Ipod sync and audio cable mod
I've been thinking about making my own iPod dock build into my desk. One of the features I would like is that I can also listen to music while it's docked without having to put an extra cable in the top.
Now, I know cables exist with both USB and stereo line out connectors. So this should be possible.
However, since I want to work the cables away it is gonna be plugged into the USB port of my computer all the time.
I'm not 100% sure on this, but I'm guessing that the iPod will go to sync mode once I connect it without the ability to play music before ejecting it in iTunes.
What I want to do is make a toggle switch, so I can choose between sync and charge or audio (or better even, audio and charge if this is possible)
My guess is that the best way of achieving this is to put a toggle switch on the data+ on the USB line, since the iPod can no longer recognize the computer like that (and therefore will not go to sync mode)
Am I correct in this? I am aware that it will not charge this way because of the voltages needed on the data pins for charging.
A better solution would be to switch both data connections from the standard USB connection to the voltages needed for the iPod to charge (causing it to still charge in audio mode). However, I'm not sure how easy this would be to achieve with only 1 toggle switch (since I need to change 2 cables without shorting them out). I know the voltages and resistors needed (they can easily be found here on instructables or other sites through google) but the switch is what is bugging me.
It would be nice if this can be done without microcontrollers (I never used them so yeah...) If I need to build a circuit that is ok (soldering isn't the problem, I just don't feel like learning to program a microcontroller just for this project)
Can someone please tell me the best way to achieve my goal, and if it's possible at all.