Bill, Kevin
I too have been exploring 3D printing for a digital sundial (see
http://www.sundials.org/index.php/dial-links/videos/digital-sundials ).
Because I do a lot of programming, openSCAD is wonderful, allowing
precise control of shapes and allowing structures that until now were
only a dream. [Note: for the moment, unless you spend a fortune, you
must be content with PLA or ABS plastic ... but through commercial 3D
print houses you can get metal as well, but very pricey].
As Bill suspects, the digital dial shown at
http://3dprint.com/103289/open-source-3d-print-sundial/ does not work at
high sun declinations toward the solstices. I downloaded the model and
used Slic3r, MatterControl and CURA as visulaizers (they produce G-code
as well) and confirmed that the dial only works to +/- 15 deg solar
declination. Sad, because it's a neat design.
My original digital dial (1995) showed both hours (8am-4pm) and minutes
at 10-minute intervals. Both Scharstein and I received independent
patents for essentially the same thing... except that he has been able
to commercialize his dial. Mine cost too much to build.
At the June 2015 NASS meeting in Vancouver I presented (in abstentia) a
video (see URL above) of the principles and construction of a new
digital gnomon dial. The design only shows hours, but accurately
changes hour with an resolution of 90 seconds. So now I'm taking up the
challenge to include minutes, and of course include a way to accommodate
the Equation of Time.
Willing to collaborate with whoever is interested. This stuff is fun.
Bob Kellogg
Potomac, MD
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