The Challenges Of 3D Printing Reliable Springs

April 27, 2026 by Maya Posch 17 Comments

Springs are great, but making them out of plastic tends to come with some downsides, for fairly obvious reasons. Creating a compliant mechanism that can be 3D printed and yet which doesn’t permanently deform or wear out after a few uses is therefore a bit of a struggle. The compliant toggle mechanism that [neotoy] designed is said to have addressed those issues, with the model available on Printables for anyone to give a shake.

The model in question is a toggle, which is the commonly seen plastic or metal device that clamps down on e.g. rope or cord and requires you to push on it to have it release said clamping force. Normally these use a metal spring inside, but this version is fully 3D printable and thus forms a practical way to test this particular compliant mechanism with a variety of materials.

The internal spring is a printed spiral spring, with the example in the video printed in PETG. You can of course also print it in other materials for different durability and springiness properties. As noted in the video, PLA makes for a very poor spring material, so you probably want to skip that one.

We covered compliant mechanisms in the past for purposes like blasters, including some that you can only see under a microscope.

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Trying Pair Programming With An LLM Chatbot

April 27, 2026 by Maya Posch 70 Comments

When it comes to software developers, there are a few distinct types. For example, the extroverted, chatty type, who is always going out there to share the latest and newest libraries and projects with everyone, and is very much into bouncing ideas off others, regardless of whether they know what you’re talking about. Then there is the introverted loner, who prefers to tackle programming challenges by bouncing things around inside their own minds and going on long walks to mull things over before committing to anything significant.

This leads to interesting scenarios when it comes to management-enforced ‘optimization’ strategies, like Pair Programming. This approach involves two developers sharing the same computer and keyboard, theoretically doubling the effective output by some kind of metric, but realistically often leading to at least one side feeling pretty miserable and disconnected unless you put two of the chatty types together.

As a certified introverted loner developer, the idea of using an LLM chatbot as a coding assistant naturally triggers unpleasant flashbacks to hours of forced awkward pair ‘programming’. However, maybe using an LLM chatbot could be more pleasant because you can skip the whole awkward socializing bit. In order to give it a shake, I put together a little experiment to see whether LLM-based coding assistants is something that I could come to appreciate, unlike pair programming.

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How Pizza Tycoon Simulates Traffic On A 25 MHz CPU

April 27, 2026 by Maya Posch 18 Comments

Although the game Pizza Tycoon – known as Pizza Connection in Europe – probably doesn’t ring a bell for many folk, this 1994 DOS title is special enough for [cowomaly] to write an open source engine to bring it into the modern age as Pizza Legacy. Along the way, some questions popped up, such as how to animate the little cars that you see driving around in the simulated city and how the heck this was done back in the day on a 25 MHz 386 CPU.

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Dyson Vacuums And The Curse Of Cooked Capacitors

April 26, 2026 by Maya Posch 44 Comments

It seems to be becoming a bit of a theme that consumer electronics are dying not due to some critical fault, but due to Cooked Capacitor Syndrome (CCS). Case in point, Dyson handheld vacuums and the capacitors on its driver board. After having his $800 Dyson V15 handheld vacuum die after two and a half years of regular use, [LeftyMaker] found himself elbows-deep in the dusty innards of the vacuum just to replace some capacitors.

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Building An IBM PCjr BIOS From Source Using Original Printed Source Code

April 26, 2026 by Maya Posch 20 Comments

As unloved as IBM’s PCjr was, with only a one-year production run, it’s hard to complain about the documentation available for it. This includes the x86 assembly listing for the BIOS, which [dbalsom] recently used this print version to create an ASM project that can be built into a byte-identical copy of the PCjr BIOS.

In order to build the BIOS image, a ZIP file has been made available that contains the requisite assembler and linker tools, all of which can be run in DOS (or DOSBox) using the provided build.bat file. This creates an executable file, which can then be converted into a BIN file using the provided exe2bin.py Python script, or of course, manually.

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Quantum Computers Are Not A Threat To 128-bit Symmetric Keys

April 25, 2026 by Maya Posch 20 Comments

A lot has been made about a post-quantum computer future in which traditional encryption methods have suddenly been rendered obsolete. With this terrifying idea in mind, it’s reassuring to see some recent pushback to the idea with some factual evidence. In a recent blog post by [Filippo Valsorda] – a cryptography engineer – the point is raised that 128-bit symmetric keys like AES-128 and hashing algorithms like SHA-256 are not at risk of being obliterated in a post-quantum future.

Rather than just taking [Filippo]’s word for it, he takes us through a detailed explanation of the flawed understanding of Grover’s algorithm that underlies much of the panic. While it’s very true that this quantum search algorithm can decrease the amount of time required to find a solution, the speed-up with a single thread is quadratic, not exponential. While asymmetric cryptography systems like ECDH, RSA, and kin are very much at risk courtesy of Shor’s algorithm, the same is not true for symmetric systems.

An interesting detail with Grover’s is also that you cannot simply run a search in parallel to get a corresponding speed-up, as it’s not a parallel problem. Barring a breakthrough that replaces Grover’s with something that lends itself better to such a parallel search, it would seem that we won’t have to abandon classical encryption any time soon.

Incidentally, even for Shor’s algorithm, there are still some hold-ups. Current quantum computers are not even able to factor 21 yet. Meanwhile, supposed quantum computing breakthroughs are being trolled with a Commodore 64.

Rescuing The Data On A 1960s LGP-21 Computer’s Disk Memory

April 25, 2026 by Maya Posch 33 Comments

One of the nice things about magnetic storage is that as long as the magnetic layer remains intact, the data it contains should stay readable pretty much indefinitely. That raises the prospect of recovering data from really old computer systems featuring magnetic memory, such as the 63-year old LGP-21 that [David Lovett] of Usagi Electric is currently restoring. Its magnetic memory disk is nothing amazing by modern standards, but after initial testing it seems to spin up and read data just fine, raising the question of what was left on the drive when it was last used, meaning what was in memory at the time.

The read/write head side of the LGP-21's magnetic memory. (Credit: Usagi Electric, YouTube) — The read/write head side of the LGP-21’s magnetic memory. (Credit: Usagi Electric, YouTube)

Non-invasive data recovery here involves writing a program that will simply read the entire disk from beginning to end. Tracks 0 and 1 were found to be unreadable due to some kind of hardware issue, but track 2 could be backed up by looking at the output on the CRT, thus providing a track to use. Fascinatingly the LGP-21’s memory disks uses interleaved tracks to reduce the number of read/write heads as part of the overall cost-saving measures relative to the more expensive LGP-30. As you might expect, this slows down memory access a lot over its big brother.

Before any recovery attempt could begin, the Flexowriter typewriter that forms the user interface to the computer had to be given some serious maintenance, along with a few other components like a switch and the paper tape reader. This restored the ability to even properly enter data and receive output instructions.

The subsequent effort to recover the stored data involved a bootstrap program that got loaded into memory, after which the remainder of the program was loaded from paper tape. Following this everything worked swimmingly, though with the caveat that with not even a floppy drive to use, the raw hexadecimal data was hammered out on paper with the Flexowriter over the course of 1.5 hours.

This data will now be scanned in and OCR-ed into something that can hopefully be easily analyzed. Hopefully we’ll know before long what this system was last used for.

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