Day: February 17, 2025

Get Ready For KiCAD 9!

February 17, 2025 by 54 Comments

Rev up your browsers, package managers, or whatever other tool you use to avail yourself of new software releases, because the KiCAD team have announced that barring any major bugs being found in the next few hours, tomorrow should see the release of version 9 of the open source EDA suite. Who knows, depending on where you are in the world that could have already happened when you read this.

Skimming through the long list of enhancements brought into this version there’s one thing that strikes us; how this is now a list of upgrades and tweaks to a stable piece of software rather than essential features bringing a rough and ready package towards usability. There was a time when using KiCAD was a frustrating experience of many quirks and interface annoyances, but successive versions have improved it beyond measure. We would pass comment that we wished all open source software was as polished, but the fact is that much of the commercial software in this arena is not as good as this.

So head on over and kick the tires on this new KiCAD release, assuming that it passes those final checks. We look forward to the community’s verdict on it.

Integrated Micro Lab Keeps Track Of Ammonia In The Blood

February 17, 2025 by 6 Comments

We’ve all got our health-related crosses to bear, and even if you’re currently healthy, it’s only a matter of time before entropy catches up to you. For [Markus Bindhammer], it caught up to him in a big way: liver disease, specifically cirrhosis. The disease has a lot of consequences, none of which are pleasant, like abnormally high ammonia concentration in the blood. So naturally, [Markus] built an ammonia analyzer to monitor his blood.

Measuring the amount of ammonia in blood isn’t as straightforward as you think. Yes, there are a few cheap MEMS-based sensors, but they tend to be good only for qualitative measurements, and other solid-state sensors that are more quantitative tend to be pretty expensive since they’re mostly intended for industrial applications. [Marb]’s approach is based on the so-called Berthelot method, which uses a two-part reagent. In the presence of ammonia (or more precisely, ammonium ions), the reagent generates a dark blue-green species that absorbs light strongly at 660 nm. Measuring the absorbance at that wavelength gives an approximation of the ammonia concentration.

[Marb]’s implementation of this process uses a two-stage reactor. The first stage heats and stirs the sample in a glass tube using a simple cartridge heater from a 3D printer head and a stirrer made from a stepper motor with a magnetic arm. Heating the sample volatilizes any ammonia in it, which mixes with room air pumped into the chamber by a small compressor. The ammonia-laden air moves to the second chamber containing the Berthelot reagent, stirred by another stepper-powered stir plate. A glass frit diffuses the gas into the reagent, and a 660-nm laser and photodiode detect any color change. The video below shows the design and construction of the micro lab along with some test runs.

We wish [Markus] well in his journey, of course, especially since he’s been an active part of our community for years. His chemistry-related projects run the gamut from a homebrew gas chromatograph to chemical flip flops, with a lot more to boot.

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A Forgotten Consumer PC Becomes A Floating Point Powerhouse

February 17, 2025 by 23 Comments

[Michael Wessel] found some of his old DOS 3D graphics software and tried to run it on an 8088 PC. The tale of adding an 8087 co-processor to speed up the rendering was anything but straightforward, resulting in a useful little project.

There was a point around the end of the 1980s when the world of PCs had moved on to the 386, but the humble 8086 and 8088 hung around at the consumer end of the market. For Europeans that meant a variety of non-standard machines with brand names such as Amstrad and Schneider, and even surprisingly, later on Sinclair and Commodore too.

Of these the Schneider Euro PC was an all-in-one design reminiscent of an Amiga or Atari ST, packing a serviceable 8088 PC with a single 3.5″ floppy drive. A cheap machine like this was never thought to need an 8087, and lacked the usual socket on the motherboard, so he made a small PCB daughter board for the 8088 socket with space for both chips.

It’s a surprisingly simple circuit, as obviously the two chips were meant to exist together. It certainly had the desired effect on his frame rate, though we’re not sure how many other Euro PC users will need it. It does make us curious though, as to how quickly a modern microcontroller could emulate an 8087 for an even faster render time. Meanwhile if you’re curious about the 8087, of course [Ken Shirriff] has taken a look at it.

Probably The Most Esoteric Commodore 64 Magazine

February 17, 2025 by 10 Comments

The world of computer enthusiasts has over time generated many subcultures and fandoms, each of which has in turn spawned its own media. [Intric8] has shared the tale of his falling down a rabbit hole as he traced one of them, a particularly esoteric disk magazine for the Commodore 64. The disks are bright yellow, and come with intricate home-made jackets and labels. Sticking them into a 1541 drive does nothing, because these aren’t standard fare, instead they require GEOS and a particularly upgraded machine. They appear at times in Commodore swap meets, and since they formed a periodical there are several years’ worth to collect that extend into the 2000s, long after the heyday of the 64.

