Author: Al Williams

2909 Articles

Better Scope Measurements

September 22, 2022 by 6 Comments

There was a time when few hobbyists had an oscilloscope and the ones you did see were old military or industrial surplus that were past their prime. Today you can buy a fancy scope for about what those used scopes cost that would have once been the envy of every giant research lab. However, this new breed of instrument is typically digital and while they look like an old analog scope, the way they work leads to some odd gotchas that [Arthur Pini] covers in a recent post.

Some of his tips are common sense, but easy to forget about. For example, if you stack your four input channels so each uses up a quarter of the screen, it makes sense, right? But [Arthur] points out that you are dropping two bits of dynamic range, which can really jack up a sensitive measurement.

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A Love Letter To Small Design Teams, And The B-52

September 22, 2022 by 60 Comments

The true measure of engineering success — or, at least, one of them — is how long something remains in use. A TV set someone designed in 1980 is probably, at best, relegated to a dusty guest room today if not the landfill. But the B-52 — America’s iconic bomber — has been around for more than 70 years and will likely keep flying for another 30 years or more. Think about that. A plane that first flew in 1952 is still in active use. What’s more, according to a love letter to the plane by [Alex Hollings], it was designed over a weekend in a hotel room by a small group of people.

A Successful Design

One of the keys to the plane’s longevity is its flexibility. Just as musicians have to reinvent themselves if they want to have a career spanning decades, what you wanted a bomber to do in the 1960s is different than what you want it to do today. Oddly enough, other newer bombers like the B-1B and B-2 have already been retired while the B-52 keeps on flying.

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Wow! You Could Have A (Tiny) V8!

September 21, 2022 by 29 Comments

If you grew up before high gas prices and strict emission control regulations, you probably had — or wanted — a car with a V8 engine. An engineering masterpiece created in France, it would define automotive power for the best part of a century. Of course, you can still get them, but the realities of our day make them a luxury. [Vlad] shows us his latest Christmas list addition: a fully-functioning but tiny V8 — the Toyan FS-V800 that has a displacement of two centiliters.

It runs on R/C nitro fuel and is claimed to be the world’s smallest production V8. You can buy the thing built or as a kit and we suggest to protect your street cred, you claim you bought the kit even if you go for the assembled version. The cylinder bores are 17 mm and 16 tiny valves regulate the flow. There are even tiny mufflers for the manifold exhaust. [Dennis] has a video of his operating that you can see below, and his YouTube channel has a lot of information on building the kit and some modifications, too.

Cooling? Water-cooled, of course. The manufacturer claims the engine can rev to 12,500 RPM and can produce over four horsepower. The total size would allow it to fit easily in a five inch cubical volume. You could build it into something, or just display it as a conversation piece. Be prepared for sticker shock, though. We hear the going price for these is about $1,500.

If you’re a bit short on cash or would rather just play with some pretend ponies, this impressive open source engine simulator might be just what you’re looking for.

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Raspberry Pi Grants Remote Access Via PCIe (Sort Of)

September 20, 2022 by 25 Comments

[Jeff] found a Raspberry Pi — well, the compute module version, anyway — in an odd place: on a PCI Express card. Why would you plug a Raspberry Pi into a PC? Well, you aren’t exactly. The card uses the PCI Express connector as a way to mount in the computer and connect to the PC’s ground. The Pi exposes its own network cable and is powered by PoE or a USB C cable. So what does it do? It offers remote keyboard, video, and mouse (KVM) services. The trick is you can then get to the PC remotely even if you need to access, say, the BIOS setup screen or troubleshoot an OS that won’t boot.

This isn’t a new idea. In fact, we’ve seen the underlying Pi-KVM software before, so if you don’t mind figuring out your mounting options for a Raspberry Pi, you probably don’t need this board. Good thing too. Judging by the comments, they are hard to actually buy — perhaps, due to the chip shortage.

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Open Source: Free As The Air You Breathe

September 20, 2022 by 18 Comments

[Carolyn Barber] recently interviewed a 15-year-old who has been making Corsi-Rosenthal boxes for people in his community that are at risk for COVID. Not only is it great that a teenager has such community spirit, but it is also encouraging that [Richard Corsi] and [Jim Rosenthal] made an open-source design that can help people at a greatly reduced cost.

If you haven’t seen one of these boxes, it is essentially a box fan inside a cardboard box with MERV-13 filters on all sides. While these high-quality filters aren’t as efficient as HEPA filters, the box makes up for it by moving a prodigious amount of air and by being much less expensive. The article says you can build a unit for $60 to $100, which is considerably cheaper than other filters with similar performance.

There’s been at least one research paper on the efficacy of the filters and the results were generally quite positive. Schools are taking a great interest in these boxes because they are inexpensive and effective. Of course, the filters don’t last forever, but one of the creators estimates in a classroom with 25 students, a three-year run of the box would run about $4.46 per student per year. Not a lot to pay for clean air.

We love hearing about tech helping people and especially open source that makes big impacts. Usually, when we think of air filtering, we are thinking about laser cutters or 3D printers. However, we have seen inexpensive HEPA filters, too.

IGY: The Year We All Got Along

September 20, 2022 by 24 Comments

If you are a Steely Dan fan, you might know the Donald Fagen song, “IGY.” In it, Fagen sings about a rosy future with high-speed undersea rail, solar power, giant computers making life better, and spandex jackets. Since that song was on the 1982 album Nightfly, it is already too old for some people to remember, but the title goes back even further: the International Geophysical Year which was actually a little longer than a year in 1957 and 1958. The year was a concerted effort by 67 countries to further mankind’s knowledge of the Earth. It was successful,  and was big news in its day, although not much remembered now.

The real origin dates back to even earlier. In 1882 and 1932 there were International Polar Years dedicated to researching the polar regions of the Earth. In a way, it makes sense to do this. Why should 60 or more countries each mount difficult, dangerous, and expensive expeditions to such a hostile environment? However, instead of a third polar year, James Van Allen (who has a famous belt) and some other scientists felt that advances in many fields made it the right time to study geophysics. From the scientific point of view, the IGY coincided with the solar activity cycle maximum. But there were other forces at play, too.

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Glass 3D Printing Via Laser

September 19, 2022 by 5 Comments

If you haven’t noticed, diode laser engraver/cutters have been getting more powerful lately. [Cranktown City] was playing with an Atomstack 20 watt laser and wondered if it would sinter sand into glass. His early experiments were not too promising, but with some work, he was able to make a crude form of glass with the laser as the source of power. However, using glass beads was more effective, so he decided to build his own glass 3D printer using the laser.

This isn’t for the faint of heart. Surfaces need to be flat and there’s aluminum casting and plasma cutting involved, although some of it may not have been necessary for the final construction. The idea was to make a system that would leave a layer of sand and then put down a new layer on command. This turned out to be surprisingly difficult.

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