Battery-based USB chargers are pretty cheap, but it's always cheaper and more fun to make your own. The basic concept is a battery that powers a USB port so that you can juice up your gadgets.
You'll only need a few components in order to make your own battery-powered USB charger. As with all builds involving electricity, you'll need some knowledge of electronics. This is needed as you don't want to fry your devices in the process. You'll need a basic 9V battery, so make sure that you have the right connectors. You'll need a female USB port that you can salvage off an old computer.
Putting this together is extremely simple. All you need is to setup the wires as shown in the diagram and solder it. It's pretty straightforward. The positive lead from the battery goes to the regulator's left leg, and the regulated 5V goes from its right leg to the left pin of USB port. The ground wire goes from the battery to the middle leg of the regulator, then continues onto the right pin of the USB port. A glue gun will do wonders in sticking it into some kind of casing. It's quite compact and easy to carry around.
It's good to note that not all devices will be able to get a charge from this setup. There are some inherent limitations, including the ones that are put in by the manufacturers of your devices, but this shouldn't discourage your from trying out this simple and effective way of charging up your gadgets by using a few dollars worth of equipment. Possible improvements include using a larger array of batteries, like 5 D batteries.
[via Anythingbutipod, photos by Andreas Ødegård]
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