Running low on iPhone battery when you are spending time outdoors is not ideal. The K-Tor Pocket Socket 2 is a hand crank charger that lets you charge your smartphone anywhere. Unlike solar or wind chargers, the Pocket Socket relies on your own power to generate electricity. You will have to go faster than 2 revs per second to start charging your phone.
The Pocket Socket s is available in a USB version too. Simply attach your phone, rotate the handle, and you are set. It is a good workout too. The above video shows how it works. Pocket Socket has a portable design, so you can easily take it anywhere.[HT]