It feels as though I'm endlessly rebuilding it, for diminishing improvements. But in the most recent rebuild I finally solved a mystery that has been bugging me. When the display had been running for a while, it would quite abruptly lose balance and start vibrating. After the last occurrence, it was never quite the same. On stripping it down I found this.
That's the mount for the slip ring. A cylinder carrying a couple of copper bands fits over the pillar, and an M4 bolt goes own the middle to hold it all together. It has very clearly become bent, and without any signs of cracking. Presumably, as it spins, it heats up enough to soften the PLA, and the spring loaded brushes push it out of alignment.
I've reprinted it in ABS; going to see how well that lasts.
I needed some hydrogen peroxide, so I ordered some online from a place that seems *really* into hydrogen peroxide as a lifestyle choice. It came accompanied by a leaflet which uses the term "nature's own magic water". I've decided to find it charming.
I've implemented parts of a content pipeline for rendering a scene on the PC and streaming it to this display, but writing video streaming code is so much less fun than playing with voxels that it may take a while to finish. Here, I've stored the animation uncompressed on the display itself, and am updating it as fast as the Pi's SD card can handle. (Not very fast.)
My target for this display is 600 rpm - lower than that and it's too flickery; higher than that and I can't refresh fast enough to get 400 voxels around the circumference without dropping to 1 bpc. I'm nudging 400 rpm here, and it's still pretty unfilmable and absolutely terrifying to be close to. I have to decide whether the overall approach is worthwhile enough to start spending money on aluminium and polycarbonate.
The other problem I have is that to sell the 3D effect I need to move the camera around a lot, so I'm going to have to put some effort into building a studio backdrop.
I had a panel left over, and I thought I should have another stab at an oscillating display. I wanted to give it an undulating motion and came up with what seemed like a nice linkage, but the end result looks like it was designed by Trevithick.