Persistence of Vision (POV) is a curious part of the human visual system. It’s the effect by which the perception of an image lingers after light has stopped entering the eye. It’s why a spinning propeller appears as a disc, and why a burning sparkler appears to leave a trail in the air. It’s also commonly used as a display technology, where a series of flashing LEDs can be used to create messages that appear to float in the air. POV displays are a popular microcontroller project, and today, we’ll explore the basic techniques and skills required in such builds.
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.
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.
Persistance of Vision, or POV, displays are ever popular around these parts. Spin a few LEDs and you can make images appear in almost-thin air – just don’t stick your finger in the way. [FriskP] found a great application for this hardware – creating an anime-styled spellcasting gun.
The basic gun is built around a Nerf blaster, which is common in a lot of this type of steampunk and anime build. A Phantom3D POV display is then bolted on to the front along with some 3D printed components for style. The ensemble is then painted in a suitably awesome fashion.
We’re not sure on the software used, but [FriskP] has the gun displaying some amazing spell-type graphics that appear to hover in the air when the user pulls the trigger. The artwork is stunning, showing off some of the best graphics we’ve seen in the POV arena.
Overall, it’s a highly aesthetically pleasing build that any cosplayer would be more than proud to wield. It relies on the builder’s strong finishing and integration abilities more than raw electronic skill, but the end result is truly impressive.
We’ve seen plenty of POV displays around here before – you can get started with something as simply as a PC fan! Video after the break.
[Thanks to AnimeFreak for the tip!]
3 hackers, 16 LEDs, 15 years of development, one goal: A persistence of vision display stick that fits into your pocket. That’s the magicShifter 3000. When waved, the little, 10 cm (4 inches) long handheld device draws stable images in midair using the persistence of vision effect. Now, the project has reached another milestone: production.
The design has evolved since it started with a green LED bargraph around 2002. The current version features 16 APA102 (aka DotStar) RGB LEDs, an ESP-12E WiFi module, an NXP accelerometer/magnetometer, the mandatory Silabs USB interface, as well as a LiPo battery and charger with an impressive portion of power management. An Arduino-friendly firmware implements image stabilization as well as a React-based web interface for uploading and drawing images.
After experimenting with Seeedstudio for their previous prototypes, the team manufactured 500 units in Bulgaria. Their project took them on a roundtrip through hardware manufacturing. From ironing out minuscule flaws for a rock-solid design, over building test rigs and writing test procedures, to yield management. All magicShifter enclosures are — traditionally — 3D printed, so [Overflo] and [Martin] are working in shifts to start the 500 prints, which take about 50 minutes each to complete. The printers are still buzzing, but assembled units can be obtained in their shop.
Over all the years, the magicShifter has earned fame and funding as the over-engineered open hardware pocket POV stick. If you’re living in Europe, chances are that you either already saw one of the numerous prototype units or ran into [Phillip Tiefenbacher] aka [wizard23] on a random hacker event to be given a brief demo of the magicShifter. The project always documented the status quo of hardware hacking: Every year, it got a bit smaller, better, and reflected what parts happened to be en vogue.
The firmware and 3D-printable enclosure are still open source and the schematics for the latest design can be found on GitHub. Although, you will search in vain for layout or Gerber files. The risk of manufacturing large batches and then being put out of business by cheap clones put its mark on the project, letting the magicShifter reflect the current, globalized status of hardware hacking once more. Nevertheless, we’re glad the bedrock of POV projects still persists. Check out the catchy explanatory video below.
Whoa. We’re just blown away by this new project by [Maximilian Mali] and [Sebastian Haushofer]. It’s a stacked Persistance of Vision display, with 9 layers — effectively creating a Volumetric 3D POV Display.
We recently shared one of [Maximilian’s] other projects, The Ripper CNC Machine. As it turns out, the reason he built The Ripper was to aid in the manufacture of his VoLumen project. He’s been designing these Volumetric 3D displays for about 3 years now, with the first iteration called the viSio, capable of 40 fps 3D video without the need for any 3D glasses.
The new and improved VoLumen features 34 micro-controllers, each with 512MB flash memory for storing animation data. In total there are 1024 high power RGB LEDs, which draw a whopping 200W at full load, making it bright, crisp and visible even in direct sunlight. It’s an incredible project that [Maximilian] started when he was only 16 years old.
You have to see the video of this thing in action.
Persistence of vision displays are always cool, although we must admit this one looks like it could very well explode at high speeds…
Safety concerns aside, this desk fan based display provides a great starting point for learning about making POV displays. It makes use of an old cellphone battery, an ATmega8, some LEDs, Veroboard, assorted wires and solder and of course, a high-speed desk fan.
[shparvez001] also provides the full code on his blog for the project, making it very easy to replicate. Though we might also suggest you keep it small enough that the original fan cage still fits on top.
From an aesthetic point of view, the display looks fine in the dark — but when the lights are on you might get some odd looks. We can see this project being greatly improved by mounting the LEDs through one of the fan blades, and the control electronics on the back side of the other blades. Maybe throw in some wireless charging for the battery while the fan is off too?
Anyway, stick around after the break to see the display in action. If you want a more permanent fan POV try adding display hardware to a ceiling unit.