin header, so you basically have to use an IFrame.

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