Scanwheel: A Pocket-Sized POV TV

July 26, 2026 by Matt Varian 20 Comments

When you hear the word TV, you probably think of a big LED screen, maybe even the old CRT TVs, but in either case it’s something large and fairly complicated. However, thanks to the persistence of vision, it doesn’t have to be. In this handheld-sized project from [Ancient], the Scanwheel is born, a miniature mechanical TV that uses a spinning disk and some LEDs to produce an image.

The electronics of the Scanwheel are pretty straightforward. The smarts come from a Raspberry Pi Pico, an A4988 motor driver, a couple of LEDs, and a small 21-02485 stepper motor. The Raspberry Pi Pico is used to command the motor speed as well as coordinate the LEDs to turn on at the right time. The case is 3D printed; the base includes space for the various support electronics as well as some small light baffles to ensure the LEDs don’t bleed over outside their intended area. The top of the case is a disk that includes 20 small holes spaced evenly around the perimeter at varying heights, allowing light to only leave the disk when one of these holes is in front of the LEDs.

When you put all these pieces together, spin the motor up to roughly 900 RPM, and turn the LEDs on in a precise order, you end up with a really cool result: a miniature TV. And due to the five different LEDs in this build, you actually have a color 20×20 pixel display in the center and, on either side of that, two more 20×20 black-and-white displays capable of showing different images. Thanks [Ancient] for sharing this awesome build that takes advantage of the persistence of vision effect to create a unique display. Be sure to check out the video below as well as the instructions on how to build your own. And if you enjoy this sort of thing, check out some of our other persistence-of-vision projects as well.

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CRTs Are Too Mainstream, So Game On A Mechanical TV Instead

May 12, 2026 by Tyler August 18 Comments

Aside from nostalgia, people claim to like CRTs because they’re apprehendable– the technology just makes more sense than the arcane wibbly-wobbly solid-state madness going on inside the driver chip of your new OLED. CRTs weren’t the first technology used to display moving images though, and their mechanical forebears were even easier to understand. For that reason we suppose it was only a matter of time before one of The Youths– in this case a British YouTuber by the name of [smill]–tried gaming on a mechanical television display.

The game in question was Minecraft— because of course it was, that’s the new generation’s DOOM–and the mechanical TV in question is not a priceless 1920s antique but a commercial kit that reproduces [John Logie Baird]s 1925 televisor. If you’re not familiar, it uses a flat disk– called a Nipkow disk after its inventor– with a series of holes in a spiral to demodulate a single lamp’s brightness variations into monochrome image made of scan-lines. As you might imagine, the resolution depends both on the size of the disk and its speed, so with a tabletop example you’re not going to get much– in this case, 32 holes for 32 lines. At least they’re not interlaced this time.

Getting a video signal from the computer to the LED in the televisor kit was the hard part of the hack. Aside from actually playing on the diminutive monochrome display, that is. There is a “video2NBTV” tool that can do the job, as the Narrow Band TV signal used by amateur radio enthusiasts still has the compatible timing values and modulation as what the televisor kit uses. We suspect that’s because the Televisor people used the modern NBTV standard as a starting point for their electronics, since [Baird]’s device reportedly ran 30 lines at only 5 frames per second, compared to the 32 lines at 15 FPS here.

Some of you may turn your nose up at this as a mere YouTube stunt, which is fair enough. At the same time, we cannot wait for the eventual arms race. Imagine when someone decides to go for 4K cred? Staring through a supersonic Nipkow disk makes pointing a particle accelerator at your face downright mundane. The kit [smill] used was monochrome, but if you want to repeat his antics in glorious colour, you can 3D print your own TV.

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POV Globe Takes To The Skies

October 22, 2025 by Tyler August 14 Comments

LED billboards are cyberpunk-dystopian enough for most, but it can get worse. For example, this project by [Concept Crafted Creations] that takes the whole concept and takes it airborn (literally) in the form of a flying POV sphere called “Zippy”.

We love persistence-of-vision (POV) displays, and have featured plenty before, from the very complicated to the fairly simple. The idea is simple: take one or more rings of LEDs and spin them rapidly enough that the persistence-of-vision effect creates a solid image in your visual field. We covered the basics years back. “Zippy” has one ring of addressable LEDs that surrounds the thing that makes it unique: the quadcopter at its core. None of those other projects could fly, after all.

You might imagine a big, spinning ring is going to have a lot of torque to cancel out, and that is true — about 2.3 kgf — and it led to a lot of prototypes crashing early on. After trying to use flaps to direct the downwash of the quadcopter rotors to counter the spin, [Concept Crafted Creations] eventually added two extra props for yaw control, and that seemed to do the trick. We say “quadcopter” because that’s the configuration, but Zippy ended up heavy and needs eight lift motors to fly. PVC pipe and PLA aren’t the lightest build materials, after all. That’s ten props, total, plus another outrunner to spin the POV ring. All those motors, plus the current draw of the LEDs means the flight time might not impress — but Zippy sure does, at last as long as the batteries hold out.

