Hackaday Europe 2026: Fluid Kernels And Optimizing C++ For MCUs

September 3, 2026 by Zoe Skyforest 1 Comment

Oftentimes, when we’re using a microcontroller, we’re whipping up some very specific code focused on executing a particular task. The device is set up to execute code that does exactly what we want with minimal overhead. However, sometimes, there are scenarios where it pays to go with a somewhat heavier setup, wherein the microcontroller runs an operating system for the benefits that offers.

Federico Terraneo came to Hackaday Europe to discuss this very topic. He talks about kernel architecture, real-time operating systems, and how to best use C++ in the world of microcontrollers.

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A Thoroughly Modern Minimalist Transceiver

September 3, 2026 by Jenny List 2 Comments

Making a radio is so often a case of taking tried and tested designs and working with them to create something new. It’s a safe way to make something that works. [Riyas] however has gone for an entirely different tack, creating an entirely modern transceiver with as much as possible going on in the silicon.

At its heart are three integrated circuits, the familiar Si5351 as a transmit VFO, an Si4372 receiver, and an RP2040 tying it all together. This microcontroller functions both as controller, and as an ADC to provide a software defined radio via its USB port. The Si4372 having an internal SDR architecture and its output being digitized again is not lost on us.

It’s for digital modes and CW only, but we’d venture the opinion that those are where the interesting stuff is anyway. We certainly like it for its simplicity, and also for the one-cable solution it offers. So many other designs need a sound card and extra cables, this one makes for a lot less clutter. We hope we’ll see more development on this design over time, it could become a favorite in the homebrew rig stakes.

Meanwhile the Si5351 is notoriously annoying to program. A while back we covered a library that might help, if you get stuck.

From A Ten-Line Script To A Real Utility With Codex

September 3, 2026 by Al Williams 21 Comments

I’m an experienced programmer, and I’ve worked in many different languages. Sometimes being a programmer is a two-edged sword. You want to accomplish something, and you can do it easily — but it can be a lot of work to do it right. Maybe more work than you want to do.

Normally, I’ll kick out a few lines of script for something I want and be done, accepting that it isn’t production-hardened. This time, however, I decided to try an AI tool to see whether they could do the work I was too lazy to do myself. While I’ve played with chatbots, I wanted to try one of the dedicated coding agents, in this case, Codex. Outside of asking ChatGPT to write a simple function or find the cause of an error message, I haven’t done much coding with AI assistance, so I was interested to see what these agents brought to the table.

A Radio Problem

The problem was simple: I wanted an easy way to put buttons on my Linux desktop that launched Internet radio stations. Sure, I could open a player and paste in a long URL, but I’m far too lazy to remember all those URLs.

I searched for a way to make Shortwave — an Internet radio player — open a URL from the command line. Apparently, you can’t. Google Gemini suggested writing a script that launches cvlc, the command-line VLC player, with the URL as an argument.

That’s easy, so I did it. Of course, then I had to find the stream URLs for all my favorite stations. It turns out that Radio Browser maintains an extensive database of stations. I considered scraping the site or using its API, but honestly, the little script was becoming too much of a project.

Besides, I was already struggling to manage the media player’s lifetime. I didn’t want a new station playing on top of one that was already running, and I wanted a command to stop playback, so the script had already grown larger than I first imagined.

My first version used a temporary file containing the player’s process ID so a future script execution could kill the old player. That usually works, but it isn’t very robust, and I knew it. But how much work did I really want to do here? I decided I had done enough and turned the rest over to Codex, OpenAI’s coding assistant.

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Rescuing A Rescue Device With A DIY Battery Pack

September 3, 2026 by Tom Nardi 2 Comments

If you find yourself lost in the woods or adrift in the ocean, a GPS-enabled Personal Locator Beacon (PLB) is certainly a handy thing to have as it will pinpoint your location for rescuers. The one [Steve Jernigan] has is relatively affordable considering it might save your life one day, but it turns out that replacement batteries for the unit are extremely expensive and hard to come by because the manufacturer would rather you send the unit back to them for refurbishment. So naturally, he took it apart and figured out how to do it himself.

