Here is a upcoming device that has the potential to put out 20W of power by hand crank, the solar works great when the sun comes out but this gives you the same potential when there is no sun. It's the same power source for the $100 laptop (one laptop per child), so if it is what they say it will do, it should be less that $100 I'd assume or buy the laptop and take out the power supply.

One minute of Pulling on the cable gets you:
25 minutes of cell phone (talk time)
1 hour of LED lighting
Ipod Shuffle 230 minutes
Nintendo DS 45 minutes

Website:

http://potenco.com/index.html

Video Links:

http://www.olpcnews.com/hardware/power_supply/steve_cisler_potenco.html

http://www.youtube.com/watch?v=H2OWEAMLKBQ&mode=related&search=

Colin explained that they had done research on the best kind of string, using some new synthetic material, and as backup, there are two extra sets coiled inside the housing of the device. They have designed it so that it can be hacked. For instance, by removing the cover (top picture) it could be attached to a bicycle hub and generate more than 20 watts of power.

Interesting...

At first the idea of the pull string seems horrible and bound for failure, but it appears in the videos as if the load isn't too significant and the ability for self maintenance changed my mind on that.

In the first article linked it is stated that they hope to sell the generator for about $17.00, which is a great pricepoint for such an item if it can produce the kind of juice that they claim.

I was hoping to invent something that was easier to use than the typical hand crank generators by making them more ergonomic and maximizing potential while minimizing workload, but it looks like I was beaten to the punch. Bummer.

You can take their idea though and apply it to all kinds of various gear. I doubt they have a patent on the spool type generator.

The motion will cause repetitive injury in some even with minimal resistance.

True on both counts.

The Dynamo isn't the new technology just the "mechanism" to spin the dynamo, which isn't new itself except perhaps in its application.

There is certainly a risk for repetitive motion injuries, or repetitive stress injuries and that's one of the reasons I like the spooled dynamo. In the demonstration he pulls the cord once per second lightly. In comparison, I have a dynamo flashlight and in the documentation it suggests that the crank must be turned for 2 minutes at 80 revolutions per minute for an adequate charge. Granted, I don't know how much power I'm producing for the flashlight.

Even so, at the end of the two minutes of cranking, my arms and hands have a decent burn going. The motion isn't what I'd call natural because I'm not maximizing the potential of my muscles by fully extending and contracting them and probably burning more calories in the short jerky motions.

I could be wrong though, I'm not a doctor. It's all speculation from me.

It looks like it might have some potential. A lot of its utility depends on the details of the design. Like:

How rugged is it?

Will it withstand normal abuse, being dropped, exposure to sand, mud and water?
How long will the string, bearings and return spring last?
If the string breaks or wears through can it be replaced with commonly available materials and without tools?

I'm reminded of the much larger and heavier manual generator that was used to run radios in WW2 when other power sources were unavailable. A sturdy cylindrical body with legs and a two-sided crank like you see on a bicycle. Usually it is depicted as being cranked with the arms but it could be worked with the feet. Evidently it was very ruggedly constructed as it was used by remote and hostile locations world-wide.

Looks like a yo-yo. Too bad you couldn’t generate power and recharge an internal battery by playing yo-yo with it. Walking the dog would practically be free energy (almost).

Thanks for the link, this is my kind of thing!

No problem, I'm hoping they will start to produce this item, I think it would be a great must have for electronic devices.