$100 laptop ditches hand crank
The One Laptop per Child project appears to have settled on a means to power its budget laptop for developing nations. Early prototypes of the system included a hand crank, but that design has now been replaced by a pull string.
The new generators, which will be field-tested beginning this October, abandon the bulky and inefficient hand-crank design featured on an early mock-up of the laptop in favor of a more compact off-laptop design that uses a pull string to spin a small generator. It was developed by Squid Labs, Emeryville, CA, a design and engineering group whose co-founders include several graduates of MIT's Media Lab, where the laptop project originated.
According to one of the pull string generator's designers, users can comfortably generate 20 watts, and sustain 10 watts for "as long as [they] want." That's a significant improvement over the hand crank, which reportedly requires more effort to generate just five watts. The string pull generator also varies resistance based on user strength, allowing it to make the most of each tug.
With a projected cost of less than $10 per unit, the string pull generator seems like a reasonable solution for the $100 laptop project. Heck, I can imagine that a few road warriors in the developed world wouldn't mind having a pull string to recharge their mobile devices.