2026-01-13 11:00:15
It turns out, that mold is everywhere. The problem is when it becomes too much, as mold infestations can have serious health effects on both humans and animals. Remediation is extremely expensive, too. So there are plenty of benefits to finding mold early. Now, German researchers are proposing an electronic “nose” that uses UV-activated tin oxide nanowires that change resistance in the presence of certain chemicals, and they say it can detect two common indoor mold species.
The nanowire sensors can detect Staachybotrys chartarum and Chaetominum globosum. The real work, though, is in the math used to determine positive versus negative results.
Traditional methods take some sort of physical sample that is sent to a lab and require days to process. However, trained dogs can also smell mold, but as you might expect, there aren’t many dogs trained to find mold. Besides, the training is expensive, you have to maintain the dog all the time, and if the dog knows what kind of mold it is, it can’t say. So an electronic nose that can give fast, specific results is quite attractive.
Even if you don’t care about mold, the data crunching to classify the sensor data has application to many types of sensors. They used training to build multiple models, then they combine the outputs using a regression algorithm to predict the true output. Finally, they use a majority voting technique to combine the results of the model and the regression output.
Could you make a sensor like this? Reading section 4.2 of the paper, it looks like you need a pretty stout set of lab gear to play. But the math ideas are certainly something you could replicate or use as a starting point for your own sensor fusion projects.
Want a deep dive into sensor fusion? You should have been at the Hackaday Superconference a few years ago. Luckily, you can still watch [Christal’s] talk about fusing multiple streams of sensor data.
2026-01-13 08:00:50
You’ve heard of wind tunnels– get some airflow going over a thingy, put some some smoke on, and voila! Flow visualization. How hard could it be? Well, as always, the devil is in the details and [toast] is down in there with him with this Hot-Wheels sized wind tunnel video.
To get good, laminar flow inside of a wind tunnel, there are important ratios to be followed– the inlet and outlet diameters must relate to the interior size to get the correct slope on the contraction and exhaust cones. You need a flow straightener on both ends. All of it can be easily 3D printed, as [toast] shows, but you have to know those design rules and pay attention to, which [toast] does… this time. One of his “don’t do this” examples in this video is previous build of his where he did not follow all the rules, and the difference is clear.
Now, unless you’re hooked on flow visualizations —guilty— or are a Hot-Wheels aficionado, since that’s what this wind tunnel is sized for, you probably won’t rush to gumroad to buy [toast]’s STLs. On the other hand, if you pay attention to the lessons [toast] has learned in this video you can apply them to wind tunnels of whatever size and construction technique you need, be it cardboard or junk box plastic and get a more stable result.
2026-01-13 05:00:18
Over the decades the number of Linux distributions has effectively exploded, from a handful in the late ’90s to quite literally hundreds today, not counting minor variations. There lately seems to be a counter-movement brewing in response to this fragmentation, with Project Bluefin’s Distroless project being the latest addition here. Also notable are KDE’s efforts, with KDE Linux as its own top-down KDE-based distro, but now with a switch to BuildStream from Arch likely as a distroless move.
It should be clear that there is no obvious course here yet, and that opinions are very much divided. The idea of ‘Linux’ becoming a more singular OS appeals to some, while to others it’s the antithesis of what ‘Linux’ is about. This much becomes clear in [Brodie Robertson]’s exploration of this topic as well.
The way to think about ‘distroless’ is that there is a common base using the Freedesktop SDK on which the customization layer is applied, such as Bluefin, KDE or Gnome’s environments. You could think of this base as the common runtime, using the Freedesktop standards for interoperability for a user-selected layer that’s installed on top. This way the idea of basing a distro on a specific distro is tossed out in favor of something that’s vaguely reminiscent of the Linux Standard Base attempt at standardization.
It’ll be fascinating to see how things will move from here, as there are definite arguments to be made in favor of less fragmentation and resultingly less duplicated effort. In many ways this would bring Linux closer to for example FreeBSD, which avoids the Linux Chaos Vortex problem by having a singular codebase. FreeBSD ‘distros’ like GhostBSD and NomadBSD are therefore essentially just specialized customizations that target a sub-group of FreeBSD users.
