Author: Al Williams

3808 Articles

A LEGO Orrery

June 9, 2024 by 5 Comments

We aren’t sure how accurate you can get with LEGO, but a building block orrery looks cool, if nothing else. [Marian42] saw one done a few years ago and decided to build a version with a different mechanism. At first, the plan was to use some 3D printed fixtures, but the final product is made entirely from LEGO bricks. Very impressive. The video below shows that it has been complete for awhile, but the write-up that goes into great detail has only just arrived and it was worth the wait.

This is one of those things that seems simple if you don’t think too hard about it. However, when you sit down to actually do it, there are a number of challenges. For one thing, the Earth tilts at 23.5 degrees, and as the planet rotates, the tilt stays in the same direction, making it tricky to model mechanically.

The moon also has a 5.15 degree inclination, but since that’s hard to notice at this scale, the LEGO orrery exaggerates it. So, the Moon’s track has its own set of design problems. The whole thing has to rotate on a concentric shaft, which is also tricky to get right with kids’ building blocks.

Compared to the last orrery we saw, this one is huge. We’ve always been partial to ones that you have to look up to.

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What If The Matrix Was Made In The 1950s?

June 9, 2024 by 30 Comments

We’ve noticed a recent YouTube trend of producing trailers for shows and movies as if they were produced in the 1950s, even when they weren’t. The results are impressive and, as you might expect, leverage AI generation tools. While we enjoy watching them, we were especially interested in [Patrick Gibney’s] peek behind the curtain of how he makes them, as you can see below. If you want to see an example of the result first, check out the second video, showing a 1950s-era The Matrix.

Of course, you could do some of it yourself, but if you want the full AI experience, [Patrick] suggests using ChatGPT to produce a script, though he admits that if he did that, he would tweak the results. Other AI tools create the pictures used and the announcer-style narration. Another tool produces cinematographic shots that include the motion of the “actors” and other things in the scene. More tools create the background music.

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The IBM PC: Brainchild Of A Misfit

June 7, 2024 by 27 Comments

We’ve read a number of histories of the IBM PC and lived through that time, too. But we enjoyed [Gareth Edwards’] perspective in a post entitled The Misfit who Built the IBM PC. The titular character is Don Estridge, a decidedly atypical IBM employee who was instrumental in creating the personal computer market as we know it.

It’s not that IBM invented the personal computer — far from it. But the birth of the PC brought personal computers to the mainstream, especially in offices, and — much to IBM’s chagrin — opened up the market for people to make add-on cards for printers, videos, and other accessories.

IBM was a computer juggernaut in the late 1970s. Its divisions were the size of other companies, and some have compared it to a collection of mafia families. The company was heavily invested in big computers, and management was convinced that personal computing was, at most, an avenue to video games and most likely a fad.

Known as a conservative company, the PC project drew from a number of corporate misfits who had been technically successful but often punished for coloring outside the lines. They developed a prototype. The post quotes one of the people involved as saying, “The system would do two things. It would draw an absolutely beautiful picture of a nude lady, and it would show a picture of a rocket ship blasting off the screen. We decided to show the Management Committee the rocket ship.” Wise choice.

That’s just the kind of tidbit in this post, and if you have any interest in computer history of the 1980s, you’ll definitely want to check it out. Estridge died in 1985, so he didn’t get to see much of the result of the market he opened up. Of course, there were many other players who appear in this story. The PC has many parents, as you might expect.

We’ve done our own recounting of this story. However, we tend to obsess more over the internals.

Hackaday Podcast Episode 274: Capstan Robots, Avionics Of Uncertain Purpose, And What The Frack?

June 7, 2024 by No comments

What do capstans, direct conversion receivers, and fracking have in common? They were all topics Hackaday editors Elliot Williams and Al Williams found fascinating this week. If you wonder what makes an electrical ground a ground, or what a theodolite is, you should check it out.

