Direct FDM Printing With Granules

May 6, 2026 by No comments

The idea of FDM 3D printing using granules rather than filament is an appealing one: rather than having to wrangle spools of filament that need to adhere to strict dimensions and cannot be too flexible, you can instead just keep topping up a big hopper with fresh granules. This is what [HomoFaciens] has been tinkering with for a while now, with their Direct Granules Extruder V7.0 showing significant improvements.

There’s also an accompanying article, with details of previous granule extruder attempts detailed on the same site. Many of the improvements here focus on making sure the granules melt properly before they reach the end of the extruder, with the auger screw helping to push things along. While this seems straightforward, there are many details to get right, with the previous v6.2 version having issues like the hot plastic backing up into the cold section and clogging things up.

For the test bench a Prusa Mk4 FDM printer is used, with the standard extruder swapped for the experimental extruder. On the extruder the cold, top part is water cooled to ensure it stays cold, with each turn of the wood-screw-turned-auger providing the right extrusion speed. As can be seen with the print tests, the results look pretty good despite the extruder not having been tuned yet.

If you want to give it a shot yourself, the article page provides files for download.

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Taking Polyphony To A New Level

May 6, 2026 by 2 Comments

There are all manner of musical synthesis techniques, from the early electromechanical instruments through analogue tape systhesis, the all-electronic waveform synthesisers of the 1960s onwards, and Yamaha’s FM systhesis of the 1980s, to name but a few. One of the attributes of such a machine lies in how many voices it has, or in simple terms, how many notes it can play simultaneously. Electronic complexity limited those early synths, but what happens on an FPGA where vast numbers of circuits can be made with little extra cost? [Tsuneo.Ohnaka] is pushing the envelope a little, by cramming 10240 individually controllable oscillators onto a Terasic DE10-nano FPGA board.

While this thing can in theory generate 10240 different notes at once, in practice that doesn’t mean it has 10240 voices. Instead he calls it a spectrum engine, in that with such a large number of oscillators all with individually controllable frequency, phase, and amplitude, he’s made the part of all those Fourier transform maths where all the different frequencies are combined, in hardware. It’s as though you had a sound card which wasn’t based around a DAC fed with samples, instead all those spectrum points you’d derive from a Fourier transform. Because it’s a massive parallel array of real oscillators it all happens concurrently, instantaneously in real time, and is not held back by the processing constraints of a microprocessor. Think of it as something akin to a software defined radio transmitter, but for the world of audio synthesis.

In that light, it can emulate all those other forms of audio synthesis driven by software, but without the software overhead of generating the waveforms. It’s certainly a different approach to generating audio from a computer, and he’s posted a cacophonic demo video below of it as an 80-voice polyphonic synthesiser. We like it.

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AI On Every Machine: The LLM You Probably Didn’t Want

May 6, 2026 by 10 Comments

It’s been a story of the last week or so if you follow the kind of news channels a Hackaday scribe does, that Google have quietly installed an LLM as part of the Chrome browser. Reports vary as to when they did this because there’s a lot of confusion online with their online Gemini features also present in the browser, but it seems Chrome users are noticing its effect through slower performance and hefty disk access. Given that Chrome is by far the most popular web browser, this means that billions of users will have downloaded the four gigabyte Gemini Nano model, and now have an LLM they didn’t know about. It will be used to provide advanced auto-correct and other text suggestion features that their online version of Gemini would presumably be overburdened with, and since it’s available through a set of in-browser APIs we expect that it will find its way into a lot of websites, online applications, and plugins.

It’s caused a bit of a fuss in some circles, and we think, with some justification. When billions of computers unwittingly install an extremely energy intensive software component the effect on global power consumption will be significant, with a consequent uptick in the carbon footprint of computing. It’s not a phenomenon restricted to Chrome, as an example Siri has used a local LLM on Apple devices for a while now. We’ve seen rumblings of discontent and talk of getting European climate regulators involved, but perhaps instead it’s time to have a conversation about local AI models. The key is not whether or not they are a good thing to have, but when and how they operate.

