To build a windmill, determine the average wind speed in the area where the windmill is to be installed, get all material for the windmill ready, and build the sails. Connect the windmill to a generator to produce electricity as the blades spin.
A windmill works efficiently when it is exposed to winds of around seven to 10 miles per hour. Determine the average wind speed in the area, and check on local building codes for windmills. Take a sheet of plywood, cut it into eight to 10 sails and varnish the sails.
Cut out a circle of wood, divide it into eight equal sections with pencil lines and drill a small hole in the center of the circle. Draw a line across the width of the wooden disc along the circumference of the circle so that the pencil lines are visible on the unmarked side. Turn the circle over, mark eight lines approximately 1.5 centimeters to the right of each pencil line from the other side and join every opposite pair of marks. Draw a parallel line with each of these lines with a width a little larger than the width of the sails.
Use a saw to cut to a depth of approximately a third of the circle, along both slanting lines. Fit each sail into the cut out grooves, and fix them with wood glue or a small nail. Attach the windmill to a pole that can be driven into the ground, and connect it to a generator or to an alternating current motor and a battery bank.