I've seen quite a few, but being a road warrior, space/size and weight are paramount to me. And finding a 9 volt battery is pretty easy.

I originally made this for my old Palms.  With a few resistors it works for the iPhone.

Simple design.  A DB-9 hood with the ears cut off as the case, the ubiquitous 7805 as the regulator and a 9volt battery connector.  (I used one from an old battery, its stiffer then the ones you would buy at Da Shack)  Granted the 7805 is far from efficient, but it works and keeps the whole thing small and easy to build.

Parts list:
7805 5 volt positive regulator
100K SMT resistor (2 pieces) Size 2012
20K SMT resistor (1 piece.  I didn't have a 20K but used a 10K) Size 2012
USB female connector  (I gutted a device to get mine)
9 volt battery connector (I got mine from an old battery, worked best for me, plus its less in the landfill)
DB 9 hood  plastic for easier modifications

Wire, solder, heat shrink, potting compound (optional)
Wire cutters/strippers
Rat tail file
Dremel  (though I used a milling machine, a bit overkill)
Soldering iron  (hot air SMT with paste works best, but I didn't dig up that stuff for such a small project)
ex-acto knife

On with the show!

Step 1:

Gather your stuff.  I didn't take pics of tools (should I?)

The USB connector:

Pre solder the pins for soldering the SMT resistors.  I did it far from the end as not to unsolder it when soldering on the wires later.  I also snapped off the PCB mounting lugs
<p>My iPhone 5S says, &quot;This accessory may not be supported&quot; and then stops charging. :(<br>Any solutions?</p>
Sorry, no. I don't use a iphone any more. And rarely use my ipod touch.
So just to be clear it can't charge an iphone 5?
what iPhone does the author have? my iPhone 4 doesn't charge, but my iPod t 2 does, but it was made pre-revisessd apple charging standards update( which is the point of the resistors) ?
well.. project semi complete. my iphone only told me to restore it on my computer. i tested the leads with my dmm and i have a 5v DC current with .58 amps. WHY DOES IT DO THIS? i plugged a ps3 controller into it and nothing happened. WHAT IS WRONG?!? I NEED THIS DONE BY TOMORROW!!! (and nothing is shorting it out, im not that dumb)
ps3 controllers dont charge the same as other usb stuff, but neither does iPhones. but ps3 controllers has a totally unique way of charging, nothing should charge those except a ps3. so you can't use that to analyze your results.
i think your amperage is a lil too lean there .. or too much.. check the specs online for the milliamps that those devices can tolerate
Can I use regular sized resistors with the same ohms?
This won't charge any newer apple devices iPod touch 3rd+, iPhones the data pins need 2volts each
But dont the 2 &amp; 3 pin on the usb need 2 volt for to work with iphone
That's the purpose of the resistors, a voltage divider.
does it work with ipad mini?
You'd need a bunch of 9volts. Ain't a ton of juice in a single 9volt.
I'm curious as to how many 9v batteries it will take to charge a dead iphone 4? Great article! <br> <br>Thanks
Actually this does not work for the iPhone 3GS because it draws 1 amp. Obviously a problem. Ladyada Who made the minty boost and that somehow takes .5 amps and makes the iPhone charge... Magic?.. I'm starting to think so. Haha.
Joule thief?<br><br>Though that may not work with charging... suggestions?
what is the significant difference between a 20k and a 10k resister? all the shack had was 10k resistors.<br>
then solder two of the 10K in series.. it wont hurt them!
is this for the 3GS? because i got a LOT of those regulators!
can i get the right USB female connector from a USB extension cable?<br>
Answer please!!
Yeah, most you can cut open and use. Some may be unusable though. Can't tell until you open it.
ok thanks again, i am just going to get a wall to usb converter, that way i can just unsolder it<br>
Verry nice and good explained instructable<br>Could I use it for charging other usb devices?<br>f.e. PSP, Cellphone?
It charges anything that uses a USB to charge.
can i get the resisters at radio shack? and do they have to be the small ones?
Yes you can get resistors from the Shack. But not the surface mounts. I used them to keep it small inside and reduce the chance of things shorting out when it got crammed in. (plus had them in house) No prob using 'normal' resistors.
thank you very much, and nice job on the instructable.
Will this actually charge it to any ammount?
I would expect a 900-1000mAh charge from a single 9v battery due to an average 9v battery containing about 500mAh and since the voltage is being nearly cut in half, the milliamps are doubled. So that would mean a near complete charge for an ipod touch and about a 2/3 charge for an iphone.
Very good job!

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