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Hacker reveals how Apple artificially restricts iPhone chargers (video)
Most cell phone manufacturers have charging standards these days, even if they can't always agree on which version of USB to use, but as the hair-tearing message above shows, third-party renditions of Apple's proprietary dock connector haven't always been universal solutions for iPods and iPhones. Now we know another important reason why -- secret resistors placed on the data lines in connectors for each iDevice. Minty Boost creator ladyada recently reverse-engineered the chargers for a variety of Apple gadgets, and discovered that iPhones in particular don't draw electricity until they detect 2.8V and 2V signals when they attempt to charge. At that voltage, the handsets suck down about one amp, leading to a rapid filling of your device's Li-ion belly, but by adding additional resistance to drop the voltage further, the iPhone can be coerced into accepting 500mA instead -- perfect for the set of AAA batteries you stashed away in that Altoids tin. Video after the break, full explanation at our source link.
MintyBoost unlocks the secret of Apple's chargers
The folks at Minty Boost have unveiled a rather interesting Apple secret: just how the company charges its devices. In the video on the next page, you can see the whole process reverse-engineered. It's rather technical, but as long as you make sure all the wires go where they need to go (you need to lay out a certain series of resistors on the USB data lines, so that the device thinks it's hooked up to an official charger), you can actually build your own iPhone or iPod charger. In fact, there's a new Minty Boost kit which comes with prebuilt circuitry that you can use (inside an Altoids tin or whatever you want to use) to create your own iPhone USB charger. You can read about the whole process of reverse engineering Apple's process over on the official blog -- it's fascinating both how Apple implemented this process of "verifying" a certain USB charger, and also how Minty Boost eventually figured it out. It's definitely very technical, especially when you get into some of the final steps of amps and volts, but the bottom line is that by lining up those resistor levels, almost anyone can put together a working charger for any Apple device. Keep in mind that if you aren't familiar with basic electronics safety, these are not the projects for you.
