Interesting Optics Make This Laser Engraver Fit In A Pocket

We’re going to start this post with a stern warning: building a laser engraver that can fit in your pocket is probably not a wise idea. Without any safety interlocks and made from lightweight components as it is, this thing could easily tip over and sear a retina before you’d even have time to react. You definitely should not build this, or even be in the same room with it. Got it?

Safety concerns aside, [DAZ] has taken a pretty neat approach to making this engraver, eschewing the traditional X-Y gantry design in favor of something more like the galvanometers used for laser projectors, albeit completely homebrew and much, much slower than commercial galvos. Built mostly of 3D-printed parts, the scanning head of this engraver uses a single mirror riding on an angled block attached to gimbals with two degrees of freedom. The laser module and mirror gimbals are mounted on a stand made of light aluminum so that the whole thing is suspended directly over a workpiece; the steppers slew the mirror to raster the beam across the workpiece and burn a design.

The video below shows it at work, and again, we have to stress that this is about as close to this build as you should get. It shouldn’t be too hard to add some safety features, though — at a minimum, we’d like to see a tilt-switch that kills power if it’s knocked over, and maybe some kind of enclosure. Sure, that would probably spoil the pocketability of the engraver, but is that really a feature valuable enough to risk your eyesight for?

If there’s a laser build in your future, please read our handy guide to homebrew laser cutter safety — before you can’t.

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Inside An EBay Marking Laser

When it comes to trolling eBay for cool stuff, some people have all the luck. Whereas all we ever seem to come across is counterfeit chips and obviously broken gear listed as, “good condition, powers on”, [Les Wright] actually managed to get more than he bargained for with one of his recent eBay purchases.

In his video teardown and tour of an industrial marking laser, [Les] suggests that he was really just in it for the optics — which is not a surprise, given his interest in optics in general and lasers in particular. The 20-W CO2 laser once etched barcodes and the like into products on assembly lines, but with a 2009 date code of its own, it was a safe bet that it was pitched due to a burned-out laser tube. But there were still high-quality IR optics and a precision X-Y galvanometer assembly to be harvested, so [Les] pressed on.

The laser itself ended up being built around a Synrad RF-stimulated CO2 tube. By a happy accident, [Les] found that the laser actually still works, at least most of the time. There appears to be an intermittent problem with the RF driver, but the laser works long enough to release the magic smoke from anything combustible that gets in its way. The galvos work too — [Les] was able to drive them with a Teensy and a couple of open-source libraries.

Galvos, lenses worth more than $800, and a working laser tube — not a bad haul. We’ll be following along to see what [Les] makes of this booty. Continue reading “Inside An EBay Marking Laser”

Old Printer Becomes Direct Laser Lithography Machine

What does it take to make your own integrated circuits at home? It’s a question that relatively few intrepid hackers have tried to answer, and the answer is usually something along the lines of “a lot of second-hand equipment.” But it doesn’t all have to be cast-offs from a semiconductor fab, as [Zachary Tong] shows us with his homebrew direct laser lithography setup.

Most of us are familiar with masked photolithography thanks to the age-old process of making PCBs using photoresist — a copper-clad board is treated with a photopolymer, a mask containing the traces to be etched is applied, and the board is exposed to UV light, which selectively hardens the resist layer before etching. [Zach] explores a variation on that theme — maskless photolithography — as well as scaling it down considerably with this rig. An optical bench focuses and directs a UV laser into a galvanometer that was salvaged from an old laser printer. The galvo controls the position of the collimated laser beam very precisely before focusing it on a microscope that greatly narrows its field. The laser dances over the surface of a silicon wafer covered with photoresist, where it etches away the resist, making the silicon ready for etching and further processing.

Being made as it is from salvaged components, aluminum extrusion, and 3D-printed parts, [Zach]’s setup is far from optimal. But he was able to get some pretty impressive results, with features down to 7 microns. There’s plenty of room for optimization, of course, including better galvanometers and a less ad hoc optical setup, but we’re keen to see where this goes. [Zach] says one of his goals is homebrew microelectromechanical systems (MEMS), so we’re looking forward to that.

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Laser Augmented Reality Glasses Show You The Way

Tech companies like Google and Microsoft have been working on augmented reality (AR) wearables that can superimpose images over your field of view, blurring the line between the real and virtual. Unfortunately for those looking to experiment with this technology, the devices released so far have been prohibitively expensive.

