Spellcasting Gun Uses POV Display, Not Magic

May 29, 2018 by 25 Comments

Persistence 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.

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A Nicely Crafted POV Lightsaber

May 27, 2018 by 7 Comments

We need to have a talk. As tough a pill as it is to swallow, we have to face that fact that some of the technology promised to us by Hollywood writers and prop makers just isn’t going to come true. We’re never going to have a flux capacitor, actual hoverboards aren’t a real thing, and nobody is going to have sword fights with laser beams.

But just because we can’t have real versions of these devices doesn’t mean we can’t make our own prop versions with a few value-added features, like this cool persistence-of-vision lightsaber. [Luni], better known around these parts as [Bitluni] and for his eponymous YouTube channel where he performs wizardry like turning an ESP32 into a software-defined television station, shows he’s no slouch at more mechanical builds either. The hardware is standard POV fare, with a gyro to sense the position of the lightsaber hilt and an ESP32 to run the long Neopixel strip in the blade. There’s also a LiPo pack and a biggish DC-DC converter; the latter contributes mightily to the look of the prop, with its large heatsinks that stick out from the end of the aluminum tubing hilt. There’s also a small speaker and amp for the requisite sound effects on startup and shutdown, and the position-sensitive thrumming is a nice touch too. Check out the POV action in the video below.

What’s that you say? You recall seeing a real lightsaber here before? Well, sort of, but that’s pushing things a bit. Or perhaps you’ve got this more destructive version in mind.

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Lucky Cat POV Display Ditches The Waving And Windmills Out Of Control

May 15, 2018 by 10 Comments

If you’ve been in a Japanese restaurant, you’ve probably seen a maneki-neko, the lucky cat charm, where a cat welcomes you with a beckoning arm. It’s considered to bring good luck, but we’re not sure if [Martin Fitzpatrick] is pushing his luck with this Lucky Cat POV display. He hacked one of the figurines so the arm forms a persistence of vision (POV) display, where blinking LEDs on the paw create a dot-matrix style display.

Inside the hapless neko is a Wemos D1, motor driver, and a few other components that turn the cat into a working display. The five LEDs he attached to the paw are wide enough to display 5×7 characters. The tricky part in the mechanical design is getting signals from a stationary base to a spinning arm(ature). In this case it was easily solved with a 6-wire slip ring from Adafruit. [Martin] revs the lucky cat up using a brushed DC motor and a couple of gears.

The ESP8266 is running MicroPython — the combination should make this a snap to hook into any web service API you want to display your own messages. Right now the arm doesn’t have positional awareness so the message isn’t locked in a single position like it would be if a hall effect sensor was used. But [Martin] says there’s plenty of room left inside the cat and a future upgrade could include stashing the batteries inside for a cordless, all-in-one build. If he takes that on it’s a perfect time to add some type of shaft encoding as well.

Check the Lucky Cat showing off in the clip after the break.

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Building A POV Display On A PC Fan

April 21, 2018 by 18 Comments

We’ve covered plenty of persistence of vision (POV) displays before, but this one from [Vadim] is rather fun: it’s built on top of a PC fan. He’s participating in a robot building competition soon and wanted to have a POV display. So, why not kill two birds with one stone and build the display onto a fan that could also be used for ventilation?

The display is a stand-alone module that includes a battery, Neopixels, Arduino and an NRF240L01 radio that receives the images to be displayed. That might seem like overkill, but putting the whole thing on a platform that rotates does get around the common issue of powering and sending signals to a rotating display: there is no need for slip connections.

[Vadim] goes into a good level of detail on how he built the display, including the problems he had diagnosing a faulty LED chip, and why it is important to test at each stage as it is easier to debug when the display isn’t whizzing around at high speed.

It’s a bit of a rough build that uses more protoboard than might be necessary, but we’re keeping our fingers crossed that it doesn’t fly off during the competition.

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A Simple POV Business Card

March 9, 2018 by 28 Comments

The business card is an odd survivor from the past, when you think about it. When a salesman in a Mad Men style suit stepped out of his Studebaker and walked past a room full of typists to the boss’s wood-paneled office, he would have handed over a card as a matter of course. It would get filed away in the Rolodex.

These days, making your card stand out from the crowd of print-shop specials has become an art form. In our community this extends to cards with integrated electronics, such as this one with a persistence-of-vision display driven by an ATtiny from [James Cochrane], shown in the video below.  It’s by no means the first such card, but he takes us through its design and construction in great detail which makes the video below the break worth a look. If you have never made a toner transfer PCB for example, you can see how his was made.

He makes the point that while a POV spinner needs only to display in one direction, a card has to be waved back and forth. Thus it needs to change the direction of its display, and needs a tilt sensor to activate this. His construction method uses through-hole components, but is surface mount in that they are soldered to the top surface of the board. The result is a rather attractive POV card that maybe isn’t something you’d hand out to all and sundry, but perhaps that’s not the point.

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Not Your Typical POV Clock

February 7, 2018 by 23 Comments

Persistence of vision displays are fun, and a natural for clocks, but they’re getting a little Nixie-ish, aren’t they? There are only so many ways to rotate LEDs and light them up, after all. But here’s something a little different: a POP, or “persistence of phosphorescence” clock.

[Chris Mitchell] turned the POV model around for this clock and made the LEDs stationary, built into the tower that holds the slowly rotated display disk. Printed from glow-in-the-dark PLA, the disk gets charged by the strip of UV LEDs as it spins, leaving behind a ghostly dot matrix impression of the time. The disk rotates on a stepper, and the clock runs on a Nano with an RTC. The characters almost completely fade out by the time they get back to the “write head” again, making an interesting visual effect. Check it out in the video after the break.

Our only quibble is the choice to print the disk rather than cut it from sheet stock. Seems like there has to be commercially available phosphorescent plastic, or even the glow-in-the-dark paper used for this faux LED scrolling sign. But if you’ve got glowy PLA, why not use it?

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POV Display Is FAN-tastic

December 23, 2017 by 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?