A team from University of Texas, Arlington have developed a micro-windmill that generates wind energy and may become a solution for mobile devices like cell phones whose batteries drain quickly under heavy use. Smitha Rao and J.C. Chiao designed and built the devices that measure only about 1.8 mm at the widest point. They explained that to give you a sense of scale that you could fit ten of these tiny windmills onto a single grain of rice. Wind could power the charging by waiving the device in the air, placing it in front of a fan, holding it up to an open window, or in the direction of the wind travel when outdoors.
They also hope to port the technology to larger, yet still tiny in comparison to large outdoor windmills to supplement home energy use. Rao’s design combines origami practices into conventional wafer-scale semiconductor layouts so complex that 3D moveable mechanical structures can be assembled by commercially available electroplating techniques. The micro-windmills were first tested successfully in September 2013. The micro-windmills performed successfully under artificial windows without any bending or fracture of the material due to utilization of durable nickel alloy and intelligent aerodynamic design.
http://www.hardware-360.com/micro-windmills-can-charge-your-mobile-devices/