Retrotechtacular: Learning The Slide Rule The New Old Fashioned Way

December 2, 2025 by Al Williams 14 Comments

Learning something on YouTube seems kind of modern. But if you are watching a 1957 instructional film about slide rules, it also seems old-fashioned. But Encyclopædia Britannica has a complete 30-minute training film, which, what it lacks in glitz, it makes up for in mathematical rigor.

We appreciated that it started out talking about numbers and significant figures instead of jumping right into the slide rule. One thing about the slide rule is that you have to sort of understand roughly what the answer is. So, on a rule, 2×3, 20×30, 20×3, and 0.2×300 are all the same operation.

You don’t actually get to the slide rule part for about seven minutes, but it is a good idea to watch the introductory part. The lecturer, [Dr. Havery E. White] shows a fifty-cent plastic rule and some larger ones, including a classroom demonstration model. We were a bit surprised that the prestigious Britannica wouldn’t have a bit better production values, but it is clear. Perhaps we are just spoiled by modern productions.

We love our slide rules. Maybe we are ready for the collapse of civilization and the need for advanced math with no computers. If you prefer reading something more modern, try this post. Our favorites, though, are the cylindrical ones that work the same, but have more digits.

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How Cross-Channel Plumbing Fuelled The Allied March On Berlin

December 2, 2025 by Lewin Day 29 Comments

During World War II, as the Allies planned the invasion of Normandy, there was one major hurdle to overcome—logistics. In particular, planners needed to guarantee a solid supply of fuel to keep the mechanized army functional. Tanks, trucks, jeeps, and aircraft all drink petroleum at a prodigious rate. The challenge, then, was to figure out how to get fuel over to France in as great a quantity as possible.

War planners took a diverse approach. A bulk supply of fuel in jerry cans was produced to supply the initial invasion effort, while plans were made to capture port facilities that could handle deliveries from ocean-going tankers. Both had their limitations, so a third method was sought to back them up. Thus was born Operation Pluto—an innovative plan to simply lay fuel pipelines right across the English channel.

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Give Us One Manual For Normies, Another For Hackers

December 2, 2025 by Lewin Day 67 Comments

We’ve all been there. You’ve found a beautiful piece of older hardware at the thrift store, and bought it for a song. You rush it home, eager to tinker, but you soon find it’s just not working. You open it up to attempt a repair, but you could really use some information on what you’re looking at and how to enter service mode. Only… a Google search turns up nothing but dodgy websites offering blurry PDFs for entirely the wrong model, and you’re out of luck.

These days, when you buy an appliance, the best documentation you can expect is a Quick Start guide and a warranty card you’ll never use. Manufacturers simply don’t want to give you real information, because they think the average consumer will get scared and confused. I think they can do better. I’m demanding a new two-tier documentation system—the basics for the normies, and real manuals for the tech heads out there.

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3D Printing And The Dream Of Affordable Prosthetics

December 1, 2025 by Maya Posch 13 Comments

As amazing as the human body is, it’s unfortunately not as amazing as e.g. axolotl bodies are, in the sense that they can regrow entire limbs and more. This has left us humans with the necessity to craft artificial replacement limbs to restore some semblance of the original functionality, at least until regenerative medicine reaches maturity.

Despite this limitation, humans have become very adept at crafting prosthetic limbs, starting with fairly basic prosthetics to fully articulated and beautifully sculpted ones, all the way to modern-day functional prosthetics. Yet as was the case a hundred years ago, today’s prosthetics are anything but cheap. This is mostly due to the customization required as no person’s injury is the same.

When the era of 3D printing arrived earlier this century, it was regularly claimed that this would make cheap, fully custom prosthetics a reality. Unfortunately this hasn’t happened, for a variety of reasons. This raises the question of whether 3D printing can at all play a significant role in making prosthetics more affordable, comfortable or functional.

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Hackaday Podcast Episode 347: Breaking Kindles, Baby’s First Synth, And Barcodes!

November 28, 2025 by Kristina Panos 3 Comments

This week, Hackaday’s Elliot Williams and Kristina Panos met up over coffee to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous seven days or so.

On What’s That Sound, Kristina got sort of close, but of course failed spectacularly. Will you fare better and perhaps win a Hackaday Podcast t-shirt? Mayhap you will.

After that, it’s on to the hacks and such, beginning with an interesting tack to take with a flat-Earther that involves two gyroscopes. And we take a look at the design requirements when it comes to building synths for three-year-olds.

Then we discuss several awesome hacks such as a vehicle retrofit to add physical heated seat controls, an assistive radio that speaks the frequencies, and an acoustic radiometer build. Finally, we look at the joys of hacking an old Kindle, and get a handle on disappearing door handles.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download in DRM-free MP3 and savor at your leisure.

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Chinese Regulators May Kill Retractable Car Door Handles That Never Should Have Existed

November 26, 2025 by Lewin Day 157 Comments

Headlights. Indicators. Trunk releases. Seatbelts. Airbags. Just about any part of a car you can think of is governed by a long and complicated government regulation. It’s all about safety, ensuring that the car-buying public can trust that their vehicles won’t unduly injure or maim them in regular operation, or in the event of accident.

However, one part of the modern automobile has largely escaped regulation—namely, the humble door handle. Automakers have been free to innovate with new and wacky designs, with Tesla in particular making waves with its electronic door handles. However, after a series of deadly incidents where doors wouldn’t open, regulators are now examining if these door handles are suitable for road-going automobiles. As always, regulations are written in blood, but it raises the question—was not the danger of these complicated electronic door handles easy to foresee?

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So Long Firefox, Hello Vivaldi

November 25, 2025 by Jenny List 115 Comments

It’s been twenty-three years since the day Phoenix was released, the web browser that eventually became Firefox. I downloaded it on the first day and installed it on my trusty HP Omnibook 800 laptop, and until this year I’ve used it ever since. Yet after all this time, I’m ready to abandon it for another browser. In the previous article in this series I went into my concerns over the direction being taken by Mozilla with respect to their inclusion of AI features and my worries about privacy in Firefox, and I explained why a plurality of browser engines is important for the Web. Now it’s time to follow me on my search for a replacement, and you may be surprised by one aspect of my eventual choice.

Where Do I Go From Here?

Hackaday in the Ladybird browser — It’s Hackaday, in Ladybird! (Ooof, that font.)

Happily for my own purposes, there are a range of Firefox alternatives which fulfill my browser needs without AI cruft and while allowing me to be a little more at peace with my data security and privacy. There’s Chromium of course even if it’s still way too close to Google for my liking, and there are a host of open-source WebKit and Blink based browsers too numerous to name here.

In the Gecko world that should be an easier jump for a Firefox escapee there are also several choices, for example LibreWolf, and Waterfox. In terms of other browser engines there’s the extremely promising but still early in development Ladybird, and the more mature Servo, which though it is available as a no-frills browser, bills itself as an embedded browser engine. I have not considered some other projects that are either lightweight browser engines, or ones not under significant active development. Continue reading “So Long Firefox, Hello Vivaldi” →