3D-Printed Woven Coasters Save Tabletops In Style

August 20, 2023 by Kristina Panos 6 Comments

When regular people think of 3D printing, they likely imagine semi-newfangled objects like twisty vases and useless trinkets. But there is so much more to 3D printing, as [andrei.erdei]’s printed, woven coasters demonstrate.

The design is based on the stake and strand basket weaving technique, which uses rigid strips called stakes in one direction and thinner strips called strands in the other. Since the flexibility of PLA is questionable, [andrei] printed the stakes already bent in a square wave pattern that accommodates the strands fairly easily. To tie the coasters together and make them look more polished and commercial, [andrei] designed a holder as well.

The awesome thing about this technique is that you can do so much with it, like varying the stakes’ widths or making them diagonal instead of square. [andrei] designed these in Tinkercad using Codeblocks; of course, they are open source. Be sure to check out the assembly video after the break.

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Data Recovery In The Woodshed

August 18, 2023 by Al Williams 26 Comments

A 1TB drive fails. How do you recover the data? If you are like us, you imagine a high-tech lab with serious-looking technicians and engineers. [John Graham-Cumming] managed it in his woodworking shop. Granted, it was a solid-state drive, so a clean room wasn’t necessary, but we still found it an unexpected story.

[John’s] gaming rig had two Seagate Firecuda 530 SSDs and decided not to boot. A quick analysis found one of the drives failed — it happens. However, the drive showed some signs of life after cooling off. A 30-minute trip to the freezer made the drive work again until it got warm again.

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China May Have A New Submarine Tracking Technology

August 17, 2023 by Lewin Day 69 Comments

Submarines have always been about stealth; that’s always been the whole point of putting them underwater. Tracking them can be difficult, even to this day, but China may have a new technique to help in this endeavour, as reported by the South China Morning Post.

Nuclear missile subs are nicknamed “boomers,” and can spend months underwater. Tracking them is of prime concern to many countries around the world. *US Navy*

The news comes from a study published in a Chinese journal, regarding detection of the most advanced American submarines. The stealthiest examples use all kinds of sophisticated systems to damp vibrations and reduce acoustic signatures to make detection as hard as possible. However, a new type of magnetic detector could change all that.

A research team used computer simulations to determine whether nuclear-powered submarines could be detected via the bubbles produced when cruising at high speed underwater. When these bubbles inevitably collapse, it can apparently produce a detectable signal that is orders of magnitude higher than the sensitivity of the best magnetic anomaly detectors. The signal is found on the order of 34.19 to 49.94 Hz, deep in the ELF range, according to researchers.

This could yet create another arms race, as submarine designers begin designing vessels to reduce bubble shedding at speed. Or, for all we know, this is already a well-known principle in the high-stakes world of submarine surveillance and combat. If you’re in the know, please don’t reveal any classified information in the comments section. It’s not worth your job or ours! If you recreate such a detector at home in a non-treasonous manner, though, don’t hesitate to let us know!

An LM386 Oscillator Thanks To Tungsten Under Glass

August 10, 2023 by Dan Maloney 41 Comments

Once ubiquitous, the incandescent light bulb has become something of a lucerna non grata lately. Banned from home lighting, long gone from flashlights, and laughed out of existence by automotive engineers, you have to go a long way these days to find something that still uses a tungsten filament.

Strangely enough, this lamp-stabilized LM386 Wien bridge oscillator is one place where an incandescent bulb makes an appearance. The Wien bridge itself goes back to the 1890s when it was developed for impedance measurements, and its use in the feedback circuits of vacuum tube oscillators dates back to the 1930s. The incandescent bulb is used in the negative feedback path as an automatic gain control; the tungsten filament’s initial low resistance makes for high gain to kick off oscillation, after which it heats up and lowers the resistance to stabilize the oscillation.

For [Grug Huler], this was one of those “just for funsies” projects stemming from a data sheet example circuit showing a bulb-stabilized LM386 audio oscillator. He actually found it difficult to source the specified lamp — there’s that anti-tungsten bias again — but still managed to cobble together a working audio oscillator. The first pass actually came in pretty close to spec — 1.18 kHz compared to the predicted 1.07 kHz — and the scope showed a very nice-looking sine wave. We were honestly a bit surprised that the FFT analysis showed as many harmonics as it did, but all things considered, the oscillator performed pretty well, especially after a little more tweaking. And no, the light bulb never actually lights up.

