Speech Jammer Gets Jammed Up

May 10, 2026 by 12 Comments

This project is perhaps the single most passive-aggressive thing we’ve ever seen on this site: rather than tell someone directly to ‘shut up’, [Blytical]’s speech jammer lets you hack their brain from across the room to stop them from speaking. It’s also a bit of an object lesson in why you shouldn’t just copy reference implementations without careful study — by his own implementation, [Blytical] was forced to learn a lot more than he intended going into this project.

The brain hack behind it is called ‘delayed auditory feedback’: by feeding their speech back to the target with a short delay — only 50 to 200 ms — it creates a confounding effect that is apparently very difficult to speak through. The array of ultrasound transducers is used to accurately aim the audio by serving as an inaudible, low-spread carrier wave, as we saw in another project this year. A shotgun mike picks up the audio from the speaker you wish to harass, and an array of audio processing circuitry takes care of the rest.

That’s where problems happen, as [Blytical] admits he just tossed some reference implementations onto a PCB without bothering to think too hard about what he was doing. It’s the datasheet version of vibe coding, and it usually goes about as well — sometimes perfectly, but rarely without a lot of troubleshooting. That troubleshooting is really, really hard when you don’t quite understand why things were laid out the way they were on the datasheet. We don’t blame [Blytical], you can learn a lot when you bite off more than you can chew. The fact that he risked this failure mode rather than do the whole thing in software with a Pi says good things about how he’s conducting his education.

It’s a shame, though, because we’ve been waiting to see another one of these speech jammers in action for quite some time. Perhaps someone will try again; the ultrasonic array portion seems solved, so if the delay circuit was the problem, perhaps a tiny tape loop would suffice. Continue reading “Speech Jammer Gets Jammed Up” →

Tracing Olfactory Receptor Mapping Between The Nose And Brain

May 10, 2026 by 1 Comment

The way that the sense of smell works is that olfactory sensory neurons (OSNs) are wired up to olfactory receptors (ORs) in the nasal epithelium, from which they send signals to the brain. Once arrived there, a hierarchy of processing results in us experiencing the sensation of ‘smelling’. Exactly how the olfactory receptor-to-brain mapping works during development, and whether its physical pattern in the nasal epithelium is replicated in the brain, remained major questions until now. In a study published in Cell by [David H. Brann] and others, many of these questions have now been answered, at least for mice.

As it turns out, the mapping between OSNs and ORs isn’t performed by a random selection process, but instead creates a receptor map that’s closely matched between the nasal epithelium and the brain. What has complicated answering this question up till now is that the nasal epithelium isn’t a flat surface, but a convoluted labyrinth that maximizes surface area to smell better.

The second issue was linking the physical location of OSNs and gene expression in the nasal epithelium. Using a new approach, the researchers showed an intricate patterning in this epithelium, with the basal stem cells from which it regenerates maintaining this patterning. This makes for a system very similar to, for example, the auditory system, where the detection of frequencies in the inner ear, as a linear system, is found to be replicated in the brain.

Although it does not provide us with all the answers yet about how this genetic patterning works, it offers a glimpse at a fascinating system that would seem to be used repeatedly across sensory systems. It may also provide potential treatments for medical conditions affecting the olfactory system, whereby the sense of smell is missing, reduced, or oddly miswired, for example, after a SARS-CoV-2 infection of the olfactory nerve that leads to symptoms such as a constant sensation of a burning smell.

You have to wonder if a better understanding of the nose will revive interest in digitally creating and sending smells?

Challenging The Way We Pedal

May 9, 2026 by 8 Comments

The bicycle is an invention that has not changed in its fundamentals since the first recognisably modern machines appeared in the closing years of the 19th century. Its frame uses a structure of two triangles, its wheels are equal in size, and it’s propelled by a pedal crank and (in most cases) a chain. Bicycles have improved vastly in materials and performance, but if you were to wheel a 2026 tourer into an 1886 bike shop, the Victorian proprietor would recognise it. Only a very brave engineer would try to fundamentally change such a formula, but here’s [Not programming] with a crankless bicycle.

The idea is to replace the crank’s circular motion with a linear one, thus providing a more constant propulsion. The build was inspired by another that used a sinusoidal track in a rotating cylinder to achieve the necessary conversion. This design takes a different tack, using an arrangement of gears and freewheels he describes as a mechanical rectifier to convert the back-and-forth motion of pedaling into rotation. The pedals themselves are stirrups mounted at each end of a V-belt.

This build is an exercise in pushing the limits of 3D print strength, as prototype after prototype shears under load. He does finally get the thing to work, though, and we admire his persistence. Oddly, this isn’t the first 3D-printed bicycle geartrain we’ve seen.

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A web interface is shown providing information about a cellular network base station.

Running Your Own 3G Network

May 9, 2026 by 9 Comments

CDMA2000 was one of the protocols defined for 3G networks and is now years out of date and being phased out worldwide. Nevertheless, there are still vast numbers of phones that will happily connect to it, creating an opportunity for hackers seeking to run their own cellular networks. [Chrismoos] recently made this endeavour significantly easier by releasing 1xBTS, a Rust implementation of the lower three layers of a CDMA2000 network.

