Portable ESP32 RGB Lasershow Has All The Trimmings

Perhaps there was a time when fancy laser effects were beyond those without the largest of bank accounts, but today they can be created surprisingly easily. [Corebb] shows us how with a neat unit using an off the shelf RGB laser module and mirror module, driven by a ESP32 with software designed to make it as easy as possible to use.

The video below the break is in Chinese so you’ll have to turn on the subtitles if you’re an Anglophone, and it takes us through the whole process. It’s mounted in an SLA 3D printed enclosure which neatly holds all the parts. The ESP32 module drives a couple of DACs which in turn drive the galvanometer motors through a pair of amplifiers.

Then the software allows all sorts of custom displays for your creative expression, including uploading quick sketches over WiFi. Beyond pretty patterns we see it mounted on a bicycle for a head-up display of speed and navigation info. Even if it does fall off and break at one point we can see that could be an extremely useful accessory.

All the code can be found in a GitHub repository should you wish to try for yourself. Meanwhile we’ve covered a lot of laser projector projects here in the past, including most recently this one using stepper motors in place of galvanometers.

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Madness Or Genius? FDM Printing With Resin

We aren’t sure what made him think of it, but [Proper Printing] decided to make an FDM printer lay down resin instead of filament. Why? We still aren’t sure, but we admire the effort nonetheless. In principle, extruding resin shouldn’t be much different than other liquid things you print like icing or concrete. Then you’d need to UV-cure the viscous liquid quickly. In fact, they wound up making up a paste-like resin using several chemicals and a filler.

Armed with the paste, it would seem like the big obstacles would be over. Instead of part cooling fans, the printer now has two laser heads focused on the print area. Printing in vase mode avoids some problems, but the first few attempts were not very successful.

With a bit of perseverance, the setup did work — for a while. More fine tuning got acceptable results. However, he eventually changed the filler material and got a passable Benchy to print. Nothing to be proud of, but recognizable. Honestly, we were surprised that the laser’s didn’t cure the material still inside the nozzle and cause terrible clogs.

Why put this much effort into doing this? We have no idea. Should you try it? Probably not. Of course, being able to print a paste has its own value. Perhaps delivering glue or solder paste, for example. But you generally won’t need to make tall prints with that kind of material. Then again, we’ve never been opposed to doing something “just because.”

After all, why make a musical instrument out of a Game Boy? Why make a modem with tin cans? You might as well extrude resin.

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Laser Projector Relies On Steppers Rather Than Galvanometers

Laser light shows have always been real crowd-pleasers. There’s just something about the frenetic movement of a single point of intensely bright light making fluid animations that really captures the imagination. Large-scale laser shows require a lot of gear, of course, but that doesn’t mean you can’t get in on the fun yourself using something like this homebrew X-Y laser projector.

This is actually [Stanley]’s second pass at a stepper-based DIY projector; we featured his previous build back in 2016. This time around, he wanted to move beyond the “module mix-and-match” style of construction, so rather than use an Arduino and stepper shield, he rolled his own controller PCB to hold an ESP32 and a pair of STSPIN220 stepper drivers. The business end of the new version saw improvements, too — given that he was seeing unwanted softening of corners and curving of straight lines in the first projector’s images, he opted for smaller steppers holding smaller mirrors this time around. There’s also a new 3D printed chassis to hold everything, simplifying the build and keeping the two mirrors in better alignment.

The video below has the build details and some nice footage of the projector in action — it’s hard to go wrong with lasers and smoke. The performance seems pretty good, so the improvements seem to have paid off. And for those of you tapping out your “Should have used galvos” comments below, relax; [Stanley] says he’s thinking about ways to make his own galvanometers for the next version.

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Laser Engraving, Up Close

You know you aren’t supposed to watch your laser while it is cutting or engraving. But [Alex] hosted Wired in his studio and showed them how lasers engrave metal with a fiber laser. You can see the video below.

If you haven’t used a fiber laser, you might be surprised that while a 60 W model can burn metal, it does absolutely nothing to [Alex’s] hand. We wouldn’t try that, by the way, with the common diode lasers you see in most hacker’s labs these days. The video isn’t terribly technical, but it is interesting to see different metals succumb to the powerful laser. There are a few tips about marking different metals in different ways and how to deal with thermal expansion and other effects.

Fiber lasers aren’t as common as diode engravers in private shops, but we assume it is just a matter of time before they get cheaper. Not to mention their widespread use commercially means surplus units might become available, too.

If you are interested in lasers, [Alex’s] YouTube channel has quite a few interesting videos to check out. If you need more power, how’s 200 kW? Then again, even 20 W will get you something useful.

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Laser Zaps Cockroaches Over One Meter

You may have missed this month’s issue of Oriental Insects, in which a project by [Ildar Rakhmatulin] Heriot-Watt University in Edinburgh caught our attention. [Ildar] led a team of researchers in the development of an AI-controlled laser that neutralizes moving cockroaches at distances of up to 1.2 meters. Noting the various problems using chemical pesticides for pest control, his team sought out a non-conventional approach.

The heart of the pest controller is a Jetson Nano, which uses OpenCV and Yolo object detection to find the cockroaches and galvanometers to steer the laser beam. Three different lasers were used for testing, allowing the team to evaluate a range of wavelengths, power levels, and spot sizes. Unsurprisingly, the higher power 1.6 W laser was most efficient and quicker.

The project is on GitHub (here) and the cockroach machine learning image set is available here. But [Ildar] points out in the conclusion of the report, this is dangerous. It’s suitable for academic research, but it’s not quite ready for general use, lacking any safety features. This report is full of cockroach trivia, such as the average speed of a cockroach is 4.8 km/h, and they run much faster when being zapped. If you want to experiment with cockroaches yourself, a link is provided to a pet store that sells the German Blattela germanica that was the target of this report.

If this project sounds familiar, it is because it is an improvement of a previous project we wrote about last year which used similar techniques to zap mosquitoes.

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DVD Drives Turned Into Microscopes

With the advent of streaming services, plenty of people are opting to forego the collection of physical media. In turn, there are now a lot of optical drives sitting unused in parts bins and old computers. If you’d like something useful to do with this now-obsolete technology, you can have a try at turning one into a laser microscope.

This build requires two DVD pickups. By scanning once horizontally and once vertically and measuring the returning light from the DVD laser, an image can be created. For this build, the second pickup is used to move the object itself. The entire device is controlled by an Analog Discovery 2, although this principle could be ported to other microcontroller platforms. Thanks to the extremely fine laser in a DVD and the precise movements of the motors found in the control machinery, the images obtained using this method have the potential to be more detailed than comparable visible light microscopes.

While this isn’t quite scanning electron microscope territory, it’s good enough to clearly image the internal workings of a de-capped integrated circuit. Something like this could be indispensable for reverse-engineering ICs or troubleshooting other comparably small electronics, with resolutions higher than can typically be obtained with visible light microscopes. We’ve even seen similar builds in the past which build microscopes like this as dedicated lab equipment.

Glass 3D Printing Via Laser

If you haven’t noticed, diode laser engraver/cutters have been getting more powerful lately. [Cranktown City] was playing with an Atomstack 20 watt laser and wondered if it would sinter sand into glass. His early experiments were not too promising, but with some work, he was able to make a crude form of glass with the laser as the source of power. However, using glass beads was more effective, so he decided to build his own glass 3D printer using the laser.

This isn’t for the faint of heart. Surfaces need to be flat and there’s aluminum casting and plasma cutting involved, although some of it may not have been necessary for the final construction. The idea was to make a system that would leave a layer of sand and then put down a new layer on command. This turned out to be surprisingly difficult.

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