Thanks to [Grug] for going down this particular rabbit hole and sharing what he learned. We love builds like this that unearth seemingly obsolete circuits and bring them back to life with modern components. OK, calling the LM386 a modern component might be stretching things a bit, but it is [Elliot]’s favorite chip for a reason.

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Automate Your Pin Header Chopping Chores Away

July 29, 2023 by Dan Maloney 7 Comments

In most cases, cutting pin headers is a pretty simple job to tackle with a pair of cutters or even your bare fingers. But if you’re doing a lot of it, like for kitting up lots of projects for customers, then you might want to look at something like this automatic pin header cutter.

Even if you don’t need to follow [Mr. Innovative]’s lead on this, it’s worth taking a look at the video below, which has a couple of cool ideas that are probably applicable to other automation projects, especially those where lots of small parts are handled. Processing begins with a hopper that holds a stack of header strips over what we’d call a “reverse guillotine,” consisting of a spring-loaded plunger riding on a cam. A header strip is pushed out of the hopper to expose the specified number of terminals, the cam rotates and raises the plunger, and the correct length header is snapped off.

For our money, the neatest part of this build is the feed mechanism for the hopper. Rather than anything complicated like a rack-and-pinion, [Mr. Innovative] opted for a pusher made from a stiff yet flexible strip of plastic, which is forced along the bottom of the hopper by a pair of stepper-driven drive rollers. The plastic pusher is stored rolled up in a spiral fixture so it doesn’t take up much room.

Overall, it’s a simple and largely effective design. [Mr. Innovative] does express a little dissatisfaction with some aspects of the build, though; it looks like the stack of header strips needs a little weight on top of it to keep them feeding properly, and we notice a couple of iterations of the cutting mechanism in the video. The cut headers do seem to either fly off into the stratosphere or stay attached to each other, which could lead to jamming problems.

But still, it’s a solid design and reminds us of some other projects by [Mr. Innovative], like this SMD tape slicer or a CNC gear cutter.

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Understanding And Using Unicode

July 28, 2023 by Chris Lott 43 Comments

Computer engineer [Marco Cilloni] realized a lot of developers today still have trouble dealing with Unicode in their programs, especially in the C/C++ world. He wrote an excellent guide that summarizes many of the issues surrounding Unicode and its encoding called “Unicode is harder than you think“. He first presents a brief history of Unicode and how it came about, so you can understand the reasons for the frustrating edge cases you’re bound to encounter.

There have been a variety of Unicode encoding methods over the years, but modern programs dealing with strings will probably be using UTF-8 encoding — and you should too. This multibyte encoding scheme has the convenient property of not changing the original character values when dealing with 7-bit ASCII text. We were surprised to read that there is actually an EBCDIC version of UTF still officially on the books today:

UTF-EBCDIC, a variable-width encoding that uses 1-byte characters designed for IBM’s EBCDIC systems (note: I think it’s safe to argue that using EBCDIC in 2023 edges very close to being a felony)

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An E-ink display showing Conway's Game of Life, with a solar cell beneath it

Solar Powered Game Of Life Follows The Sun’s Rhythm

July 28, 2023 by Robin Kearey 6 Comments

Conway’s Game of Life is a beautiful example of how complex behavior can emerge from a few very simple rules. But while it uses biological terminology such as “cells”, “alive” and “generation”, the basic game is too simplistic to be a model for any real-world biological process. It’s easy to add features to make it a bit more life-like, however, as [David Hamp-Gonsalves] has done by giving the Conway’s creation something of a circadian rhythm.

The basic idea is that the speed at which [David]’s Game of Life evolves is governed by the amount of ambient light. The game runs off a solar cell that charges a battery, with the battery’s voltage determining how long it takes to advance the game by one generation. The system is therefore highly active in full sunlight, and grinds almost to a complete halt at night.

An ESP32 runs the simulation and outputs the result to a 400 x 300 pixel e-ink display. The display is extremely power-efficient by its very nature; the ESP’s main processor core, on the other hand, is deliberately placed into deep sleep mode most of the time to save as much power as possible. The Ultra Low Power (ULP) co-processor, meanwhile, keeps an eye on the lithium battery’s voltage as it’s slowly being charged by the solar cell. When the voltage reaches 3.3 V, the main CPU wakes up and computes the Game’s new state. In bright sunlight this happens every few seconds, while on an overcast day it could take minutes or even hours.

[David]’s interesting idea of changing Life‘s activity based on the amount of energy available turns the Game into something resembling a cold-blooded animal. We’ve seen a similar approach in a “solar creature” that runs a Life-life simulation on a seven-segment LCD. If it’s speed you care about however, you’re better off implementing Life in an FPGA.