I'd rather not fry my new shuffle

[copierguy]

I just got a 2G shuffle and being the guy I am, rather than buy the $30 Apple wall charger, I built one for it. I'm just looking for some validation on my design before I plug in a brand new shuffle and cook it:

http://www.geocities.com/copierguy_mobile/DSCN2329.JPG

This is what I came up with. The power supply outputs 5.33 VDC with no load and has a capacity of 3 amps (I know it's a little overkill but it's what I had).

The 5.3 VDC is on the Red line of the USB socket (pin 1), The black line (pin 4) is of course ground (the USB cables shielding is also connected to ground).

Here's where I'm a little nervous. The USB data lines (green and white, pins 2 & 3) should be unused in this type charger, so per the USB 2.0 specs I have terminated each one to ground through a 15K ohm resistor. However when I check the Apple wall charger (one I borrowed from a friend) I find a little over 3VDC on each of the data lines. Anybody know what's going on with that and If it's something I should worry about?

-thanks in advance, Greg

For my next project, I've got some 4 conductor 3.5mm phone plugs comming so that I can build a short cable and be free of the stupid dock.

[Kutanks]

Borrow a Friends shuffle, idk, i'm not an electrical engineer,

[bobb-mini]

oh comeon, where is your sense of adventure! :D

Try THIS (http://forums.ilounge.com/showthread.php?t=162262&highlight=resistor+ground).

[copierguy]

cool. Thanks for the link, I will give it a try.

[bonewitz]

post what the outcome of the charger is , sounds interesting.

[copierguy]

The charger seems to work fine as originally constructed. Based on the info Bob-mini posted, I think I could make it run at a higher current level and charge faster with a slight mod.

But given how easy the first one was to build, I'll just build a new one with a different design...

and here's a pic of the finished cable (no more dock for me!!) with the charger.

http://www.geocities.com/copierguy_mobile/DSCN2333.JPG