June 12
2007
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 | Just finished building an AA-battery iPod
charger, by the excellent design of Ladyada's. I found I could fit
mine comfortably within the battery house of an IKEA christmas light
thingie. This holds 4 AA batteries, so it had plenty of space. The
female USB connector is from a USB->USB extension cable, which came with a memory stick I
bought. I opted not to etch a PCB, to save time + space. The "soldering-together-components" scheme is
something I picked up from M. Tilden's excellent robot book; Junkbots,
Bugbots & Bots on Wheels.
Anyway, just a few thoughts: I assumed the wiring in the USB cable I
used was straight-forward, and that the red cable was +5V, and the
black one GND. HOWEVER, connecting the iPod to this, sent it straight
into a coma -- fortunately, it just rebooted and came back on. It
seems the cable I'm using has +5V on the black, and GND at
red... for some reason. I checked this by plugging the other
half (male end) of the cable into my PC, and simply measuring the
red/black wires using a voltmeter (which showed -5V when I had things
the wrong way). After simply desoldering and swapping the wires on my
circuit, and pulling the data lines high (3V),
the charger seems to
work finally works!
Still, the importance of checking the USB wiring should be stressed in the
instructable, if it's not already... This can kill your iPod - I
must've been lucky!
Also, I notice on the (version 1) Eagle
schematic, she's labelled C1 and C4 as 1uF, which should read
0.1uF.
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 |
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Old version (please bear with the crummy soldering...) | 
Updated version v1.2. Note that the legs on
the MAX756 can only be bent twice, before they break off! Still, it's
possible to solder components to the stump, but it's a fragile joint
(yes, LBI snapped in my case). |
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Debugging Notes |
June 12 2007
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Version
1.2: It seems the newer generation iPods need the data lines to be
tied to 3V (or GND, depending on the model, apparently). By adding
some resistors, the circuit finally works! Also, there's the
nifty LED, which (as I understand) lights up when the batteries need
to be changed. Or does it light when the iPod is charging? Not
sure. In my case, it turns on when the iPod charges, but maybe the
batteries are just old? Recommend browsing through
ladyada.net, especially the forum. Lots of great info there! |
June 8 2007
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After I finished
building, I checked with the voltmeter that the 3V from the batteries
is in fact transformed into 5V. When I connect my iPod nano, the
battery icon changes to the "lightning icon," and the green background
(in the icon) blinks, which seems to indicate that it's charging.
However, after a while, the icon goes back to normal battery, and when
I unplug the iPod, I can't see that the battery level has increased at
all... Granted, the AA batteries are not fresh out da box, but I
expected the design to be quite energy efficient. Or do I always need
spanking new batteries to charge? OR, obviously, there's something
wrong with my build.
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This page is my private stuff, and not affiliated with the University
of Bergen. Any hacks and cracks to your iPod is at your own
risk.
