How to make a revolving light

Written by richard gaughan | 13/05/2017
How to make a revolving light
Building a lighthouse beacon is quite a job, but a smaller rotating light can be a home project. (beacon on lighthouse image by jimcox40 from

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.

How to make a revolving light
A torch mirror is a reasonable choice for a good, light reflector for a rotating beam assembly. (flashlight image by Maciej Mamro from

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.

How to make a revolving light
A small DC motor with an appropriate drive speed will make an attractive rotating beam. (motor.jpg image by Aussiebloke from

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.

How to make a revolving light
Even a small torch bulb can be visible for long distances at night. (light bulb image by Edsweb from

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.


Although a full reflector works, a truncated reflector (with "slices" taken from the top and bottom) lets the lens be positioned closer to the centre of the reflector without interfering with the rotation. Although there is a certain joy to constructing homemade assemblies, rotating beams ranging from those suitable for limited indoor use to assemblies rugged enough for continuous outdoor use are commercially available.


Make sure the motor torque rating will handle the load of the reflector and lens, if used.

Things you need

  • Three-Watt flashlight bulb
  • Bulb socket, screw-in or push-in
  • Truncated flashlight reflector
  • Large gear, 2.5 to 5 cm (1 inch to 2 inch) diameter
  • DC motor with geared driveshaft
  • Power supply for bulb and motor
  • Optional lens
  • Optional filter

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