Picking up nuggets of information over time, he traces them to Oregon, and the Astoria Commodore User Group, and to [Lord Ronin], otherwise known as David Mohr. Sadly the magazine ended with his death in 2009, but until then he produced an esoteric selection of stories, adventure games, and other software for surely one of the most exclusive computer clubs in existence. It’s a fascinating look into computer culture from before the Internet, even though by 2009 the Internet had well and truly eclipsed it, when disks like these were treasured for the information they contained. So if you find any of these yellow Penny Farthing disks, make sure that they or at least their contents are preserved.

Surprisingly, this isn’t the only odd format disk magazine we’ve seen.

Measuring Local Variances In Earth’s Magnetic Field

February 17, 2025 by 11 Comments

Although the Earth’s magnetic field is reliable enough for navigation and is also essential for blocking harmful solar emissions and for improving radio communications, it’s not a uniform strength everywhere on the planet. Much like how inconsistencies in the density of the materials of the planet can impact the local gravitational force ever so slightly, so to can slight changes impact the strength of the magnetic field from place to place. And it doesn’t take too much to measure this impact on your own, as [efeyenice983] demonstrates here.

To measure this local field strength, the first item needed is a working compass. With the compass aligned to north, a magnet is placed with its poles aligned at a right angle to the compass. The deflection angle of the needle is noted for varying distances of the magnet, and with some quick math the local field strength of the Earth’s magnetic field can be calculated based on the strength of the magnet and the amount of change of the compass needle when under its influence.

Using this method, [efeyenice983] found that the Earth’s magnetic field strength at their location was about 0.49 Gauss, which is well within 0.25 to 0.65 Gauss that is typically found on the planet’s surface. Not only does the magnetic field strength vary with location, it’s been generally decreasing in strength on average over the past century or so as well, and the poles themselves aren’t stationary either. Check out this article which shows just how much the poles have shifted over the last few decades.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Cutting Board Keyboard

February 17, 2025 by 4 Comments

Doesn’t this look fantastic? Hard to believe it, but the base of this keyboard began life as a cutting board, and there’s a gallery to prove it. This is actually [androidbrick]’s second foray into this type of upcycling.

This time, [androidbrick] used a FiiO KB3 and replaced the bottom half of the plastic shell with a hand-routed kitchen cutting board. The battery has been disabled and it works only in wired mode, which is fine with me, because then you get to use a curly cord if you want.

A lovely keyboard built into a kitchen cutting board.
Image by [androidbrick] via reddit
The switches are mostly Gateron EF Currys, though [androidbrick] left some of the original Gateron G Pro 3.0 on the stabilized keys just for comparison. As you might imagine, the overall sound is much deeper with a wooden bottom. You can check out the sound test on YouTube if you’d like, though it’s pretty quiet, so turn it up.

Those keycaps look even nicer from top-down, which you’ll see in the sound test video linked above. Just search ‘JCM MOA GMK’ on Ali and you’ll find them in a bunch of colorways for around $20. Apparently, [androidbrick] was saving them for months, just waiting for this build.

Via reddit

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Decoy Killswitch Triggers Alarm Instead

February 17, 2025 by 43 Comments

There are a few vehicles on the road that are targeted often by car thieves, whether that’s because they have valuable parts, the OEM security is easily bypassed, or even because it’s an antique vehicle that needs little more than a screwdriver to get started. For those driving one of these vehicles an additional immobilization feature is often added, like a hidden switch to deactivate the fuel pump. But, in the continual arms race between thieves and car owners, this strategy is easily bypassed. [Drive Science] hopefully took one step ahead though and added a decoy killswitch instead which triggers the alarm.

The decoy switch is placed near the steering column, where it would easily be noticed by a thief. Presumably, they would think that this was the reason the car wouldn’t start and attempt to flip the switch and then start the ignition. But secretly, the switch activates a hidden relay connected to the alarm system, so after a few seconds of the decoy switch activating, the alarm will go off regardless of the position of this switch. This build requires a lot of hiding spots to be effective, so a hidden method to deactivate the alarm is also included which resets the relay, and another killswitch which actually disables the fuel pump is also added to another secret location in the car.

As far as “security through obscurity” goes, a build like this goes a long way to demonstrate how this is an effective method in certain situations. All that’s generally needed for effective car theft prevention is to make your car slightly more annoying to steal than any other car on the road, and we think that [Drive Science] has accomplished that goal quite well. Security through obscurity is generally easily broken on things deployed on a much larger scale. A major European radio system was found to have several vulnerabilities recently thanks in part to the designers hoping no one would look to closely at them.

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