Wednesday, September 21, 2011

Pico Projector + Light Fixture + Free Code = Desktop Spherical Display

Science on a snow globe!

September 19, 2011 9:00 AM
by Sean Michael Ragan

Pico Projector + Light Fixture + Free Code = Desktop Spherical Display

Sometimes, I get this feeling like I've seen it all—that nothing that comes along is ever going to inspire or delight me the same way that certain ideas, systems, inventions, and/or artworks did when I was younger. It always passes, sooner or later, but while I'm under that spell it can be…well, it can be a bit depressing, honestly. So I feel like I ought to thank International Man of Mystery Nirav Patel, somewhat more personally than usual, for making and sharing this wonderful thing. I am inspired.

He calls it Science on a Snow Globe, and it was, itself, inspired by NOAA's Science on a Sphere project. Whereas the Science on a Sphere globe displays are 8′ across, use four projectors and five computers apiece, and cost thousands of dollars individually, Nirav's system sits on a desktop, projects onto an 8″ frosted glass lamp globe, uses a single laser picoprojector and a single computer, and costs about $200. Nirav writes:

The basic design here is to shoot a picoprojector through a 180° fisheye lens into a frosted glass globe. The projector is a SHOWWX since I already have one, but it likely works better than any of the non-laser alternatives since you avoid having to deal with keeping the surface of the sphere focused. Microvision also publishes some useful specs, and if you ask nicely, they'll email you a .STL model of their projector. The lens is an Opteka fisheye designed to be attached to handheld camcorders. It is by far the cheapest 180° lens I could find with a large enough opening to project through. The globe, as in my last dome based project is for use on lighting fixtures. This time I bought one from the local hardware store for $6 instead of taking the one in my bathroom.

Nirav printed a custom bracket that holds projector, lens, and globe together in the right arrangement, and mounted the whole thing on a small off-the-shelf tripod. Lots of nummy technical details are available here, and the code, which Nirav wrote himself, is at Github. [Thanks, Matt Mets!]


Electronics Imaging Science display masterpieces projection sphere

Dr. Art Trembanis
Associate Professor
109 Penny Hall
Department of Geological Sciences
The College of Earth, Ocean, and Environment
University of Delaware
Newark DE 19716

"Education is not the filling of a pot, but the lighting of a fire." -W. B. Yeats

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