Mysterious Files PH

CDMA2000 was one of the protocols defined for 3G networks and is now years out of date and being phased out worldwide.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

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.

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.

Recently we featured an unusual Commodore 8-bit computer on the bench of [Tynemouth Software] — a Commodore 64 in a PET case. One of the unique parts it had was a board which took the composite output from the mainboard and split out the sync pulses for the monitor, and now they’re back to give it a full reverse engineer.

Perhaps the first surprise is why this board is necessary at all, after all one might expect an 8-bit machine to have those signals already at hand. It seems that the VIC chip inside the 64 did the combination to composite internally, so no such luck for the Commodore engineers. The board they designed then is a complete and very well-engineered sync splitter.

The technology of a video signal has its origins in the 1930s, so it’s not hard to extract both vertical and horizontal sync pulses with little more than a few passive components and a couple of transistors. The trouble with such a simple approach is that the output will work, but it will be messy and crucially, not have quite the required timing. The Commodore board uses the same approach as a simple discrete circuit of having a pair of filters with a time constant selected to catch the relevant sync, but extends it with extra logic. There are one-shots designed to provide clean pulses of exactly the right length, and gates that provide blanking to remove the chance of pulses ending up where they shouldn’t. The video path is the only part which might differ from a conventional sync splitter, because as the output from the 64 is all-digital, it takes a TTL-level through a gate rather than a more conventional analogue path.

You can see the rest of the machine in our original write-up, and we’re reminded that the boards haven’t been cleaned at their owner’s request, to preserve their patina.

In this episode, Hackaday Editors Elliot Williams and Tom Nardi start things off by discussing the latest reason that cheap PCB fabrication isn’t quite as cheap as it once was. The conversation will then move on to hacking electronic shelf labels, stylish e-ink status displays, cutting metal at home with high current and a bit of water, a solarpunk message board hiding in a IKEA-style lantern, and pushing NFC out of its comfort zone. From there you’ll hear about a matching transistors, taking pictures of the International Space Station, and Linux on the PS5. They’ll wrap up this week’s episode by going over the surprisingly simple concept behind flow batteries, and learn who’s still using leaded gasoline and why.

Check out the links if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download in DRM-free MP3.

Episode 369 Show Notes:

News:

• You’ve Seen The Chip Shortage And The Memory Shortage, Now Prepare For The PCB Shortage
• The Zen Of Mechanical Keyboard Wiring
• Hackaday Europe: Last Round Of Speakers, Workshops

What’s that Sound?

• Think you know that sound? Fill out the form for a chance to win!

Interesting Hacks of the Week:

• TagTinker Lets You Hack Electronic Shelf Labels
  • Game Boy Vs. Electronic Shelf Labels
• E-paper Dashboard Reimagines Smart Home’s Connection With Technology
• Three-Axis Camera Slider From 3D Printer Parts
  • Camera Slider: Build Instead Of Buy Goes Awry
  • FluidNC Wiki Home Page
• Cutting Steel Gears With Homemade EDM
  • Powercore Aims To Bring The Power Of EDM To Any 3D Printer
• ESP32 Hosts SolarPunk Message Board
• Using NFC To Power Devices Instead Of Qi
  • ATtiny Chip Abused In RFID Application

Quick Hacks:

• Elliot’s Picks:
  • Matching Transistors
  • A Tool For Testing CANopen Networks
  • A Digital Audio Recorder For TOSLink
• Tom’s Picks:
  • Running Linux On The PS5 With A Hypervisor Exploit
  • A Shortwave Sensor To Monitor The Ionosphere
  • Photographing The ISS With A Thrift Store Lens Is Challenging

Can’t-Miss Articles:

• How Giant Tanks Of Fluid Could Help Support The Power Grid
  • A Vanadium Redox Flow Battery You Can Build
  • An Open Source Flow Battery
  • This Flow Battery Operates With No Pump Required
• Why Leaded Fuel Is Still A Thing