laser

517 Articles

Laser Etches Solar Absorbing Material

February 6, 2020 by 19 Comments

Having a laser cutter these days isn’t a big deal. But [Chunlei Guo], a professor at the University of Rochester, has a powerful femto-second pulse laser and used it to create what might be the perfect solar absorber. You can see a video about the work, below.

It stands to reason that white materials reflect most light and therefore absorb less energy than black materials — this is part of what makes a radiometer work. Tungsten, in particular, is a good metal for absorbing solar power, but this new laser treatment — which builds nanostructures on the surface of the metal — increases efficiency by 130% compared to untreated tungsten.

Continue reading “Laser Etches Solar Absorbing Material” →

Array Of Useless Machines Is Useless

February 5, 2020 by 38 Comments

What’s the collective noun for a group of useless machines? A passel of useless machines? A failure? A waste? A 404?  Whatever you want to call it, [Martin Raynsford] has produced one here with this collection of 24 useless machines arranged into a 5 by 6 array. He produced it for an event at a hackerspace to amuse visitors, and it certainly seems to do the job in the video after the break.

[Martin] built the case by modifying the design of his Useless Machine kit, stretching out the case to hold multiple mechanisms. The original plan was to use a 6 by 6 matrix, but that wouldn’t fit into the laser cutter, so it ended up with 24 mechanisms in a 5 by 6 array. All of those are driven by 2 AAA batteries, and the mechanisms are efficient enough that it survived a full day of button flipping before it began to run out of juice.

Continue reading “Array Of Useless Machines Is Useless” →

Burning Things With Big Lasers In The Name Of Security

January 29, 2020 by 4 Comments

Several fields of quantum research have made their transition from research labs into commercial products, accompanied by grandiose claims. Are they as good as they say? We need people like Dr. Sarah Kaiser to independently test those claims, looking for flaws in implementation. At the 2019 Hackaday Superconference she shared her research on attacking commercially available quantum key distribution (QKD) hardware.

Don’t be scared away when you see the term “quantum” in the title. Her talk is very easy to follow along, requiring almost no prior knowledge of quantum research terminology. In fact, that’s the point. Dr. Kaiser’s personal ambition is to make quantum computing an inviting and accessible topic for everyone, not just elite cliques of researchers in ivory towers. You should hear her out in the video below, and by following along with the presentation slide deck (.PPTX).

Quantum Key Distribution

So why is QKD is so enticing? Unlike existing methods, the theoretical foundation is secure against any attacker constrained by the speed of light and the laws of physics.

Generally speaking, if your attacker is not bound by those things, we have a much bigger problem.

But as we know well, there’s always a difference between the theoretical foundation and the actual implementation of cryptography. That difference is where exploits like side-channel attacks thrive, so she started investigating components of a laser QKD system.

As a self-professed “Crazy Laser Lady”, part of this investigation examined how components held up to big lasers delivering power far outside normal operating range. This turned up exciting effects like a fiber fuse (~17:30 in the video) which is actually a plasma fire propagating through the fiber optic. It looks cool, but it’s destructive and useless for covert attacks. More productive results came when lasers were used to carefully degrade select components to make the system vulnerable.

If you want to learn more from Dr. Kaiser about quantum key distribution, she has a book chapter on the topic. (Free online access available, but with limitations.) This is not the first attempt to hack quantum key distribution, and we doubt it would be the last. Every generation of products will improve tolerance to attacks, and we’ll need researchers like our Crazy Laser Lady to find the reality behind advertised claims.

Continue reading “Burning Things With Big Lasers In The Name Of Security” →

A Beginner’s Guide To X-Ray Crystallography

January 21, 2020 by 6 Comments

In graduate school, I had a seminar course where one of the sections was about X-ray crystallography. I was excited, because being able to discern the three-dimensional structure of macromolecules just by shining X-rays on them seemed like magic to me. And thanks to a lackluster professor, after the section it remained just as much of a mystery.

If only I’d had [Steve Mould] as a teacher back then. His latest video does an outstanding job explaining X-ray crystallography by scaling up the problem considerably, using the longer wavelength of light and a macroscopic target. He begins with a review of diffraction patterns, those alternating light and dark bands of constructive and destructive interference that result when light shines on two closely spaced slits — the famous “Double-Slit Experiment” that showed light behaves both as a particle and as a wave and provided our first glimpse of quantum mechanics. [Steve] then doubled down on the double-slit, placing another pair of slits in the path of the first. This revealed a grid of spots rather than alternating bands, with the angle between axes dependent on the angle of the slit pairs to each other.

Photograph 51, an X-ray crystallogram of the B-form of DNA, by Gosling and Franklin, 1952. Source: Wikipedia

 

To complete the demonstration, [Steve] then used diffraction to image the helical tungsten filament of an incandescent light bulb. Shining a laser through the helix resulted in a pattern bearing a striking resemblance to what’s probably the most famous X-ray crystallogram ever: [Rosalind Franklin]’s portrait of DNA. It all makes perfect sense, and it’s easy to see how the process works when scaled down both in terms of the target size and the wavelength of light used to probe it.

Hats off to [Steve] for making something that’s ordinarily complex so easily understandable, and for filling in a long-standing gap in my knowledge.

Continue reading “A Beginner’s Guide To X-Ray Crystallography” →

Node-RED Laser Shooting Gallery Goes Anywhere

January 14, 2020 by 6 Comments

When you think of a shooting gallery, you might envision a line of tin cans set up along a split-rail fence, or a few rows of ducks or bottles lined up at a carnival. But what do these have in common? You, standing in one spot, and shooting in the same general direction. You’re exposed! If those targets could shoot back, you’d be dead within seconds. Wouldn’t it be more fun if the targets were all around you in 360°? We think so, too.

