mouldy.org

Here's yet another way to build a battery-powered USB port. You can use it to charge your iPod or phone or lights or whatever. It should last about ten times as long as designs based on 9V batteries.

It's based around my favourite batteries of all time, AA NiMH cells. They're cheap, rechargeable, and perfectly suited to this project. I used this cable to keep my iPod charged on a bicycle tour of Victoria last year.