Building a simple electric generator at home involves building a frame on which to mount a magnet suspended on a steel bar. Insert the magnet and steel bar into cardboard tubing wrapped with copper wire and mount it in the frame. Leave both ends of the wire loose and attach them to a flashlight bulb or small lamp. Spin the steel bar quickly to produce enough voltage to power the bulb or lamp.
The generator's frame should be in the shape of a U. Cut wood into two 6-inch pieces and one 12-inch piece. Nail the 6-inch pieces to the sides of the 12-inch piece. Drill a 1/4-inch hole in the center of both of the 6-inch pieces and ensure that they are aligned. Drill a 1/4-inch hole through the middle of a bar magnet's longest side. Place a metal shaft through one of the holes in the boards and slide the bar magnet onto the shaft.
The cardboard tube should be at least 4 inches in length and wide enough to fit around the bar magnet with enough clearance for the magnet to spin. When wrapping the copper wire around the tube, leave 16 to 18 inches loose. To increase the amount of power the generator puts off, wind more wire around the tube. Add legs to the tube in order to keep it stable while it generates power.
Glue the magnet to the shaft with hot glue or epoxy, and once dry, put the shaft through the tube and place the other end of the shaft through the other hole in the frame. Use the same adhesive materials to glue a washer on the outside of the frame around the area where the shaft was inserted. Attach the item to be powered and spin the shaft.