Author: Tyler August

232 Articles

BlueSCSI: Not Just For Apple

October 13, 2025 by 11 Comments

Anyone into retro Macintosh machines has probably heard of BlueSCSI: an RP2040-based adapter that lets solid state flash memory sit on the SCSI bus and pretend to contain hard drives. You might have seen it on an Amiga or an Atari as well, but what about a PC? Once upon a time, higher end PCs did use SCSI, and [TME Retro] happened to have one such. Not a fan of spinning platters of rust, he takes us through using BlueSCSI with a big-blue-based-box.

Naturally if you wish to replicate this, you should check the BlueSCSI docs to see if the SCSI controller in your PC is on their supported hardware list; otherwise, your life is going to be a lot more difficult than what is depicted on [TME Retro]. As is, it’s pretty much the same drop-in experience anyone who has used BlueSCSI on a vintage Macintosh might expect. Since the retro-PC world might not be as familiar with that, [TME Retro] gives a great step-by-step, showing how to set up hard disk image files and an iso to emulate a SCSI CD drive on the SD card that goes into the BlueSCSIv2.

This may not be news to some of you, but as the title of this video suggests, not everyone knows that BlueSCSI works with PCs now, even if it has been in the docs for a while. Of course PCs owners are more likely to be replacing an IDE drive; if you’d rather use a true SSD on that bus, we’ve got you covered.

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SLM Co-extruding Hotend Makes Poopless Prints

October 13, 2025 by 17 Comments

Everyone loves colourful 3D prints, but nobody loves prime towers, “printer poop” and all the plastic waste associated with most multi-material setups. Over the years, there’s been no shortage of people trying to come up with a better way, and now it’s time for [Roetz] to toss his hat into the ring, with his patent-proof, open-source Roetz-End. You can see it work in the video below.

The Roetz-End is, as you might guess, a hot-end that [Roetz] designed to facilitate directional material printing. He utilizes SLM 3D printing of aluminum to create a four-in-one hotend, where four filaments are input and one filament is output. It’s co-extrusion, but in the hot-end and not the nozzle, as is more often seen. The stream coming out of the hot end is unmixed and has four distinct coloured sections. It’s like making bi-colour filament, but with two more colours, each aligned with one possible direction of travel of the nozzle.

What you get is ‘directional material deposition’: which colour ends up on the outer perimeter depends on how the nozzle is moving, just like with bi-color filaments– though far more reliably. That’s great for making cubes with distinctly-coloured sides, but there’s more to it than that. Printing at an angle can get neighboring filaments to mix; he demonstrates how well this mixing works by producing a gradient at (4:30). The colour gradients and combinations on more complicated prints are delightful.

Is it an MMU replacement? Not as-built. Perhaps with another axis– either turning the hot-end or the bed to control the direction of flow completely, so the colours could mix however you’d like, we could call it such. That’s discussed in the “patent” section of the video, but has not yet been implemented. This technique also isn’t going to replace MMU or multitool setups for people who want to print dissimilar materials for easily-removable supports, but co-extruding materials like PLA and TPU in this device creates the possibility for some interesting composites, as we’ve discussed before.

As for being “patent-proof” — [Roetz] believes that through publishing his work on YouTube and GitHub into the public domain, he has put this out as “prior art” which should block any entity from successfully filing a patent. It worked for Robert A. Heinlein with the waterbed, but that was a long time ago. Time will tell if this is a way to revive open hardware in 3D printing.

It’s certainly a neat idea, and we thank [CityZen] for the tip.

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Your LLM Won’t Stop Lying Any Time Soon

October 10, 2025 by 48 Comments

Researchers call it “hallucination”; you might more accurately refer to it as confabulation, hornswaggle, hogwash, or just plain BS. Anyone who has used an LLM has encountered it; some people seem to find it behind every prompt, while others dismiss it as an occasional annoyance, but nobody claims it doesn’t happen. A recent paper by researchers at OpenAI (PDF) tries to drill down a bit deeper into just why that happens, and if anything can be done.

Spoiler alert: not really. Not unless we completely re-think the way we’re training these models, anyway. The analogy used in the conclusion is to an undergraduate in an exam room. Every right answer is going to get a point, but wrong answers aren’t penalized– so why the heck not guess? You might not pass an exam that way going in blind, but if you have studied (i.e., sucked up the entire internet without permission for training data) then you might get a few extra points. For an LLM’s training, like a student’s final grade, every point scored on the exam is a good point. Continue reading “Your LLM Won’t Stop Lying Any Time Soon” →

PLA Gears Fail To Fail In 3D Printed Bicycle Drivetrain

October 10, 2025 by 33 Comments

Anyone who has ever snapped a chain or a crank knows how much torque a bicycle’s power train has to absorb on a daily basis; it’s really more than one might naively expect. For that reason, [Well Done Tips]’s idea of 3D printing a gear chain from PLA  did not seem like the most promising of hacks to us.

Contrary to expectations, though, it actually worked; at the end of the video (at about 13:25), he’s on camera going 20 km/h, which while not speedy, is faster than we thought the fixed gearing would hold up. The gears themselves, as you can see, are simple spurs, and were modeled in Fusion360 using a handy auto-magical gear tool. The idler gears are held in place by a steel bar he welded to the frame, and are rolling on good old-fashioned skateboard bearings–two each. (Steel ones, not 3D printed bearings.) The healthy width of the spur gears probably goes a long way to explaining how this contraption is able to survive the test ride.

