YES, you can build a very small wind generator
, and its simple.
Simple does not mean easy tho.
Any permanent magnet DC motor
can be used to generate electricity. A small one, like from a remote
control car or toy could be used. In Canada
we have a store called Princess Auto where these can be purchased pretty cheap
Next, you need some fan blades. Plastic window blinds work well.
Now just some way to mount the blades, and connect to the motor
. Maybe playdoh?
Any voltage over 13 will charge a 12volt battery
. The current
will be so low that you won't need a voltage regulator
However, its a lot of work for a little power, when, like another poster said, you could just buy a small solar panel. Still, would be a cool project
. Maybe get your kids
to build one for science fair.