A Hobson’s Coupler Leads To A Weird Engine

August 10, 2023 by Al Williams 19 Comments

You want to join two shafts. What do you need? A coupler, of course. If the shafts don’t line up, you might consider an Oldham coupler. But what if the shafts are at a 90-degree angle to each other? Then you need a Hobson’s coupler. [Robert Murray-Smith] has the 3D printed hookup for you and a video that you can see below.

The part isn’t all 3D printed, though. You do need some bearings and steel rods. [Robert] proposes using this to couple a windmill’s blades to a generator, although we assume some loss is involved compared to a standard shaft. However, we’ve heard that the coupler, also called a Hobson’s joint or a stirrup joint, is actually pretty efficient. However, you rarely see these in practice because most applications will use a gear train employing a bevel gear.

While it may not be practical, the second video below shows an elbow engine that would look undeniably cool on your desk. By making some changes, you can create a Cardan joint which happens to be half of what you think of as a universal joint. The Hobson coupler and the Cardan joint seem to be made for each other, as you’ll see in the video.

We aren’t sure what we want to make with all these mechanisms, but as [Robert] points out, with new materials and techniques, these mechanisms might have a role to play in future designs, even though they have been mostly discarded.

There are, of course, many kinds of couplings. Then again, not all useful joints have to move.

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Canadian Engineers? They Have A Ring About Them

August 10, 2023 by Al Williams 100 Comments

How can you spot an engineer? It can be tricky, but it is a little easier in Canada. That’s because many Canadian engineers have been through the Ritual of the Calling of an Engineer and wear an iron or steel ring to symbolize their profession. The ring has a very odd history that originated in 1922 as the brainchild of Professor H. E. T. Haultain. While he may not be a recognizable name, at least one famous person was involved with creating the Ritual.

The ring itself has facets on the outer surface, and you wear it on the little finger of your dominant hand. Originally handmade, the ring reminds the wearer of the engineer’s moral, ethical, and professional commitment. In addition to being a visible reminder, the ring is made to drag slightly as you write or draw, as a constant reminder of the engineer’s obligation. With more experience, the ridges wear down, dragging less as you get more experience.

There is a rumor that the first rings were made from the metal of a bridge that collapsed due to poor design, but this appears untrue. The presentation ceremony is understated, with limited attendance and very little publicity.

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Inside The PET Keyboard

August 8, 2023 by Al Williams 10 Comments

These days, you have a certain expectation for computer keys on a keyboard. Of course, there are variations and proponents of different mechanisms and noise levels. However, back in the late part of the 20th century, it was a different world. Computers came with a bewildering and sometimes befuddling array of keyboards. Since the IBM Selectric was the king of typewriters, we assumed the IBM PC keyboard would be spectacular, but it wasn’t. The PC Jr was even worse! Atari experimented with flat keyboards to save costs, and many computers had keys more reminiscent of calculator keys than you would imagine. The market voted. In general, a keyboard that wasn’t really a keyboard was the kiss of death for a computer. Case in point: the Commodore PET with its infamous chicklet keyboard, which gets a detailed examination in a recent post from [Norbert Landsteiner].

The PET keyboard gets some bad rap due to software limitations. Because of this, some games would use their own scan routines, and [Norbert] has worked on emulation able to accommodate software that wants to read the hardware directly. The resulting insights into the old keyboard is very interesting. For example, you can press more than one key at once. The result? The answer to that question takes up about half the post.

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Hacking Fake Food

August 8, 2023 by Al Williams 24 Comments

Ever seen a restaurant where they display fake models of the food on the menu? We never thought much about how shokuhin sampuru — the Japanese name — were made until we watched [Process X]’s video showing a 71-year-old artist creating food models. We aren’t sure what we — or you — would do with this information, but it is a striking process, and there must be something you could do with it. We suggest turning on the English captions, but you’d probably enjoy watching the unusual craftsmanship even with no words.

In years past, the food models were primarily made from wax, but since the 1980s, it is more common to use polyvinyl chloride, silicone, and resin. While some factories produce items, sometimes with a mold, single craftsmen like the one in the video still make up the largest part of the market.

We aren’t sure, but we think the material in the video is wax. We couldn’t help but think that some of this could have been 3D printed, but even with the finest resins and resolution, it probably wouldn’t be quite as artistic. We think wax is mainly underutilized in today’s tech. But there are some places it still shows up.

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Linux Containers The Hard Way

August 7, 2023 by Al Williams 10 Comments

If you want to make containers under Linux, plenty of high-level options exist. [Lucavallin] wanted to learn more about how containers really work, so he decided to tackle the problem using the low-level kernel functions, and he shared the code with us on GitHub.

Containers are more isolated than processes but not quite full virtual machines. While a virtual machine creates a fake computer, a container is more like a fake operating system. Applications can run with their own idea of libraries, devices, and other resources, but it doesn’t try to abstract the underlying hardware.

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Noisy Keyboards Sink Ships

August 6, 2023 by Al Williams 40 Comments

Many of us like a keyboard with a positive click noise when we type. You might want to rethink that, though, in light of a new paper from the UK that shows how researchers trained an AI to decode keystrokes from noise on conference calls.

The researchers point out that people don’t expect sound-based exploits. The paper reads, “For example, when typing a password, people will regularly hide their screen but will do little to obfuscate their keyboard’s sound.”

The technique uses the same kind of attention network that makes models like ChatGPT so powerful. It seems to work well, as the paper claims a 97% peak accuracy over both a telephone or Zoom. In addition, where the model was wrong, it tended to be close, identifying an adjacent keystroke instead of the correct one. This would be easy to correct for in software, or even in your brain as infrequent as it is. If you see the sentence “Paris im the s[ring,” you can probably figure out what was really typed.

We’ve seen this done before, but this technique raises the bar. As sophisticated as keyboard listening was back in the 1970s, you can only imagine what the three-letter agencies can do these days.

In the meantime, the mitigation for this particular threat seems obvious — just start screaming whenever you type in your password.

Prepare To Brake: Quick Intro To Metal Bending

August 5, 2023 by Al Williams 9 Comments

If you want to bend metal to make shapes, you might use equipment like a brake. But if you don’t have one, no worries. You can still do a lot with common tools like a vise and torches. [Bwrussell] shows you how. He welds together a die to use as a bending jig and makes a set of table legs.

You might think that putting metal in a vise and bending it isn’t exactly brain surgery. It isn’t, but there is more to it than that. Starting with a bending plan and the creation of the jigs, clamping and bending is only part of it. You can see a little bit of the action in the video below.

Speaking of planning, the design was in Fusion 360’s sheet metal workflow. To facilitate the bends, the build uses two torches. A MAPP torch gets very hot, and a propane torch makes sure that a larger area stays hot. There are quite a few tips you can pick up in this post, even if you aren’t making table legs.

Fusion 360 does a lot of the design work, but if you want a quick lesson on what happens when you bend metal, we can help. Want to make your own metal brake?

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