Phosphorescent Laser Painting

January 18, 2011 by Joseph Thibodeau 23 Comments

Here’s a simple and interesting idea that increases the visual persistence of a laser scanner image. Using glow-in-the-dark paint, [Daito Manabe] prepares a surface so that the intense light of a laser leaves a trace that fades slowly over time. He’s using the idea to print monochromatic images onto the treated surface, starting with the darkest areas and ending with the lightest. The effect is quite interesting, as the image starts out seeming quite abstract but reveals its self with more detail over time.

As evidenced in the test videos, the bursts of laser scanning are matched to the fade rate of the paint. Therefore it would seem that the time taken to “write” an image is directly proportional to the desired visual persistence of the final image. We wonder, by combining clever timing and variable laser intensity could you write images much more quickly? How hard would it be to use this for moving pictures? With the ability to create your own tiny laser projector, and even an RGB scanner, there must be a lot of potential in this idea for mind-blowing visual effects. Add portability by using a phosphor-treated projection screen!

Share your ideas and check out the test videos after the break.

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RGV Laser

February 10, 2010 by Jakob Griffith 12 Comments

[Carl] sure has come a long way with laser modifications, now introducing his portable RGV Full Colour Laser. Although it feels just like yesterday when he showed us his green spiro and his Lego diffraction grating projector.

But enough of the past, the RGV laser is built using a White Fusion Mixing Kit and his own Full Colour Driver Extension. We couldn’t find any circuit diagrams or code to build your own at the moment, but it appears fairly straight forward and you can always take a look at [c4r0’s] Colour Laser.

Light Replaces Electrons For Giant Vector-Graphics Asteroids Game

March 8, 2017 by Dan Maloney 24 Comments

For all its simplicity, the arcade classic Asteroids was engaging in the extreme, with the ping of the laser, the rumble of the rocket, the crash of crumbling space rocks, and that crazy warble when the damn flying saucers made an appearance. Atari estimates that the game has earned operators in excess of $500 million since it was released in 1979. That’s two billion quarters, and we’ll guess a fair percentage of those coins came from the pockets of Hackaday’s readers and staff alike.

One iconic part of Asteroids was the vector display. Each item on the field was drawn as a unit by the CRT’s electron beam dancing across the phosphor rather than raster-scanned like TV was at the time. The simple graphics were actually pretty hard to create, and with that in mind, [standupmaths] decided to take a close look at the vector display of Asteroids and try to recreate it using a laser.

To be fair, [Seb Lee-Delisle] does all the heavy lifting here, with [standupmaths] providing context on the history and mathematics of the original vector display. [Seb] is a digital artist by trade, and has at the ready a 4-watt RGB laser projector for light shows and displays. Using the laser as a replacement for the CRT’s electron beam, [Seb] was able to code a reasonably playable vector-graphic version of Asteroids on a large projections screen. Even the audio is faithful to the original. The real treat comes when the laser is slowed and a little smoke added to show us how each item is traced out in order.

All [Seb]’s code is posted on GitHub, so if you have a laser projector handy, by all means go for it. Or just whip up a custom vector display for your own tabletop version of Asteroids.

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Too Many Pixels

January 14, 2023 by Elliot Williams 39 Comments

Sometimes simpler is more impressive than complicated, and part of this is certainly due to Arthur C. Clarke’s third law: “Any sufficiently advanced technology is indistinguishable from magic.”. It’s counter-intuitive, though, that a high-tech project would seem any less amazing than a simpler one, but hear me out.

I first noticed this ages ago, when we were ripping out the blue laser diodes from Casio XJ-A130 laser projectors back when this was the only way to get a powerful blue laser diode. Casio had bought up the world’s supply of the 1.5 W Nichias, and was putting 24 of them in each projector, making them worth more dead than alive, if you know what I mean. Anyway, we were putting on a laser show, and the bright blue diode laser was just what we needed.

RGB Laser show — A sweeter setup than mine, but you get the idea.

Color laser setups take three or more different lasers, combine the beams, and then bounce them off of mirrors attached to galvos. Steer the mirrors around, and you can project vector images. It’s pretty cool tech, and involves some serious fine-tuning, but the irony here is that we were tearing apart a device with 788,736 microscopic DLP mirrors to point the lasers through just two. And yet, a DIY laser show is significantly cooler than just putting up your powerpoint on the office wall.

The same thing goes for 2D plotting machines like the AxiDraw. The astonishing tech behind any old laser printer is mind-numbing. Possibly literally. Why else would we think that art drawn out by a pen in the hands of a stepper-powered robot is cooler than the output of a 1600 DPI unit coming from HP’s stable? I mean, instead of running an hours-long job to put ink on paper with a pen, my Laserjet puts out an image in ten seconds. But it’s just not as much fun.

