Transferring data using Audio

signal in AndroidSudar Muthu

http://sudarmuthu.comhttp://twitter.com/sudarmuthu

Yes you heard it right

It’s possible

Basic IdeaIn any data transmission system, data

flows from Transmitter to Receiver

Transmitter Receiver

Basic IdeaAndroid Audio Player Plays audio and

becomes Transmitter

Audio PlayerPlays audio

Basic IdeaAndroid Audio Recorder records audio and

becomes the Receiver

Audio Player

Receives Audio

Basic IdeaSo now the data (audio) flows between

Audio Player and Audio Recorder

Audio Player Audio RecorderAudio

Data

Data inside AudioSound/Audio is Analog

Your data is Digital (0 or 1)

Data and Audio are combined using Frequency Shift keying (FSK)

Android has a built in analog to digital Convertor

What is FSK?

http://en.wikipedia.org/wiki/Frequency-shift_keying

Code Sample – Audio Recorder

Code Sample – Audio Track

So why would anyone want to

use it?Zero power transmission

Less battery usage, when compared with WIFI or Bluetooth

Can work with any audio device

Very simple to plug into your phone

Commercial projects

Process credit cards – http://propay.com

Tata sky – Converts your mobile into a remote

Audio cassette interfaces to mobile

Project IdeasCommunication between multiple audio devices like your PC, iPod/iPad/iPhone

Hide data inside an audio file

Broadcast data as a music file. Imagine what happens if your radio station does that

Hook up your Arduino and control robots (and that’s what got me interested in this ;) )

How to get started?

Things you need

Android Phone

Audio cable (4 pole 3.5 mm)

SoftModem – http://www.sparkfun.com/products/10331

Any additional device (another phone or even an Arduino)

Libraries/Projects to check out

Androino - http://code.google.com/p/androino/

AndroinoTerminal - http://code.google.com/p/androino/wiki/AndroinoTerminal

Arms22 - http://code.google.com/p/arms22/

Demo

Thank You

Sudar Muthuhttp://sudarmuthu.comhttp://github.com/sudarhttp://twitter.com/sudarmuthu