While many of us are sick to death of AI slop and have not been lured into AI psychosis by an over-reinforcing chatbot, the fact remains that LLMs can do some useful things, they’re here to stay whether we like it or not, and having one under your control on your own computer doesn’t have to be a bad thing. Install Llama.cpp on your machine, and you’ve got an LLM of your very own, upon which your usage data isn’t going to be sold, and your content isn’t going to reinforce the finest plagiarism device the world has ever seen.

Opt-In and Opt-Out

The concerning development with the Chrome LLM is that not only has it been installed without the user’s consent, it runs without their consent too, and they can’t use it for anything except what Google Chrome wants it to be used for. Unlike the Llama.cpp mentioned above, it’s not under their control, instead it’s a compute-hungry monster ultimately controlled by Google. The prospect of a future in which multiple pieces of everyday software install their own similarly out-of-control multi-gigabyte CPU-munchers is a concerning one. Anyone who remembers Microsoft’s Clippy grabbing all the resources in a 1990s desktop as its stuttering animation played its course will know where this is going.

If local LLMs are an inevitability, what’s needed is a way to make them like any other application, one that the user chooses and installs themselves. Such an LLM could make its services available to applications such as a web browser if the user allows it to, but not run unless asked. It’s fairly obvious that installing Llama.cpp or similar is beyond many users, but it shouldn’t lie beyond the bounds of possibility to package something like it as an application they can install.

We know that the previous paragraph is pie-in-the-sky wishful thinking, and that as the person who knows computers in your family your next few Christmases will be spent wrestling with six different LLMs running on some elderly family member’s PC. But perhaps in Clippy lies the answer. If the consumer can learn to associate built-in AI features with their computer grinding to a halt just as they did with an office assistant thirty years ago, then perhaps they’ll demand change. We can hope.

Why Opposed Piston Internal Combustion Engines Are Great

May 6, 2026 by 17 Comments

Converting the ignition of a fuel-air mixture into usable mechanical energy lies at the core of a dizzying number of internal combustion engines developed over the course of more than century. Although typical piston engines with a cylinder head and valve-train are the most common by far, and even rotary engines are quite well-known, the opposed-piston engine design is significantly more obscure. In a recent video by [driving 4 answers], this type of engine is covered and why it’s actually a pretty nifty ICE design with many benefits.

Achates opposed-piston design. (Source: driving 4 answers, YouTube)
Achates opposed-piston design. (Source: driving 4 answers, YouTube)

Above all, the design is mechanically far more simple, as it omits all the valves and timing-related hardware of the typical four-stroke ICE. Each ignition event pushes against two pistons at the same time, allowing for more of the kinetic energy to be converted into usable power, as well as enabling largely vibration-free operation in a more compact package, especially in the case of the Asender design that eliminates the second crankshaft of the Achates design. This makes the Asender rather similar to the 1914 Simpson’s design.

Despite these many advantages, opposed-piston engines have mostly led a quiet life in industrial and military applications, including tanks, submarines and airplanes. This is where the video also sees their continued use, but as a 2021 article in Autoweek suggests, we might be seeing more of these engines in everywhere from trucks to cars as well. Even if it’s only in hybrid cars where it would be in a generator role, there are many reasons why this ICE design would fit right into certain roles.

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Retrotechtacular: Julius Sumner Miller Breaks Lamps With Magnets

May 6, 2026 by 2 Comments

If you watched the Mickey Mouse Club way back when, you might remember Professor Wonderful, who was, in reality, physics professor [Julius Sumner Miller]. He also had his own show, “Why Is It So?” along with appearances on talk shows. We recently ran across one of the shows from 1962 where [Miller] uses electromagnets to break a lamp.

[Miller] moved to Australia, and this episode is from the Australian version of “Why Is It So?” As you might expect, given the topic, the professor covers Oersted and Faraday.

