Author: Tyler August

559 Articles

A false colour image of the region of sky containing the CMZ.

Unsolved Questions In Astronomy? Try Dark Matter!

April 23, 2025 by 21 Comments

Sometimes in fantasy fiction, you don’t want to explain something that seems inexplicable, so you throw your hands up and say, “A wizard did it.” Sometimes in astronomy, instead of a wizard, the answer is dark matter (DM). If you are interested in astronomy, you’ve probably heard that dark matter solves the problem of the “missing mass” to explain galactic light curves, and the motion of galaxies in clusters.

Now [Pedro De la Torre Luque] and others are proposing that DM can solve another pair of long-standing galactic mysteries: ionization of the central molecular zone (CMZ) in our galaxy, and mysterious 511 keV gamma-rays.

The Central Molecular Zone is a region near the heart of the Milky Way that has a very high density of interstellar gases– around sixty million times the mass of our sun, in a volume 1600 to 1900 light years across. It happens to be more ionized than it ought to be, and ionized in a very even manner across its volume. As astronomers cannot identify (or at least agree on) the mechanism to explain this ionization, the CMZ ionization is mystery number one.

Feynman diagram: Space-time vectors for electron-positron annihilation
Feynman diagram of electron-positron annihilation, showing the characteristic gamma-ray emission.

Mystery number two is a diffuse glow of gamma rays seen in the same part of the sky as the CMZ, which we know as the constellation Sagittarius. The emissions correspond to an energy of 515 keV, which is a very interesting number– it’s what you get when an electron annihilates with the antimatter version of itself. Again, there’s no universally accepted explanation for these emissions.

So [Pedro De la Torre Luque] and team asked themselves: “What if a wizard did it?” And set about trying to solve the mystery using dark matter. As it turns out, computer models including a form of light dark matter (called sub-GeV DM in the paper, for the particle’s rest masses) can explain both phenomena within the bounds of error.

In the model, the DM particles annihilate to form electron-positron pairs. In the dense interstellar gas of the CMZ, those positrons quickly form electrons to produce the 511 keV gamma rays observed. The energy released from this annihilation results in enough energy to produce the observed ionization, and even replicate the very flat ionization profile seen across the CMZ. (Any other proposed ionization source tends to radiate out from its source, producing an uneven profile.) Even better, this sort of light dark matter is consistent with cosmological observations and has not been ruled out by Earth-side dark matter detectors, unlike some heavier particles.

Further observations will help confirm or deny these findings, but it seems dark matter is truly the gift that keeps on giving for astrophysicists. We eagerly await what other unsolved questions in astronomy can be answered by it next, but it leaves us wondering how lazy the universe’s game master is if the answer to all our questions is: “A wizard did it.”

We can’t talk about dark matter without remembering [Vera Rubin].

DIY Record Cutting Lathe Is Really Groovy

April 22, 2025 by 12 Comments

Back in the day, one of the few reasons to prefer compact cassette tape to vinyl was the fact you could record it at home in very good fidelity. Sure, if you had the scratch, you could go out and get a small batch of records made from that tape, but the machinery to do it was expensive and not always easy to come by, depending where you lived. That goes double today, but we’re in the middle of a vinyl renaissance! [ronald] wanted to make records, but was unable to find a lathe, so decided to take matters into his own hands, and build his own vinyl record cutting lathe.

photograph of [ronald's] setup
[ronald’s] record cutting lathe looks quite professional.
It seems like it should be a simple problem, at least in concept: wiggle an engraving needle to scratch grooves in plastic. Of course for a stereo record, the wiggling needs to be two-axis, and for stereo HiFi you need that wiggling to be very precise over a very large range of frequencies (7 Hz to 50 kHz, to match the pros). Then of course there’s the question of how you’re controlling the wiggling of this engraving needle. (In this case, it’s through a DAC, so technically this is a CNC hack.) As often happens, once you get down to brass tacks (or diamond styluses, as the case may be) the “simple” problem becomes a major project. Continue reading “DIY Record Cutting Lathe Is Really Groovy” →

The central solenoid taking shape in the ITER assembly hall.

What’s Sixty Feet Across And Superconducting?

April 22, 2025 by 54 Comments

What’s sixty feet (18.29 meters for the rest of the world) across and superconducting? The International Thermonuclear Experimental Reactor (ITER), and probably not much else.

