MATERIALS
To design this mechanism, I embraced the concept of bricolage, or designing and building with whatever materials are available. Thus, before considering any design ideas, I searched my house for materials that could be useful. I knew that I would need gears to produce an appropriate fan speed. I found two sets of gears in a manual lawnmower (Fig. 1), various gears in our Roomba, and gears from an extra bike cassette. I also found PVC pipes, dowels, and scrap wood l that I could use to build a linkage mechanism and supporting structure. I also needed to fashion joints for gears and linkages to spin smoothly. I decided I could use nuts and bolts as revolute joints, although the movement would be less smooth than using shafts and bearings. I did not have properly-sized shafts my gears. To solve this problem, I wrapped dowels in duct tape to fit them into lawnmower gears and used small nails for the Roomba gears.