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You’ve Seen The Chip Shortage And The Memory Shortage, Now Prepare For The PCB Shortage

May 6, 2026 by 27 Comments

It’s nice to hide away in our little corner of the internet and talk tech, safely away from the turmoil of world events. Sometimes though, geopolitics intrude even into our space, and Reuters are here reporting on a new concern that will probably affect many Hackaday readers. Conflict in the Gulf of Arabia, and in particular raids on Saudi petrochemical plants, is threatening PCB production far away in China.

Most of us probably have a mental image of tankers sailing through the Strait of Hormuz laden with Gulf crude, off to be processed by refineries somewhere else in the world. Certainly a load of oil takes just that route, but for the Saudis and other oil-producing nations in the region, it also makes economic sense to site petrochemical industries at source. They export the much more valuable refined products, among which is the polymer resin used in PCB production. The Reuters report says that consequent to this and a rise in copper prices, the cost of a PCB in China has risen by 40%. Naturally this doesn’t sound like good news.

Here at Hackaday, when it comes to component shortages this isn’t our first rodeo. We’re in the middle of a memory shortage due to AI companies, and the COVID-era chip shortage is still fresh in our minds. Unfortunately, this type of thing as been a regular of the technology world for decades. Here we are with another one, and should we be worried? In the short term it’s certainly a concern as the Gulf conflict is still searching for an end to its uneasy stalemate, but remembering previous shortages we think that global industry will adapt and expand other sources where necessary. Just as with the similar IC encapsulation resin shortage back in the ’90s, it may eventually be the panic more than the shortage which becomes responsible for the price hikes.

We’ve taken an abstract look at global electronic supply chains before.

Header image: Gabriela P., CC BY 4.0.

RGB image from the projector, with human for scale.

RGB Laser Projector Does Colorful Asteroids And Much More

May 6, 2026 by 8 Comments

Have you thought about building a galvonometer-based laser projector, but don’t know where to start? There are a lot of resources out there, but you could do worse than to check out [Breq] and [Mia]’s laser vector project, which provides a very well-documented and low-cost starting point. They boast that the most expensive part of the project was the ANSI-certified safety glasses, which shows a dedication to safety we wish more people would show when playing with coherent light.

The rest of the parts — from the galvos to the RGB lasers module with dichoric mirrors to keep everything on the same beamline, to the ESP32 module driving everything — was ordered from AliExpress, and not from the most expensive vendors, either. Considering that, it works remarkably well.

If you’re not playing Asteroids on your vector display, why even bother?

Like all DIY laser projectors, this one does vector graphics, sweeping the beam fast enough that the human eye registers crisp, clean lines. Galvonometers, or galvos for short, take analog input, so a DAC is needed — fortunately the ESP32-S2 comes with a pair built in. The custom PCB of course has audio-in for the usual Lissajous lightshow or oscilloscope music, but with an ESP32 as the brains, you can do a lot just inside the projector.

Like what? Well, play Asteroids, for instance, using Wiimote controllers. Project a lovely clock. Render text input in various single-stroke fonts. More to the point, since this is a projector, take arbitrary SVG data and project literally any image you’d like — as long as it doesn’t have too many lines, at least. The galvos in this project are rated at 20,000 points per second, which is not exceedingly fast: they were chosen to meet the budget, not the greatest-possible speed.

More to the point is that this is one of the better-documented projects of this type we’ve seen. [Breq] doesn’t just tell us how to build the projector, but why they designed it that way. We really encourage you to give it a read if you’ve been thinking of getting into this sort of display.

We’ve seen plenty of laser projectors before, most of them producing vector images like this one. If you really must have a raster display, though, that’s also an option. Don’t count out vector images, though — they could even replace your Christmas lights.

Thanks to [CapinRedBeard] for the tip! Remember to send any bright ideas you see to our tips line, coherently lit or no.