Digital Sundial

 

Digital Sundial

 

 

U.S. Pat. 4,782,472

 

Recognized by the North American Sundial Society as

“The first true digital sundial”

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The Digital Sundial was developed as an optical analog-to-digital converter and uses no electrical power.  The sun shines through slits, onto the ends of optical fibers, that illuminate segments of 7-segment numerals at the opposite end of the optical fibers.

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Construction:

 

 

      Optical fibers are shown epoxied in holes in the clear Plexiglas encoding cylinder (combining the functions of a rotary encoder and the gnomon of other sundials).  The opposite ends of the fibers are attached to segments, of a 7-segment numerical display, with clear epoxy.  Depending on the position of the sun, various optical fibers illuminate segments to form the numbers.  

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An end view of the encoder shows the sunlight shining through slits, on the ends of optical fibers as the sun moves across the sky.  The opposite end illuminates a segment of the display to form a readable number.

 

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The four categories of time-keeping devices:

 

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Sundial Information:

• National Maritime Museum, Greenwich, England
• Smithsonian Institution, Washington DC
• North American Sundial Society

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How it works:

Tens-of-hours (Xx:xx)	Hours (xX:xx)	Tens-of-minutes (xx:Xx)	Minutes (xx:xX)
A single opening in the top of the cylindrical encoder allows light to illuminate two fibers in the bottom of the cylinder, from 10:00 AM to 12:59 PM, to form the “1” which is the tens-of-hours numeral.	In an interval of one hour, a single one-hour-wide band of sunlight sweeps across the ends of fibers to form the units-hours numeral between 9 AM and 4 PM.	Each hour during the day, light shining through a different slit sweep over this cluster of optical fibers to repeat the 0-1-2-3-4-5 sequence necessary for the tens-of-minutes numeral.	The limit of accuracy of any sundial is ±2 minutes.  The Digital Sundial reads in the smallest available digital increment above 2 minutes: 10 minutes, with the units-minutes fixed at “0”.

 

 

 

 

 

 

 

Activity:

• plans ordered by Rick Steenblik, September 18, 1985
• U.S. Patent 4,782,472, issued to S. Hines, November 1, 1988
• Solar Today Magazine, August 20, 1994 issue, p. 39
• plans ordered bt Phillip Rogen, September 6, 1994
• plans ordered by Robert McGrath, September 10, 1994
• plans ordered by William Georgian, September 27, 1994
• plans ordered by Robert Siebert, Nov. 1, 1994
• plans ordered by William Georgian, September 23, 1994
• plans ordered by James Luttrell, January 21, 1995
• plans ordered by Hans Sassenburg, May 1, 1999
• information requested by Sundials magazine, November 29, 2001
• plans ordered by Till Liepmann, April 1, 2002
• incorporated in paper presented by Bob Kellogg, at the North American Sundial Society conference in Banff, Alberta, Canada, August 21-24, 2003
• plans ordered by Charles Ashcroft, Sept. 7, 2007
• plans ordered by Punjab Engineering College, India, February 6, 2008
• plans ordered by Bret Niemeyer, June 28, 2011
• plans ordered by Pat O’Grady, Sept. 4, 2014
• North American Sundial Society (NASS) declares it “The First True Digital Sundial”, October 2, 2014
• plans ordered by Edgar Kogler, April 24, 2018
• “Great design“, Jean-Baptiste Rouquier, Dec. 27, 2022

 

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      PDF sundial plans are available by email for US$200.  

 

 

HinesLab P.O. Box 2271 Virginia Beach, VA, USA  23450