Possible Duplicate:
How could you transfer data over an audio line?

I'm trying to make my Android phone talk to my robot which uses an Atmega8535L chip. The idea is to use the phone's camera as a line follower's sensor (already done) and send information to my robot's wheels.

As of now I have a quite naive idea of how it'll work: I'll use left audio channel as clock and right as data over a simple scavenged audio cable which I'll connect to analog pins (as the audio jack doesn't put out much voltage, the threshold will be low). Since I cannot output digital signal from my Android phone (I think) I'll use some noise as 1 and no noise as 0.

I'd like to use no electronics whatsoever between my phone and my robot... if that's even possible. I've heard about FSK, but it seems complicated, especially the demodulation part.

Is this even feasible without additional electronics?

  • \$\begingroup\$ None of these mention any direct connection between the 2 devices, if that's not feasible (be it hard or not) I'll learn FSK. \$\endgroup\$
    – Solenoid
    Commented Mar 5, 2012 at 18:40
  • \$\begingroup\$ How much data are you wanting to pass? I might be able to write something up for you. \$\endgroup\$
    – Kellenjb
    Commented Mar 5, 2012 at 20:16
  • \$\begingroup\$ I'm not looking for existing libraries, this is my way of learning this stuff. What I really want to know is if it's possible without additional electronics, preferably without FSK. \$\endgroup\$
    – Solenoid
    Commented Mar 5, 2012 at 20:52
  • \$\begingroup\$ That is fine. This question can be reopened as long as it can be shown to not be a duplicate of that other one. I actually think the other is a very poor question, but that is beside the point. In order to make this question acceptable, you will need to edit your question to be about a specific design problem. As it is now it is pretty broad. Things like your data rate, why you don't want external components, etc should all be included in your question. \$\endgroup\$
    – Kellenjb
    Commented Mar 5, 2012 at 20:58


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