The drive gear at the wheel is steel-reinforced by part of the donor bike’s cassette, as [Well Done Tips] recognized that the shallow splines on the freewheel hub were not exactly an ideal fit for PLA. He does complain of a squeaking noise during the test ride, and we can’t help but wonder if switching to helical gears might help with that. That or perhaps a bit of lubricant, as he’s currently riding the gears dry. (Given that he, too, expected them to break the moment his foot hit the pedal, we can’t hardly blame him not wanting to bother with grease.)

We’ve seen studies suggesting PLA might not be the best choice of plastic for this application; if this wasn’t just a fun hack for a YouTube video, we’d expect nylon would be his best bet. Even then, it’d still be a hack, not a reliable form of transportation. Good thing this isn’t reliable-transportation-a-day!

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Motors Make The Best Knobs With SimpleFOC

October 9, 2025 by 17 Comments

The worst thing about a volume knob is that, having connected it to a computer, it might be wrong: if you’ve manually altered the volume settings somewhere else, the knob’s reading won’t be correct. [I Got Distracted] has a quick tutorial on YouTube showing how to use a BLDC, a hall effect sensor, Pi Pico and the SimpleFOC library to make a knob with active haptic feedback and positioning.

We covered the SimpleFOC library a few years ago, but in case you missed it, it’s, well, a simple library for FOC on all of our favorite microcontrollers, from Arduino to ESP to Pico. FOC stands for field-oriented control, which is a particular way of providing smooth, precise control to BLDCs. (That’s a BrushLess DC motor, if the slightly-odd acronym is new to you.) [I Got Distracted] explains exactly how that works, and shows us just how simple the SimpleFOC project is to use in this video.  Why, they even produce their own motor controllers, for a fully-integrated experience. (You aren’t restricted to that hardware, but it certainly does make things easy.)

The haptic feedback and self-dialing knob make for an easy introductory project, but seeing how quick it hacks together, you can doubtless think of other possibilities. The SimpleFOC controller used in this video is limited to relatively small motors, but if you want to drive hundreds of kilowatts through open source hardware, we’ve covered that, too.  

Arguably, using a motor as a knob isn’t within the design spec, and so could almost qualify for our ongoing Component Abuse Challenge, had [I Got Distracted] thought to enter.

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2025 Component Abuse Challenge: The Sweet Sound Of A Choking Transformer

October 9, 2025 by 13 Comments

The Component Abuse Challenge is dragging all sorts of old, half-forgotten hacks out of the woodwork, but this has got to be the most vintage: [KenS] started using a transformer as a variable choke on his speakers 55 years ago.

The hack is pretty bone-dead simple. A choke is an inductor in an audio (or any other) circuit designed to, well, choke off higher-than-desired frequencies. We featured a deep dive a few years back if you’re interested. An inductor is a coil of wire, usually (but not necessarily) wound around a core of iron or ferrite. A transformer? Well, that’s also a coil of wire around a core… plus an extra coil of wire. So when [KenS], back in his salad days, had a tweeter that a was a little too tweety, and no proper choke, he grabbed a transformer instead.

This is where inspiration hit: sure, if you leave the second winding open, the transformer acts like a standard choke. What happens if you short that second winding? Well, you dampen the response of the first winding, and it stops choking, to the point that it acts more like a straight wire. What happens if you don’t short the second winding, but don’t leave it wide open? [KenS] stuck a potentiometer on there, and found it made a handy-dandy variable choke with which to perfectly tune the tone response of his speakers. Changing the resistance changes the rate at which high frequencies are choked off, allowing [KenS] to get the perfect frequency response with which to rock out to Simon & Garfunkel, The Carpenters and The Guess Who. (According to the Billboard Top 100 for 1970, those are who you’d be listening to if you had conventional tastes.)

While we can’t say the transformer is really being tortured in this unusual mode, it’s certainly not how it was designed, so would qualify for the “Junk Box Substitutions” category of the Component Abuse Challenge. If you’ve made similar substitutions you’d like to share, don’t wait another 55 years to write them up– the contest closes November 11th.

Transformer image: Hannes Grobe, CC BY-SA 4.0.

2025 Hackaday Component Abuse Challenge

2025 Component Abuse Challenge: Load Cell Anemometer

October 9, 2025 by 22 Comments

When you think anemometer, you probably don’t think “load cell” — but (statistically speaking) you probably don’t live in Hurricane Country, which is hard on wind-speed-measuring-whirligigs. When [BLANCHARD Jordan] got tired of replacing professionally-made meteorological eggbeaters, he decided he needed something without moving parts. Whatever he came up with would probably qualify for the Component Abuse Challenge, but the choice of load cells of all things to measure wind speed? Yeah, that’s not what the manufacturer intended them for.

In retrospect, it’s actually a fairly obvious solution: take a plate of known area, and you’re going to get a specific force at a given air speed. The math isn’t hard, it’s just not how we normally see this particular measurement done. Of course, a single plate would have to be pivoted to face the wind for an accurate reading, which means moving parts– something specifically excluded from the design brief. [Jordan] instead uses a pair of load cells, mounted 90 degrees to one another, for his anemometer. One measures the force in a north-south axis, and the other east-west, allowing him to easily calculate both wind speed and direction. In theory, that is. Unfortunately, he vibe coded the math with ChatGPT, and it looks like it doesn’t track direction all that well. The vibe code runs on an ESP32 is responsible for polling data, tossing outliers, and zeroing out the load cells on the regular.

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