This week, the hacks came fast and furious. Capstans, instead of gears, work well for 3D-printed mechanisms, a PI Pico can directly receive radio signals, and the guys saw a number of teardowns and reverse engineering triumphs. You’ll also find solid-state heat pumps, flying wings, spectroscopy, and more.

The can’t miss articles this week? Learn about theodolites, a surveying feat from ancient Greece, and how fracking works.

Check out the links below if you want to follow along, and as always, tell us what we’ve mispronounced — or any other thoughts on the episode — in the comments!

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What’s The Difference Between Tang 9K And 20K (It Isn’t 11…)

June 6, 2024 by 18 Comments

[Grug Huhler] has been working with the Tang Nano 9K FPGA board. They are inexpensive, and he noticed there is a 20K version, so he picked one up. Of course, you’d expect the 20K board has a different FPGA with more gates than the 9K, but there are also a number of differences in the host board. [Grug] was kind enough to document the differences in the video below.

In addition to the differences, there’s a good demo of the boards hosting a system-on-chip design. The little DIP package is handy for breadboarding. All of the 20K pins are 3.3 V, according to the documentation. The 9K does have some 1.8 V pins. There are more external devices on the 20K board but that eats up more uncommitted pins. Depending on your design, that may or may not be a problem.

We keep meaning to pick some of these up to play with. The Verilog is easy enough, and the tools look adequate. If you need a refresher on Verilog, we have a boot camp for you that would probably port easily enough to the Tang system. We’ve been following [Grug’s] work on these chips lately, and you should, too.

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Old Knobs With A Cast Of Thousands

June 5, 2024 by 6 Comments

You have an old radio — in the case of [The Radio Mechanic], a Stromberg Carlson — and it needs new knobs. What do you do? You can’t very well pop down to the local store and find any knobs anymore. Even if you are lucky enough to be around an electronics store, they aren’t going to have knobs to do justice to an antique radio. You could 3D print them, of course, but there are a number of issues with transferring the old knob to a CAD file for printing. So [The Radio Mechanic] decided to cast them instead.

He printed some fixtures to help with the molding using two-part molding silicone. He mounted the knob on a shaft in a jig, filled the jig with silicone, and lowered the knob into the mix. The next day, he had a good-looking mold.

The next step, of course, is to cast with resin. Admittedly 3D printing would have been faster, but would not have as nice a surface finish. The epoxy resin is clear, but he was hopeful that some caramel pigment would match the original knob color. Spoiler alert: it didn’t. The resulting knob looked translucent, like a root beer barrel candy, rather than the brown sugar color of the original knob.

The knob needed a spring insert to hold the shaft, so he repurposed some from a different kind of radio. Overall, this is the kind of thing we always think we are going to do when we need something and then we rarely follow through. Then again, we rarely have the patience to wait as long as these two knobs took to make.

Of course, a casting guerrilla doesn’t have to make just knobs. You can even add metal powders to do cold metal casting.

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Fourier, The Animated Series

June 5, 2024 by 7 Comments

We’ve seen many graphical and animated explainers for the Fourier series. We suppose it is because it is so much fun to create the little moving pictures, and, as a bonus, it really helps explain this important concept. Even if you already understand it, there’s something beautiful and elegant about watching a mathematical formula tracing out waveforms.

[Andrei Ciobanu] has added his own take to the body of animations out there — or, at least, part one of a series — and we were impressed with the scope of it. The post starts with the basics, but doesn’t shy away from more advanced math where needed. Don’t worry, it’s not all dull. There’s mathematical flowers, and even a brief mention of Pink Floyd.

The Fourier series is the basis for much of digital signal processing, allowing you to build a signal from the sum of many sinusoids. You can also go in reverse and break a signal up into its constituent waves.

We were impressed with [Andrei’s] sinusoid Tetris, and it appears here, too. We’ve seen many visualizers for this before, but each one is a little different.