The reflector module is really a simple concept but it can be a bit difficult to construct. Its job is to reflect the laser beam at an angle that constantly changes to make a circular pattern. This is accomplished by placing a mirror at an angle on the shaft of a small electric motor. As the motor turns, the angle is changed making a circular pattern.

In a foggy room, we can see the pattern as a cone from the striking point of the laser on the rotating mirror outward. With a dense wispy fog created by a small fog machine, the vortex affect we desire is created by reflecting more of the concentrated laser light off of the denser areas of fog.

This how-to should show you how to make a cheap reflector for your laser vortex relatively easy. It should also give some ideas on improving your design if you want to put in some extra effort.

Mounting the mirror to the shaft of the motor can be a perplexing problem. I was told to try a hobby shop for the simple pre-made piece so it would be easy to build but this may not be easy for everyone to find. Here is a design that should be easy for most everyone to find parts to make and do. (The attached fan blade could be used but the blades would need to be cut away. These blades would create wind causing the fog to dissipate along with the vortex affect.)

Find a metal bottle cap in good shape, the twist offs from beer bottles are perfect because most twist off caps are removed without damage to the cap. Use a nail no larger than the shaft of the motor to punch a hole in the center of the cap. Using a nail as a punch rather than a small drill bit will give us some added grip on the motor shaft that we could not get with a clean drilled  hole.

We will be mounting a one inch round mirror at an angle in the cap. This is a small angle but sufficient for creating the vortex. The mirrors can be found in the craft department of most stores such as Mal-Mart or at a craft store. They usually come in packages of 10 or 20 for less than two dollars. 

Three notches will be bent on the cap to hold the mirror securely in the cap and at an angle. Two of the notches need to be bent as close to the edge of the cap rim as possible so the mirror can extrude as far as the cap will allow. A small piece of foam is used to prop the mirror up from this point where the 2 shallow notches are. The one used here was part of a foam packing peanut.

Once the notches are made and the foam is in place to prop the mirror, the mirror is placed in the cap and the final bend is made to secure it at its angle. Be cautious not break the mirror while doing this.

Mount the cap on the motor using the hole punched earlier. This should be a tight fit holding it securely but the metal bent out from punching the hole can be used to make a tighter fit if needed. Using an adhesive such as super glue could also help secure the cap on the shaft if needed.

These small motors are usually powered by two AA batteries, 1.5 volts each for a total of 3 volts. No where near the full speed of this motor is needed so we will be using one AA giving it 1.5 volts. If you know how to reduce the voltage down further it is recommended so vibration of the unbalanced cap in the motor is reduced along with noise but this how-to will not be going into that much detail.
 

Once the electrical connections are made you will likely see why we don't want it to spin so fast. These cheap motors are fast and loud especially when they have not been loaded down with a larger object to move.

Break out your laser and point it at the spinning mirror. The reflected beam should create a circle rather than a point. In low light, point a small fog machine so the dense fog passes across the path of the reflected laser beam and you should have your vortex

You will find the vortex will look different depending on where you position the fog machine and angle of the laser. Play around with the positions and see what you get. You will notice that if you allow the room to fill with hazy fog, the affect will be less and less. The affect is created by laser light reflecting off the dense wisps of fog passing through the beam in some areas but not visible where there is no fog to reflect off of. A hazy room will just create a hazy cone shape at best. If this happens, its time to air out the room to get your affect back.

I recommend watching the video if you can. It contains some ideas for other more suitable motors that could be used. A higher voltage DC motor could also be purchased at your local Radio Shack, electrical store or hobby shop. Using a higher voltage motor and placing a lower voltage on it is a good way to reduce the speed for smoother operation.

I would love to see and post images or video of your vortex, so feel free to email them to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

My next article on this will cover tips for positioning the fog machine and showing off the final produced vortex.

Some Good Information From Part One

Lasers to use

Lasers used in the past were red key chain pointers or parts pulled from laser levels. A darkened room or low light area was needed with a red laser for the vortex to be seen but still nice for Halloween night. Red laser pointers are less visible but will work fine. You can find them in an office supply store and most department stores if you buy one locally. These are some stores that carry them online for reasonable prices.

• Discounttown
• Things You Never Knew Existed...And other items you can't POSSIBLY live without!
• ThinkGeek.com

The green laser pointer used this year is much more visible and still under 5mW output power because the human eye can see the color green much better than red. With a green laser, the vortex is visible in a normally light room. These green laser pointers can be used to point out stars in the dark night sky because you can actually see the beam reflecting off particles in the air. Green is most visible but more expensive. You can usually get a green <5mW laser pointer on eBay for around $20 to $30 shipped from these eBay

The laser vortex uses fog produced by a fog machine to make the dispersed laser beam visible. The wispy slow moving fog best provided by a low output fog machine (such as the small the one on sale for $19.99 with fog juice and about $6 shipping as of October 2006 from MusiciansFriend.com ) gives the best affect. Every angle of the laser and direction the fog machine is pointed gives a different affect. Larger fog machines will actually reduce the affect. Diffusers (misters or mist makers) can create a different affect but mostly you’ll just get everything wet from all the water particles. 

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Related Items:

• Laser Vortex in MAKE Magazine Halloween
• Making the Most of Your Haunt
• Glowing Sky Orb LED Mod
• Laser Vortex Performance Tips/Tricks
• Laser Vortex Project Part One

Related Links:

• American Science & Surplus