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Hardware Hackers Reveal Apple's Charger Secrets
ptorrone writes "In this 7-minute video we explore the mysteries of Apple device charging. Usually, device makers need to sign a confidentially agreement with Apple if they want to say their charger 'works with iPhone / iPod,' and they're not allowed to talk about how the insides work. If you don't put these secret resistors on the data lines too, you get the dreaded Charging is not supported with this accessory. We demonstrate how anyone can make their own chargers that work with iPhone 4, 3Gs, etc."
Resistance is Futile
Lots of companies do this. APC puts a RS-232 serial port on a UPS but wait! They move the pins around so you need a special cable. Cisco used to have a product called the Gigastack that used a standard 6-pin Firewire cable, but no! Pins 1&2 were shorted in the "special" cables Cisco provided.
this is my sig
"She's certainly well-geeky, but 'hot' she's not ;-)"
Nonsense! She has all the characteristics of hotness:
Airway.
Breathing.
Circulation.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
Not only does she have a well stocked desk, she has her own company and sells some geeky stuff to us tinkerers: http://adafruit.com/ Her monochron pong playing clock was featured on /. a while back.
"Something's wrong with you...and I hope we never do meet again." - Deftones When Girls Telephone Boys
But the shown resistors don't look like the standard micro-USB connector. So is Apple breaking it's prommisses? Or am I missing something?
Do you even have to ask? Yes, we should have a right to repair, and a right to build interface devices.
People often talk about how wasteful Americans are and the problems of a throw-away society. If people were more willing to repair their devices, especially complex electronic devices (most of which fail because of simple and repairable problems, like a broken lead), we would be better off. Aside from less electronics in landfills (let's face it, few people actually dispose of electronics properly), people would not be spending their money so quickly, and presumable that would mean fewer debt problems (or they might just spend it elsewhere).
Of course, we will never see anyone other than a few activists pushing this sort of mentality -- corporations have enjoyed ever larger profits because people are unwilling and unable to repair their own equipment (or to find a local repairman to do it for them).
Palm trees and 8
I'm still trying to figure out if you're talking about catching her on a day with low self-esteem... or rape.
>>>but 'hot' she's not
Come here sonny. I want to give a brief talk. I recently went to my 15th reunion, and you know those "hot" girls in my class? Well they ain't hot no more! In fact they were downright repulsive (sorry, but it was true). So might as well go for the brainy, geeky girl because that will last. The beauty won't.
If you want "hotness" that will last, go Playboy.
The 1995 centerfold will always be hot,
even if the model no longer is.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
The source is a video repair shop in flyover territory which charges $60/hour for labor. Here in China, I can get my DVD player repaired for $3-10 because the cost of labor is so low. Indeed, one of the delights of living here is you can actually get things repaired. I'm just so used to automatically buying a new electric razor, rice cooker, electric lamp, (etc) when mine breaks. Here, I can actually get it fixed! In America, don't even bother phoning the repair shop as they'll just tell you that the cost of a new unit is less than the cost of their labor.
Don't let that put you off of blaming stupid Americans who are unwilling and unable to repair their own equipment and of course blaming those eeeeevil profit-makers. The only people who see the world the right way are a small group of activists, for example yourself!
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
Reading the article, it appears that the purpose of the resistors is NOT to lock out manufacturers, but to inform the ipod of the amount of current to draw from the charger. They found different manufacturers using different values of resistors. From the looks of it, one resistor sets the amount, and the other resister serves as a "checksum of sorts, complementing the other resistor correctly to verify the value. Getting the value wrong could very easily cause a fire, so this is important to make sure you get it right.
This is not surprising, as USB does not allow variable voltage, and current is supplied completely on demand with no regard to the provider. So you either have your device set to draw a fixed amount of power (current) and limit your options to *1*, or you develop some simpler way to tell the device how much power (current) a device can demand from any given charger.
The only other option would be to use the data pins and actually communicate over the usb spec normally and outright tell the device how much power to draw. (which is actually already in the USB specs) Apple would have probably preferred to go this route, but that would significantly increase the complexity of the power adapters. All the people that are whining about Apple being nasty about this need to get some education. Apple's other two options were to make chargers cost more, or to not be able to offer both fast (wall power) and slow (AA batts) chargers.
The only group that's more thick-headed than the Apple zealots, are the anti-Apple zealots.
I work for the Department of Redundancy Department.
Is there a practical reason that the iPhone / iPod cannot be recharged and / or synced via a simple USB mico connector interface?
Yes... Profit!
For justice, we must go to Don Corleone
We all love to call out Apple when they design deliberate incompatibility into their devices, but there is a perfectly valid technical reason for what Apple is doing here, and, in fact, they are following a USB specification (which LadyAda unfortunaterly didn't even test).
Without data communications or when suspended, devices may legally draw no more than 2.5mA from a host, which is useless for charging. In fact, even if you're generous and pretend they're connected, devices are not allowed to draw more than 100mA without negotiating for a higher current, which requires actually talking to the host, and 100mA is still too little to charge properly. 500mA is the maximum allowed by the USB spec, but devices must negotiate it (there may be too many devices on the bus for negotiation to succeed).
Before there was a spec for "dumb" USB chargers, Apple used the resistors as a sentinel to avoid drawing too much current from undersized chargers in order to avoid damaging the host. This is a hack, but it works, and honestly, we're smart enough to figure out a couple resistors on the data lines. It's not like they're using crypto auth on the charger. They have a perfectly valid reason to do this. Devices which charge from "dumb" chargers aren't following the spec, though this is a common industry practice.
As it turns out, the USB-IF came up with a USB Battery Charging spec. The spec is long and boring, but it boils down to: short together the data lines (no resistors required) and you indicate that you're a dumb charger that can supply anywhere from 0.5A to 1.5A.
Guess what happens when you short the data lines of an iPhone 3G and supply 5V. Did Apple just follow a standard? Incredible!
(Yes, I'm not following the USB spec there by in turn using a USB cable to supply the 5V and not negotiating over its data lines. I didn't feel like grabbing a dedicated 5V PSU for the shot, so sue me.)
Airway.
Breathing.
Circulation.
Dick? (checks) Nope. Houston we're ready for liftoff.
Erection? (checks self) Nope. Houston, we have a problem.
When you have nothing left to burn you must set yourself on fire
Funny, my Android phone does the same exact thing and it uses a standard USB micro interface. You need a special plug to get the full 1000ma charging, but it can use regular plugs too and charge at 500ma without frying anything.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
But there is nothing to stop them just drawing the 500mA if the right sort of charger is not detected. Refusing to charge at all unless the licensed parts are present is pure market control, nothing else.
Since when did jerking off in the bushes outside someone's bedroom window count as rape? Jesus, guys...it's not as if I'm sort of sicko.
Actually, it has occurred to me, as I am a personal friend of Sarah's. You may not believe me, but either way, that's somewhat besides my point. I'm sure she wants attention for her outreach work and her scientific research, but to get attention only or primarily because of one's looks is to very unwelcoming. It serves to alienate people, to denigrate them-- it's why we have terms like "sexual objectification" in our language.
OK, this just keeps getting better and better. As I read more of your posts about this girl, I begin to see what your motivation is. You're the overprotective geek friend/wannabe lover who thinks by defending her honor on some random geek message board, you will curry favor with her and this will somehow lead to her fucking you. I'm sad to inform you this will never happen.