Glow In The Dark Globe On A Spherical Screen

Terrestrial globes are almost a thing of the past in an era of Google Earth, but they can still be an exciting object worth hacking together, as [Ivan Miranda] shows with his glow-in-the-dark globe. It’s a globe, it’s a display, and it’s a great use of glow in the dark filament.

For the mechanical part of this build, [Miranda] used glow in the dark filament to 3D print a sphere and a reinforcing ring that hides inside. A threaded rod through the middle secured with screws and bearings make an appropriate spindle, and is attached to a stepper motor in the 3D printed stand. So far, it’s a sphere made of glowey plastic. Where’s the ‘globe’ part coming from?

To project a globe onto this sphere, [Miranda] used a strip of WS2812B LEDs stuck to the inside of the stand’s arc are programmed to selectively illuminate the globe as it rotates on its axis. After a brief hiccup with getting the proper power supply, he was ready to test out his new….. giant light ball.

It turns out, the filament was a bit more transparent than he was expecting so he had to pull it all apart and cover the interior with aluminium tape. [Miranda] also took the chance to clean up the wiring, code, and upgrade to a Teensy 3.1 before another test.

Despite the resulting continental projection being upside-down, it worked! [Miranda] added a USB cable before he closed it up again in case he wanted to reprogram it and display any number of images down the line.

[Thanks for the tip, olivekrystal!]

18 thoughts on “Glow In The Dark Globe On A Spherical Screen

    1. It is definately wrong. The Earth spins Eastward. Anyone who watches orbital rocket launches knows that. They also go Eastward, getting a ~700 mph (varies based on launch location) boost from already spinning on the Earth’s surface. One could also say the image is inverted upside-down. Reverse the inversion or reverse the temporal part and you put it right, either South pole up, or North pole up. Both right, your choice. :-) Sounds like an easy fix.

      1. “Anyone who watches orbital rocket launches knows that…”
        Or, if you could wrest your eyes from your computer screen, you may observe that the sun rises in the east.

  1. I’ve often thought that myself that the general accepted view of the globe is the wrong way around. I have a map floating around here somewhere that depicts the orientation the right way up :-) it means Tasmania cant be called the arse end of the world :eek:

  2. Now if you could have the national weather radar (cloud cover) beamed onto it, that would be what trips my trigger!
    Could the human eye pick up enough difference in the glow, to see a cloud pattern?
    Perhaps could use an inside liner printed with the earth map and then just the cloud patterns get light printed per rotation?

    How about some translucent glow paint washed onto a globe and the radar imagery light painted per revolution?

    1. Maybe, but would the resolution be good enough?

      Don’t know about you but I usually care about weather that’s within a maximum 256km radius of me. Stuff that’s happening in Perth really doesn’t have much affect on what I’m doing here in Brisbane (about 3900km away) . Much like those in Florida don’t worry much about weather in Seattle (about 4500km away).

      1. Hmm. Well I have always loved the idea of owning a globe of 4~5 feet in diameter! The cloud/water vapor would just ad something a little extra to get a wee bit mesmerized by.
        Alas, Where the heck would I even stuff such a large one into my domicile. :/
        But I still love the thoughts of it.
        Thanks to [Miranda] for setting my mind on a flight of fancy.

  3. Now this is a fun project.
    The idea of projecting onto the globe using a printed sphere of glow in the dark material is a fine example of how well this filament can work. I wonder how long the glow of this material will last, but for this project it works perfectly fine. Indeed more interesting info (like satellite or space station visibility) could be printed on the globe as well. Perhaps with the outline of the countries drawn with black lines (marker) and the visibillity spots drawn in green (glow in the dark light) on the globe.
    Really fun and exapandable project. Very original.
    Thanks for posting!

  4. Neat idea. I’ve got some of that filament. I’ll have to try something like this.

    I sure wish he made the globe rotate in the correct direction though. Gives me a tic, that.

      1. You may as well just use a shift register, really. Or just a bit of multiplexing, and over-drive the LEDs with current for a fraction of the time.

        UV LEDs aren’t cheap, but blue can do a good enough job depending on your needs. I don’t expect red would be much use. Did I dream it, or is it possible to use IR light to stop that stuff glowing? Might be useful.

        1. IR light causes the stored energy to released more-or-less immediately, yes. Could be used to get a better black level, I suppose.

          I think red light works too? At least I have this memory of people describing using red laser pointers. But then you have the problem of your red and blue LEDs being co-sited in normal strips.

        2. Can you PWM a shift-register? The attraction in the WS2812 is not just that you can daisy-chain them to control many LEDs, but also that the intensities are controllable.

          The closest I’ve come to multiplexing a PWM channel is using PWM on the output-enable pin of a 74HC174. Thus I could “latch” a LED, then PWM it. Spread across 8 LEDs, I had ⅛ duty cycle maximum per LED.

          The WS2812 and APA102 controllers would avoid that problem completely, every LED can be 100% intensity or any value in between.

          1. there is one simple solution to PWM with shifter used in JumboTrons, but it requires you to have VERY fast shifters, CPU, cabling, (and fast LEDs?)

            just send several sets of identical data/frames but blank some of the data.

            with a 4x increase of framerate you can do PWM in 4 steps; 0% 25% 50% 75% 100% (the 75% might be useless as power does NOT equal brightness due to logarithmic human-vision)

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