************************************************************************** * * * * * * * Make Your Own Laser Light Shows * * * * * * Written by: The Professor * * * * 07/91 * *------------------------------------------------------------------------* * SOURCES: * * * The Laser Cookbook (88 Practical Projects), Gordon McComb, * * Tab Books. 1988 * * * * * Midwest Laser Products, PO Box 2187, Bridgeview, IL 60455 * * (708) 460-9595 Ask for free catalog. Great prices on * * laser equipment! * * * * * ************************************************************************** I.) FOREWORD This file has been written based on my experiences with homemade laser light shows. I have used Helium Neon lasers to create an array of light show effects. For those of you who are not aware, Helium Neon lasers come in many sizes from 1/2 milliwatt to 40 milliwatt output power. They produce an INTENSE beam of light usually visible for at least a MILE! I can see the spot produced by my 1.4 milliwatt HeNe laser on the water tower 8 blocks from my house! The beam from a HeNe laser is usually red (633 nanometer wavelength.) They do come in other colors but are very expensive and usually on the low power scale. A good 1-2 milliwatt HeNe laser can be purchased mail-order for under $100 (See Sources,just under the title.) II.) INTRODUCTION When light travels through space it is un-seen, only when it reflects off of an object or particle can it be seen. What does this mean? Well, the beam of light produced from any laser is invisible as it travels through the air unless the laser is of considerable power, like 40 milliwatts(mW). Why does it take such power? In order for the beam of light to be seen, the photons of light must be reflected off of any of the tiny particles in the air to reach your eye. Only the higher power lasers emit enough light energy (number of photons) to create a sufficient amount of reflection off of the particles. This fact allows us to categorize light shows into two different types of effects: 1) Beam Effects 2) Projection Effects. III.) BEAM EFFECTS Beam effects are cool! Beam effects are those effects where the actual beam of light is seen. These are usually done by using a fog-machine. This permits these effects to be done with any 1/2 mW or greater laser. Usually the entire room where the audience sits is filled with a light fog (or cigarette smoke) with dim or no lighting. This creates a good medium for beam effects! The Cone The cone effect creates a cone of light floating in the air. This effect can remain stationary or be scanned slowly through the air. This effect is most easily created by taking a small dc hobby motor and mounting a mirror perpendicular to its shaft like so: ----------------- | [ ] |____[ ] | [ ] | [ ] ----------------- mirror^ ^motor^ How do you mount a mirror onto a motor in that fashion? Got a penny? That, a small drill bit and a little glue is all it takes. Use a drill bit slightly smaller than the shaft of the motor and drill a hole in the center (in the middle column of the Lincoln Memorial) of the penny. Note, newer pennies are softer and easier to drill. Now fit the shaft into the hole. Make sure the shaft does not stick out on the other end, a snug fit is required. Use a drop of super glue to keep them stuck together. Now you are ready to mount the mirror. Find a small, thin piece of mirror about 1/2 inch square. If you don't have a piece of mirror that small use a glass cutter to cut the mirror or just break it and look for a nice piece. The figure of 1/2 inch square is just an approximation and the mirror does not have to be perfectly square. Use some thick glue like silicon, RTV gasket sealant, Shoe Goo, or whatever. Apply it to the back of the mirror and stick the mirror onto the penny. Allow it to dry for awhile. Now you are set! Power the motor with a small dc power supply, batteries, train- set power pack, whatever, and shine the laser into the mirror. The reflected beam will scan a perfect circle that gets larger and larger the further out it goes. To observe the cone effect fill the room with smoke or fog. Set the motor across the room and aim the laser into it so that the cone appears right over your couch or chair. Grab a seat and enjoy! How does this work? Well, when the mirror was mounted to the motor it was mounted so that the mirror 'warbled' a little bit. It was slightly off-axis. It is nearly impossible to mount it perfectly on-axis; also the bearings (or sleeve) that holds the shaft will have play in it allowing the mirror to 'warble'. The more off-axis the mirror is, the faster the cone will expand. The Sheet or Artificial Wall/Ceiling Effect This effect can be created in several ways. One way