The lowest layer of the stack is an SDR for the actual radio communications. It’s been tested with the USRP B200 and B210, the LimeSDR Mini 2, and the BladeRF Micro 2.0. The code might work with certain other SDRs using the SoapySDR abstraction layer. The SDR is controlled by the base station (BTS) software, which, in turn, is controlled by the base station controller (BSC) over an Abis link. The BSC manages channels and mobile device associations, and exchanges frames with the mobile switching center (MSC), which handles message switching.

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The Noctua Fan Files And The Limits Of 3D Printing PC Fans

May 9, 2026 by 13 Comments

After Noctua recently released CAD files for a range of their computer fans, one of the first thoughts that popped up for most people was: Can you just to 3D print their fans? Even though Noctua begs you not to 3D print the files and even says they changed the design slightly so it wouldn’t be the same anyway, the question persists. Fortunately, [Steve] of Gamers Nexus is here to help us answer the question of whether it makes sense to 3D print a computer fan.

Unsurprisingly, the answer is mostly a resounding ‘no’. After reworking the original CAD models to be both printable on a Bambu Lab FDM printer and printing the parts in PLA, the arguably most important part, the motor, still had to be sourced from an original Noctua fan. Although you could source a cheaper motor, that could change the fan’s characteristics.

The other issue is materials. The special polymer that Noctua uses for its fans is designed not to change shape significantly when the fan blades are spinning, whereas PLA and basically every other thermoplastic will likely deform enough to hit the inside of the fan with the blades. For this reason, a 3 mm gap was used in the PLA print compared with the approximately 0.5 mm gap of the original Noctua fan.

Using the professional fan tester and semi-anechoic chamber over at Gamers Nexus, the original and replica fans were compared, showing that the 3D-printed fan had a similar noise profile but produced only about half the airflow. This is likely due to the blade shape and angle, the increased gap, and probably a dozen other details that presumably justify putting a cool $40 down for the original fan.

In short, you’re probably best off using these Noctua fan CAD models for fit testing in a larger CAD model, or 3D printing it for a similar purpose, rather than for a functional fan design. At least now we know. Thanks, [Steve].

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Remembering The BBC Computer Literacy Project

May 9, 2026 by 10 Comments

There comes a point in everybody’s life when things that they were a part of are presented as history, and for the 8-bit generation, that time is now. It’s interesting to see the early history of 8-bit home computers presented as history, not from a 2026 perspective but from the early 1990s. The BBC archive has recently posted a retrospective from 1992 looking at ten years of the Computer Literacy Project, a British government programme intended to equip the young people of the 1980s with the skills they would need to approach the information age. It’s a much more immediate history of something which was largely still in place at the time, making it a time capsule in which this past isn’t quite the other country we see it as today.

The Computer Literacy Project was run by the nation’s broadcaster and included a raft of TV programming about computers, as well as the commissioning of a machine specifically for the project. You know this machine as the Acorn BBC Micro, and aside from eventually providing the genesis of what would become ARM, it remains one of the most high-spec 8-bit machines in terms of built-in hardware. We hear from the luminaries of Acorn about the development of this machine, and then the film moves into some of the wider cultural effects.

If you were there, you’ll doubtless remember some of the TV programmes featured, and you might have used a BBC Micro at school. If you weren’t there, it’s an encapsulation of the promise on offer in that era, an optimism that seems sad when you reflect that educational computing descended into learning Microsoft Word during the following decade. It would be another two decades before the Raspberry Pi and BBC micro:bit picked up that fallen torch.

The Beeb, it seems, has long had an interest in home computers. Schools, too.

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Machining A Two-Stroke Engine Out Of Aluminium

May 9, 2026 by 21 Comments

Recently [Camden Bowen] took a swing at machining a two-stroke engine out of billet aluminium, following adventures in 3D printing such an engine, as well as building one out of parts largely sourced from a hardware store. The sketchiest part here is probably the use of only a basic mill and lathe, making the milling of certain shapes a definite OSHA violation.

Two-stroke internal combustion engines are pretty simple from a mechanical point of view, with designs readily available. Add in a suitable material to machine and a modicum of machining and welding skills, and presto, you got yourself a not too shabby looking engine.

Of course, back in reality things are a bit more hairy. Not only are there many different ways to produce the parts – with some coming with a time penalty, monetary penalty, or both – but there are also myriad ways to hurt yourself and/or others. Fortunately [Camden] scraped by with just some (expensive) lessons learned and a major ruined part.

The final design features a single cylinder, with an initial pressure test showing a solid 150 PSI (10 bar) of compression. With that encouraging sign, a coil pack and contactor were added for some spark and a test run with the usual premixed gasoline-oil fuel.

Boringly, the engine mostly just runs and work as it should. This is of course not unexpected, much like how following the recipe for a pie produces said pie. But it does demonstrate how easy things are when you do not stray off the beaten path. The only significant issue was the flywheel wobbling slightly, likely due to a small manufacturing glitch, but this should not cause too many issues.

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