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...
https://mitxela.com/projects/hardware
Personal favorite: the MIDI slide whistle.
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...
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.
This gave me a wild idea: what if you could encode a low-resolution 3D video on the left channel of a stereo vinyl groove? [1] A special record player with a spinning plexiglass plate could then play holographic albums. The hologram would stay perfectly in sync with the music if you changed speeds or did turntable scratching.
[0] If anyone can find a link to the original spinning hard drive hologram project please drop it!
[1] I assume this wild idea isn't feasible given vinyl data rates?
Data rates go up if you spin the disk faster, and can get fast enough for 2D video. I don’t think it was vinyl, but https://en.wikipedia.org/wiki/Television_Electronic_Disc:
“Program information was stored in the form of ridges in the surface of a thin, flexible foil disc, which was claimed to be sufficiently robust to withstand being played 1,000 times. The main technological breakthrough was the vertical recording method that reduced the track pitch to 0.007 mm, and increased the rotation speed to 1,500 rpm, making it possible to record 130–150 grooves per millimeter, compared with the typical 10–13 grooves on an audio disc. This increased the available bandwidth from around 15 kHz to 3 MHz.”
A little later:
"Some time ago, I got access to a pick and place machine (a Charmhigh CHM-T36VA). I have it on semi-permanent loan."
Why is it, that it still makes sense to assemble boards yourself while outsourcing PCBs is a no-brainer?
It doesn't have to be "essentially free", but isn't there an assembly service that is suitable for hobby projects like this?
I assembled a fair share of PCBs, both for hobby and professionally (in R&D), but I neither have the time nor the space to do it anymore.
The PCB manufacturers typically also offer assembly services, but individual assembly orders require individual sets of components. So you either need parts feeders with a huge variety of components (read: expensive) or you need to intelligently group the orders that use the same set of parts. And for minimum cost, you'd need to group the orders that used similar parts onto the same panel so they could all go through the P&P at the same time.
I suspect that it's feasible, but there's not enough cost pressure on assembling PCBs for the manufacturers to bother going down that road.
this is a solveable problem tho. I hope someone solves it.
I am always banging on about software is a new form of literacy and I love and encourage any attempt to get kids coding, but there is a huge gap of "maker" style hands on availability - more libraries with "maker" areas, more encouragement
The UK supposedly has a large software gaming industry now because of things like BBC micro and the cottage industries that sprang up in the early eighties
I conjecture that a similar industry of light-medium hardware will spring out of building sufficient open access and just letting creative people find entirely new ways to build.
In short, me wanna try that, and I am egotistical enough to believe everyone else will too
Several points:
Reading code solely does not make you good expert in it.
Literacy is needed in any area, while artisans can go without software and still produce.
Software is about logic, literacy is about conveying meaning.
Knowing how to code does not at all teach you how to communicate.
Neither does reading words. Literacy is not just reading - but it's a big component. Reading a book on cooking does not make one a chef. Reading the code in a toyota robot won't make you a kanban focused floor manager.
>>> Literacy is needed in any area, while artisans can go without software and still produce.
My argument is that so much of the world is going to be eaten by software that being illiterate will put you at enormous disadvantages. Not every part of work will be software-replaced, but so much of the surrounding "B-work" will be that, I don't know, an artisan bricklayer can still do their work well if they are illiterate but they will be disadvantaged "in life", from invoicing to whatsapp messages.
>>> Software is about logic, literacy is about conveying meaning.
Straight nope to that. More and more software is encoding meaning and enforcing that meaning. Unless we are talking about evoking emotions - and even then let me introduce you to some edges of the gaming community.
>>> Knowing how to code does not at all teach you how to communicate.
I think pretty much every software list of advise since 1980s has included something along the lines of "learn to write english better"
Each pixel on such a setup travels along a circle. Spinning at 1200 rpm = 20/second, a 1000 Hz display would have a resolution of 50 segments along this circle. With a 10 cm diameter, this would make the outer "pixels" in the virtual 3D display around 6mm long.
The outer edge of the display would also experience a force of 80 G at that point, so bigger and/or faster spinning quickly becomes challenging (although it's only linear).
Driving monochrome OLED displays at 500+ Hz has already been done https://blog.adafruit.com/2012/02/03/adafruit-ssd1306-monoch...
When each pixel actually represents multiple pixels in a circle, you need a much higher refresh rate than 60 Hz.
I wonder how they respond to being dunked in epoxy.
compatible with the exact same pick-and-place machines, you just need to drill a hole in the PCB
Here's another cool one I found a while ago: https://www.youtube.com/watch?v=wM_Byrv9iBI
https://thepihut.com/products/ito-indium-tin-oxide-coated-gl...
Need one the size of a 5gal bucket.
As it is, I'd stick one on my gimcrack cabinet.
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.
Imagine the LED circuit board placed flat on a table. He's talking about adjusting the position of the LEDs in the vertical direction, which means adjusting the position of their board. Moving the LEDs relative to their board won't help.
The code is lean too, seems like one could learn a lot by trying to do this themselves.
https://www.forbes.com/forbes/2007/0723/060.html?sh=3c183bcb...
