Digital Sundial

Hines Digital Sundial

 

 

   

A nearby roof blocked the sun until 9:40 AM.

 

Recognized by:

 

     The digital sundial, invented by Steve Hines in 1984, and patented in 1988, shows the time with a true 7-segment numerical display.  The sun shines through slits in the encoder, onto the ends of optical fibers, that route the light to the 7-segment numerals in the display.

 

 

The four categories of timekeeping devices:

 

     All timekeeping devices fall into one of four categories, analog or digital clocks, or analog or digital sundials.  The digital sundial category has gone without an example for 3,600 years until 1984, and is recognized by the North American Sundial Society, Wikipedia, and Siri (ask your phone) as the first true digital sundial.  

 

 

Construction:

 

 

      Optical fibers are epoxied in holes in the clear Plexiglas encoding cylinder (the gnomon of analog sundials).  The opposite ends of the fibers are clear epoxied to backs of the segments, in the numerical display.   

 

 

The sundial in a museum:

 

 

 

 

 

 

 

 

 

print → web

 

    The digital sundial can be displayed in a museum setting where visitors rotate a “sun” handle around a globe, to sequence the overhead “sunlight”.

 

 

Advantages of the Hines digital sundial over other other sundials: 

  • It provides the time at a glance.  
  • The display can be at any convenient distance, hundreds or thousands of feet from the encoding cylinder.  
  • The time is displayed in 10-min. increments.
  • This is the world’s first optical analog-to-digital converter. Other A-to-D converters are electronic.  

 

 

Advantage of the Hines digital sundial over other timekeeping devices of any type:

  • A digital clock without electrical power.  

 

 

Sundial Resources:

 

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How it works:

 

      As the sun moves across the sky, sunlight shines through slits in the top of the encoding cylinder and sweeps over the ends of optical fibers in the bottom of the cylinder to illuminate the segments of the numerals.  The following animations are without any phase relationship.

 

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 illuminate two fibers, from 10:00 AM to 12:59 PM, to form the “1”.

A one-hour-wide band of light sweeps across the ends of fibers between 9 AM and 4 PM.

 

 Light shines through different slits to sweep over these fibers to repeat the 0-1-2-3-4-5 sequence for the tens-of-minutes numeral.   The Digital Sundial reads in the smallest available digital increment above 2 minutes, with the units-minutes fixed at “0”.

 

 

 

Blueprints:

 

      Blueprints to build one 4″-diameter cylinder digital sundial are available for $200.  

 

      3D-printed shadow-mask sundials appeared in approximately 2015, 31 years after the 1984 Hines’ digital sundial, and do not use actual 7-segment numerals.  The Hines’ Digital Sundial is the only true digital sundial with 7-segment numerals.  

 

 

Activity:

  • Siri, Alexa and Google describe the Hines’ Sundial as “the world’s first digital sundial”, Feb. 2025.
  • “Great design“, Jean-Baptiste Rouquier, Dec. 27, 2022
  • plans ordered by Edgar Kogler, April 24, 2018
  • North American Sundial Society (NASS) declares it “The First True Digital Sundial“, October 2, 2014
  • plans ordered by Pat O’Grady, Sept. 4, 2014
  • plans ordered by Bret Niemeyer, June 28, 2011
  • plans ordered by Punjab Engineering College, India, February 6, 2008
  • plans ordered by Charles Ashcroft, Sept. 7, 2007
  • 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 Till Liepmann, April 1, 2002
  • information requested by Sundials magazine, November 29, 2001
  • plans ordered by Hans Sassenburg, May 1, 1999
  • plans ordered by James Luttrell, January 21, 1995
  • plans ordered by Robert Siebert, Nov. 1, 1994
  • plans ordered by William Georgian, September 27, 1994
  • plans ordered by Robert McGrath, September 10, 1994
  • plans ordered bt Phillip Rogen, September 6, 1994
  • Solar Today Magazine, August 20, 1994 issue, p. 39
  • plans ordered by Rick Steenblik, September 18, 1988
  • U.S. Patent 4,782,472, issued to S. Hines, November 1, 1988

 

Hines’ original lab notebook entries for this invention.  
p. 38 p. 39

click to enlarge

 

 

HinesLab

 

Virginia Beach, VA, USA

 

email: [email protected]

 

ph. 818-507-5812

 

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