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Tiny Volumetric Display

tromp
4 replies
2h54m

The centering issue could be solved by putting two led boards on top, back to back.Perhaps one board could shift the leds over by half to create an interlacing effect while doubling resolution.

swayvil
3 replies
2h25m

There's gotta be some way to replace the rack-of-leds-spinner with something lighter. Mirrors? Acrylic light pipe matrix?

lstodd
2 replies
1h30m

I wonder if it would be simpler to just spin two phone screens glued back-to-back. You get higher resolution in about the same weight. Bandwidth would be a problem though.

mistercow
1 replies
1h15m

The fundamental problem is refresh rate. If you have two phones that refresh at 240Hz (the fastest I know of), and you want your frame rate to be 12 Hz, you’ll still only be getting 20 refreshes per 180 degree rotation. So your angular resolution will only be 9 degrees. Assuming you use portrait mode, that will make your outermost voxels ~5 mm arcs.

And even there, 12 Hz is probably pushing it in terms of flicker.

lstodd
0 replies
38m

Yeah, well, that's not going to work. Interesting problem all the same.

For a 1 meter diameter and height cylinder at 60Hz voxel refresh and say 1mm resolution at the edge one would need the plane rotating at obviously 3600 rpm, and edge pixels switching at about 380KHz. Since rgb is nice to have that's 10 gigabit for a somewhat coarse display. Nothing impossible, but not a DIY territory yet.

I think one'd want the LEDs either on the receding or the advancing halves of the plate, depending on which is best for the cooling -- not all on the same side or on both -- that would be just a waste.

Or even just on one half of the plate, the other being just a countermass. This way cuts the bandwidth in two.

swayvil
3 replies
2h33m

This is tight. Presently working on a list of uses.

Need one the size of a 5gal bucket.

As it is, I'd stick one on my gimcrack cabinet.

ilaksh
1 replies
2h27m
leetbulb
0 replies
1h50m

Wow this one is cool. First time I've seen it. Reciprocating screen? How the hell do they get it to move that quickly? That is very high energy.

Edit found another video showing it starting up https://www.youtube.com/watch?v=SMz4bJA47Js

Now that I think about it, I suppose if you match the resonate frequency of the display component and its carrier it should be fairly efficient. Really cool stuff.

ilaksh
0 replies
2h23m
Tenemo
3 replies
2h51m

I would pay $200+ for a bigger (50x50?), rugged, RGB version of this that you can make to display different images without coding.

leetbulb
2 replies
1h57m

It's not volumetric, but it's still really cool and may fit your use case https://spinprojector.com/

alright2565
1 replies
41m

Only place I've seen these before is at the Atlanta airport, where they use them to show a 3d-animated sign to remind you not to bring your gun through the security checkpoint.

wongarsu
0 replies
25m

I sometimes see them at trade fairs as an eye catcher. With the right background you can get a pretty convincing 3d effect out of them despite the "display" only being 2d

wvh
2 replies
2h28m

Creative. I probably have the persistence and interest to pull something like this off, but I lack the fantasy to come up with such cool projects. Luckily there's the internet to see what impressive stuff people come up with.

mistercow
0 replies
1h29m

Tom 7 mentioned a thing in one of his videos, which is to keep a list, and write down every idea when you think of it, regardless of how stupid it is. Winnowing is for later. That way, when you have the energy to work on a project, you don’t have to waste it on coming up with an idea.

It really makes a huge difference in what you can get done with side projects. You probably have more interesting ideas than you think you do, but if having them doesn’t line up with having the time and energy to act on them (or even to just expand on them), they’ll fade away.

gnramires
0 replies
51m

Creativity can be trained just like any other skills! :)

I second taking note of stuff; like most things, genuinely practicing means you will get better.

Something that's also overlooked often is (1) Technical knowledge, (2) Methodical invention (3) Motivation!.

Technical knowledge helps you know which projects are possible (or just economically feasible), and map the roadblocks on the way; impossible inventions are not really useful.

Methodical invention means methodically looking at things instead of just randomly inventing. So you analyze a problem, like: (a) I want to make a volumetric display, (b) I want to bring (virtual) 3D objects to life. Notice the subtle difference between the two. Volumetric displays (a) can range from a lightfield display, which is a very elegant theoretical foundation (and can be realized in a number of ways), to volumetric persistence-of-vision displays like the own shown here. It's likely you will eventually arrive at whatever solutions are possible when you deeply research about a problem domain. Bringing a 3D object to life (b) can mean anything from digital fabrication, VR glasses, haptic interaction, robots, and more. It's a much wider problem domain.

Motivation is also really important. Understanding why you're inventing, and what you what you want to bring to life is also significant. Are you going to bring people joy, is it just very cool, is it a useful medical device that can save lives, etc.. Focusing on worthy subjects is also something you can study and that will really increase how good you are at inventing. Of course making stuff just because [we like it] is also important and valid :)

And for me the most important part is to have fun while you're at it...

twoodfin
2 replies
3h17m

One of those brilliant ideas that seems obvious in retrospect.

