As cellphones become increasingly important tools for communication in the developing world, innovators are finding ways to allow users to charge their phones even when they're far away from the power grid. Students at the Institute for Information Technology in Delhi, India, have designed a wind-powered micro turbine to allow mobile phone users to charge their phones with wind power. The turbine, still a laboratory prototype, produces under four watts of power, and is small enough to fit in a pocket. Despite its small size, it's sufficiently powerful to recharge a mobile phone, especially if the user is located in a coastal area with regular wind power. Students hope to make the product available for under 200 rupees, about $5 US dollars. (via Gizmodo.)
Slightly more expensive, but now commercially available is the Sidewinder cellphone charger, which uses a small hand crank to power cellphones. At $25, the product appears to be designed for travelling executives, not developing world users, but the concept could be adopted by developing world engineers and customized for local needs. Motorola is offering a similar product, Free Charge, designed in collaboration with FreePlay, well known for their work making wind-up radios and flashlights. Unfortunately, Free Charge will set you back at least $70, making it unlikely to have a major impact for developing world users.