Of course, when we start talking about package managers and other base-distro specific features, we may very well risk igniting the same problems that tore apart the LSB so many years ago. Will we also standardize on RPM over DEB package files and kin, or something else?
2026-01-13 03:30:50
We suspect there are three kinds of people in the world. People who have access to a Michelson Interferometer and are glad, those who don’t have one and don’t know what one is, and a very small number of people who want one but don’t have one. But since [Longest Path Search] built one using 3D printing, maybe the third group will dwindle down to nothing.
If you are in the second camp, a Michelson interferometer is a device for measuring very small changes in the length of optical paths (oversimplifying, a distance). It does this by splitting a laser into two parts. One part reflects off a mirror at a fixed distance from the splitter. The other reflects off another, often movable, mirror. The beam splitter also recombines the two beams when they reflect back, producing an interference pattern that varies with differences in the path length between the splitter and the mirror. For example, if the air between the splitter and one mirror changes temperature, the change in the refraction index will cause a minute difference in the beam, which will show up using this instrument.
The device has been used to detect gravitational waves, study the sun and the upper atmosphere, and also helped disprove the theory that light is transmitted through a medium known as luminiferous aether.
The tolerances for such a device are tight, but within the capability of modern 3D printers. The CAD files are online. The key was the mirror mounts, which use springs and thumbscrews. So you do need some hardware and, oh yeah, a laser, although that’s not as hard to obtain as it once was. You obviously can’t 3D print the mirrors or the beam splitter either.
The post claims the device is cheap because the bill of materials was roughly $3, although that didn’t include the beamsplitter, which would bring the cost up to maybe $20. The device, in theory, could detect distance changes as small as one wavelength of the laser, which is around 650nm. Not bad for a few bucks.
Not all Michelsons use lasers. The man behind the Michelson instrument also worked out how to do Fourier analysis with a mechanical computer.
2026-01-13 02:00:21
All right, I’ll cut to the chase: Cheap03xD is mainly so cheap because the PCB falls within a 10 x 10 cm footprint. The point was to make a very affordable keyboard — all the parts come to ~40 Euro (~$47). So it would seem that [Lander03xD_] succeeded.
Those are MMD Princess silent switches, which I wouldn’t choose, but [Lander03xD_] is taking this board to the office, so I get it. They sure are a nice shade of pink, anyway, and they go really well with the pastels of the DSA keycaps and the bezel.
One cool thing to note is that the PCBs are reversible, like the ErgoDox. This isn’t [Lander03xD_]’s first board, and it won’t be the last.
Now, let’s talk batteries. [Saixos] pointed out that the design doesn’t appear to include a protection circuit. In case you can’t tell from where you’re sitting, those are nice!nano clones that [Lander03xD_] is using, and they expect a protection circuit.
[Lander03xD_] is going to look through the docs and see what’s what. The goal is not to have any daughter boards, so this may take some rethinking.
Via reddit
So Arc Raiders is this cool-looking, stripe-logoed, multiplayer extraction shooter that just came out a couple of months ago for all the platforms. It’s not something I could personally play as it’s way too immersive (read: time-consuming), but it definitely looks good, much like this keyboard that [RunRunAndyRun] designed to play it.
No matter; just make a new one. Why not? This rustic beauty runs on the Waveshare RP2040 Zero. The case was 3D printed on a Prusa Mk4, which you’d never know unless you blew up the picture. And then [RunRunAndyRun] gave it that nice patina using Panduro hobby acrylics and a bit of weathering powder.
For now, it’s working pretty well, though [RunRunAndyRun] is still perfecting the keymap. If you’d like to build one yourself, the STLs are available here, and the firmware is on GitHub.
Thanks for the tip, [John]!
Do you rock a sweet set of peripherals on a screamin’ desk pad? Send me a picture along with your handle and all the gory details, and you could be featured here!
This spartan beauty was named after the state in which it was made, Pennsylvania. Manufactured between 1898 and 1903, the Keystone was invented by William Prehn Quentell.
