Before Stargate SG1 there was MacGyver for Richard Dean Anderson and in this show, he could build almost anything from stuff that was just lying around. In the same spirit Instructable user The King of Random, has come up with this brilliant human powered charger for Smartphone batteries, its ideal for those emergency situations when the power is down and you need to make that important phone call in order to save the day.
These are the tools that you need;
A cordless drill
Anything you can find to help secure it in place and spin it by hand.
These are the materials required;
A piece of wood 2″ x 4″
1 mixing beater
1 salad fork
A piece of aluminium foil
Some Scotch tape
There is no price for this just a few materials and your time.