World S Smallest Windmills To Power Cell Phones
The micro-windmills (technically called horizontal axis wind turbines) have a three-bladed rotor 1.8 mm in diameter mounted on a tower about 2 mm tall. The mount is a friction hub, but this probably becomes an air bearing when the rotor is spinning. The thickness of the windmills is about 100 microns. Despite their size, the micro-windmills can endure strong winds, owing to being constructed of a tough nickel alloy (rather than the silicon and silicon oxide layers typical of MEMS designs) and smart aerodynamic design....