Author: Al Williams

4460 Articles

Read QR Codes Without A Computer

January 22, 2024 by 23 Comments

Did you ever watch Star Wars and wondered how people understood what R2D2 was saying? Maybe [Luke Skywalker] would enjoy learning to decode QR Codes by hand, too. While it might not be very practical, it would be a good party trick — assuming, like us, you party with nerds.

You can start by scanning a code, or the site will create one according to your specifications or generate one randomly. It then takes the selected code and shows you how it is put together. Fun fact: 21×21 “modules” (QR-speak for pixels) is the size of a version 1 QR code. Each version increases the size by four modules.

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Inside A Fake LM358

January 22, 2024 by 23 Comments

[IMSAI Guy] got some fake LM358 op-amps. Uncharacteristically, these chips actually performed well even though they didn’t act like LM358s. [IMSAI Guy] did a video about the fake chips and someone who saw it offered to analyze the part compared to a real LM358 to see what was going on. You can see it too in the video below.

A visual inspection made it obvious that the chip was probably a fake. X-ray analysis was a little less obvious but still showed poor quality and different internals. But the fun was when they actually decapsulated the part.

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Bell Labs Is Leaving The Building

January 22, 2024 by 21 Comments

If you ever had the occasion to visit Bell Labs at Murray Hill, New Jersey, or any of the nearby satellite sites, but you didn’t work there, you were probably envious. For one thing, some of the most brilliant people in the world worked there. Plus, there is the weight of history — Bell Labs had a hand in ten Nobel prizes, five Turing awards, 22 IEEE Medals of Honor, and over 20,000 patents, including several that have literally changed the world. They developed, among other things, the transistor, Unix, and a host of other high-tech inventions. Of course, Bell Labs hasn’t been Bell for a while — Nokia now owns it. And Nokia has plans to move the headquarters lab from its historic Murray Hill campus to nearby New Brunswick. (That’s New Jersey, not Canada.)

If your friends aren’t impressed by Nobels, it is worth mentioning the lab has also won five Emmy awards, a Grammy, and an Academy award. Not bad for a bunch of engineers and scientists. Nokia bought Alcatel-Lucent, who had wound up with Bell Labs after the phone company was split up and AT&T spun off Lucent.

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3D Printed Screw Compressor Revisited

January 22, 2024 by 12 Comments

[Indeterminate Design] tried to 3D print a screw compressor some time ago but wasn’t satisfied with the result. He’s trying it again, and you can check it out in the video below. You can also download the 3D printable files.

This isn’t a 3D-printed keychain. The screw threads have to mesh with a small space between them, and the design is not trivial. Even if you don’t want to build your own, the look inside the engineering behind these devices is interesting, and there is quite a bit of background about how the rotor’s shapes are optimized.

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FM Radio Is Discriminating

January 21, 2024 by 13 Comments

AM radios were easy to understand. The strength of the signal goes up and down, and the audio follows. FM radio is a little more difficult. [AllAmericanFiveRadio] has an old tube FM set and takes us on a tour of how the FM discriminator works. You can see the video below.

The first step is to look at the IF signal on the scope. It is hard to see, but the frequency is changing, and that’s the basis of modulation that the discriminator has to resolve.

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Simulating Cellular Biology In The Browser

January 21, 2024 by 7 Comments

[Technistuff] read a paper about simulating a “minimal” cell — apparently a cell with only 493 genes. This led to a goal: reproduce the simulation in TypeScript so it can run in a web browser. Why? We don’t know, but it is an interesting look at both in-depth biology and how to handle complex simulations. The code is available on GitHub.

For a point of reference, E. Coli has over 4,500 genes. The cell in question — JCVI-syn3A — actually has seven more genes than truly necessary. The data for this bacteria is available from a research lab, again, using GitHub.

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Computer Logic Spins With No Electricity

January 21, 2024 by 21 Comments

We’ve often said you can make a logic gate out of darn near anything. [The Action Lab] agrees and just released a video showing how he made some logic gates from chains and gears. Along the way, he makes the case that the moving chain is an analog for electric current. The demonstration uses a commercial toy known as Spintronics, but if you are mechanically handy, you could probably devise your own setup using 3D printing or gears.

A spring wound motor is a “battery.” Gears act like resistors and junctions to distribute “current” in multiple directions. Seeing series and parallel resistance as moving chains is pretty entertaining and might help someone new learn those concepts.

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