POV Display Is FAN-tastic

December 23, 2017 by Will Sweatman 13 Comments

Persistence-of-vision displays come in all shapes and sizes. But when you get a couple of [Bruce Land’s] students involved, well let’s just say they tend to up the ante. When [Emily] and [Han] decided to make a POV display for their next class project, they did so with style. Unsatisfied with smaller displays they saw on YouTube – they decided to make a larger one out of an old box fan and a DotStar LED strip, which are similar to NeoPixels except they use SPI, which means you can update the LEDs at a much faster rate. This makes them perfect for a POV display!

As usual with projects out of Cornell’s EE class – this POV project is extremely well documented and it’s nice to see the fundamental details of a POV display explained. So be sure to check out this project if you’re rusty on the inner workings of POV displays.

We’ve seen some interesting POV displays here at Hackaday, including one strapped to a dog to display its running speed. What’s the coolest POV display you’ve seen?

Dog-POV: Canine Speed Indicator

October 7, 2017 by John Baichtal 16 Comments

[Johan Beyers] built an elegantly simple Dog Speedometer project that uses a POV display to display a running dog’s speed without the benefit of an accelerometer. Using an Arduino (looks like it might be a D-love) and a line of 5 LEDs, [Johan] built a dirt-simple POV — 39 lines of code — that times out the flashes so that an immobile viewer sees the dog’s speed. How do you know your pup’s loping speed? That’s the beauty of this project.

Instead of putting all of the LEDs in a line, they are arranged in a V-shape. Because of this spatial offset, the patterns flashed out only “look right” at the right speed. Each number is flashed at a different speed, so you just look for the least distorted numeral.

[Johan]’s code does only what it needs to get the job done. The character data are stored in arrays that are played back directly to the pins of PORTD — avoiding most of the usual Arduino-style complexity with pin definitions and other foolery.

POV displays can be leveraged to add pizzazz to any project — this CD-ROM POV clock and this wind-powered POV weather station come to mind.

Spinning 3D POV Display: A High School Term Project

November 16, 2016 by Jenny List 25 Comments

If you are a fan of sci-fi shows you’ll be used to volumetric 3D displays as something that’s going to be really awesome at some distant point in the future. It’s been about forty years since a virtual 3D [Princess Leia] was projected to Star Wars fans from [R2D2]’s not-quite-a-belly-button, while in the real world it’s still a technology with some way to go. We’ve seen LED cubes, spinning arrays, and lasers projected onto spinning disks, but nothing yet to give us that Wow! signaling that the technology has truly arrived.

We are starting to see these displays move from the high-end research lab into the realm of hackers and makers though, and the project we have for you here is a fantastic example. [Balduin Dettling] has created a spinning LED display using multiple sticks of addressable LEDs mounted on a rotor, and driven by a Teensy 3.1. What makes this all the more remarkable is that he’s a secondary school student at a Gymnasium school in Germany (think British grammar school or American prep school).

There are 480 LEDs in his display, and he addresses them through TLC5927 shift registers. Synchronisation is provided by a Hall-effect sensor and magnet to detect the start of each rotation, and the Teensy adjusts its pixel rate based on that timing. He’s provided extremely comprehensive documentation with code and construction details in the GitHub repository, including a whitepaper in English worth digging into. He also posted the two videos we’ve given you below the break.

What were you building in High School? Did it involve circuit design, mechanical fabrication, firmware, and documentation? This is an impressive set of skills for such a young hacker, and the type of education we like to see available to those interested in a career in engineering.

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MagicShifter 3000: An Over-Engineered POV Stick With A 15-Year Journey

August 22, 2016 by Moritz Walter 64 Comments

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.

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Blinktronicator’s POV Sends Our Eyebrows Rocketing Skyward

July 1, 2016 by Mike Szczys 18 Comments

You think you’ve seen everything that there is to see regarding blinking LEDs and then a simple little trick proves you wrong. Our friend [Zach Fredin], aka [Zakqwy], added a pander mode to his blinky board which shows the Hackaday Jolly Wrencher in a Persistence of Vision mode. We love pandering, and obviously you just need to start the mode and wave the board back and forth. But in thinking the obvious you’d be wrong.

blinktronicator-board — Badass deadbug soldering to “fix” a mirrored shift register footprint

In the video after the break [Zach] demonstrates all the features of the blinktronicator and it’s recently finalized firmware. The tiny little board is a USB dongle featuring two buttons and an arc of sixteen LEDs in a rainbow of colors. When we say tiny, we mean it. Those LEDs are 0402 components and the board was small enough (and interesting enough) to receive an honorable mention in the Square Inch Project.

