Ever since I saw Star Wars as a small boy I wanted to build a light saber. Decades later, I've crossed it off my bucket list. This instructable will show you how to make your very own laser sword/light saber using a laser array, an electronic cigarette, a couple of fans, a switch, and a 3D printed enclosure. It's mostly harmless and looks amazing, especially at night. Unlike the usual bright-lights-in-a-tube light saber, this one can be plunged into things, blazes dynamically and has the weightless blade you expect from a real light saber.
The idea is a simple one, and was born when I cycled home one frosty night. While waiting for the lights I exhaled right down the axis of my 2000 lumen LED bike light, and a brilliant white beam lanced across the road. By the time I'd got home I'd hatched a plan to make a laser sword. The principal idea was that if I focused some laser beams as a plume of vapor dispersed, the light output would be roughly stable up to the focal point, beyond which both the beams and the smoke would BOTH be dispersing rapidly and therefore vanish, giving the beam a realistically finite length. I was an Artist in Residence at Autodesk's amazing Pier 9 workshop in the Fall of 2016, so what better chance to realize a childhood dream?
The trickiest thing I soon found was going to be focusing the lasers and producing fog reliably. My first prototype used dry ice and laser pointers (first photo), and while it proved the concept to be sound, the beams were all over the place (second photo) and the dry ice was awkward and short-lived. Soon after I arrived at Pier 9 I prototyped a 3D printed laser array (3rd photo) and hooked it up to a mains-powered fog machine (the kind you have at parties) and this looked pretty cool, even outside and without it being dark (animation above).
After a ton of online shopping research into small, battery-powered commercial fog machines ($800! Are you kidding me! And not even that small) I gave up and designed my own using a small fan, a 3D printed enclosure and an electronic cigarette. That problem being solved, I then designed a 3D printed array of 12 lasers that could be focused on a single point using set screws. It took a ton of testing and more prototypes than I have ever made for anything (except perhaps my 3D periodic table).