Wednesday, January 22, 2020

Wrist-Dial

Years ago, I designed a wrist-dial, journal published by the NASS. Worn like a wrist-watch, it would tell time by the sun (without problems of alignment, as one would have, say, with a garden dial). I had proofs of concept, but no working model -- so I finally decided this week to make one. But things have changed since the proofs of concept nearly 20 years ago. One doesn't find the pieces any more. Conceptually, the wrist-dial is quite easy to build, but the gnomon (a kind of pointer) is critical to the whole. I have not yet found parts for this. OBSERVATION: The image on the right shows Cape Town's sun path -- about all one needs to know to build my device.

POSTSCRIPT: My biggest problems are a sliver of thin mirror about 2 mm wide, and thin, rigid metal plate which can be bent to shape.

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