While they might not be able to compete with the latest Microsoft HoloLens, these laser AR classes from [Joel] promise to be far cheaper and much more approachable for hackers. By bouncing a low-power laser off of a piezo-actuated mirror, the hope is that the glasses will be able to project simple vector graphics onto a piece of reflective film usually used for aftermarket automotive heads-up displays (HUDs).

Piezo actuators are used to steer the mirror.

[Joel] has put together a prototype of what the mirror system might look like, but says driving the high-voltage piezo actuators poses some unique challenges. The tentative plan is to generate the vector data with a smartphone application, send it to an ESP32 microcontroller within the glasses, and then push the resulting analog signals through a 100 V DC-DC boost converter to get the mirror moving.

We’ve seen the ESP32 drive a laser galvanometer to play a game of Asteroids, but recreating such a setup in a small enough package to fit onto a pair of glasses would certainly be an impressive accomplishment. Early tests look promising, but clearly [Joel] has quite a bit of work ahead of him. As a finalist for the Rethink Displays challenge of the 2021 Hackaday Prize, we’re looking forward to seeing the project develop over the coming months.

Laser Artistry Hack Chat

Join us on Wednesday, April 1 at noon Pacific for the Laser Artistry Hack Chat with Seb Lee-Delisle!

It’s hard to forget the first time you see a laser light show. A staple at concerts starting in the 1980s, seeing a green laser lance out over the heads of tens of thousands of screaming fans to trace out an animated figure or pulsating geometric shapes was pure fascination, and wondering how it was all done was half the fun. As we all know now, it was all done with mirrors, tiny and connected to low-inertia galvanometers capable of the twitchiest of movements, yet precise enough to position the beam of light exactly where it needed to be to create the desired illusion. It was engineering, science, and art all wrapped up into one package.

Fast forward to the present day, and laser show technology has certainly advanced. Bulky laser tubes have been replaced by solid-state devices, more colors are available, and galvo designs have improved. The art and artistry of the laserist have grown with the tech, which is where our guest Seb Lee-Delisle comes into his own. We’ve featured some of Seb’s work before, like an Asteroids laser vector display and enormous public laser displays. And now he’ll stop by to talk about how the art and the tech combine in his hands to produce something much greater than the sum of its parts.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 1 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Building A Laser Head With High Speed, High Resolution

A test exposure on cyanotype paper shows off the prototype’s resolution, around 100 microns.

Typically, when it comes to scanning a laser, it’s done with galvos or a rotating mirror assembly. However, these methods can be slow and cumbersome, or restricted due to existing patents. [Rick] aimed to find an alternative solution with the Hexastorm project, using a rotating prism to build a high speed, high resolution laser head.

The project currently uses a Beaglebone for the brains, with a polygon motor sourced from a photocopier used to rotate the prism at over 20,000 rpm. The project aims to be a proof of concept for rotating prism technology, which can then be adapted to specific tasks. With the promise of high speed and high resolution, the system could be used in fields as diverse as PCB manufacture, 3D resin printing, and even virtual reality displays. [Rick] explores these potential markets in a pitch deck, comparing to existing solutions in the marketplace.

If you’re interested in high performance optical systems, [Rick]’s work makes compelling reading. It’s not the first time we’ve explored cutting edge laser hacks, either. Video after the break. Continue reading “Building A Laser Head With High Speed, High Resolution”

Tracking Ants And Zapping Them With Lasers

Thanks to the wonders of neural networks and machine learning algorithms, it’s now possible to do things that were once thought to be inordinately difficult to achieve with computers. It’s a combination of the right techniques and piles of computing power that make such feats doable, and [Robert Bond’s] ant zapping project is a great example.

The project is based around an NVIDIA Jetson TK1, a system that brings the processing power of a modern GPU to an embedded platform. It’s fitted with a USB camera, that is used to scan its field of view for ants. Once detected, thanks to a little OpenCV magic, the coordinates of the insect are passed to the laser system. Twin stepper motors are used to spin mirrors that direct the light from a 5 mW red laser, which is shined on the target. If you’re thinking of working on something like this we highly recommend using galvos to direct the laser.

Such a system could readily vaporize ants if fitted with a more powerful laser, but [Robert] decided to avoid this for safety reasons. Plus, the smell wouldn’t be great, and nobody wants charred insect residue all over the kitchen floor anyway. We’ve seen AIs do similar work, too – like detecting naughty cats for security reasons.

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