Holograms Display Time With ESP32

Holograms and holographic imagery are typically viewed within the frame of science fiction, with perhaps the most iconic examples being Princess Leia’s message to Obi-Wan in Star Wars, or the holodecks from Star Trek. In reality, holograms have been around for a surprising amount of time, with early holographic images being produced in the late 1940s. There are plenty of uses outside of imagery for modern holographic systems as well, and it’s a common enough technology that it’s possible to construct one using an ESP32 as well.

In this build, [Fiberpunk] demonstrates the construction and operation of a holographic clock. The image is three-dimensional and somewhat transparent and is driven by an ESP32 microcontroller. The display is based around a beamsplitter prism which, when viewed from the front, is almost completely invisible to the viewer. The ESP32 is housed in a casing beneath this prism, and [Fiberpunk] has two firmware versions available for the device. The first is the clock which displays an image as well as the time, and the second is more of a demonstration which can show more in-depth 3D videos using gcode models and also has motion sensing controls.

For anyone interested in holography, a platform like this is might make an excellent entry point to explore, and with the source for this build available becomes even easier. It’s almost certainly less expensive than these 3D printers that can turn out custom holographic images, and has the added benefit of being customizable and programmable as well.

30 thoughts on “Holograms Display Time With ESP32

  1. While a neat project, this is neither a hologram nor 3D. Any claim otherwise is downright misleading. It’s a Pepper’s Ghost illusion (a totally flat image), which is not a true hologram. This is [hackaday]; nobody here is going to be fooled.

    1. Seems like they’re using a gyro to match perspective in the first image though. That’s an interesting take on Pepper’s Ghost which allows some more 3D visualization.

    2. 100% agree. This is in no way, shape, or form a hologram. Nor is it any other kind of volumetric display. It’s a plain old 2D display (demoed with showing 3D renders, the same as we see every day in games).

      The author (and editor) either has no idea what a hologram is, or is being deliberately misleading.

      Disappointed with the wasted time reading this article.

    3. It is literally ALWAYS some version of pepper’s ghost. Out of all the tech I’ve ever followed, nothing is surrounded by more BS than holograms. And every single article for the last 30 years starts with “Remember Princess Leia? Well now… blah blah blah”. What’s most frustrating is that they know what we actually want, and then do everything they can to mask that they’re faking it. And then write-ups like this to support their fake hologram tech.

      1. Ironically, a Pepper’s ghost arrangement could be part of a true volumetric display, but of course not in this simplistic fashion. I’ve got /ideas/ one of which would involve it, combined with something like a reverse zeotrope and a lot of other optics, ending up with something washing machine sized to get an image space about as big as a roll of toilet paper on top. The prototypes tending toward the electro-opto-junk/visible-product ratio of early TV sets. (Also true of the couple other methods I’ve got in mind)

        Not in a real rush though, been waiting 30 years for easily achievable data bandwidth to catch up. Terabit will be a start, but Petabit will actually look good. That’s only for pre-rendered content though. Real time rendering (visible 360 degrees, in fractions of as degree so it’s not just looking like a stack of planes, not just two eyeball shifted frames) is as ridiculous still as expecting to do Crysis on a Z80. However, capture and interpolation would be a viable content production method in the near term. Need to start a Motion Holograph Experts Group to design algorithms to compress this shiz. MHEG one might fit 30 secs on a BRD, never know.

      2. I’ve seen using multiple laser beamers aiming to same spot in free air to excitate nitrogen in atmosphere to emit light. By pointing beams to different spots, you can draw 3D hologram in free air.
        Downside is if you put hand in the beam…it will definitely hurt you a lot.

    4. Technically speaking, the original version of Pepper’s Ghost involved the use of a live stage performer standing out of sight but visible through the refraction of the glass, making the image in the glass actually have accurate depth (even fooling human stereoscopic vision) akin to a mirror. You are right however that this implementation of it is absolutely 2-dimensional and cannot be called 3D.

    1. It’s not that anybody’s an expert. It’s more like some bs that isn’t what it says it is. Imagine someone selling a house but when you go see it. It’s a flat cutout that you can’t even fit inside of

  2. Good timing. I ordered that same prism at the beginning of April. It should be arriving at the end of May.

    Not sure what I was going to build with it, maybe a weather cube?

      1. Yes, it is worthless. No one will change their behavior because of their comments.
        No, it isn’t criticism. That would require saying something related to the project itself.
        Of the 18 comments, 9 do not mention the project at all and will not provoke any positive change, only provoking further worthless non-criticisms.
        … Of which now there are 10

  3. As someone that first saw an early optical[1] hologram ~50years ago (i.e. 10years after the first optical hologram in ’62), and has been taking stereoscopic photos for the last 40 years, that is neither a hologram nor stereoscopic.

    The author (and by implication Hackaday) should be ashamed of technically rubbish and clickbait.

    (OTOH at least I haven’t recently seen a link to a project based on dangerously powerful lasers.)

    [1] discounting electron microscope holography

  4. I’ve had ideas for real 3d displays since I was a kid. Good to know that my ideas are still not implemented! Maybe I still have a chance to get my ideas out there first.

    1. Are you sure they haven’t been implemented? There have been many many many different types of computer stereoscopic display demonstrated over the decades.

      Before spending significant time on your ideas, you would be wise to become well versed in the history of the subject.

    2. Do it now. I regret not doing that when I had the ideas fresh in my mind and the time. Now I have neither.

      Do it even (or especially) if it’s already been implemented. Make it better.

  5. It’s a “Pepper’s Ghost” using a prism, instead of a thin sheet of transparent material.
    So about as “holographic” as the amusement rides in Disneyland, or as one of those el-cheapo “HUD speedometer” with a LED numerical display and a piece of angled clear plastic.

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