Laser Spirograph

With an upcoming open house, everyone around the observatory is frantically trying to get everything in place. There will be all manner of science exhibits throughout the observatory headquarters complex. Exhibits about our research, controlling the telescopes, an IR camera display (Get your portrait in IR!), liquid nitrogen ice-cream, just a lot of fun.

Laser Spirograph
A two mirror laser spirograph build
I am coordinating an exhibit we named Optics Lab… As you would expect, most of the exhibits in our area teach basic optics, light, lenses, etc. Understanding light and optics is a basic skill in a large observatory. We will have a few lenses on rails, a laser ray-trace table with acrylic lenses, an exhibit on polarization, and even a simple laser interferometer.

When attempting to teach something, a little eye-candy is helpful to catch the attention of the audience, particularly kids. Our group includes a laser engineer and a laser tech, so the use of lasers was obvious. There is little that catches the eyes of a kid faster than a bright laser beam. One of the first ideas they tossed on the table was a laser spirograph. After a few moments thought the answer was clear… I can build that!

SpiroLaser PCB
Schematic for the SpiroLaser control PCB
Time to dig about in the scrap box! Actually more than a few boxes in my case, I am a bit of an electronics pack rat. A green laser module… Check! Small DC motors… Check! A few voltage regulators… Check! A couple potentiometers… Check! First surface mirrors… Check! In an hour of rummaging about I quickly located everything that was needed.

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