So Many Analog To Digital Converters

June 11, 2026 by No comments

An old algebra teacher used to say, “You have to take what you know and use it to get what you don’t know.” You might say the same thing about converting analog signals into digital. Computers know how to count and keep time. [Eric Explains] has a video purporting to explain “every type of analog-to-digital converter.” We aren’t sure he got every possible method, but there’s still a lot of information in the video, which you can see below.

From the flash ADC, using a ton of comparators to the successive approximation converter, which essentially plays a game of hi/lo, guessing the answer and figuring out if the real answer is higher or lower.

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Repairing A Pair Of Voodoo 2 GPUs For Some SLI Action

June 11, 2026 by 3 Comments
Well there's your problem. (Credit: Bits und Bolts, YouTube)
Well there’s your problem. (Credit: Bits und Bolts, YouTube)

Recently [Bits und Bolts] stumbled over a pair of Dragon 3000 branded 3dfx Voodoo 2 cards in his unfixed cards pile, and decided that the best course of action was to not only fix them, but also run them in SLI for some sweet Unreal Tournament action. Naturally, these cards being in the broken cards pile meant that he first had to figure out why they were broken and fix all issues.

The advantage of having two identical Voodoo 2 cards is of course that any missing components, like some resistors on one card, could be referenced on the other card. Beyond that it was mostly a matter of reflowing clearly corroded pins on the ICs and replacing damaged resistors and resistor arrays before the first tests could be run.

Using the mojo utility it was easy enough to spot that there were still some lingering issues, with clear issues visible in 3D games as well. These were tracked down to a dodgy pin on one of the texture mapping units (TMUs) that needed some more reflowing, and a very sneaky resistor array that was cracked but not obviously so until prodded with a multimeter.

With both cards now making happy noises when individually tested, it was time to go full SLI, fire up the Pentium 2 system and enjoy the glory of 24 MB of VRAM at high resolutions in Unreal Tournament. Considering that the bloke who had sent in these cards had found them while cleaning up a shed, it’s quite amazing how little rework was needed to once again party like it’s 1999.

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An image of the surface of Europa. The top half of the sphere is illuminated with the bottom half dark. The surface is traced with lineae, long lines across its surface of various hues of grey, white, and brown. The surface is a brown-grey, somewhat like Earth's Moon with the highest brightness areas appearing white.

Evidence For Water Vapor Plumes On Europa Vanishes In Re-Analysis

June 11, 2026 by 4 Comments

Unlike on Mars where for decades we have had dozens of orbital and ground-based platforms zipping and scurrying about to prod at every bit of emitted radiation, rock type and twitch of dust devils in its thin atmosphere, for other planets and their moons we have to do a lot more speculative interpretation of data. Such was the case with the presumed existence of water plumes on Jupiter’s moon Europa. These now appear to have been a statistical fluke, per research by [L. Roth] et al. in Astronomy & Astrophysics.

As succinctly summarized in the article on this by [Javier Barbuzano] of Sky and Telescope, the original 2013 finding of said water plumes by the same team was based on faint UV emissions from Europa’s southern hemisphere as captured by the Hubble Space Telescope. However, in more recent captures these emissions were not detected again, leading them to reexamine their original analysis of the 2013 data.

One of the main flaws was in the assumption of where Europe was located on Hubble’s 1,000 x 1,000 resolution detector, with the re-analysis showing that they were off by a couple of pixels. A second flaw was quite understandable as since 2013 we have learned that Europa has a thin hydrogen exosphere which interacts with the Sun’s UV radiation. The resulting scattering induces a UV glow which could be mistaken for UV radiation emanating from the moon’s surface.

Even with this one intriguing feature turning out to be a mirage, it doesn’t make Europa any less interesting as it’s still assumed to have vast liquid water oceans. Along with Uranus’ moon Miranda this makes it very worth it to experience more of the sights and sounds of these alien worlds, whether in person or via our robotic friends.

Mechanical Stability For Your Coils

June 11, 2026 by 5 Comments

If you work with radio, the chances are that before too long you’ll be winding an inductor. At radio frequencies these won’t be big chunky transformer style chokes, but often air-cored affairs supported by their own rigidity. As grizzled old radio amateurs will tell you though, relying on such a coil for stability is a fool’s errand. It will shift inductance from the slightest movement, thermal expansion, or even sound. Luckily [SolderSmoke] is here to remind us of the trusty fix, in the form of Q-dope, or a polystyrene solution that dries to form a rigid low-dielectric coating.

Where this is being written it wasn’t on the market so it was more usual to use nail lacquer, but reading the piece it seems American hams swore by the stuff. That’s in the past tense because it seems it’s no longer on the market. Even there though help is at hand, because dissolving packaging polystyrene in solvent yields an acceptable substitute. There’s even an 11-year-old how-to video linked from the SolderSmoke post, should you fancy making some of your own. We suggest you proceed with caution though, polymers dissolved in solvents sounds a lot like home-made napalm, and probably puts out fumes you don’t want to breathe.

