Laser Scanning A Cave With Homebrew Gear

June 24, 2026 by Zoe Skyforest 10 Comments

How do you measure the inside of a cave? You could do a bunch of hard work with classic surveying gear… or you could just use a laser scanner. [9nl] did the latter, with a scanning rig of his own creation.

The build is based around an Ouster VLP-16 mid-range lidar sensor. It shoots out pulses of light and measures how long it takes them to bounce back in order to determine the range of objects in the vicinity, and thus can be used to great effect for 3D scanning tasks. For [9nl], though, the sensor had a serious limitation. Since it only had a 40-degree field of view, it wasn’t ideal for the desired application of scanning a cave. However, by building a custom rig that could rotate the sensor, [9nl] ended up with a rig that could 3D scan an area through a full 360 degrees. There’s nothing wildly complex involved, just some good old mechanical engineering—putting the sensor on a shaft and spinning it with a belt drive. Then it’s just a matter of processing the data correctly. The hard part is then getting the rig in and out of the cave without breaking anything.

There are plenty of off-the-shelf 3D scanning solutions that can do this work, but few of them come cheap. Plus, rolling your own teaches you a great many things as you hone your solution to your particular needs. Video after the break.

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2026 Frikkin Lasers Contest: Steampunk, 360 O-Scope Does It With Tubes

June 17, 2026 by Tyler August 10 Comments

Audiophiles all know everything sounds better fed through vacuum tubes, but did you know visualizers look better with them, too? That’s what we’re forced to conclude looking at the Tachyscope Laser, a 360-degree oscilloscope display that is [Daniel Ross]’s entry into the ongoing Frikkin Lasers contest.

The diagram makes it look easier than building it probably was.

The laser is a good old-fashioned helium–neon tube — something we see less and less of in this era of solid state lasers — and the wavelength gives the waveform display a retro charm. The actual display is unique in our experience, with the beam shining up through a hollow shaft to bounce off a galvanometer mirror on a spinning platform. Galvo sweeps the laser across a translucent target, which creates the waveform by persistence of vision as it spins at 100 RPM or so.

Does the fact that the audio signal feeds through a tube amp to drive the single galvanometer actually improve the visuals? Only in the sense that those tubes make the steampunk-style enclosure look really, really cool, as does the exposed laser tube. That all of the steampunk elements obviously have a point to them rather than just being a another “glue some gears on it” project is icing on the laser-flavored cake.

The contest runs until July 23rd, so there’s lots of time to get laserin’ — and remember that there are categories for DIY lasers and anything that isn’t a display, just in case you think this project puts the bar too high for a light show. We’ve actually featured one of [Daniel]’s tachyscope waveform visualizers before, but that one, madly enough, spun an actual CRT.

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Image of an elf projected by the laser scanner

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

June 16, 2026 by Tyler August 10 Comments

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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The Frikkin Lasers Contest Starts Now

May 28, 2026 by Elliot Williams 8 Comments

We don’t need to tell you: lasers are awesome. Those tiny red beams aren’t just for frustrating cats, but can do real work, be a source of infinite beauty, or constitute a science project in its own right — and you can win a $150 DigiKey gift certificate simply by writing your project up on Hackaday.io. The contest runs until July 23rd.

Of course, red lasers are only the beginning. If you have enough energy to move electrons into higher orbitals, you can make nearly anything lase. RGB setups can be breathtaking. Powerful IR and UV lasers are real tools. And the DIY side of lasering combines physics and electronics, with a spicy side of danger that needs to be contained.

We love laser builds of all sorts, and we’d like to see yours! Create a new Hackaday.io project that features what you’re working on, and we’ll pick our three favorites for a $150 gift certificate courtesy of this contest’s sponsor, DigiKey.

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A 3D-printed telescope with an infrared laser on the side is pointed out the window of a building at night.

Long-Range Night Vision With An Infrared Laser

May 18, 2026 by Aaron Beckendorf 19 Comments

Most consumer-grade night vision devices are basically a standard camera without the usual filter to block near infrared (NIR) light, which are then paired with a NIR light source that’s not visible to the human eye. Unlike the passive night vision provided by an image intensifier tube, these can’t resolve objects beyond the beam of their illumination source. On the other hand, if, as [Project 326] did, you use an infrared laser to illuminate the scene, you can still get a very long range out of these devices.

