diff --git a/clients/chrome/README.md b/clients/chrome/README.md
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+# microbit-chrome
+Prototype chrome addon that exposes the micro:bit's serial output to webpages. 
+* watch the [demo video](https://vimeo.com/146207766)
+
+# Installation
+See [developer.chrome.com](https://developer.chrome.com/extensions/getstarted#unpacked)
+for instructions on how to install the local version into your chrome browser.
+
+# Requirements
+* Chrome 48 or later.
+
+# Sample page
+The `demo.html` webpage goes along with the
+https://github.com/Microsoft/microbit-touchdevelop/blob/master/examples/tcs34725.cpp
+program. Run `http-server` from this directory, then visit
+http://localhost:8080/demo.html
+(keep in mind that pages served from `file://` cannot open ports).
+
+# Building
+
+Open a command prompt and run the following commands.
+
+````
+npm install
+typings update
+````
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diff --git a/clients/chrome/background.js b/clients/chrome/background.js
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+///<reference path='typings/browser.d.ts'/>
+var connections = [];
+// A list of "ports", i.e. connected clients (such as web pages). Multiple web
+// pages can connect to our service: they all receive the same data.
+var ports = [];
+function byPath(path) {
+    return connections.filter(function (x) { return x.path == path; });
+}
+function byId(id) {
+    return connections.filter(function (x) { return x.id == id; });
+}
+function onReceive(data, id) {
+    if (ports.length == 0)
+        return;
+    var view = new DataView(data);
+    var decoder = new TextDecoder("utf-8");
+    var decodedString = decoder.decode(view);
+    ports.forEach(function (port) { return port.postMessage({
+        type: "serial",
+        data: decodedString,
+        id: id
+    }); });
+}
+function findNewDevices() {
+    chrome.serial.getDevices(function (serialPorts) {
+        serialPorts.forEach(function (serialPort) {
+            if (byPath(serialPort.path).length == 0 &&
+                serialPort.displayName == "mbed Serial Port") {
+                chrome.serial.connect(serialPort.path, { bitrate: 115200 }, function (info) {
+                    // In case the [connect] operation takes more than five seconds...
+                    if (info && byPath(serialPort.path).length == 0)
+                        connections.push({
+                            id: info.connectionId,
+                            path: serialPort.path
+                        });
+                });
+            }
+        });
+    });
+}
+function main() {
+    // Register new clients in the [ports] global variable.
+    chrome.runtime.onConnectExternal.addListener(function (port) {
+        if (/^(micro:bit|touchdevelop|yelm|pxt|codemicrobit|codethemicrobit)$/.test(port.name)) {
+            ports.push(port);
+            port.onDisconnect.addListener(function () {
+                ports = ports.filter(function (x) { return x != port; });
+            });
+        }
+    });
+    // When receiving data for one of the connections that we're tracking, forward
+    // it to all connected clients.
+    chrome.serial.onReceive.addListener(function (info) {
+        if (byId(info.connectionId).length > 0)
+            onReceive(info.data, info.connectionId);
+    });
+    // When it looks like we've been disconnected, drop the corresponding
+    // connection object from the [connections] global variable.
+    chrome.serial.onReceiveError.addListener(function (info) {
+        if (info.error == "system_error" || info.error == "disconnected" || info.error == "device_lost")
+            connections = connections.filter(function (x) { return x.id != info.connectionId; });
+    });
+    // Probe serial connections at regular intervals. In case we find an mbed port
+    // we haven't yet connected to, connect to it.
+    setInterval(findNewDevices, 5000);
+    findNewDevices();
+}
+document.addEventListener("DOMContentLoaded", main);
diff --git a/clients/chrome/background.ts b/clients/chrome/background.ts
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+++ b/clients/chrome/background.ts
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+// A list of: {
+//   id: number;
+//   path: string;
+// } where [id] is the [connectionId] (internal to Chrome) and [path] is the
+// OS' name for the device (e.g. "COM4").
+interface Connection {
+  id: string;
+  path: string;
+}
+let connections: Connection[] = [];
+
+// A list of "ports", i.e. connected clients (such as web pages). Multiple web
+// pages can connect to our service: they all receive the same data.