is to use a cylindrical lens. The lens expands the beam in only one direction. The arc of light is then shined through the smoke or fog. This creates the effect of an artificial ceiling, or sheet of light. Move the laser or lens around to create a moving sheet of light. Best effects are when the sheet goes above and below the audiences eyes, or just over the ground. If you do not have a cylindrical lens you can create this effect using a dc hobby motor again. This time the mirror must be mounted so that it rotates around with the shaft (reflective surface parallel with the shaft.) This requires that the mirror be glued to the length of the shaft. Use strong glue that will fill gaps (Super Glue probably would not be a good choice.) Now shine the laser into the mirror and notice that the beam scans a line. If you were to slow down the motor, you'd see that the beam is not reflected for half the period of rotation (That is, when the beam strikes the back of the mirror.) When the beam hits the reflective part of the mirror it is reflected outward in an arc. Unfortunately this reduces the power of the beam as it is scanned. Laser Beams Everywhere This effect creates many laser beams moving around in the air all coming from one location.This effect is really cool! What you do is get 3 mirrors like the 1 foot square ones sold at all building supply stores. Place them next to each other like the corner of a room. One is like the floor and the other two mirrors are like walls. Now place a small clear crystal ball in the corner of the mirrors. The crystal ball must be a multi-facet ball, shaped like a 20 (or more) sided die. They can be found in crystal shops and some department stores among other places at the mall. You may even find something similar hanging on a chandelier or lamp at home or a friends house. Now, the laser is aimed into the crystal ball. What happens? Well, when the laser beam goes into the crystal it gets refracted and reflected and comes out as several beams of light. Some of these beams will get reflected by the mirrors back into the crystal to create even more beams of light. The others will shine out across the room. They will all appear to be coming from the crystal ball. I like to hold the laser while shining it into the crystal that way I can move it around a bit and make the beams change and move around in the air. Once again since this is a beam effect it requires a dim, smoke or fog filled room. The thicker the smoke or fog the better. Well, that's it for the beam effects. If you have difficulty creating the proper medium for beam effects try simply blowing smoke near the particular 'effect generator' to get an idea of how it will look. The effect will look even better in the entire room. IV.) PROJECTION EFFECTS These effects are created by scanning the beam rapidly in random or predetermined patterns to create images projected onto a wall or ceiling. If you have ever been to a laser show where they show the world rotating, or Mickey Mouse, or some other animation these are examples of projection effects. Doing these effects requires some expensive scanning equipment like galvanometers, galvo drivers, a computer, and some other hardware. These systems range in price from about seven thousand on up. A guy at Midwest Laser Products says they will have a sophisticated laser light show using an Amiga computer (because of its audio outputs) for around $2900. There are several other ways to create cool projection effects. I will start with the simplest. Mirror on Speaker For this effect take an old speaker and glue a small mirror on the front of the cone. Play music through the speaker so that the mirror vibrates. Shine your laser into it and have it reflect the beam onto the wall or ceiling. You will see a bunch of random patterns pulsating to the bass of the music. I have found that a great way to view this effect is by placing a mirror (at least 2 feet by 2 feet in size) against the wall of a room at a corner of the room; not necessarily next to the floor or ceiling, just at the edge of two walls. Now position the reflected beam from the speaker so that it is in the corner of the wall next to the mirror. When music is played into the speaker the random pattern that is created is now symmetrical on each side of the corner. With this set-up people have claimed to see butterflies, bats, upside-down bunny rabbits, etc.This type of effect is great with music like Pink Floyd. Try all sorts of music. Music with only single notes played create cool patterns. Experiment! The Spirograph Remember how the cone was produced? Well using several dc hobby motors (2 is enough) you can create all sorts of spirograph type patterns including a