Laser Vortex How To!

What is a laser vortex? In my opinion it's the most dramatic, coolest effect you make with no techie and/or fabrication skills for under $30 bucks. With the help of your fog machine it creates an almost ethereal cone shaped tunnel of swirling green (almost liquid like) fog. It's tough to describe, and impossible (for me anyway) to get a good picture of. The best example would be to imagine a creepy green wormhole, maybe like in Evil Dead II.

Regardless, EVERYONE that sees it will go "Cool!!" and stare until you tell them to move along.

So how to build one on the cheap that performs great? That was the challenge and after much error, and some trial I think I got it.

Before I jump in, I want to single out GoE member Pete for his help. Pete gave me some great advice on where to start for the main resistor value, and also was an tremendous help along the way offering tips/ideas as I went through the usual hoops of finding a decent module, trying different motors etc. And kudos to him for showing me the one he built, as seeing one live gave me the inspiration I needed to finally build my own.

In essence, it's a hell of a simple prop. Put a mirror on a motor attached at a slight angle, then shine a laser into it as it spins. It makes a cone, and you blow some fog into it. Done. Like any prop though, unless you have a good parts list you're going to end up like me - trying different motors, resistors, smoking a cheap laser module, etc. Your laser vortex will cost about $30. Mine... well not so much. But at least I can share now, and the extra bread will be worth it to see some members build and enjoy this prop. So really, this isn't so much a how-to (it's easy to build, trust me) it's more of what-not. As in, what not to buy.

Here's a pic of the vortex. It pretty much explains the whole thing.

You'll notice my vortex has a potentiometer with a tone knob I stole off some Fender guts I had lying around. Yours won't have that, but I did include the part number in case you want to add this for fine tuning the motor speed. Frankly, it's not needed.

Step 1!
This is (pinky promise) the only tricky part of the whole operation. First, grab a dime and the motor. Then get your soldering iron turned on set it aside to heat up. Take the motor and your trusty dremel (you're a haunter, you better have a dremel) and grind a slight angle into the gear using a sanding wheel attachment.

Refer to super fancy example pic:

As you can see, only a little angle is required. Bear in mind (read this part) this is the single most important step. The angle will dictate how wide the cone is over a distance. A small angle will make a tight cone, say 4 feet diameter at 20 feet. A deep angle will make a large cone, say 10' diameter at 20'. And a little difference in angle makes a big difference in size. Start small You can redo this later. About 10 degrees will make about a 8 foot wide cone at 20'.

Once the angle is ground into the pinion gear, it's time for the part where your burn your fingers. At least I did. Thrice.

Put the dime down on some scrap lumber you don't care about. Then get your soldering iron, tin the tip with some solder, and heat that dime up in the center. Might take a bit as we want it HOT. Wait until the solder is freely flowing from the tip to the dime. Now run a little blob of solder into the center of the dime, then grab your motor and with the solder still molten and pooled place the angled (the ground down bit) gear dead center of the dime. You should keep applying heat to the dime/gear, whatever it takes to re-liquefy the solder and then hold that motor down on the dime, maintaining the small angle of the dime on the gear. Let it cool while holding it still and dead center, then once the solder sets you can pick it up and let it cool some more.

You'll notice now that the dime ain't going anywhere, it's darn near welded on and it's at a nice slight angle on it.

Refer to some pics from our last drink and think for action shots of members doing this step, and the finished bit:

Now then, get some of the our super bond double sided tape, and cut a square about 1"x1". Apply dead center of the cooled dime, and keep the backing on. Trim it with an exacto knife, then put it aside. Grab a mirror, if you used my link they come with the handle attached. Put the handle in a vise, and work the mirror side to side to break the tiny spot welds holding the mirror to the handle. Then grind down the raised bits were it was tacked.

Now, attach mirror to motor. And guess what? We're almost done.

Get what you're using for a base. Now make a couple mounting blocks like you see in my pic. For reference I used 5/8" particle board. Dry wall screw the mounting blocks onto the base like in the pic. One screw about dead center for the motor block, you'll want the adjustability later. The get a little double sided tape and stick the motor on, then the same for the battery holders and switch. We'll stick on the laser after it's wired up because we need to make sure it's aligned.

Now then. Let's wire this puppy!

Grab the soldering iron and some hook up wire and make this (you'll notice I used a professional schematic program for this).

As a side note we added a capacitor to this design later, which is wired parallel with the resistor. This serves to help "kick start" the motor, as without it you may need to give it a little nudge to get spinning. It's not needed, but a nice addition.

Once you have it all wired up throw the switch, and line up the laser and mirror. Make a pencil mark where you want the laser to be and then stick it on. That's it!

ADDENDUM: See the heat sink on mine? It's a buck, buy one. It makes the laser much happier when running for extended periods of time. I used some needle nose pliers to twist off the aluminum posts to make a "tunnel" for the heat sink to sit in. My dremel then smoothed it out, and I bent the posts adjacent to the module to snug in there real good and create as much module to heat sink contact as possible. This has mad my module a happy module. I advise you do the same.

Parts list:

(1) 5mw green laser module $22 with shipping (approx)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160341334481
Note: there are similar modules out there at about the same price. Not all are same! Some in fact, suck quite a bit. These guys have the good stuff, and ship super fast.

(2) D cell battery holders ($1.75 per)
http://www.allelectronics.com/make-a-store/item/BH-142/BATTERY-HOLDER-2-D-CELLS/-/1.html

(1) Double pole, double throw knife switch

(1) Dental mirror ($1.00)
http://www.allelectronics.com/make-a-store/item/DMR-4/23MM-FRONT-SURFACE-DENTAL-MIRROR-AS-IS/1.html

(1) Heat Sink ($1.20)
http://www.allelectronics.com/make-a-store/item/HS-150/BLACK-ANODIZED-HEATSINK-54-X-47-X-20MM/1.html

(1) Dime ($0.10)

(1) 3Vdc motor ($3.50)
http://www.radioshack.com/product/index.jsp?productId=2102828

(1) 10ohm 10Watt resistor ($2.00)
http://www.radioshack.com/product/index.jsp?productId=2062290

(1) Roll Super Duty Scotch Exterior mounting tape ($5.00) < - this stuff is great, my new favorite product
Home Depot

Misc:
Lumber bits for base and mounting points (your scrap pile)
Stranded hook up wire 20g (Radio Shack)

Optional
5k Ohm linear taper potentiometer ($3.00)
http://www.radioshack.com/product/index.jsp?productId=2102789