Persistence of vision projects are a dime a dozen, but by adding a third dimension [Madaeon] succesfully created one to stand out from the crowd. Instead of waving around a single line of LEDs, he is moving a 2D grid of them vertically to create a volumetric POV display.
The display consists of oscillating 3D printed piston, powered by a small geared motor, on top of which sits a 8 x 8 RGB LED grid and diffusing film. The motor drives a cylindrical cam, which moves a piston that sits over it, while an optical end stop detects the bottom of the piston’s travel to keep the timing correct. [Madaeon] has not added his code to the project page, but the 3D files for the mechanics are available. The current version creates a lot of vibration, but he plans to improve it by borrowing one of [Karl Bugeja]’s ideas, and using flexible PCBs and magnets.
He also links another very cool volumetric display that he constructed a few years ago. It works by projecting images from a small DLP projector onto an oscillating piece of fabric, to created some surprisingly high definition images.
POV displays are good projects for learning, so if you want to build your own, take a look a simple POV business card, or this well-documented POV spinning top.
In that case, for even less vibration, I would use bare fiber optics…
How would you use fiber optics? The current prototype has 8×8 leds (but planned to go to 16×16), resolution on the z is already approx 64 Z “slices”.
By waving a bunch of fibers it would remove the mass of the leds from the moving part and a higher speed could perhaps be achieved…
The magic would be in how to place the fibers so they keep the same distance from each other, and in how they would be terminated to diffuse light (maybe with the ends molten in a sphere?)
Instead of LEDs, why not project an image onto a lightweight screen that moves up and down?
Doh should have finished reading: “It works by projecting images from a small DLP projector onto an oscillating piece of fabric, to created some surprisingly high definition images.”
Great job.
I made a slightly different one years ago, but ended up spinning the display around:
https://www.youtube.com/watch?v=WbBUz21BZq4
Spinning the electronics was an overly complicated route in the end.