A couple ideas for improvement. If you have extra identical motors and disassemble two, you can fashion a rotating power transmission system from the brushes in two assemblies. You sacrifice two motors for each unit, but it's a perfect fit and very reliable (with a cap and rectifier), and you don't have to worry about batteries anymore.
The rectifier also provides a signal that the assembly has completed a rotation, so you can maintain image stability based on actual position, rather than guessing how long a cycle is.
Transmitting power via induction might work, but I was never able to deliver it efficiently enough, so to make it work I had to turn up the source voltage so high that I worried about fires.
That's all true, but I liked his solution of using an IR sensor for the sync. It was so cool how he was able to rotate the display by changing the position of his finger. No guessing involved.
Standard displays are 60 Hz. You need a much higher framerate because not only do you want 60 frames a second, but you also want some number of frames per angular rotation. For 1° of angular resolution, you would need: 360°*60 Hz = 21,600 Hz display. Liquid crystals can be modulated at KHz speeds, but you're not going to find associated driving circuitry to do that. It's not easy, and there's no demand for it.
A TI DLP DMD can modulate at those high speeds, and there's readily available driving circuitry for it. However, it's a small reflective based display designed for projectors, and you would then need a light source to reflect off of it.
MicroLEDs would let you increase your pixel pitch with fast modulation frequency, but the display area is still small at the moment because of low yields. You also need a custom chip to drive the microleds at the required high framerate.
I might be misunderstanding the idea, but I don't think it addresses the original problem that wires can't connect the two parts of something that rotates in a single direction.
If the drive motor was asynchronous you could use the inductive windings on the rotor to power your rotating electronics, but the phase difference may get pretty extreme
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?
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.
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.
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.
100%. And the "weird" (not weird -- useful!) thing that happens with time is that once you start writing down ideas (and you should definitely note pretty much all of them - regardless of how good/bad they seem), your mind gets into "having more ideas" mode... You sort of get a second wind - or more accurately, you start developing your "what if" muscle. And the stronger it gets, the more "what if"s you'll have. And some of those will 100% be really really good (whatever good means to you).
It's also ok to have really """bad""" ideas. They're always funny to read back (a month/year) later. They're fun to share with friends and strangers. And sometimes they lead to good ones as you think about what made you think the bad ones were bad in the first place.
But when you write it down - please include more than two or three words - because it's hillarious to come back to a list when a lot of time has past to see an idea written simply as 'The pope of physics' <- from my own list. I have no idea what I was thinking...
I have the reverse issue, I am constantly coming up with creative ideas, so that by the time I am done building idea A prototype v1 (something like what you see in this video) or v2, idea B comes along and distracts me from seeing idea A all the way through. And when the persistence and discipline is there, bills need to be paid, and the distraction is not idea B, but merely some mundane work.
I solve it like this: when at work the soldering iron is in the garage. That little barrier helps a lot when temptation to tinker strikes.
One thing that I really like about this site is that the creator spends a ton of time on documenting it all. I am usually so busy with projects I don't get around to it. Another problem is that, especially for larger projects, that you need to store and maintain them. And that gets old pretty quickly when you're lugging around 200 pound windmills and such.
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...
I forgot to add: it's unlikely anything you come up with (while trying to develop your creativity) is going to be legitimately useful or even fun. It's like expecting to play a violin like Hillary Hahn (or <insert skilled musician>) after you've just picked it up. But the time to play an instrument so that at least you can tolerate your own sounds and have fun is much shorter -- and frankly, necessary I think not to give up before you can play really well (if that matters at all).
This is very similar to how hologram fans work - all the electronics is in the spinning part. With the fans they often use wireless power transfer to drive the top board.
For anyone based in or visiting London, exhibitions at 180 Studios [1] often use this kind of tech for art shows. Well worth checking out if you are into art and tech.
(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.
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.
There's another similar thing needing correction, which is that the LEDs near the center sweep a much smaller volume than the ones at the edge, and should be dimmed in order to yield equivalent luminance. LEDs describing tiny circles very close to the center would need to be dimmed a lot since they'd essentially be stationary. Wouldn't it be better then to sweep slightly larger circles at the middle anyways?
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.
Readit News
The rectifier also provides a signal that the assembly has completed a rotation, so you can maintain image stability based on actual position, rather than guessing how long a cycle is.
Transmitting power via induction might work, but I was never able to deliver it efficiently enough, so to make it work I had to turn up the source voltage so high that I worried about fires.
This advice comes from my 2001 Burning Man art project. A very sad early prototype is pictured here: https://github.com/sowbug/tqw/blob/master/photos/side.jpg. The final installation worked great.
It makes me wonder how different LIDAR vendors manage it.
1: https://www.adafruit.com/product/1407 2: https://www.adafruit.com/product/2162
A TI DLP DMD can modulate at those high speeds, and there's readily available driving circuitry for it. However, it's a small reflective based display designed for projectors, and you would then need a light source to reflect off of it.
MicroLEDs would let you increase your pixel pitch with fast modulation frequency, but the display area is still small at the moment because of low yields. You also need a custom chip to drive the microleds at the required high framerate.
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?
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/
https://mitxela.com/projects/hardware
Personal favorite: the MIDI slide whistle.
[0] https://mitxela.com/projects/headphone_amps
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.
It's also ok to have really """bad""" ideas. They're always funny to read back (a month/year) later. They're fun to share with friends and strangers. And sometimes they lead to good ones as you think about what made you think the bad ones were bad in the first place.
I have no problem coming up with, and remembering, cool projects. I just rarely have the energy or the lasting enthusiasm to actually follow through.
One thing that I really like about this site is that the creator spends a ton of time on documenting it all. I am usually so busy with projects I don't get around to it. Another problem is that, especially for larger projects, that you need to store and maintain them. And that gets old pretty quickly when you're lugging around 200 pound windmills and such.
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...
https://youtu.be/bT716nyK0AY
[1] https://www.180studios.com/
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.