Meanwhile should you fancy experiments of your own with inductors, we’ve got you covered.

3D Printed Hose Sprayer Sets Phasers To Suds

June 11, 2026 by 1 Comment

The weather is warming up, and for many of us that means more time spent working out in the yard. You probably won’t find any new life or new civilizations out there, but if you’ve spent the last few months indoors on your computer, the garden may as well be a strange new world. In that case, you’d do well to equip the members of your landing party with this Star Trek: The Original Series hose sprayer designed by [Curt Turner].

If you’re wondering how [Curt] managed to 3D print a functional hose sprayer, the short answer is that he didn’t. Once assembled, the printed parts cleverly attach to the top of a standard sprayer, specifically the model 56516 “Pro Flo” from Orbit. Without the design constraints that would have come from trying to make the thing actually contain pressurized water, [Curt] was free to focus on the aesthetics, and it shows.

Even with a garden variety — no pun intended — sprayer strapped to the bottom, it’s remarkable how much the “Sprayser” looks like the real thing. Well, not real, but you know what we mean.

[Curt] has also done an excellent job documenting this project for others that want to imagine they’re fighting off Romulans in their backyard. He’s got assembly diagrams that break down which color each of the principle components is to be printed in, as well as a build video that we’ve embedded below.

We’ve seen a fair number of Star Trek props built over the years, some of which have packed in considerably more functionality than anything they would have had back on the set. These days you can even by an officially licensed tricorder that can actually do some of the things the fictional versions were capable of.

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The Merits Of Comment-Driven Development As Counterweight To TDD

June 11, 2026 by 21 Comments

The world of software has seen many paradigms come and go, all of which were supposed to revolutionize its development. Still, one of the basic tenets in engineering of there being no shortcuts to just doing the work properly also rings true in the field of software engineering: trying to skip ‘nice to haves’ like proper documentation, code formatting, and proper testing inevitably results in developers nervously trying to ignore the looming avalanche of technical and other project debts as they keep piling up.

While Test-Driven Development (TDD) once got praised as the silver bullet, the principle of writing tests before writing code merely postpones the inevitable project collapse. The elephant in the room is that you cannot pass on the basics in engineering and expect to come out fine on the other end. There’s a reason why phrases like “all tests green, successfully failed in production” have become common.

This is where the concept of Comment-Driven Development (CDD) comes into play. What started as a bit of a joke many years ago stuck in my mind and led me to my current approach in software development that tries to effectively mirror solid engineering principles.

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A boiling flask is mounted in a heating manted, with a tube leading from it to a U-shaped tube. From here, the tube continues to a bottle of yellow fluid, from which another tube emerges. A flame is emitted from this last tube.

Building A Desktop Catalytic Cracker

June 11, 2026 by 4 Comments

Although crude oil contains a vast diversity of hydrocarbons, a comparatively small number of these make up the bulk of demand for oil. Cracking solves this mismatch: most of the demand is for light, short-carbon-chain molecules, so a cracker breaks down long-chain hydrocarbons into lighter, more commercially-valuable chemicals. This is usually done in massive industrial plants, but as [Markus Bindhammer] showed, it’s possible even in a tabletop apparatus.

There are several methods of cracking, but [Markus] used catalytic fluid cracking: a feedstock high in alkanes (hydrocarbons containing fully saturated carbon-carbon bonds) is heated in the presence of a catalyst, whereupon its long alkane chains split to form alkenes (hydrocarbons with a carbon-carbon double bond) with the loss of a hydrogen molecule. In [Markus]’s setup, a heating mantle heated a boiling flask containing paraffin oil and an amorphous silica-alumina catalyst. Vapors from this flask passed through a condenser tube and a bottle of bromine water, then escaped through a flashback arrestor. Bromine reacts far more readily with alkenes than with alkanes, so the disappearance of its characteristic yellow color would visually indicate the production of alkenes.

To avoid unwanted oxidation, [Markus] purged the cracker with argon before using it. While running the cracker, a flammable mixture of light hydrocarbons and hydrogen escaped from the flask of bromine water. The yellow color of bromine disappeared, and two phases formed: one aqueous, and a lighter phase of hydrocarbons and brominated hydrocarbons. The hot side of the reactor did not survive well; the catalyst turned black with coke, and the heating mantel’s cover fused to the boiling flask. However, the reaction undoubtedly succeeded: while a pool of normal paraffin oil wouldn’t ignite, the cracked oil lit easily.

To go the other way, from small molecules to larger hydrocarbon chains, [Markus] has also used the Fischer-Tropsch process.

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