I had a post a while back on charging an iDevice (iPhone, iPad, iPod) and talked about and showed a schematic for the charging circuit. This design is based (and the schematic is almost exact!) off of Ladyada’s Reverse engineering Apple’s secret charging methods. (video link, it’s good, you should watch it!) I give her full credit for the circuit. Now, the boards I whipped up in a few hours, and had it made from DorkbotPDX service. I sent off the files and 2 weeks later, I got three perfect purple PCB’s. The boards cost a total of $4.69. Shipped. You can’t beat that with a stick! Now, I have a nice little iDevice charger that accepts standard 5 volt power from any standard power supply. Although I do tend to favor 5V 2A supplies from Adafruit.
I used the same circuit I had in the old post, just added an LED and resistor for a power indicator. I had an old cell phone from 2006, and saved the keypad because it lit up blue. (Can you blame me?) Now, 6 years later those tiny 603 blue LED’s come in handy. I got the 603 resistor from an old PC motherboard. Motherboards have a slew of SMD things on them. So I fired up the hot air rework station, grabbed my tweezers, and voila! SMD parts! (I did order some reels of 603 resistors and LED for use in future kits, sorry peeps, no old motherboard parts for you!) I use a good pair of tweezers, and a viewfinder from an old camcorder to inspect my work. “But Jeremy? Where do you keep all of those SMD parts?” you ask? Good question, I use these awesome Modular Snap SMD component storage boxes from Adafruit. They have spring loaded tops, and they are modular, you can form them in any configuration you want! How cool is that?!
I needed to charge an iPad, but I couldn’t do it the “normal” way because it was stuck in a wall! I had mounted 2 iPads in walls at a customers house. I did this by cutting a big iPad sized hole in the wall, and then building a custom mounting dock for it. I also embedded an arduino bootloaded ATmega 328 in there along with a MAX3232 (RS232 to TTL) chip for controlling the iPad via RS232. Now all I had to do was keep it charged. I found Ladyada’s mintyboost resources a huge help. She even has a video on Reverse engineering Apple’s secret charging methods. With her video and mintyboost page, I was able to build a working charging circuit that has worked perfect since December of 2010.
On a side note, you may ask yourself why would anyone put an iPad in a wall? Well, it serves as a lot of cool things, but the main one is to control the home automation systems I install. And an iPad is about the same price (with my dock) as a touchscreen the automation company sells. The automation system controls HVAC, lighting, security, audio (multi room/source), video, intercom, and also have close contact output as well as 5 RS232/485 ports, Ethernet, and telco connectivity. I’ll have to show off my automation system one day, it’s really an amazingly flexible system.
Why not just use the stock iPad charger? Because I don’t do cheesy. Apple chargers are cheesy? No, of course not. I will not tolerate any wires in plain sight at a customer installation. Ever. And I have seen a number of on wall (not in wall) iPad docks that have a wire going down to an outlet. Let’s just say, that’s not my style. NEC code does not allow for exposed high voltage inside a wall, like an outlet with an Apple charger sticking out. So the answer was to build my own solution with low voltage only. For power, I used 2 5v 2A power supplies from Adafruit.
Keep in mind that an iPad charger will charge an iPhone, but an iPhone charger will not charge an iPad. At least this is what Apple tells you. The truth be told, an iPhone charger will charge an iPad when it’s asleep, but that’s at a trickle rate that is painfully slow. I say all that to say this: I’m not clamming this is the only way to charge iDevices, it’s just the way I did it. This method will charge any device currently out right now including the iPad 2.
Here is a shot of the end result. The wow factor is there with authority.