MintyBoost unlocks the secret of Apple's chargers

All she really had to do was use her volt meter and measure the voltage on the D+ and D- pins. A little work with her calculator and one $30 Griffin TuneJuice charger would have lived to charge another iPod.

So basically, trying out the solder rework station cost some one $30.

If you have enough power in your powersource, you can simply short the datalines - no need for resistors.
At least this works for my iTouch 2G, and it willostensibly allow the fastest possible charge.

The resistors are only needed when you need to limit the current drawn.
As 'me' in the video shows, she can use the resitsors to signal to the iPhone that it should limit its consumption to either 0.5 A or 1.0 A, and she needs to do that for the mintyboost, because - as she explains the AAA batteries it uses can't deliver more than 0.5 A.
However according to the wikipedia entry on USB, she is not correct when she says that the 1.0 A setup, is the fastest possible charging-setup:

http://en.wikipedia.org/wiki/Usb#Power

" A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured."

I have actually made a very simple USB-battery-box with 4 *AA* batteries, and with the datalines shorted, and it charges my iPod Touch 2G fine and fast.
I haven't measured how much current it draws, but I might (when I get my desk uncluttered).

As I understand the iPad charger is capable of delivering about 2 A, and it could be interesting to see, if it also simply shorts the datalines, or if it maybe uses a third resistor-setup, that signals a higher current-capacity.

I can't help to think, that it's somewhat odd, that we're left to reverse engineer these matters. It would seem quite obvious, that Apple has these specifications, and that they would communicate them to proper third-parties, such as Griffin.
Of course - with Apple you never know when they deem some information or feature to be restrained due to weird political considerations.

Isn't this just the standard USB charging setup mandated by the USB-IF? It's the same sort of setup required by a USB-charging Nokia or any other standards-compliant USB device.

The company is Adafruit, not MintyBoost. MintyBoost is a single product they make.

Maybe now I can buy one of those nice, cheap USB adapters that claim to work with a 3Gs and actually do work. Every single one and even monoprice cables do not work with my damn phone. My iPad is less forgiving about charging!

I've tried the cheap chinese eBay adapters, Monoprice adapters (and cables), and nothing charges my phone like the ridiculously priced Apple adapters. Can anyone help me out? The Monoprice cables let me sync, but I get the 'this accessory doesn't support charging' blah blah whenever I plug it in (to my PC or wall adapter)

Pretty cool. Isn't that a wheatstone bridge they're using?

So according to the pictured schematic it seems they simply put 3.3v on the data lines.