The last parts of the central solenoid assembly have finally made their way to France from the United States, making both a milestone in the slow development of the world’s largest tokamak, and a reminder that despite the current international turmoil, we really can work together, even if we can’t agree on the units to do it in.

A cutaway diagram of the ITER tokamak showing the central solenoid
The central solenoid is in the “doughnut hole” of the tokamak in this cutaway diagram. Image: US ITER.

The central solenoid is 4.13 m across (that’s 13′ 7″ for burger enthusiasts) sits at the hole of the “doughnut” of the toroidal reactor. It is made up of six modules, each weighing 110 t (the weight of 44 Ford F-150 pickup trucks), stacked to a total height of 59 ft (that’s 18 m, if you prefer). Four of the six modules have been installed on-site, and the other two will be in place by the end of this year.

Each module was produced ITER by US, using superconducting material produced by ITER Japan, before being shipped for installation at the main ITER site in France — all to build a reactor based on a design from the Soviet Union. It doesn’t get much more international than this!

This magnet is, well, central to the functioning of a tokamak. Indeed, the presence of a central solenoid is one of the defining features of this type, compared to other toroidal rectors (like the earlier stellarator or spheromak). The central solenoid provides a strong magnetic field (in ITER, 13.1 T) that is key to confining and stabilizing the plasma in a tokamak, and inducing the 15 MA current that keeps the plasma going.

When it is eventually finished (now scheduled for initial operations in 2035) ITER aims to produce 500 MW of thermal power from 50 MW of input heating power via a deuterium-tritium fusion reaction. You can follow all news about the project here.

While a tokamak isn’t likely something you can hack together in your back yard, there’s always the Farnsworth Fusor, which you can even built to fit on your desk.

Printed Perpetual Calendar Clock Contains Clever Cams

April 21, 2025 by 12 Comments

At Hackaday, it is always clock time, and clock time is a great time to check in with [shiura], whose 3D Printed Perpetual Calendar Clock is now at Version 2. A 3D printed calendar clock, well, no big deal, right? Grab a few steppers, slap in an ESP32 to connect to a time server, and you’re good. That’s where most of us would probably go, but most of us aren’t [shiura], who has some real mechanical chops.

The front face of the perpetual calendar clock.
There’s also a 24-hour dial, because why not?

This clock isn’t all mechanical. It probably could be, but at its core it uses a commercial quartz movement — you know, the cheap ones that take a single double-A battery. The only restriction is that the length of the hour axis must be twelve millimeters or more. Aside from that, a few self-tapping screws and an M8 nut, everything else is fully 3D printed.

From that simple quartz movement, [shiura]’s clock tracks not only the day of the week, the month and date — even in Febuary, and even compensating for leap years. Except for the inevitable drift (and battery changes) you should not have to adjust this clock until March 2100, assuming both you and the 3D printed mechanism live that long. Version one actually did all this, too, but somehow we missed it; version two has some improvements to aesthetics and usability. Take a tour of the mechanism in the video after the break.

We’ve featured several of [shiura]’s innovative clocks before, from a hybrid mechanical-analog display, to a splitless flip-clock, and a fully analog hollow face clock. Of course [shiura] is hardly our only clock-making contributor, because it it always clock time at Hackaday. Continue reading “Printed Perpetual Calendar Clock Contains Clever Cams” →

Benchy, printed upside down on [Josh's] Core R-Theta printer.

Non-planar Slicing Is For The Birds

April 20, 2025 by 15 Comments

When we say non-planar slicing is for the birds, we mean [Joshua Bird], who demonstrates the versatility of his new non-planar S4-Slicer by printing a Benchy upside down with the “Core R-Theta” printer we have featured here before.

A benchy model, upside down, with the path from the end of the prow to the printbed highlighted.
S4 slicer uses the path from any point (here, Benchy’s prow) as its basis…

This non-planar slicer is built into a Jupyter notebook, which follows a relatively simple algorithm to automatically generate non-planar toolpaths for any model. It does this by first generating a tetrahedral mesh of the model and then calculating the shortest possible path through the model from any given tetrahedron to the print bed. Even with non-planar printing, you need to print from the print-bed up (or out).

Quite a lot of math is done to use these paths to calculate a deformation mesh, and we’ll leave that to [Joshua] to explain in his video below. After applying the deformation, he slices the resulting mesh in Cura, before the G-code goes back to Jupyter to be re-transformed, restoring the shape of the original mesh.

… to generate deformed models for slicing, like this.

