This instructable details my efforts to make a simple solar battery charger made out of a playing card, some solettes, some magnets and super glue -- if anyone has ideas on how to make this simpler and more effective, please let me know in the comments.
No soldering is required for this project. It should take about 10-15 minutes.
First, check out this video. There are two playing-card solar projects detailed in here -- one for a AA charger, and another for an arduino charge card (described in more detail here: http://www.instructables.com/id/Solar-powered-arduino-on-the-back-of-a-playing-car/ )
p.s. Where can you get the small bits of solar cells -- the solettes -- needed for these Instructables? Well, it's a pain right now. You can track these puppies down from suppliers in China, but they aren't easy to pin down: http://manilamantis.wordpress.com/2012/04/25/the-dark-side-2/
So, to make this easier, my buddies and I are launching a Kickstarter campaign (Aug 15 - Sept 14) for all your solar DIY needs: http://www.kickstarter.com/projects/alex9000/the-solar-pocket-factory-an-invention-adventure Bangorang!
Step 1: Materials
++ Super glue (the thin stuff, also known as cyanoacrylate)
++ A couple playing cards
++ 4 NdFeB magnets between 1/4" - 1/2" diameter, 1/32" - 1/8" thick, any grade N42 - N52 (available lots of places, including www.kjmagnetics.com)
++ 4-8 solettes, depending on what type of additional indicators or dark-current blocking diodes you add to the basic charger
++ A few AA rechargeable batteries. This will work best with NiMH AA and AAA batteries, but can also work with NiCads (which are not the most environmentally benign battery in the world, so best to avoid buying these if you don't own them already)
++ [Optional] Schottky diode
++ [Optional] Indicator LED
++ [Optional] Rigid backing, like a scrap piece of 1/8" thick acrylic that's a big smaller than a playing card