You will merely require an old wheel of your bicycle for making your mini-windmill at home. Just ensure that the wheel you are selecting has perfectly adjusted spokes and does not wobble while spinning. However, the wobbling wheel will also serve the purpose of generating electricity but its side-to-side movements will result in wastage of mechanical energy, eventually hampering the spinning speed of the windmill.
You already know that every windmill needs to have blades so that wind can propel them to produce electricity. You have to prepare blades from used aluminium cans. This will also help you to recycle some aluminium as well!
Use scissors or a kitchen knife to cut the top and bottom sides of the can all the way round. You will get a hollow cylinder after you have done with the cutting. Now cut the vertical slice all the way up to open up the cylinder and making a rectangular aluminium sheet. You will need several such aluminium cans to make blades for your windmill.
Now take the aluminium sheet and mount it onto two adjacent spokes of the bicycle wheel. Wrap the aluminium sheet on two spokes and then crease it over tightly to form a blade. Make sure you have placed the blades closer to the rim.
Keep adjusting aluminium sheets on every two alternative spokes and you will get a complete circle of blades. Remember that all the blades you have installed much face the same direction for the windmill to work.
You are now required to build a mount for the windmill. You can build your own mounting structure out of metal rods or simply take an unused bicycle fork for this purpose. Just insert the wheel’s axle into the arms of the fork and tighten the nuts securely. Now take your windmill outside and see it spin.