Modern Spin on an Old Technology

It seems that the longer a technology has been around, the more likely it is that all of the ideas and uses for that technology will be fleshed out. For something that’s been around for around 5500 years it must be especially rare to teach an old dog new tricks, but [Sebastian] has built a sundial that’s different from any we’ve ever seen.

Once done with all of the math for the sundial to compute its angles and true north based on his latitude and longitude, [Sebastian] used Autodesk Inventor to create a model. From there it was 3D printed, but the interesting part here is that the 3D printer allowed for him to leave recesses for numbers in the sundial. The numbers are arranged at such angles inside the sundial so that when it’s a particular hour, the number of the hour shines through the shadow of the sundial which creates a very unique effect. This would be pretty difficult to do with any machine tools but is easily accomplished via 3D printing.

[Sebastian] wanted a way to appreciate the beauty of time, and he’s certainly accomplished that with this new take on  the sundial! He also wonders what it would be like if there was a giant one in a park. This may also be the first actual sundial build we’ve featured. What does that mean? Check out this non-pv, sun-powered clock that isn’t a sundial.

Thanks to [Todd] for the tip!

36 thoughts on “Modern Spin on an Old Technology

        1. In all the years I’ve been up at 2 or 3 am and outside where one would find said sundial, I haven’t been too overly concerned about the exact time.

          If one really wanted to learn the correct hour just speak it out loud.

          “Damn… the store is closed.” It’s usually around 9 or 10.
          “Hey! Let’s go check out….” it’s usually around 11 or 12.
          “Yeah… I want two tacos, a combo #5 with Coke and…” it’s between Midnight and 1 AM.
          “Aww… da barh ish closhedez… ” 2 AM.
          “Yeshh… I washt 50 tacos and uh……” around 3
          “Sshhhhhh….” 4 as you try to climb into bed… usually not in your house….
          After 4, just ask the cop.

  1. Really nice idea! As pointed in the discussions on the page, the change in Sun’s elevation over the year will cause problems. Living further away from the equator and having quite extreme changes in Sun’s elevation (almost no sunset in summer or no sunrise in winter) would probably mean that without constant adjustments the projection works properly only some weeks in a year. With this somehow solved, I’d buy one right away.

    1. I can’t picture a sundial being accurate to more than +/- 15 min. not being familiar w/ all the math behind them, assuming you have enough sun to use it, is that a serious issue?

      1. You’d need a clock/calendar to point it though, and that would be cheating.
        But maybe there is another way to determine the timing also using the sun? Maybe some markings on the floor and reading the offset of the shadow?

        1. I was thinking in terms of only moving it along one axis so you only account for how high the sun sits. But not sure how to measure that. You would end up with at least a microcontroller and some way to measure how high the sun goes over time.. But yeah. Cheating.

          1. You need to compensate either for tilt and rotation or height and rotation.
            To solve that you make the peg free and connect it to a couple step motors controlled by a microcontroler that has a GPS and COMPASS connected and use them to calculate the position of the peg//motors in order to compensate for sun dial location and orientation. Of course, at night you still need a sand clock…

          2. To Joao Ribeiro: The romans used a water clock rather than sand. And you could maybe mechanically move a solar-charged LED projector LED to simulate the sun at night? If you need to be silly that is.

            As for determining, that’s why I said marking on the ground, because it changes to a known pattern over the year you could determine the shadow offset from some markings to determine the month it is I was thinking. And use that determination to adjust the hour holes to work correctly. That way you need only to do some pre-calculations and some simple visual checking system to compare the current shadow distance from say a half-circle on the floor.

            But I’m not really thinking too hard about this so I leave it to enthusiast to flesh it out :)

      2. What would be super-amazing, would be some Long Now Clock-style mechanism, perhaps using stored heat, and the fact that the average temperature / hours of sunlight change throughout the year. This could tilt the gnomon (yes! that’s what it’s called!) to the correct angle. Something to do with expansion, or maybe bimetallic strips.

      3. Would simply tapering out the number holes on the sunward side to account for the range of angles the sun might shine at depending on its elevation not work? When it’s ‘off angle’ the numbers would likely be somewhat compressed or stretched vertically but it should be relatively minor and still readable.

    2. So solve that you make the peg free and connect it to a couple step motors controlled by a microcontroler that has a GPS and COMPASS connected and use them to calculate the position of the peg//motors in order to compensate for sun dial location and orientation. Of course, at night you still need a sand clock…

  2. you could use the same idea to align to the angle of the Sun. A hole drilled through at 90 degrees would show a perfect circle at midday. add a hinge at the bottom and you can adjust as the year goes on. (also accounts for distance from equator).

  3. It reminds me of the. wing that goes through the tree trunk “what ever the costumer wants” attitude.
    I experimented with a solid a few years back which had different profiles on each side. I quite like this design I might have to build a mini version of it at some point.

  4. I was once having lunch with some friends at the NCAR crapateria and was brainstorming what I could do with my hundreds of 0.016″ dia PCB drill bits… what kind of art could we come up with? Based on our conversation we came up with the idea of a sun dial where depending on the angle of the sun, would only let through light through certain holes, leaving the shadow of the time on the ground. A little goggling showed that it was recently (at the time) patented…. So I wasn’t the first to come up with a ‘good idea’….

  5. I am a horologist (watchmaker in this case), and I find this to be absolutely awesome. Comments about Earth tilting
    on it’s axis changing shadow effect causing problems seconded though. I wonder if we could indeed print around that?

    As for the accuracy of sundials, yes, once calculated for exact placement, they can be very accurate indeed if scaled up!
    Google the Jantar Mantar sundial in India. It is a UNESCO world heritage site. A giant sundial- whose shadow can be seen
    moving 1mm a second. So yes- there are very accurate sundials. They just have to be laid out very, very carefully!

    I want a giant version of this in my backyard. This project is just awesome.

  6. I don’t understand why this would be so difficult for machine tools. You could even do it pretty easily on a manual machine. Stick the tube in a small vertical rotary table on an engraving machine and cut the numbers. Done.

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