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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?
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.
Many years ago, someone did a similar holographic hack with a spinning hard drive motor, a piece of reflective plexiglass mounted upright on it, and a small projector. As the plexiglass carved out a cylinder, the projector sent a series of frames adjusted for each little slice of 3D space. [0] 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…
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.”
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.
Free time is an excuse for most people - I'm not calling you out because I don't know you but most people spend a lot of time on YouTube - Hn - Watching TV etc and they could be working on a cool project instead.
Many years ago, someone did a similar holographic hack with a spinning hard drive motor, a piece of reflective plexiglass mounted upright on it, and a small projector. As the plexiglass carved out a cylinder, the projector sent a series of frames adjusted for each little slice of 3D space. [0] 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…
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.
Earlier quoted context omitted.
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 a…
For [2] it does not look swept. Appears static.
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,…
It makes me wonder how different LIDAR vendors manage it.
1: https://www.adafruit.com/product/1407 2: https://www.adafruit.com/product/2162