A Mechanical Laser Show with 3D-Printed Cams and Gears

Everyone knows how to make a POV laser display — low-mass, first-surface mirrors for the X- and Y-axes mounted on galvanometers driven rapidly to trace out the pattern. [Evan Stanford] found a simpler way, though: a completely mechanical laser show from 3D-printed parts.

The first 10 seconds of the video below completely explains how [Evan] accomplished this build. A pair of custom cams wiggles the laser pointer through the correct sequences of coordinates to trace the desired pattern out when cranked by hand through a 1:5 ratio gear train. But what’s simple in concept is a bit more complicated to reduce to practice, as [Evan] amply demonstrates by walking us through the math he used to transfer display shapes to cam profiles. If you can’t follow the math, no worries — [Evan] has included all the profiles in his Thingiverse collection, and being a hand model software guy by nature, he’s thoughtfully developed a program to automate the creation of cam profiles for new shapes. It’s all pretty slick.

Looking for more laser POV goodness? Perhaps a nice game of laser Asteroids would suit you.

21 thoughts on “A Mechanical Laser Show with 3D-Printed Cams and Gears

  1. One of those brilliant and “obvious when you think about it” ideas, that some other person ends up thinking about… Very creative. I wonder if the maths can be put into python as an Inkscape plugin? It could even output OpenSCAD for the 3D files.

        1. Hehehe, cake mix fresh out of the box is supposed to be turned into actual cake :P
          the handheld laser was just supposed to be Hand Held.
          You do however have a POINT with the filter caps :D

  2. The math is very similar to how cams are designed for the old brown and sharpe automatic screw machines that predated the modern CNC. I’ve actually got a manual around here somewhere that walks an engineer through the cam design process. That said, the triangulated motion this uses makes for a bit more complicated math, but simplifies the mechanics. If I had to make the cams by hand, needed more complex patterns, and/or if I wanted to scale this up it would be easier to start with a design that had a true x and y based mechanism.

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