There’s something eye-catching about POV displays, and seeing this one drifting upwards like Kang and Kodos decided to steal the Los Vegas Sphere is even more arresting. That made the crash at the end of the video sad to see, but [Concept Crafted Creations] hasn’t ruled out rebuilding it if his viewers show enough interest. So if you like what you see, head over to YouTube and leave an encouraging comment for him to try, try again. Continue reading “POV Globe Takes To The Skies” →

Turn Your Phone Into A POV Hologram Display

February 8, 2025 by Al Williams 16 Comments

It seems obvious once you think about it, but if you can spin your cell phone and coordinate the display with the motion, you can create a 3D display. [Action Lab] had used such a setup to make a display that you could view from any angle. After he showed it, a viewer wrote him to mention that if you spin the picture at the same rate, it will appear in 3D. The results look great, as you can see in the video below.

The spinning mechanism in this case is an inexpensive pottery wheel. Whatever you use, though, you need a way to match the speed of the graphics to the speed of the phone’s rotation. For this example, there are just a few pre-spun 3D models on a website. However, creating your own viewer like this wouldn’t be that hard. Even more interesting would be to read the phone sensors and spin the image in sync with the phone’s motion.

We keep hearing about awesome commercial 3D stuff coming out “any day now.” Meanwhile, you can always settle for Pepper’s Cone.

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A Surprisingly Simple Omnidirectional Display

November 22, 2024 by Danie Conradie 37 Comments

Old-school technology can spark surprising innovations. By combining the vintage zoetrope concept with digital displays, [Mike Ando] created the Andotrope, a surprisingly simple omnidirectional display.

Unlike other 3D displays, the Andotrope lets you view a normal 2D video or images that appear identical irrespective of your viewing angle. The prototype demonstrated in the video below consists of a single smart phone and a black cylinder spinning at 1,800 RPM. A narrow slit in front of each display creates a “scanning” view that our brain interprets as a complete image, thanks to persistence of vision. [Mike] has also created larger version with a higher frame rate, by mounting two tablets back-to-back.

Surprisingly, the Andotrope appears to be an original implementation, and neither [Mike] nor we can find any similar devices with a digital display. We did cover one that used a paper printout in a a similar fashion. [Mike] is currently patenting his design, seeing the potential for smaller displays that need multi-angle visibility. The high rotational speed creates significant centrifugal force, which might limit the size of installations. Critically, display selection matters — any screen flicker becomes glaringly obvious at speed.

This device might be the first of its kind, but we’ve seen plenty of zoetropes over the years, including ones with digital displays or ingenious time-stretching tricks. Continue reading “A Surprisingly Simple Omnidirectional Display” →

Tidy POV Display Using The ESP32

November 23, 2022 by Dave Rowntree 9 Comments

Chinese Youtuber [corebb] presents the second version of his POV display. The earlier version used 5050-sized SMT addressable LEDs, which didn’t give great resolution, so he rev’d the design to use a much higher number (160 to be exact) of APA102 LEDs. These are 2mm on the side, making them a little more difficult to handle, so after some initial solder paste wobbles, he decided to use a contract assembly house to do the tricky bit for him. This failed as they didn’t ‘understand’ the part and placed them the wrong way around! Not to be deterred, he had another go with a modified solder stencil, and eventually got the full strip to light up correctly.

Based on an ESP32 (using the Arduino stack) and SDCard for control, and a LiPo cell charged wirelessly, the build is rather tidy. A couple of hall effect switches are mounted at the start of each of the two arms, presumably lining

up with a magnet on the case somewhere, although this isn’t clear. The schematic and PCB appear to have been designed with JLCEDA, which is a repackaging of EasyEDA. We can see the attraction with the heavy integration of this with the JLC and LCSC services. It appears that he even managed to get streamed video working — showing a live video from a webcam — which is quite an undertaking to pull off when you think how much processing needs to happen in real-time. As he alludes to in the video, trying to increase the resolution beyond this point is not viable with the processing capability of the ESP32.

A resin-printed case finishes off the build, with a screw-thread mount added to the rear, to allow typical camera mounts to be used to hold the thing down. A smart move we think.

We love POV displays around here, this spherical POV display is especially fabulous, but you don’t need fancy hardware if you have a handy ceiling fan and a bit of protoboard spare.

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The Basics Of Persistence Of Vision Projects

October 29, 2019 by Zoe Skyforest 6 Comments

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.

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