Math Monday: Light Dimmer Knobs

3D Printing & Imaging Education Science
Math Monday: Light Dimmer Knobs

By George Hart for the Museum of Mathematics

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I believe that in the future, 3D printing machines will commonly be used to make household parts, e.g., when you need to fix a broken appliance knob or handle. I put this into practice recently when I needed a replacement light dimmer knob and decided to make my own. So, I created this knob based on a lovely polyhedron, the rhombic enneacontahedron. It works well and looks like a little geodesic igloo on the wall.

This is a great opportunity to incorporate some mathiness around the house, so I made a second design, based on the (7,6,6) uniform tiling in the hyperbolic plane. Notice there are both 6-sided and 7-sided craters. At each corner, one 7-sided and two 6-sided craters meet.

If you have access to a 3D printer, you can make your own copies of these mathematical dimmer switches using the stl files available here. They fit right on the shafts of standard US dimmer switches.

More:
See all of George Hart’s Math Monday columns

2 thoughts on “Math Monday: Light Dimmer Knobs

  1. Greg Hora says:

    I’ve always been curious about how these complex shapes are modeled in CAD. Are there scripts or “plug-ins” out there that allow you to make these shapes?

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

View more articles by Gareth Branwyn
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