Image of an elf projected by the laser scanner

2026 Frikkin Lasers Contest: Glow Engine Is Like An Open Air Slow Scan CRT

Slow-scan CRTs were never exactly common compared to their faster cousins, but given the popularity of Slow Scan TV (SSTV) amongst hams and NASA broadcasts, many of you are probably familiar with them. The slow scan rate of SSTV meant it required much less bandwidth, but in the early days you needed a CRT with a long-persistence phosphor to hold onto the image. [AJRussell]’s Glow Engine works much the same, with one key difference — instead of cathode rays, he’s using a frikkin laser beam.

In this case, the phosphor is Strontium Aluminate, the same stuff that gives most glow-in-the-dark toys and filament its kick. Energized by a 405 nm laser of questionable wattage, the phosphor will glow for several seconds, allowing the creation of an image. So while this is a laser projector, it works more like a CRT than most galvo projectors, which rely on Persistence of Vision to create an image. Here it’s persistence of fluorescence.

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Hackaday Links: October 19, 2025

After a quiet week in the news cycle, surveillance concern Flock jumped right back in with both feet, announcing a strategic partnership with Amazon’s Ring to integrate that company’s network of doorbell cameras into one all-seeing digital panopticon. Previously, we’d covered both Flock’s “UAVs as a service” model for combating retail theft from above, as well as the somewhat grassroots effort to fight back at the company’s wide-ranging network of license plate reader cameras. The Ring deal is not quite as “in your face” as drones chasing shoplifters, but it’s perhaps a bit more alarming, as it gives U.S. law enforcement agencies easy access to the Ring Community Request program directly through the Flock software that they (probably) already use.

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Researching Glow-Powder Left A Few Scars

Content warning: Human alteration and scalpels.
General warning: We are not speaking as doctors. Or lawyers.

If you watch sci-fi, you probably do not have to think hard to conjure a scene in a trendy bar where the patrons have glowing make-up or tattoos. That bit of futuristic flair was possible years ago with UV-reactive tattoo ink, but it has the unfortunate tendency to permanently fade faster than traditional ink. [Miana], a biohacker, wanted something that could last forever and glow on its own. After months of research and testing, she presents a technique with a silica-coated powder and scarification. Reddit post with graphic content.

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Glow In The Dark PCBs Are Pretty Cool

What if circuit boards could glow in the dark? It’s a fun question, and one [Botmatrix] sought to answer when approached by manufacturer PCBWay to run a project together. It turns out that it’s quite possible to make glowing PCBs, with attractive results. (Video after the break.)

Specifically, PCBWay has developed a workable glow-in-the-dark silkscreen material that can be applied to printed circuit boards. As a commercial board house, PCBWay hasn’t rushed to explain how precisely they pulled off this feat, but we don’t imagine that it involved anything more than adding some glow-in-the-dark powder to their usual silkscreen ink, but we can only speculate.

On [Botmatrix]’s end, his video steps through some neat testing of the performance of the boards. They’re tested using sensors to determine how well they glow over time.

It might seem like a visual gimmick, and to an extent, it’s just a bit of fun. But still, [Botmatrix] notes that it could have some practical applications too. For example, glow-in-the-dark silkscreen could be used to highlight specific test points on a board or similar, which could be instantly revealed with the use of a UV flashlight. It’s an edge case, but a compelling one. It’s also likely to be very fun for creating visually reactive conference badges or in other applications where the PCB plays a major cosmetic role.

[Botmatrix] says these are potentially the first commercially-available glow-in-the-dark printed PCBs. We love glow in the dark stuff; we’ve even explored how to make your own glowing material before, too. .

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DIY Strontium Aluminate Glows In The Dark

[Maurycyz] points out right up front: several of the reagents used are very corrosive and can produce toxic gasses. We weren’t sure if they were trying to dissuade us not to replicate it or encourage us to do so. The project in question is making strontium aluminate which, by the way, glows in the dark.

The material grows strongly for hours and, despite the dangers of making it, it doesn’t require anything very exotic. As [Maurycyz] points out, oxygen and aluminum are everywhere. Strontium sounds uncommon, but apparently, it is used in ceramics.

For the chemists among us, there’s an explanation of how to make it by decomposing soluble nitrate salts. For the rest of us, the steps are to make aluminum hydroxide using potassium alum, a food preservative, and sodium hydroxide. Then, it is mixed with nitric acid, strontium carbonate, europium, and dysprosium. Those last elements determine the color of the glow.

A drying step removes the acid, followed by dissolving with urea and water. The heat of the reaction wasn’t enough to form the final product, but it took time with an oxy-propane torch to form blobs of strontium aluminate. The product may not have been pure, because it didn’t glow for hours like commercial preparations. But it did manage to glow for a few minutes after light exposure.

We try to limit our chemistry to less toxic substances, although ferric chloride can make a mess. You could probably track down the impurities with a gas chromatograph. What we really want is a glow-in-the-dark car antenna.

Spotted At Supercon: Glowtape Wearable Display

We’re big fans of unusual timepieces here at Hackaday, so it didn’t take long before somebody called our attention to the gloriously luminescent watch that [Henner Zeller] was wearing at this year’s Supercon.

He calls it the Glowtape, and it uses a dense array of UV LEDs and a long strip of glow-in-the-dark material to display the time and date, as well as images and long strings of text written out horizontally to create an impromptu banner. It looked phenomenal in person, with the energized areas on the tape glowing brightly during the evening festivities in the alleyway.

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A hand holding a paper cup pours orange resin into a mold. There are several different colors in a spiral inside a circular mold on a circular platform with holes around its perimeter sitting on a wooden table.

Reproducing Vinyl Records In Resin

While most are just plain, vinyl records can be found in a variety of colors, shapes, and some even glow in the dark. [Evan and Katelyn] decided to spruce up a plain old record by replicating it in bright, glow-in-the-dark resin.

By first making a silicone mold of the vinyl record and then pouring several different colors of resin into the resulting mold, [Evan and Katelyn] were able to make a groovy-looking record that still retained the texture necessary to transmit the original sounds of the record. The resulting piece has some static, but the music is still identifiable. That said, audiophiles would probably prefer to leave this up on the wall instead of in their phonograph.

Acrylic rings were laser cut and bolted together to build the form for the silicone mold with the original record placed at the bottom. To prevent bubbles, the silicone was degassed in a vacuum chamber before pouring over the record and the resin was cured in a pressure pot after pouring into the resulting mold.

If you’re interested in how records were originally made, check out this installment of Retrotechtacular. A more practical application of resin might be this technique to reproduce vintage plastic parts.

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