So how could you possibly set up a shooting gallery this way? [Another Maker] already solved that problem for you with ESP32s and Node-RED (YouTube). Each target has an ESP32, a laser sensor, and an LED that lights up when the target is ready, and turns off once it’s been hit. They all make an enticing ‘shoot me’ sound that goes with their graphics, and a second mp3 plays upon direct hit.

The PVC gun houses an ESP8266, a laser module at the end of the barrel, and runs on a cylindrical USB battery slipped down in the secondary grip. [Another Maker] can spread the targets out far and wide, as long as they all stay in range of the localized WiFi access point.

The best part is that the Node-RED system is target-agnostic — it doesn’t care how many you have or how they’re made, and it can juggle up to 250 of them. Because of the way the target objects are programmed, it would be quite easy to add actuators that make them drop down or fall backward when hit. You could also implement [Another Maker]’s fantastic suggestion of hitting arcade buttons with NERF darts instead. Charge those lasers and fire at the break button to see the demo and walk-through video.

If you plan to knock the targets down or over in your implementation, you’ll want an easy way to reset them. Here’s a scrap-built shooting gallery that uses a windshield wiper motor to set ’em back up.

Hackaday Links Column Banner

Hackaday Links: January 5, 2020

January 5, 2020 by 30 Comments

It looks like the third decade of the 21st century is off to a bit of a weird start, at least in the middle of the United States. There, for the past several weeks, mysterious squads of multicopters have taken to the night sky for reasons unknown. Witnesses on the ground report seeing both solo aircraft and packs of them, mostly just hovering in the night sky. In mid-December when the nightly airshow started, the drones seemed to be moving in a grid-search pattern, but that seems to have changed since then. These are not racing drones, nor are they DJI Mavics; witnesses report them to be 6′ (2 meters) in diameter and capable of staying aloft for 90 minutes. These are serious professional machines, not kiddies on a lark. So far, none of the usual government entities have taken responsibility for the flights, so speculation is all anyone has as to their nature. We’d like to imagine someone from our community will get out there with radio direction finding gear to locate the operators and get some answers.

We all know that water and electricity don’t mix terribly well, but thanks to the seminal work of White, Pinkman et al (2009), we also know that magnets and hard drives are a bad combination. But that didn’t stop Luigo Rizzo from using a magnet to recover data from a hard drive. He reports that the SATA drive had been in continuous use for more than 11 years when it failed to recover after a power outage. The spindle would turn but the heads wouldn’t move, despite several rounds of percussive maintenance. Reasoning that the moving coil head mechanism might need a magnetic jump-start, he probed the hard drive case with a magnetic parts holder until the head started moving again. He was then able to recover the data and retire the drive. Seems like a great tip to file away for a bad day.

It seems like we’re getting closer to a Star Trek future every day. No, we probably won’t get warp drives or transporters anytime soon, and if we’re lucky velour tunics and Spandex unitards won’t be making a fashion statement either. But we may get something like Dr. McCoy’s medical scanner thanks to work out of MIT using lasers to conduct a non-contact medical ultrasound study. Ultrasound exams usually require a transducer to send sound waves into the body and pick up the echoes from different structures, with the sound coupled to the body through an impedance-matching gel. The non-contact method uses pulsed IR lasers to penetrate the skin and interact with blood vessels. The pulses rapidly heat and expand the blood vessels, effectively turning them into ultrasonic transducers. The sound waves bounce off of other structures and head back to the surface, where they cause vibrations that can be detected by a second laser that’s essentially a sophisticated motion sensor. There’s still plenty of work to do to refine the technique, but it’s an exciting development in medical imaging.

And finally, it may actually be that the future is less Star Trek more WALL-E in the unlikely event that Segway’s new S-Pod personal vehicle becomes popular. The two-wheel self-balancing personal mobility device is somewhat like a sitting Segway, except that instead of leaning to steer it, the operator uses a joystick. Said to be inspired by the decidedly not Tyrannosaurus rex-proof “Gyrosphere” from Jurassic World, the vehicle tops out at 24 miles per hour (39 km/h). We’re not sure what potential market for these things would need performance like that – it seems a bit fast for the getting around the supermarket and a bit slow for keeping up with city traffic. So it’s a little puzzling, although it’s clearly easier to fully automate than a stand-up Segway.

Laser Welding With A Tattoo Removal Gun

December 25, 2019 by 49 Comments

Dating as far back as the early 1960’s, researchers were zapping tattoo inks with laser light was an effective way to remove the markings from human skin. At the time it was prohibitively expensive. But the desire to have an undo-button for badge choices is strong, and thus the tattoo removal gun was born.

These days you can pick up one of these zappy, burn-y wonders for far less than a flagship cellphone put their high-power-output to alternative use. [Andrew] recently discovered that these devices can be readily repurposed into a laser welding tool with just a bit of work under the hood.

He first came across the technology via videos from [styropyro], whose work we’ve featured before. The tattoo removal gun features a YAG laser, which is pulsed to create a high power density. In initial testing, the pulses were too short and of too high intensity to effectively weld with; instead, the pulses simply cratered the metal.

After delving in further, [Andrew] discovered that by removing the Q-switch optical component, the pulses from the laser could be lengthened. This reduces the power density, and allows the tool to weld various materials even on its lower power settings. Success was found welding steel, titanium, and other materials, though attempts to weld copper and silver faced little success. Test pieces included razor blades and small screws, which could easily be welded with the tool. Results of the razor blade welding is spectacular, with a high-quality welding bead achieved by taping the laser to a CNC mill for precise movement.

It could prove to be a useful tool for those experimenting with complex projects involving bonding metals at very fine scales. If you’re pursuing something exotic yourself, we want to hear about it!