TechyMagThings

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.

CDMA2000 was one of the protocols defined for 3G networks and is now years out of date and being phased out worldwide.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.

The stack includes standard 3G verification; before a handset can authenticate to the network, its details must be added to the home location register (HLR). Once authenticated, the handset can access all standard services: inbound and outbound voice calls via a SIP gateway, inbound and outbound SMS, and data packet transfers. A web dashboard provides a convenient management platform that includes packet tracing.

It should be noted that using this carelessly is legally hazardous; radio transmissions are strictly regulated in most countries, particularly in the cellular bands. If you’d still like to run your own cell network, we’ve also seen a few other efforts, such as this 4G implementation, this 1G recreation, and a GSM network made for a hacker camp.

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].

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.

Well, it depends when you’re going to be househunting– if it’s anytime soon, Betteridge’s law applies, but if your time horizon is a ways further out, [Miana Smith] at MIT wants to make it happen. She’s got a paper out with an open-source inchworm robot designed to assemble structures from voxels– and what is a voxel but a giant, LEGO-esque brick?

There’s a demo video below, and it’s easier to understand the motion of this thing when you see it in action. The 5 degree-of-freedom MILAbot has actuators on both ends, and no traditional base– that’s the inchworm part. It grabs a brick while anchored to one part of the structure, then stays anchored to the new brick to keep building from that locale, so on and so on.

Note that we’re not talking about concrete bricks here, though conceivably you could use an inchworm-style actuator to assemble those. The ‘voxels’ in the study are engineered space-frame blocks which come together very easily, though admittedly would make for a very drafty home– you’d want to fill them with spray foam as a finishing step. So it’s more of a framing technique than a one-and-done thing. Still it is a technique that has something to recommend it compared to the 3D-printed concrete houses that get so much hype— and are already being torn down. 

For instance, the researchers find that weather the voxels are plywood, PLA, or metal, the resulting structure has less embodied energy than any concrete structure, with 3D printed concrete being worst option by that metric– though the balloon-frame stick-build we in North America consider “conventional” is still the lowest of all. On the other hand, that balloon-frame building takes a crew to put together, and labour is expensive compared to robots. At the moment, however, the study admits balloon-framing wins on price, but that doesn’t mean it always will, and it’s a fun hack regardless.

So while your next house might not be made of LEGO by a robot inchworm, we’re still grateful to [Miana] for the tip.

Most building hacks we see here are of the 3D printed variety, but don’t count out plain old dirt. For that matter, as long as someone is willing to live in it, anything can be a house– even an airliner.

The Cheap Yellow Display is a great little module to start a project with, but it wouldn’t necessarily be our first choice for an audio device. That’s because the PWM on the ESP32 isn’t exactly going to put out hi-fi, and the I2C pins needed for the I2S audio protocol aren’t broken out on the CYD board. That didn’t stop [ivans805] AKA [Ill-Town-5623]– he wanted a mod tracker, he had a CYD board, and necessity is the mother of invention.

It isn’t exactly a ground-breaking hack: he’s just tossed a bodge wire to the pin he needs on the ESP32, and run it to the I2S sound module. Still, in this era of endless modules it’s nice to see someone hacking what they have rather than running to AliExpress or somewhere else for a part that has everything the project needs built in.

What really caught our eye when we saw this project on the ESP32 subreddit was the aesthetics. It might be called “Win95-Tracker-CYD” but that interface just screams “Amiga” to us– look at that Boing Ball! Given where MOD files come from, that’s perfect. The UI was made with Lopaka.app, which we haven’t seen before but appears to be a sort of WYSIWYG editor for embedded device interfaces.

While you don’t need an ESP32 to play mod files– the diminutive CH32 can manage the task— there’s no arguing the CYD could make a nice little player. If you actually wanted to push its limits, you might try a 3D engine instead,

Usually, when you want to make glitchy images with lots of colors and things, you have to poke around inside a camera and successfully circuit-bend the thing without bricking it. But [sharkbiscuit101] proves that this isn’t necessary, provided you have a Raspberry Pi 4 and a few other components.

Now we don’t have a lot of detail here, but [sharkbiscuit101] is being heavily encouraged to share the relevant files and a component list. What we do know is that the there’s a screen for previewing images, a portable battery, a shutter button, a rotary encoder to dial in the weirdness, and a game pad for controls. Using the script and a slider, you can tweak different aspects of the image to basically break it down in real time. If you find a nifty combination, you can use the rotary encoder to save and then recall presets.

If you’re wondering about the grip, that’s a Sharge battery from the Bezos Barn. Per [sharkbiscuit101], it is a good size, and since Pi 4 doesn’t have a power button, it can be turned on and off at the battery.

Of course, you can always mess with JPGs on a raw, textual level instead, or produce standard photographs with a pinhole camera.