perfect 5 point star. To make the spirograph generator make two motor/mirror assemblies as described in The Cone at the beginning of this text. This time you must use two variable dc power supplies, one to power each motor. Mount the motors onto a piece of wood. I used electrical conduit holders to hold the motors in place. Mount them so that the beam can be aimed into one of the mirrors and reflected onto the other and then out to a wall or ceiling. The mirrors should be close to each other (within about an inch.) The arrangement may look like this: mirror ----------- / | / mirror _|/ laser beam out. | | laser beam in. Now shine the laser into the mirrors as shown above and vary the speeds and directions of the motors. Cool huh?! It is possible to get a perfect five point star! I like to take this apparatus and shine the output pattern on a mirror about 2" by 1 1/2" mounted onto a speaker. Make it so that the whole pattern fits on the mirror. Now reflect this onto the ceiling or wall and turn up some music slowly. The patterns will distort and 'dance' to the music! Another fun thing to do with this is to use some optics to reduce the size of the image so that it can be projected onto distant objects at night. Like on the side of a building. Lumia Effects Lumia effects are created using a piece of shower door glass (or plastic) or the plastic covers over fluorescent lighting fixtures. The laser beam is shined through this material to create cloud and fibrous type patterns on the wall. It can also be used to distort images or as an awesome background. I like to move the laser slowly as it is shined through the material this will make the clouds or fibers appear to flow. V.) CONCLUDING REMARKS All laser light effects are best with music. Play around with different types of music to see what creates the best effect. There are many other ways of creating laser light effects and many variations of the effects mentioned here, EXPERIMENT. Laser light spreads out as it travels. Beam spread is usually measured in milliradians. A typical HeNe laser will have a beam spread of 1.5 mRad. As a rule of thumb this is about 1.5 millimeters spread to each meter traveled. Hence at 100 meters the beam will be about 150mm wide which is just under 6 inches in diameter. Using this formula you can calculate your beam diameter at different distances. Another thing to remember is that the mirrors that you find around the house and in the stores are rear-surface reflective mirrors. The light is reflected off of the rear-surface of the mirror. The problem with these is that the front surface of the glass will also reflect a slight portion of the beam at a slightly offset angle. This will create a thicker looking beam which is usually undesirable. To avoid this you can use front-surface mirrors. These mirrors are generally more costly and difficult to clean. Lasers are a lot of fun at college! I use to shine one out my dorm-room window onto the sidewalk at night. You should have seen the crazy way people reacted when they saw this little red dot 'walking' down the sidewalk. Me and some buddies use to shine it at the girls walking home from parties(when we weren't out) and shout to them that it was a breast enlarger. Many of them would go wild and damn near flash their tits, several of them came up to my room that night! It was great. Lasers are great. College is great. Another fun trick is to shine the laser on the ground near a cat or dog...just watch 'em try to catch it! ------------------------------------------------------------------------- The Professor. 'Knowledge is power.' [RECENT] Command: Type X-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-X Another file downloaded from: NIRVANAnet(tm) &TOTSE 510/935-5845 Walnut Creek, CA Taipan Enigma Burn This Flag 408/363-9766 San Jose, CA Zardoz realitycheck 415/666-0339 San Francisco, CA Poindexter Fortran Governed Anarchy 510/226-6656 Fremont, CA Eightball New Dork Sublime 805/823-1346 Tehachapi, CA Biffnix Lies Unlimited 801/278-2699 Salt Lake City, UT Mick Freen Atomic Books 410/669-4179 Baltimore, MD Baywolf Sea of Noise 203/886-1441 Norwich, CT Mr. Noise The Dojo 713/997-6351 Pearland, TX Yojimbo Frayed Ends of Sanity 503/965-6747 Cloverdale, OR Flatline The Ether Room 510/228-1146 Martinez, CA Tiny Little Super Guy Hacker Heaven 860/456-9266 Lebanon, CT The Visionary The Shaven Yak 510/672-6570 Clayton, CA Magic Man El Observador 408/372-9054 Salinas, CA El Observador Cool Beans! 415/648-7865 San Francisco, CA G.A. Ellsworth DUSK Til Dawn 604/746-5383 Cowichan Bay, BC Cyber Trollis The Great Abyss 510/482-5813 Oakland, CA Keymaster "Raw Data for Raw Nerves" X-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-X