A Multi-Layered Spin On Persistence Of Vision

By taking advantage of persistence in human vision, we can use modest bits of hardware to create an illusion of a far larger display. We’ve featured many POV projects here, but they are almost always an exploration in two dimensions. [Jamal-Ra-Davis] extends that into the third dimension with his Volumetric POV Display.

Having already built a 6x6x6 LED cube, [Jamal] wanted to make it bigger, but was not a fan of the amount of work it would take to grow the size of a three-dimensional array. To sidestep the exponential increase in effort required, he switched to using persistence of vision by spinning the light source and thereby multiplying its effect.

The current version has six arms stacked vertically, each of which presents eight individually addressable APA102 LEDs. When spinning, those 48 LEDs create a 3D display with an effective resolution of 60x8x6.

We saw an earlier iteration of this project a little over a year ago at Bay Area Maker Faire 2018. (A demo video from that evening can be found below.) It was set aside for a while but has now returned to active development as an entry to Hackaday Prize 2019. [Jamal-Ra-Davis] would like to evolve his prototype into something that can be sold as a kit, and all information has been made public so others can build upon this work.

We’ve seen two-dimensional spinning POV LED display in a toy top, and we’ve also seen some POV projects taking steps into the third dimension. We like where this trend is going.

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After The Sun Set On San Mateo, LED Takes Over Hackaday’s BAMF Meetup

After this Spring’s Bay Area Maker Faire closed down for Saturday night and kicked everybody out, the fun moved on to O’Neill’s Irish Pub where Hackaday and Tindie held our fifth annual meetup for fellow Maker Faire attendees. How do we find like-minded hackers in a crowded bar? It’s easy: look for tables lit by LEDs and say hello. It was impossible to see everything people had brought, but here are a few interesting samples.

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Followup: Troll Physics Solved

A month ago, we saw a marvelous demonstration of troll physics from YouTube user [Fredzislaw100]. In his video, we saw a circuit of three switches and three LEDs wired in series and but not acting like the should. A lot of the comments for this post elicited reasonable explanations like modifying the battery or pure camera wizardry via After Effects. Thankfully, [Alan] stepped in and showed us how it was done. The solution uses two AC power sources with diodes in two of the switches and LEDs and inductors in the third pair. [Alan]’s build was rather large compared to the original video, so we were wondering how this circuit could be made invisible.

[Fredzislaw100] just posted a video on how he did it. Like [Alan]’s build, it uses two AC power sources, diodes, and inductors. In contrast to every single guess about where the circuit is hidden, the majority of the build is inside the battery connector. [Fredzislaw] did some amazing work hiding a 74LV132 quad NAND Schmitt trigger inside the battery connector. The diodes were easily hidden on LEDs 1 and 3 with some red nail polish, but we’re amazed by the inductor built into the LED seen in the title pic.

So there you go. With a ton of electronics know-how and an extremely steady hand (and a microscope), you too can build your own troll circuit. Check out the video after the break.

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