Using websockets and android to control robots in realtime

Using WebSockets and Android to control robots

in real-timeSudar Muthu (@sudarmuthu)

http://hardwarefun.comhttp://github.com/sudar

http://hardwarefun.com/

http://github.com/sudar

http://hardwarefun.com

Research Engineer by profession Create robots as hobby Uses an Android phone Why not combine both of them? Has spoken in 6+ hasgeek events

Who am I?


There are at least half dozen ways to do it and I am not going to talk about each of them.

http://sudarmuthu.com/blog/building-robots-using-arduino-and-android-at-droidcon

Android and Arduino





WebSockets in AndroidHow to use it to control robots

So today…


Why hardware for a software hacker?

Fun!


Demohttp://hardwarefun.com/projects/asimijs

Let’s start with a demo

http://hardwarefun.com/projects/asimijs


Participate in the demo

Visithttp://hardwarefun.com:3000

http://hardwarefun.com:3000/



Control the bot at stage

#asimijs @hardwarefun



Now let’s see how I built it


Full-duplex over a single TCP connection Provides push support Designed to work inside browsers Works on port 80

What is WebSockets?


WebSockets vs HTTP



Server Client

Is there an update?

Is there an update?

Is there an update?

No

No

Yes

HTTP (Pull)


Server Client

Tell me when you have an update

Here is the update

Ok

WebSockets (Push)


Firewall friendly No need to reinvent protocol Real-time communication Easy to setup server

Why use WebSockets in Android


Remember, I am not talking about using WebSockets inside an Android

browser


There are lot of options, but I choose Socket.IO implementation by Kaushik Dutta (Rom

Manager fame)

https://github.com/koush/android-websockets

WebSocket implementation for Android




You should have attended jsFoo ;)

Why Socket.IO?


Additional features on top of WebSockets Node.js based server Has support for maximum no: of browsers Has clients in lot of languages

Why Socket.IO


I had the server already written

and ….


Let’s see some code


client = new SocketIOClient(URI.create(”http://hardwarefun.com:3000"),new SocketIOClient.Handler() { @Override public void onConnect() { Log.d(TAG, "Connected!"); }

@Override public void on(String event, JSONArray arguments) { Log.d(TAG, "Got event); }

@Override public void onDisconnect(int code, String reason) { Log.d(TAG, "Disconnected!); }});

In Android, create a socket









client.connect();

JSONArray arguments = new JSONArray();arguments.put("first argument");JSONObject second = new JSONObject();second.put("dictionary", true);arguments.put(second)client.emit("hello", arguments);

client.disconnect();

Send data through socket


var io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) { socket.emit('news', { hello: 'world' }); socket.on(’my other event', function (data) { console.log(data); });});

In node.js side


Checkout the full source code at http://hardwarefun.com/projects/asimijs


How the demo worked?So…

Node.js Server

Admin page

User pageUser page

User page

Android Client

Asimi (Bot)Web Socket

ADK



AsimiJS – The demo that I showed initially http://hardwarefun.com/projects/asimijs

Android websockets - https://github.com/koush/android-websockets

Getting started with hardware programming http://hardwarefun.com/tutorials/getting-started-with-hardware-programming

Getting started with Arduino http://hardwarefun.com/tutorials/getting-started-with-arduino-and-avr

Android and Arduino - http://sudarmuthu.com/blog/building-robots-using-arduino-and-android-at-droidcon

Arduino Workshop - http://hardwarefun.com/arduino-workshop

Links





http://hardwarefun.com/tutorials/getting-started-with-hardware-programming

http://hardwarefun.com/tutorials/getting-started-with-hardware-programming

http://hardwarefun.com/tutorials/getting-started-with-arduino-and-avr






http://hardwarefun.com/arduino-workshop

http://hardwarefun.com/arduino-workshop

Thank youSudar Muthu

http://hardwarefun.comhttp://github.com/sudar

http://hardwarefun.com/

http://github.com/sudar

Technology

Using websockets and android to control robots in realtime