Today I was asked by one of my many doctors offices for my cell phone number. I explained that my cell phone spends half of its life in my pocket with a dead battery and the other half of its life on a charger at home many miles from where I am. I further explained that I liked my phone better dead in my pocket because I keep a charger in my car so I can make calls whenever I want even though I can't receive calls. They gave up on the idea of getting my cell phone number.
Gee, wouldn't it be nice to have a self winding cell phone?
If you are a old enough you will remember a kind of primitive personal clock that was usually worn on the wrist or sometimes carried in a pocket. These personal clocks had "hands" and made a funny tick, tick, tick noise. These personal clocks were called "watches" (not to be confused with the iWatch). Believe it or not they could not take videos or access the web. Their only use was to keep track of the current time. These devices are so primitive that their use predates the invention of the steam engine. These primitive time keepers were replaced by the dumb cell phone and forgotten years before the advent of the smart phone.
These ancient personal clocks were, believe it or not, powered by kinetic energy derived from tension in a spring. To keep the watch working properly you had to recharge it daily by taking a few seconds to "wind" the spring using a knob on the side of the device.
People didn't like having to wind a watch any more than we like spending time charging cell phones. (Though I do have to wonder how many friendships and even romances have resulted from people clustering around public charging stations. Winding a watch was never a social occasion and was rarely done in public.)
Some early gear tech genius came up with a method to collect kinetic energy from arm motions and store it in the spring. This feature was called "self winding" and it kept your watch from stopping when it ran out of stored kinetic energy. A good self winding watch could run for years without ever running down!
It turns out that several individuals and groups have developed methods for adapting self winding gear tech for use with modern smart phones. They use the same type of kinetic energy trap and use it to charge a battery rather than adding tension to a spring. These systems have been developed and tested and they work.
So... why the hell can't I buy a self winding cell phone?