I am interested in making the netduino establish a BUS connection to the IPhone via the audio jack. Does anyone have any experience doing this? I have read a few things online...but I am somewhat lost.

  • \$\begingroup\$ At which point are you lost? Hardware; software; both? Do you mean something specific by "BUS"? \$\endgroup\$ – tyblu Dec 21 '10 at 21:42
  • \$\begingroup\$ I would say both... when i say BUS i mean communication bus...to transfer data. \$\endgroup\$ – Chris Kooken Dec 21 '10 at 21:47
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    \$\begingroup\$ What is the state of your software on the iPhone? Can you get a microphone reading from the iPhone, or set a voltage on the headphone pins? Until you're there, this isn't really an electronics problem. Ask at stackoverflow.com. \$\endgroup\$ – Kevin Vermeer Dec 21 '10 at 22:22

There is a project developed by David Jurick, Adam Stolarz, Damien Stolarz that is described in the book iPhone Hacks. They use the audio jack as a Frequency Shift Keying (FSK) modem that operates at about 1200 baud. Their project interfaces with a Cypress PSoC microcontroller to convert the audio signal to RS232. Source Code can be found at the www.perceptdev.com site.

A similar project using an Arduino to convert the signal can be found here.

Another project called HiJack harvests power and bandwidth from the iPhone's audio jack.

  • \$\begingroup\$ Now to combine power harvesting and bidirectional data connection... :) \$\endgroup\$ – tyblu Jan 15 '11 at 5:34

The Arduino CPU might be able to handle bidirectional BPSK at a low enough baud rate.


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