DIY iPod Touch 3 Charger

Man-wai Chang wrote:

Of the 3 solutions I attempted, they all gave me a yellow triangle and
reported "Charging not support on this accessory" when it's fully
charged. I found some messages about an "authentication chip" in
official chargers. Maybe that's related, or it could just be a protocol
thing.

Potential divider is the best solution.


Did you do it like this ?

R1 R2 R3
+5V --- resistor ---+--- resistor ---+--- resistor --- GND
| |
D+ D-

or did you use a four resistor circuit ?

If you did the three resistor circuit, what were the values of
R1, R2, R3 ? Just for the record...

An authentication chip seems a bit excessive. To prove it,
someone who owns the Apple adapter would have to open
it up and look for the chip, and get a number off it.

Paul

Did you do it like this ?

R1 R2 R3
+5V --- resistor ---+--- resistor ---+--- resistor --- GND
| |
D+ D-
If you did the three resistor circuit, what were the values of
R1, R2, R3 ? Just for the record...

Yes. R1=10K, R2=40K, R3=50K

An authentication chip seems a bit excessive. To prove it,
someone who owns the Apple adapter would have to open
it up and look for the chip, and get a number off it.

I got a feeling that the iPod firmware was programmed to deny
"un-licensed" charger. All 3 solutions worked in the very beginning, but
then the iPod "learnt" that they were not Apple chargers, and displayed
the yellow triangle.

--
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+5V --- resistor ---+--- resistor ---+--- resistor --- GND
| |
D+ D-
If you did the three resistor circuit, what were the values of
R1, R2, R3 ? Just for the record...
Yes. R1=10K, R2=40K, R3=50K

Oh no... wrong arrangement! Correcting it. Report back later.

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R1 R2 R3
+5V --- resistor ---+--- resistor ---+--- resistor --- GND
| |
D+ D-
If you did the three resistor circuit, what were the values of
R1, R2, R3 ? Just for the record...

Corrected values: R1=50K, R2=10K, R3=40K.

So far so good. Hot-pluggin not working as usual.

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The diagram should look like this:

R1 R2 R3
+5V --- resistor ---+--- resistor ---+--- resistor --- GND
| |
D- D+

Note that D- is between +5V & D+

Corrected values: R1=50K, R2=10K, R3=40K.
So far so good. Hot-pluggin not working as usual.



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OK, same yellow triangle when the battery was fully charged.

--
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