1.
Transferring data usingAudio signal in Android Sudar Muthu http://sudarmuthu.com http://twitter.com/sudarmuthu

2.
Yes you heard it right It’s possible

3.
Basic IdeaIn any data transmission system, data flows from Transmitter to Receiver Transmitter Receiver

4.
Basic IdeaAndroid Audio Player Plays audio and becomes Transmitter Plays audio Audio Player

5.
Basic IdeaAndroid Audio Recorder records audio and becomes the Receiver Receives Audio Audio Player

6.
Basic IdeaSo now the data (audio) flows between Audio Player and Audio Recorder Audio Audio Player Audio Recorder Data

7.
Data inside AudioSound/Audio is AnalogYour data is Digital (0 or 1)Data and Audio are combined using Frequency Shiftkeying (FSK)Android has a built in analog to digital Convertor

8.
What is FSK?http://en.wikipedia.org/wiki/Frequency-shift_keying

9.
Code Sample – Audio Recorder

10.
Code Sample – Audio Track

11.
So why would anyone want to use it?Zero power transmissionLess battery usage, when compared with WIFI orBluetoothCan work with any audio deviceVery simple to plug into your phone

12.
Commercial projectsProcess credit cards – http://propay.comTata sky – Converts your mobile into a remoteAudio cassette interfaces to mobile

13.
Project IdeasCommunication between multiple audio devices likeyour PC, iPod/iPad/iPhoneHide data inside an audio fileBroadcast data as a music file. Imagine what happensif your radio station does thatHook up your Arduino and control robots (and that’swhat got me interested in this ;) )

14.
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)

15.
Libraries/Projects to check outAndroino - http://code.google.com/p/androino/AndroinoTerminal -http://code.google.com/p/androino/wiki/AndroinoTerminalArms22 - http://code.google.com/p/arms22/

16.
Demo

17.
Thank You Sudar Muthu http://sudarmuthu.com http://github.com/sudar http://twitter.com/sudarmuthu