So yes, it is G-code bending as others have demonstrated before, but in a reproducible, streamlined, and straightforward workflow. Indeed, [Josh] credits much of the work to earlier work on the S^3-Slicer, which inspired much of the logic and the name behind his S4 slicer. (Not S4 as in “more than S^3” but S4 as a contraction of “Simplified S^3”). Once again, open source allows for incremental innovation.

It is admittedly a computationally intensive process, and [Joshua] uses a simplified model of Benchy for this demo. This seems exactly the sort of thing we’d like to burn compute power on, though.

This sort of non-planar 3D printing is an exciting frontier, one which we have covered before. We’ve seen techniques for non-planar infill, or even to print overhangs on unmodified Cartesian printers,  but this is probably the first time we’ve seen Benchy given the non-planar treatment. You can try S4 slicer for yourself via GitHub, or just watch the non-planar magic in action after the break. Continue reading “Non-planar Slicing Is For The Birds” →

Two laptops, side by side, running Llama2 in DOS.

Will It Run Llama 2? Now DOS Can

April 19, 2025 by 21 Comments

Will a 486 run Crysis? No, of course not. Will it run a large language model (LLM)? Given the huge buildout of compute power to do just that, many people would scoff at the very notion. But [Yeo Kheng Meng] is not many people.

He has set up various DOS computers to run a stripped down version of the Llama 2 LLM, originally from Meta. More specifically, [Yeo Kheng Meng] is implementing [Andreq Karpathy]’s Llama2.c library, which we have seen here before, running on Windows 98.

Llama2.c is a wonderful bit of programming that lets one inference a trained Llama2 model in only seven hundred lines of C. It it is seven hundred lines of modern C, however, so porting to DOS 6.22 and the outdated i386 architecture took some doing. [Yeo Kheng Meng] documents that work, and benchmarks a few retrocomputers. As painful as it may be to say — yes, a 486 or a Pentium 1 can now be counted as “retro”.

The models are not large, of course, with TinyStories-trained  260 kB model churning out a blistering 2.08 tokens per second on a generic 486 box. Newer machines can run larger models faster, of course. Ironically a Pentium M Thinkpad T24 (was that really 21 years ago?) is able to run a larger 110 Mb model faster than [Yeo Kheng Meng]’s modern Ryzen 5 desktop. Not because the Pentium M is going blazing fast, mind you, but because a memory allocation error prevented that model from running on the modern CPU. Slow and steady finishes the race, it seems.

This port will run on any 32-bit i386 hardware, which leaves the 16-bit regime as the next challenge. If one of you can get an Llama 2 hosted locally on an 286 or a 68000-based machine, then we may have to stop asking “Does it run DOOM?” and start asking “Will it run an LLM?”

Continue reading “Will It Run Llama 2? Now DOS Can” →

The GRIP-tape robot picking a lemon

Robot Picks Fruit And Changes Light Bulbs With Measuring Tape

April 18, 2025 by 9 Comments

How far can you stretch a measuring tape before it buckles? The answer probably depends more on the tape than the user, but it does show how sturdy the coiled spring steel rulers can be. [Gengzhi He et. al.] may have been playing that game in the lab at UC San Diego when they hit upon the idea for a new kind of low-cost robotic gripper.

An image of the GRIP-tape robot described in the article, showing the tape-loop fingers.
Four motors, four strips of measuring tape (doubled up)– one robot hand.

With the lovely backronym “GRIP-tape” — standing for Grasping and Rolling in Plane — you get a sense for what this effector can do. Its two “fingers” are each made of loops of doubled-up measuring tape bound together with what looks suspiciously like duck tape. With four motors total, the fingers can be lengthened or shortened by spooling the tape, allowing  a reaching motion, pivot closer or further apart for grasping, and move-in-place like conveyor belts, rotating the object in their grasp.

The combination means it can reach out, grab a light bulb, and screw it into a socket. Or open and decant a jar of spices. Another video shows the gripper reaching out to pick a lemon, and gently twist it off the tree. It’s quite a performance for a device with such modest components.

At the moment, the gripper is controlled via remote; the researchers plan on adding sensors and AI autonomous control. Read all the details in the preprint, or check below the fold to watch the robot in action.

This is hardly the first time we’ve highlighted a grabby robot. We’ve seen belts, we’ve seen origami — but this is the first time we’ve seen a measuring tape. Have you seen a cool robot? Toss us a tip. We’d love to hear from you. Continue reading “Robot Picks Fruit And Changes Light Bulbs With Measuring Tape” →