Misc Hacks

4194 Articles

Square Roots 1800s Style — No, The Other 1800s

November 25, 2024 by 44 Comments

[MindYourDecisions] presents a Babylonian tablet dating back to around 1800 BC that shows that the hypotenuse of a unit square is the square root of two or 1.41421. How did they know that? We don’t know for sure how they computed it, but experts think it is the same as the ancient Greek method written down by Hero. It is a specialized form of the Newton method. You can follow along and learn how it works in the video below.

The method is simple. You guess the answer first, then you compute the difference and use that to adjust your estimate. You keep repeating the process until the error becomes small enough for your purposes.

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RISC CPU Lives In Excel

November 24, 2024 by 13 Comments

Last time we checked in on [Inkbox], he had made a 16-bit CPU in Excel. Impressive, but not really practical. Presumably, his latest project isn’t any more practical, but we suspect an 8-bit RISC CPU was easier to implement in Excel and probably runs faster, too. The new machine uses a stack architecture with a simplified instruction set of ten instructions. You can follow along with his Excel adventure in the video below.

If you think about it, you may decide that doing something like this in Excel is easy because you could just script it and use Excel as the user interface. That’s true, but that’s not how [Inkbox] does it. He won’t use scripts or IF statements in a cell. That makes things much harder.

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Large gears on a bridge in Geneva, Switzerland

Gear Up: A 15-Minute Intro On Involute Gears

November 21, 2024 by 10 Comments

If you’re into CNC machining, mechanical tinkering, or just love a good engineering rabbit hole, you’re in for a treat. Substack’s [lcamtuf] has written a quick yet insightful 15-minute introduction to involute gears that’s as informative as it is accessible. You can find the full article here. Compared to Hackaday’s more in-depth exploration in their Mechanisms series over the years, this piece is a beginner-friendly gateway into the fascinating world of gear design.

Involute gears aren’t just pretty spirals. Their unique geometry minimizes friction and vibration, keeps rotational speeds steady, and ensures smooth torque transfer—no snags, no skips. As [lcamtuf] points out, the secret sauce lies in their design, which can’t be eyeballed. By simulating the meshing process between a gear and a rack (think infinite gear), you can create the smooth, rolling movement we take for granted in everything from cars to coffee grinders.

From pressure angles to undercutting woes, [lcamtuf] explores why small design tweaks matter. The pièce de résistance? Profile-shifted gears—a genius hack for stronger teeth in low-tooth-count designs.

Whether you’re into the theory behind gear ratios, or in need of a nifty tool to cut them at home, Hackaday has got you covered. Inspired?

Custom Mouse Rocks Neat Thumbstick Design

November 21, 2024 by 20 Comments

A mouse is just two buttons, and a two-dimensional motion tracking system, right? Oh, and a scroll wheel. And a third button. And…now you’re realizing that mice can be pretty complicated. [DIY Yarik] proves that in spades with his impressive—and complex—mouse build. The only thing is, you might argue it isn’t really a mouse.

The inspiration for the mouse was simple. [Yarik] wanted something that was comfortable to use. He also wanted a mouse that wouldn’t break so often—apparently, he’s had a lot of reliability issues with mice in recent years. Thus, he went with a custom 3D-printed design with a wrist rest at the base. This allows his hand to naturally rest in a position where he can access multiple buttons and a central thumbstick for pointing. In fact, there’s a secondary scroll control and a rotary dial as well. It’s a pretty juicy control surface. Code is up on GitHub.

The use of a thumbstick is controversial—some might exclaim “this is not a mouse!” To them, I say, “Fine, call it a pointing device.” It’s still cool, and it look like a comfortable way to interface with a computer.

We’ve seen some other neat custom mice over the years, too, like this hilarious force-feedback mouse. Video after the break. Continue reading “Custom Mouse Rocks Neat Thumbstick Design” →

Simple Stack Of Ferrites Shows How Fluxgate Magnetometers Work

November 20, 2024 by 8 Comments

Have you ever wondered how a magnetometer works? We sure have, which was why we were happy to stumble upon this article on simple homebrew fluxgate magnetometers.

As [Maurycy] explains, clues to how a fluxgate magnetometer works can be found right in the name. We all know what happens when a current is applied to a coil of wire wrapped around an iron or ferrite core — it makes an electromagnet. Wrap another coil around the same core, and you’ve got a simple transformer.

Now, power the first coil, called the drive coil, with alternating current and measure the induced current on the second, or sense coil. Unexpected differences between the current in the drive coil and the sense coil are due to any external magnetic field. The difference indicates the strength of the field. Genius!

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Analog Shift Register Revealed

November 17, 2024 by 18 Comments

Nowadays, if you want to delay an audio signal for, say, an echo or a reverb, you’d probably just do it digitally. But it wasn’t long ago that wasn’t a realistic option. Some devices used mechanical means, but there were also ICs like the TCA350 “bucket brigade” device that [10maurycy10] shows us in a recent post.

In this case, bucket brigade is a euphemism calling to mind how firemen would pass buckets down the line to put out a fire. It’s a bit of an analog analogy. The “bucket” is a MOSFET and capacitor. The “water” is electrical charge stored in the cap.  All those charges are tiny snippets of an analog signal.

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Making A Unique Type Of Wind Gauge For Home Assistant Use

November 11, 2024 by 13 Comments

Sometimes, it’s nice to know how windy it is outside. Knowing the direction of the wind can be a plus, too. To that end, [Sebastian Sokołowski] built himself an unusual anemometer—a wind gauge—to feed into his smart home system.

[Sebastian’s] build is able to tell both wind speed and direction—and with no moving parts! Sort of, anyway. That makes the design altogether different from the usual cup type anemometers with wind vanes that you might be used to seeing on home weather stations. [Sebastian] wanted to go a different route—he wanted a sensor that wouldn’t be so subject to physical wear over time.

The build relies on strain gauges. Basically, [Sebastian] 3D printed a sail-like structure that will flex under the influence of the wind. With multiple strain gauges mounted on the structure, it’s possible to determine the strength of the wind making it flex and in what direction. [Sebastian] explains how this is achieved, particularly involving the way the device compensates for typical expansion and contraction due to temperature changes.

It’s a really unique way to measure wind speed and direction; we’d love to learn more about how it performs in terms of precision, accuracy, and longevity—particularly with regards to regular mechanical and ultrasonic designs. We’ll be keeping a close eye on [Sebastian’s] work going forward. Video after the break.

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