Given that the results are so compelling even when pulled together by hand out of relatively primitive discrete components, I’m wondering why we shouldn’t expect to see full color, high resolution versions from every random 7-letter drop shipper on Amazon next Christmas?

m3kw9
0 replies
52m

for a 32 inch display, you gonna get a motor that may need to spin like a mofo in an area of pi*32^2.

crazygringo
0 replies
1h42m

It's not a new idea -- they're called swept-volume volumetric displays, and they've been around for a long time [1].

But they're mostly kind of just toys. When you're limited to transparent glowing surfaces and you can't even touch them, there's really not a whole ton you can do. You can see a much larger non-spinning version made of LEDs suspended on cables [2] and it's very cool, but the novelty kind of wears off after a while, and you realize it's not the kind of display you're going to use for anything productive.

If you actually want real 3D visualization that can render anything at high quality and that you can interact with, it seems like VR/AR headsets are the way. (Though there are also the new 3D monitors that don't require glasses, but not a lot of people have gotten to see those in person yet.)

Maybe there's some kind of toy you could make with them to sell on Amazon though? Not really sure if there's a "killer app" for these things.

[1] https://en.wikipedia.org/wiki/Volumetric_display#Swept-volum...

[2] https://www.ledpulse.com/

Retr0id
2 replies
2h24m

It would be hard to manufacture at scale, but what if the LEDs were mid-mounted into a slot cut into the PCB?

atticora
0 replies
2h1m

Or suspended in a wire net.

alright2565
0 replies
37m

not at all hard to do, they make "reverse mount" leds, where the diode faces into the PCB: https://www.digikey.com/en/products/detail/sunled/XZMYK55W-3...

compatible with the exact same pick-and-place machines, you just need to drill a hole in the PCB

K0balt
2 replies
2h2m

It seems like this might Work even better with a two sided OLED screen (2 screens back to back) rather than led array, for better resolution? I think that are sufficiently wide angle, at least the monochrome ones.

sporeray
1 replies
1h38m

I think OLEDs might have a refresh rate issue. The nice thing about LEDs is that you can drive them at a very high refresh rate.

buildbot
0 replies
38m

Don’t oled displays support pretty high refresh rates? And also have way lower GtG latency?

55555
2 replies
1h23m

This would look better with the LEDs on a transparent PCB, right?

bee_rider
1 replies
1h17m

I bet you could to it with those little fiber-optic wires. Not the fancy telecommunications ones, the cheap stuff they use to make decorations.

I wonder how they respond to being dunked in epoxy.

blincoln
0 replies
10m

LEDs connected directly by rigid wires (no PCB at all), then encased in resin might be worth considering too.

tasty_freeze
0 replies
1h21m

holy hell is this guy productive. it is worth scrolling through the various one-off projects he has completed and documented:

https://mitxela.com/projects

skibz
0 replies
30m

I love projects like this that exploit the POV phenomenon.

Here's another cool one I found a while ago: https://www.youtube.com/watch?v=wM_Byrv9iBI

pcdoodle
0 replies
2h21m

That is cool.

The code is lean too, seems like one could learn a lot by trying to do this themselves.

namuol
0 replies
32m

(Great YouTube channel if you’re into this sort of thing!)

I wonder if a cheap oled display could be updated fast enough to achieve a much higher resolution. It might work but could look worse since the space between radial slices would be much larger than the pitch of the pixels, most likely.

merelysounds
0 replies
1m

I’d prefer this kind of spatial computing, I like it more than AR/VR.

lordwiz
0 replies
1h12m

Looks Pretty cool, Interesting how blender was integrated into such workflows for animation in hardware

imdsm
0 replies
3h28m

I love this. Must be a lot of fun to work on it!

francisduvivier
0 replies
1h44m

Pretty cool, but the bigger the display, the more that refresh rate becomes an issue. Say you can refresh the outer pixels on the horizonal axis at 100 fps. Then if you want to have 50 pixels on the outer half circle, then you can change them at 2fps.

falker
0 replies
1h36m

The RP2040 tiny is a Nintendo Switch modchip in disguise (47 ohm resistors on 3 specific pins).

dsalzman
0 replies
2h19m

Nice example of persistence of vision display. You can use large stick versions of this to “paint” images by waving them around.

bobsmooth
0 replies
1h32m

Using blender to generate the frames is really clever.

blincoln
0 replies
7m

This is a neat project. With such a low resolution, am I wrong in thinking that the flame simulation could be done in real time on-chip using a cellular automata algorithm? It would still be nice to support pre-rendered video for other purposes, of course.

Solvency
0 replies
12m

Ok I just went down the rabbit hole of this guys projects over the last decade and I am now thoroughly impressed and utterly depressed that I'll never have as much free time as he does.

FredPret
0 replies
2h1m

The rest of the site is filled with dozens of similar very cool projects