So here we are, in an age where there’s so darn much magic all around us, in the form of sufficiently advanced technology, that comprehensible devices are actually more impressive. And my guess is that it’s partly because it’s not surprising when a device that’s already magic does something magical. I mean, that’s just what it’s supposed to do. Duh!

But when something beautiful emerges from a pair of mirrors epoxied to shafts on springs turned by copper coils, that’s real magic.

When Is One Pixel Cooler Than Millions?

July 9, 2022 by Elliot Williams 14 Comments

On vacation, we went to see a laser show – one of the old school variety that combines multiple different lasers of many different colors together into a single beam, modulates them to create different colors, and sends it bouncing off galvos to the roof of a planetarium. To a musical score, naturally.

When I was a kid, I had no idea how they worked, but laser shows were awesome. As a younger grownup hacker, and after some friends introduced me to the dark arts, I built my own setup. I now know how they work from the deepest innards out, and they are no less awesome. Nowadays, you can get a capable set of galvos and drivers for around a hundred bucks from the far east, it’s fair to say that there’s no magic left, but the awesome still remains.

RGB laser — “laser show” by Ilmicrofono Oggiono

At the same time, lasers, and laser shows, are supremely retro. The most stunning example of this hit me while tearing apart a Casio projector ages ago to extract the otherwise unobtainable brand new 455 nm blue laser diodes. There I was pulling one diode out of an array of 24 from inside the projector, and throwing away the incredibly powerful DSP processor, hacking apart the precision optical path, and pulling out the MEMS DLP mirror array with nearly a million little mirrors, to replace it with two mirrors, driven around by big old coil-of-wire electromagnets. Like a caveman.

But still, there’s something about a laser show that I’ve never seen replicated – the insane color gamut that they can produce. It is, or can be, a lot more than just the RGB that you get out of your monitor. Some of the colors you can get out of a laser (or a prism) are simply beautiful in a way that I can’t explain. I can tell you that you can get them from combining red, blue, green, cyan, and maybe even a deep purple laser.

What you get with a laser show pales in comparison to the multi-megapixel projectors in even a normal movie theater. Heck, you’ve really got one pixel. But if you move it around fast enough, and accompany it with a decent soundtrack, you’ve still got an experience that’s worth having while you still can.

[Banner image from a positively ancient RGB laser hack. We need more! Send us yours!]

The Smallest Large Display Is Projected Straight Onto Your Retina

April 15, 2020 by Maya Posch 42 Comments

For most of human history, the way to get custom shapes and colors onto one’s retinas was to draw it on a cave wall, or a piece of parchment, or on paper. Later on, we invented electronic displays and used them for everything from televisions to computers, even toying with displays that gave the illusion of a 3D shape existing in front of us. Yet what if one could just skip this surface and draw directly onto our retinas?

Admittedly, the thought of aiming lasers directly at the layer of cells at the back of our eyeballs — the delicate organs which allow us to see — likely does not give one the same response as you’d have when thinking of sitting in front of a 4K, 27″ gaming display to look at the same content. Yet effectively we’d have the same photons painting the same image on our retinas. And what if it could be an 8K display, cinema-sized. Or maybe have a HUD overlay instead, like in video games?

In many ways, this concept of virtual retinal displays as they are called is almost too much like science-fiction, and yet it’s been the subject of decades of research, with increasingly more sophisticated technologies making it closer to an every day reality. Will we be ditching our displays and TVs for this technology any time soon?

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Fluorescence Microscope On A Hacker’s Budget

March 30, 2019 by Brian McEvoy 19 Comments

Some of biology’s most visually striking images come from fluorescence microscopes. Their brilliant colors on black look like a neon sign from an empty highway. A brand new fluorescence microscope is beyond a hacker’s budget and even beyond some labs’, but there are ways to upgrade an entry-level scope for the cost of a few cups of coffee. [Justin Atkin] of The Thought Emporium published a scope hacking video which can also be seen below. He is becoming a reputed scope modder.

This video assumes a couple of things for the $10 price tag. The first premise is that you already have a scope, a camera adapter, and a camera capable of shooting long exposures. The second premise is that you are willing to break the seals and open the scope to make some reversible mods. Since you are reading Hackaday, maybe that is a given.

The premise is simple compared to the build, which is not rocket surgery, the light source from below illuminates the subject like a raver, and the filter removes any light that isn’t spectacular before it gets to the camera.

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