Engineering Lessons From The Super-Kamiokande Neutrino Observatory Failure

Every engineer is going to have a bad day, but only an unlucky few will have a day so bad that it registers on a seismometer.

We’ve always had a morbid fascination with engineering mega-failures, few of which escape our attention. But we’d never heard of the Super-Kamiokande neutrino detector implosion until stumbling upon [Alexander the OK]’s video of the 2001 event. The first half of the video below describes neutrinos in some detail and the engineering problems related to detecting and studying a particle so elusive that it can pass through the entire planet without hitting anything. The Super-Kamiokande detector was built to solve that problem, courtesy of an enormous tank of ultrapure water buried 1,000 meters inside a mountain in Japan and lined with over 10,000 supersized photomultiplier tubes to detect the faint pulses of Chernkov radiation emitted on the rare occasion that a neutrino interacts with a water molecule.

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Sheet Metal Forming With 3D Printed Dies

Sheet metal is very easy to form, including the pressing in of intricate shapes with dies and a hydraulic press, but the dies themselves are slightly harder to come by. What if we could 3D print custom dies to stamp logos and more into sheet metal? This is the premise of a recent video by theĀ Stick Shift Garage channel on YouTube in which dies are printed in PLA+ (solid infill) and used to stamp 1 and 2 mm thick sheet metal with the channel’s logo.

As can be observed in the video, the results aren’t bad at all after a couple of tweaks and adjustments to the pressure, but of course there is room for improvement. Some helpful commentators suggest improving the dies with properly rounded edges on the die’s shape and paying attention to K-factors and kin so as not to overstress or tear the sheet metal. In terms of die longevity, the PLA+ dies began to wear out after about a dozen tries but not the point of failure. Here other filament types might work even better, maybe even to the point of competing with a CNCed metal die.

Considering that this was a first attempt without a lot of pre-existing knowledge it went pretty well, and a future video was promised in which improvements will be shown off.

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Toner Transfer, But Not For PCBs

It is old news that you can print PCB artwork on glossy paper and use a clothes iron to transfer the toner to a copper board, which will resist etchant. But [Squalius] shows us how to do a similar trick with 3D prints in a recent video, which you can see below.

The example used is a QR code, although you can use anything you can print in a mirror image. Of course, heat from a clothes iron isn’t going to be compatible with your 3D-printed plastic. The trick is to use some acrylic medium on the part, place the print face down, and apply more medium to the back of the paper.

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Retrotechtacular: Soldering The Tek Way

For a lot of us, soldering just seems to come naturally. But if we’re being honest, none of us was born with a soldering iron in our hand — ouch! — and if we’re good at soldering now, it’s only thanks to good habits and long practice. But what if you’re a company that lives and dies by the quality of the solder joints your employees produce? How do you get them to embrace the dark art of soldering?

If you’re Tektronix in the late 1970s and early 1980s, the answer is simple: make in-depth training videos that teach people to solder the Tek way. The first video below, from 1977, is aimed at workers on the assembly line and as such concentrates mainly on the practical aspects of making solid solder joints on PCBs and mainly with through-hole components. The video does have a bit of theory on soldering chemistry and the difference between eutectic alloys and other tin-lead mixes, as well as a little about the proper use of silver-bearing solders. But most of the time is spent discussing the primary tool of the trade: the iron. Even though the film is dated and looks like a multi-generation dupe from VHS, it still has a lot of valuable tips; we’ve been soldering for decades and somehow never realized that cleaning a tip on a wet sponge is so effective because the sudden temperature change helps release oxides and burned flux. The more you know.

The second video below is aimed more at the Tek repair and rework technicians. It reiterates a lot of the material from the first video, but then veers off into repair-specific topics, like effective desoldering. Pro tip: Don’t use the “Heat and Shake” method of desoldering, and wear those safety glasses. There’s also a lot of detail on how to avoid damaging the PCB during repairs, and how to fix them if you do manage to lift a trace. They put a fair amount of emphasis on the importance of making repairs look good, especially with bodge wires, which should be placed on the back of the board so they’re not so obvious. It makes sense; Tek boards from the era are works of art, and you don’t want to mess with that.

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Writing A RISC-V OS From Scratch

If you read Japanese, you might have seen the book “Design and Implementation of Microkernels” by [Nu Tian Sheng]. An appendix covers how to write your own operating system for RISC-V in about 1,000 lines of code. Don’t speak Japanese? An English version is available free on the Web and on GitHub.

The author points out that the original Linux kernel wasn’t much bigger (about 8,500 lines). The OS allows for paging, multitasking, a file system, and exception handling. It doesn’t implement interrupt handling, timers, inter-process communication, or handling of multiple processors. But that leaves you with something to do!

The online book covers everything from booting using OpenSBI to building a command line shell. Honestly, we’d have been happier with some interrupt scheme and any sort of crude way to communicate and synchronize across processes, but the 1,000 line limit is draconian.

Since the project uses QEMU as an emulation layer, you don’t even need any special hardware to get started. Truthfully, you probably won’t want to use this for a production project, but for getting a detailed understanding of operating systems or RISC-V programming, it is well worth a look.

If you want something more production-ready, you have choices. Or, stop using an OS at all.

Front panel of a GPO Brooklyn with cassette player (Credit: VSchagow, Wikimedia)

Physical Media Is Dead, Long Live Physical Media

Much has been written about the demise of physical media. Long considered the measure of technological progress in audiovisual and computing fields, the 2000s saw this metric seemingly rendered obsolete by the rise of online audiovisual and software distribution services. This has brought us to a period in time where the very idea of buying a new music album, a movie or a piece of software in a physical, or even online, retail store hasĀ  become largely impossible amidst the rise of digital-only media.

Even so, not all is well in this digital-only paradise, as the problems with having no physical copy of the item which you purportedly purchased are becoming increasingly more evident. From increases in monthly service costs, to items being removed or altered without your consent, as well as concerns over privacy and an inability to resell or lend an album or game to a buddy, there are many reasons why having the performance or software on a piece of off-line, physical media is once again increasing in appeal.

Even if the demise of physical data storage was mostly a trick to extract monthly payments from one’s customer base, what are the chances of this process truly reverting, and to what kind of physical media formats exactly?

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3DBenchy Starts Enforcing Its No Derivatives License

Nobody likes reading the fine print, least of all when you’re just downloading some 3D model. While printing a copy for personal use this is rarely an issue, things can get a lot more complicated when you make and distribute a derived version of a particular model.

Case in point the ever popular 3DBenchy model, which was intended to serve as a diagnostic aid by designer [Creative Tools] (recently acquired by [NTI Group] ). Although folks have been spinning up their own versions of this benchmark print for years, such derivative works were technically forbidden by the original model’s license — a fact that the company is now starting to take seriously, with derivative models reportedly getting pulled from Printables.

The license for the 3DBenchy model is (and always has been) the Creative Commons BY-ND 4.0, which requires attribution and forbids distributing of derivative works. This means that legally any derived version of this popular model being distributed on Thingiverse, Printables, etc. is illegal, as already noted seven years ago by an observant user on Reddit. According to the message received by a Printables user, all derived 3DBenchy models will be removed from the site while the license is now (belatedly) being enforced.

Although it’s going to be a bit of an adjustment with this license enforcement, ultimately the idea of Creative Commons licenses was that they set clear rules for usage, which become meaningless if not observed.

Thanks to [JohnU] for the tip.