You would think that soldering all those LEDs by hand would be the trick, but [Zach] pulled off a much more difficult feat. Look closely at the image here (or click to embiggen). The two shift register footprints on the prototype were mirrored. He deadbug soldered each of them using — get this — the individual strands from some 28 AWG stranded wire. You sir, get the hardcore hand soldering badge and then some.

Okay, we’ll stop beating around the bush. The ATtiny45 on this board isn’t connected to the USB data lines, they’re only for power. That means, at its heart this is purely a blinking LED project, albeit one that uses the huge range of colors of the PICOLED family of parts. [Zach] did well with just two user inputs, but it’s the very simple POV party trick that really sucked us in. Instead of waving the board around, [Zach] uses a metal offset spatula as a mirror. Moving it back and forth unfolds the carefully timed flashes to draw your message in the air. Such a simple concept, but so satisfying to see it applied in a slightly different way.

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POV Globe Display Spins Up Full Color Tupac

December 24, 2015 by Dan Maloney 11 Comments

Persistence of vision projects were once all the rage, judging by a quick review of the literature here on Hackaday. They’ve tapered off a bit lately, but this impressive full-color globe display might just kick-start some new POV projects.

Built as a final project for an EE course, [Evan] and [Kyle]’s project is more about the control electronics and programming than the mechanical end of the build. Still, spinning a 12″ ring of 1/4″ thick acrylic with a strip of APA102 LEDs glued to the edge takes some thoughtful engineering. While the build appears sturdy, [Evan] does admit to a bit of wobble under full steam, which was addressed by adding some weight to the rig. We wonder if mounting half the LEDs on each side of the ring to balance the forces wouldn’t have worked better. True, it would have complicated the coding for the display, but maybe that would have been good for extra points. In any case, the display turned out well and the quality of the images is great. And as an aside: how awesome is it that we live at a time when you can order a six-circuit slip-ring for a project like this for less than $20?

It’s the end of the semester and we love seeing the final projects that have just made it across the finish line. This globe is one, yesterday we saw a voice-controlled digital eye exam, and if you have or know of a final project, don’t forget send us the link!

If POV globes are your thing, be sure to set the Hackaday WABAC machine a few years and check out this Death Star design from 2012 or this globe from 2010.

Caption CERN Contest – Not Your Father’s POV Display

May 21, 2015 by Adam Fabio 15 Comments

Accidents happen – but the awesome quotes you all sent in for Week 15 of the Caption CERN Contest were no accident. A huge thank you for our biggest week yet! The scientists in this week’s image are definitely cleaning up after some type of nasty accident. At first blush it looks like an electrical problem in the coils of what appears to be part of a beam line. With all that soot and radiation dangers to boot, only the photographer and the people in the image know for sure!

The Funnies:

“This is the second server these idiots have fried! What the hell’s a Hulu, and why are they trying to watch Gilligan’s Island with it?” Thanks to some unplanned quantum tunneling, Berners-Lee was even further ahead of his time than he thought” – [The Green Gentleman] (Two weeks in a row!)
“I found the bug. Who gets to tell Joe he’s sterile?”- [jonsmirl]
“‘I told the Captain that she couldn’t take any more’ – Scotty” – [md_reeves]

The winner for this week is [Mr. mmWave] himself, [Tony Long] with “Hardware Accelerator moto – Fail Fast, Fail Often. Also applies to Accelerator Hardware.” [Tony] will be debugging his next microwave mm band ham radio with a Logic Pirate From The Hackaday Store! Congratulations [Tony]!

Week 16: This is not your father’s POV Display!

Scientists at CERN have come up with some amazing science advancements. They’ve also needed ways to display the data they collect. This image may depict some incredible new way to display data collected from a high power physics experiment – or it could be a scientist’s project for the CERN science fair. We may never know.

The album is titled CHAMBRE A ETINCELLES DANS EXPO TECHNOL, which roughly translates to “Sparks in the technology expo room”. The lines traveling between the three horizontal display devices definitely appear to be aligned. Are they sparks of electricity? You tell us!

Last week’s prize was a Logic Pirate. This week we’re giving away a Bus Pirate from The Hackaday Store.