Using The Moiré Effect For Unique Clock Face

If you’ve ever seen artifacts on a digital picture of a computer monitor, or noticed an unsettling shifting pattern on a TV displaying someone’s clothes which have stripes, you’ve seen what’s called a Moiré pattern where slight differences in striping of two layers create an emergent pattern. They’re not always minor annoyances though; in fact they can be put to use in all kinds of areas from art to anti-counterfeiting measures. [Moritz] decided to put a few together to build one of the more unique clock displays we’ve seen.

The clock itself is made of four separate Moiré patterns. The first displays the hours with a stretching pattern, the second and third display the minutes with a circular pattern, and the seconds are displayed with a a spiral type. The “hands” for the clock are 3D printed with being driven by separate stepper motors with hall effect sensors for calibration so that the precise orientation of the patterns can be made. A pair of Arduinos control the clock with the high-accuracy DS3231 module keeping track of time, and [Moritz] built a light box to house the electronics and provide diffuse illumination to the display.

Moiré patterns can be used for a number of other interesting use cases we’ve seen throughout the years as well. A while back we saw one that helps ships navigate without active animations or moving parts and on a much smaller scale they can also be used for extremely precise calipers.

13 thoughts on “Using The Moiré Effect For Unique Clock Face

  1. I tried to do this effect on a laser printer, but the printer foiled my attempt because the lines in the image and the grating I printed just didn’t want to align with the raster pattern of the print head.

      1. I remembered most of the words, but not the source.

        You know how when you can’t think of some of a song’s lyrics and there’s the “hmm hm hmm hmm” you do in your head? It was like that.

        Google didn’t help identify the source, but it did give me all the words…. plus a few more! All of which are now stuck in my head along with the song!

      2. It’s just missing one word or syllable.

        The original lyrics go 6-6-4 while the XKCD version goes 6-5-4 unless you say the word “another” as “an other” to have a pause in the middle. If you don’t, you have to add the word “one” after to fall back into rhythm.

        While the two versions can be considered synonymous, I’ve always though of “an other” as referring to something different vs. “another” as one more of the same.

        1. IIRC, I saw it on USENET rec.humor back in the 1990s.

          “If you’re swimming across a creek,
          and an eel bites your cheek,
          that’s a moray!”

  2. Hmm makes me think there are other optical phenomena or illusions that would make similar unique clock displays… all I can think of off the top of my head would be a clock that puts the pattern into an led light that only displays when it is viewed through a camera that is out of focus and spreads the point light out into a bokeh. I saw a research paper years ago that was doing something like that as a way of making tracking markers. But there’s no hope I’ll be able to find it for this post.

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