How to make a revolving light
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Whether making your own lighthouse or creating the perfect atmosphere for that 1980s disco party, a revolving light might be just the thing. Building a 1000-watt beacon visible to ships at sea for miles around may not be a reasonable target, but a tabletop rotating beam can be built from inexpensive parts.
No matter the size, it's usually most efficient to have the light source stationary and rotate a mirror, a lens, or both, to create the rotation.
Mount the socket on a fixed post and position the gear around the fixed post. The socket can be bonded on a machine screw or bolt, attached to a wooden dowel or friction fit inside a plastic dowel. Simply slip the gear over the mounting post.
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Mount the truncated reflector vertically, attached to the large diameter gear, pointing towards the axis of the gear. The finished assembly should have the bulb socket at the vertical centre of the reflector and the open side of the reflector should be facing the bulb. The reflector can be screwed into an angle bracket, bolted into a bent piece of sheet metal or even screwed into a wooden block.
- Whether making your own lighthouse or creating the perfect atmosphere for that 1980s disco party, a revolving light might be just the thing.
- The socket can be bonded on a machine screw or bolt, attached to a wooden dowel or friction fit inside a plastic dowel.
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Mount the DC motor so that its gear interlocks with the reflector-mounted gear. Some DC motors have built-in tapped holes for mounting or use an appropriate motor mounting bracket.
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Insert a bulb in the socket on the mounting post assembled in Step 1.
Connect the wires from the bulb socket and the DC motor to the terminals on the power supply.
If a more focused beam is needed, mount a lens to the gear, opposite the reflector. If a coloured beam is wanted, a gelatin filter can also be mounted opposite the reflector. The mount can be plastic, sheet metal, wood and the lens can be mounted with a retaining ring, mounting clips or adhesive.
- Mount the DC motor so that its gear interlocks with the reflector-mounted gear.
- If a coloured beam is wanted, a gelatin filter can also be mounted opposite the reflector.
First published in 1998, Richard Gaughan has contributed to publications such as "Photonics Spectra," "The Scientist" and other magazines. He is the author of "Accidental Genius: The World's Greatest By-Chance Discoveries." Gaughan holds a Bachelor of Science in physics from the University of Chicago.