10 years ago I found this hand cranked radio in the discount bin of a
Radio Shack just after the Y2K hype was settling down. Most hand
powered devices use a small dynamo that charges an even smaller battery
that will eventually stop holding a charge over time. This unit uses a
medium sized spring that slowly releases its mechanical power after the
energy is stored in the form of hand cranks. It will hold up to 40
cranks, which equals about 20 minutes of power.
The radio is very basic and also works on a little solar cell that is embedded in the top, but only if you place it directly in the sun. I like to have it on hand as a back up power source and someday dream of building a larger version that might be more capable of powering something like our modem and router and maybe a laptop or two. It only produces enough electricity for a small flashlight, which can be considered night time entertainment during a power outage.