+let ports = [];
+
+interface Message {
+  type: string;
+  data: string;
+  id: string;
+}
+
+function byPath(path: string): Connection[] {
+  return connections.filter((x) => x.path == path);
+}
+
+function byId(id: string): Connection[] {
+  return connections.filter((x) => x.id == id);
+}
+
+function onReceive(data, id: string) {
+  if (ports.length == 0) return;
+
+  let view = new DataView(data);
+  let decoder = new TextDecoder("utf-8");
+  let decodedString = decoder.decode(view);
+  ports.forEach(port => port.postMessage(<Message>{
+    type: "serial",
+    data: decodedString,
+    id: id,
+  }));
+}
+
+function findNewDevices() {
+  chrome.serial.getDevices(function (serialPorts) {
+    serialPorts.forEach(function (serialPort) {
+      if (byPath(serialPort.path).length == 0 &&
+        serialPort.displayName == "mbed Serial Port") {
+        chrome.serial.connect(serialPort.path, { bitrate: 115200 }, function (info) {
+          // In case the [connect] operation takes more than five seconds...
+          if (info && byPath(serialPort.path).length == 0)
+            connections.push({
+              id: info.connectionId,
+              path: serialPort.path
+            });
+        });
+      }
+    });
+  });
+}
+
+function main() {
+  // Register new clients in the [ports] global variable.
+  chrome.runtime.onConnectExternal.addListener(function (port) {
+    if (/^(micro:bit|touchdevelop|yelm|pxt|codemicrobit|codethemicrobit)$/.test(port.name)) {
+      ports.push(port);
+      port.onDisconnect.addListener(function () {
+        ports = ports.filter(function (x) { return x != port });
+      });
+    }
+  });
+
+  // When receiving data for one of the connections that we're tracking, forward
+  // it to all connected clients.
+  chrome.serial.onReceive.addListener(function (info) {
+    if (byId(info.connectionId).length > 0)
+      onReceive(info.data, info.connectionId);
+  });
+
+  // When it looks like we've been disconnected, drop the corresponding
+  // connection object from the [connections] global variable.
+  chrome.serial.onReceiveError.addListener(function (info) {
+    if (info.error == "system_error" || info.error == "disconnected" || info.error == "device_lost")
+      connections = connections.filter((x) => x.id != info.connectionId);
+  });
+
+  // Probe serial connections at regular intervals. In case we find an mbed port
+  // we haven't yet connected to, connect to it.
+  setInterval(findNewDevices, 5000);
+  findNewDevices();
+}
+
+document.addEventListener("DOMContentLoaded", main);
diff --git a/clients/chrome/logo128.png b/clients/chrome/logo128.png
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diff --git a/clients/chrome/logo48.png b/clients/chrome/logo48.png
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diff --git a/clients/chrome/manifest.json b/clients/chrome/manifest.json
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+++ b/clients/chrome/manifest.json
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+{
+  "app": {
+    "background": {
+      "scripts": [ "background.js" ]
+    }
+  },
+
+  "manifest_version": 2,
+  "name": "code the micro:bit",
+  "version": "0.1.0",
+  "author": "Microsoft Corporation",
+  "short_name": "code the micro:bit",
+
+  "description": "This extension reads the serial output from connected BBC micro:bit and sends it to https://codethemicrobit.com.",
+  "icons": {
+    "48": "logo48.png",
+    "128": "logo128.png"
+  },
+
+  "permissions": [
+    "serial",
+    "usb"
+  ],
+
+  "externally_connectable": {
+    "matches": [ "*://localhost/*", "https://*.pxt.io/*", "https://codethemicrobit.com/*" ]
+  }
+}
diff --git a/clients/chrome/screenshot.png b/clients/chrome/screenshot.png
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diff --git a/clients/chrome/tsconfig.json b/clients/chrome/tsconfig.json
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+++ b/clients/chrome/tsconfig.json
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+{
+    "compiler-options": {
+        "target": "ES5",
+        "module": "amd",
+        "sourceMap": false
+    }
+ }
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