Instructables user [Dustyn] recently constructed a wind-based
lantern to provide a bit of free, renewable light in urban
settings. The project is based around a vertical-axis wind
turbine, which she says are better suited to these environments
since wind often comes from all different directions. Despite
their lower efficiency compared their horizontal-axis brethren,
this style of turbine seems to fit her needs quite well. She
provided a complete bill of materials, down to the last screw
and washer you would need to replicate her work. The wind sails
were constructed from thin aluminum flashing, and inserted
between two acrylic sheets. These were then mounted to the
central aluminum shaft of the turbine, which drives the stepper
motor built into the base. The current from the stepper motor is
rectified and run through a pair of capacitors before being used
to light the attached LED. This allows the bipolar motor to
provide current regardless of the direction the turbine is
turning, and the caps smooth things