[Project 326]’s device consists of a previously-built reflecting telescope focusing a distant scene in to a webcam with the infrared filter removed, with the infrared laser illuminating the scene. Finding a suitable laser took some effort: the first option, a secondhand fiber-coupled industrial laser, was accidentally over-volted and destroyed during testing. The second had a fiber output which proved extremely hard to terminate, and a third laser couldn’t be collimated correctly. The final laser was a Vertical-Cavity Surface-Emitting Laser (VSEL) diode array element driven at about two Watts and collimated by a small lens.

This illumination setup is safe at a long range, but only at a long range. The laser was strong enough to burn cardboard at close range, but out at about 500 meters, the beam had spread until it was less than a hundredth of the standard safety limit. To make sure that nothing else would get in the way of the beam, it was shone down from the top of a tall building. Testing with a power meter also showed that at a long range, the beam was weaker than expected. It turned out that the wavelength used (940 nm) is attenuated by water vapor, to the point that up to 70% of the beam’s strength was lost before reaching the target. Despite this, and despite a rather linear beam profile, a somewhat dark image was still visible at 650 meters.

If you’re looking for a somewhat more versatile long-range night vision device, check out one based on an image intensifier. Another approach is to use a very high-sensitivity camera.

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RGB image from the projector, with human for scale.

RGB Laser Projector Does Colorful Asteroids And Much More

May 6, 2026 by Tyler August 13 Comments

Have you thought about building a galvonometer-based laser projector, but don’t know where to start? There are a lot of resources out there, but you could do worse than to check out [Breq] and [Mia]’s laser vector project, which provides a very well-documented and low-cost starting point. They boast that the most expensive part of the project was the ANSI-certified safety glasses, which shows a dedication to safety we wish more people would show when playing with coherent light.

The rest of the parts — from the galvos to the RGB lasers module with dichoric mirrors to keep everything on the same beamline, to the ESP32 module driving everything — was ordered from AliExpress, and not from the most expensive vendors, either. Considering that, it works remarkably well.

If you’re not playing *Asteroids* on your vector display, why even bother?

Like all DIY laser projectors, this one does vector graphics, sweeping the beam fast enough that the human eye registers crisp, clean lines. Galvonometers, or galvos for short, take analog input, so a DAC is needed — fortunately the ESP32-S2 comes with a pair built in. The custom PCB of course has audio-in for the usual Lissajous lightshow or oscilloscope music, but with an ESP32 as the brains, you can do a lot just inside the projector.

Like what? Well, play Asteroids, for instance, using Wiimote controllers. Project a lovely clock. Render text input in various single-stroke fonts. More to the point, since this is a projector, take arbitrary SVG data and project literally any image you’d like — as long as it doesn’t have too many lines, at least. The galvos in this project are rated at 20,000 points per second, which is not exceedingly fast: they were chosen to meet the budget, not the greatest-possible speed.

More to the point is that this is one of the better-documented projects of this type we’ve seen. [Breq] doesn’t just tell us how to build the projector, but why they designed it that way. We really encourage you to give it a read if you’ve been thinking of getting into this sort of display.

We’ve seen plenty of laser projectors before, most of them producing vector images like this one. If you really must have a raster display, though, that’s also an option. Don’t count out vector images, though — they could even replace your Christmas lights.

Thanks to [CapinRedBeard] for the tip! Remember to send any bright ideas you see to our tips line, coherently lit or no.

Mist, Mirrors, Laser : Multi-view 3D Projection

April 26, 2026 by Tyler August 13 Comments

“Lights, camera, action!” might have been the call when recording back in the day, but for an awesome three-dimensional viewing experience, you might try yelling “Mist, Mirrors, Laser!” and following in the footsteps of [Ancient]’s latest adventure in voxel displays, which is also embedded below.

He starts with a naive demonstration: take a laser projector and toss an image into a flat cloud of mist. That demonstrates that yes, the mist does resolve an image, and that the viewing angle is very poor– that is, brightness drops off sharply when you’re out of line from the projector. In this case, that’s a good thing! It means more angles can be projected into that mist for a three-dimensional, hologram effect.

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