I love my iPhone 4 to death. I really do. Even if it sucks juice faster than a 1st grader at snack time and I often find myself on low power with a long train ride ahead of me.
I originally made my Altoids USB Charger to use with my iPhone, only to find that Apple being Apple doesn't let it's products play nice with generic USB chargers. I then set out on a long journey to find a cheap charger that would work with an iPhone 4. After sacrificing many a cheap Chinese charger to my garbage can I eventually found a great little circuit with the added bonus of having a retractable cable.
It's a cheap and easy project to put together and a great gift to give.
(If you want a USB version of this kit, I have an Instructable for that. I also published a Heavy Duty USB Version as well which is a beast; for people who need a lot of power on the go.)
Time: 30-60 minutes
Cost: Under $20
Step 1: What You Need
2x AA Battery Holder
2x Rechargeable Batteries
1N914 Blocking Diode
Solar Cell greater than 4V
Hot Glue Gun
If you're interested in this project I have kits available on my website, browndoggadgets.com, that have everything you need to make the charger. If you're not one for making things I sell premade chargers as well.
More than 12% of all profits go to dog and kitty toys. You wouldn't make a kitty cry, would you?