Quentell was living in Kansas City, MO when he first applied for a patent, and later moved to the east coast. At the time, the machine was nameless. The patent looks nothing like the finished product pictured here, but the genesis of the key feature of this “poor man’s Hammond” is there — the swinging type sector.
What this means is that the Keystone has its type on a half wagon wheel, which is evident in the patent drawing. The glyphs are molded around the outside edge of the wheel, which gets rotated into the correct position with each keystroke. This type wheel could be easily changed out for different fonts.
To imprint the paper, a spring-driven hammer strikes from behind, pushing the paper and ribbon against the type wheel. The paper is loaded into a cylindrical holder in the rear, and unfurls as one types.
So, why was it a poor man’s Hammond? Well, for one, the patent image looks like a Hammond. But the poor part is felt the hardest in the makeup of the typewriter.
In the early Keystone examples, the carriage rails were made of pig iron. Why? It’s a simple case of lateral integration. The factory that was retrofitted to manufacture the machine had previously been the Lochiel iron mill, a producer of pig iron. They were just using up old stock, I imagine.
The Keystone featured two Shift keys on the left, one for Caps and one for Figures. It was a comparatively inexpensive at $40, and then later, $35 (around $1,200 today).
Production was supposed to begin in May of 1898. But by June of ’99, “the company has been unable to fill the orders which are piling up at the works.” Sounds like your average Kickstarter. Quentell was already working on his next project by 1902, the Postal typewriter.
So this article mainly centers on the new little Blackberry-esque number from Clicks which might just be my next phone, except that it doesn’t actually telephone. Clicks is meant to be your second phone, the one you use for emailing and such. You can pre-order it for $399 if you put a $199 deposit down before February 27th. If you decide to drop the full four hundo as an early bird, you’ll get two additional back covers, which slightly change the look of the phone.
But I’d like to talk about the add-on Power Keyboard for smart phones that Clicks is also dropping at CES this year. Do you miss your Sidekick? Well, here’s a sliding keyboard with multiple positions for differently-sized smart phones, tablets, and even smart TVs. (Because forget typing with the remote control.)
It uses a 2,150 mAh battery and attaches via MagSafe or Qi2, but it also can be used with the case on. When paired with a smart TV, you just use it by itself. Honestly, it looks kind of hard to type on without the phone for support. But I don’t use the smart features of my TV, so whatever.
Honestly, I will probably start by getting the keyboard, which is $79 for early birds through their site, and $109 later on. Pre-orders started a week ago, so I guess I should get on that.
Got a hot tip that has like, anything to do with keyboards? Help me out by sending in a link or two. Don’t want all the Hackaday scribes to see it? Feel free to email me directly.
2026-01-13 00:30:41
One of the most widely recognised product brands in the world is probably Coca-Cola, and its formula is famously kept a secret through precautions that probably rival those of many nation states. There are other colas, and there are many amateurs who have tried to copy Coke’s flavour, but in well over a century, nobody has managed it. Why does [LabCoatz] think his attempt will be successful where others failed? He has friends with their own mass spectrometers.
‘The video below the break is a nearly half-hour exploration into food chemistry and the flavour profile of the well-known soft drink. It’s easy to name many of the ingredients, but some, such as acetic acid, are unexpected. Replicating the contribution from Coke’s de-cocainised coca leaf extract requires the purchase of some of the constituent chemicals in pure form. Its value lies in showing us how flavour profiles are built up, and the analytical methods used in their decoding.
He makes the point that Coke has never patented the formula because to do so would reveal it, but perhaps in that lies the real point. The value in a secret formula for brands such as Coke lies not in the secret itself, as it’s not difficult to make a refreshing cola drink. Instead, it’s the mystique of their product having a secret recipe that matters. Since this isn’t the recipe itself but something that’s supposed to taste a lot like it, that mystique stays intact. He’s not positioning his Lab-Cola as the real thing, so while we might have used a different label colour and font just to make sure, we’re guessing he’s safe from the lawyers. If you’re interested in the legal grey areas surrounding perceived infringement, though, it’s a topic we’ve looked at before.
Thanks [Hans] for the tip!
