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In this 7 minute video we explore “The mysteries of Apple device charging“. Usually device makers need to sign a confidentially agreement with Apple who want to say “works with iPhone / iPod” and never talk about how the insides work. If you don’t put these secret resistors on the data lines to you get the dreaded “CHARGING IS NOT SUPPORTED WITH THIS ACCESSORY”. We demonstrate how anyone can do this and make their own chargers that work with iPhone 4, 3Gs, etc. Video above, HD and (m4v).
We’ve updated our open source charger, the MintyBoost as well, today is its official release.
Want more details? See our article on Apple Charging with more technical info and schematics
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What stops Griffin (or some other gigantic producer of iPhone/iPod accessories) from just reverse engineering this stuff and not paying Apple for the right to sell chargers?
What prevents Apple from suing you for selling a minty boost plus after you reverse engineered what’s going on inside?
I don’t think what you’ve done is wrong, but why does Griffin pay Apple if it’s so easy to get it working?
Comment by John — August 3, 2010 @ 1:26 am
I just caught this video alongside my morning coffee.
Great article, very interesting and a good example of rudimentary reverse engineering principles.
Made me wonder about my own phone, an HTC HD2. I think that I will be trying it out over the next few days. I am guessing that a more common arrangement for chargers will be to add voltages to the D lines for a mains or car charger and leave them off for a USB charge.
Only one way to find out….
Comment by Justblair — August 3, 2010 @ 2:41 am
Very interesting. I think other devices have their own secret resistor values as well; my Samsung phone complains when attaching it to the iPod charger wall-wart (fortunately, it still charges).
Your USB squid cable looks wonderful, but I wish it included a mini-USB to micro-USB adapter. Most all modern phones use micro-USB for charging (Apple being the exception).
Comment by J. Peterson — August 3, 2010 @ 6:20 am
@john – apple can sue anyone for anything if they wanted, but reverse engineering how something works is usually not one of them.
you can read up on reverse engineering here, it has a good overview:
http://www.chillingeffects.org/reverse/faq.cgi#QID195
we can’t speak for griffin, if anyone wants to put “works with ipod” or “works with iphone” they need to work with apple.
Comment by adafruit — August 3, 2010 @ 10:24 am
Reverse engineering it is well within Griffin’s rights. Putting anything with Apple’s trademark on it, however, requires them to go through Apple.
Comment by Phelps — August 3, 2010 @ 12:50 pm
Hi,
good research, here are the original specs from Apple:
http://img16.imageshack.us/img16/4832/ipodladen.png
Comment by MrFX — August 5, 2010 @ 4:54 am
@mrfx – thank you
Comment by adafruit — August 5, 2010 @ 11:01 am
Thanks for the info! I followed this advice and changed one of the resistors on my MintyBuck circuit to limit its output current to 500ma also, since that’s as much as my little LM2674 “simple switcher” regulator is rated for.
Comment by Dave Clausen — August 22, 2010 @ 7:25 pm