His DIY battery pack consists of a small custom PCB and pair of off-the-shelf 6 volt lithium manganese dioxide cells in a 3D printed enclosure that slots into the rear of the McMurdo PLB. In assembly video below, [Steve] shows how the pack goes together and demonstrates the use of a two-part potting compound in an effort to keep the elements at bay.

Before anyone says it — putting a homemade battery pack into a device which one day might be the only thing standing between you and death is probably not a great idea. [Steve] mentions in the description of this project that this is meant for backup purposes, and that you should really spring for a legitimate battery if there’s a chance you might actually need to be rescued at some point.

If you’re interested in battery pack hacking that doesn’t potentially risk life and limb, fixing the one that came with your cordless drill might be a better project to start with. Continue reading “Rescuing A Rescue Device With A DIY Battery Pack” →

Miniaturized, Working Replica Of Vintage Leslie Speaker

September 3, 2026 by Bryan Cockfield 9 Comments

Few pieces of vintage audio gear from the turn of the century (the previous one) inspire the kind of devotion that a Leslie speaker does. Sure, there are plenty of pieces that are rarer or more valuable, but the Leslie speaker has such a big following because of its uniqueness of physically moving sound around a room. Two rotating devices in the speaker physically direct the sound around the cabinet with musician-controlled speed, and this sound remains extremely difficult to reproduce faithfully without the moving components. But originals are enormous and meant for organs, so [Eric] built a 40% replica with a few modern touches for his guitar.

The build starts with a CAD model, where [Eric] works towards making the most accurate enclosure for his speaker as possible. The CAD model heads out to a CNC machine which can care most of the details into the wood, and he eventually is able to finish it, although it took a few tries with stains and paintbrushes of various types. For the speakers themselves, he’s using modern versions including modern brushless motors to drive the rotating elements. Like the original speaker, the high range of sound is sent through a rotating set of horns, of which one is only a counterweight, and the low range is directed out of the bottom of the cabinet through a large rotating drum. Both rotating elements here are 3D printed, and with everything put together and wired up [Eric] has a much more portable, faithful recreation of the original Leslie speaker.

There are some upgrades in the wiring too, which makes it work better with a guitar rather than for an organ. It’s also much lighter, and was a hit when he took it to let a few other guitarists to play as well. It’s not the first time we’ve seen the Leslie’s movement recreated for guitar, but it is the most alike to the classic 1930s-era speaker we’ve seen so far.

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Switch Mod Fixes Fiddly Car Door Projector

September 2, 2026 by Tom Nardi 27 Comments

While the Citroën logo they project onto the pavement looks great, [OrangeTungsten] wasn’t thrilled with how their door-mounted projectors actually functioned. The mechanism for detecting when they should kick on was a bit too clever for its own good, and needed to be simplified a bit. Luckily for us, the process was meticulously documented for anyone else who might find themselves in a similar situation.

Originally, the projector detected when it should turn on by sensing the presence of a tiny magnet using a Hall effect sensor. There are certainly some advantages to this approach, but in practice, [OrangeTungsten] says the retrofitted magnet would keep falling off and leaving the projector inoperative. The fix was simple enough: figure out how the circuit worked, pull out the Hall effect sensor, and replace it with a simple button that would physically make contact with the door frame.

It’s not a terribly complex fix, but it’s a clever solution and well documented, and that goes pretty far around these parts. We were also interested in this one because an examination of the electronics inside the projector uncovered a 8-pin microcontroller — the sole purpose of which would appear to be polling the Hall effect sensor and using its status to throw a transistor which in turn powers the LED.

It’s hard to believe that whoever designed this gadget couldn’t figure out how to turn an LED on and off without a MCU, but we’re living in strange times. We assume there’s some kind of justification for this, such as some flashing or fading effects, but [OrangeTungsten] never mentions the things doing anything more complex than simply turning on and off.

Whatever the rationale was behind the original design of these projectors, the important thing is that the application of some hardware from the parts bin got them up and working again, which is something we never get tired of seeing.

Has FDM 3D Printing Hit Its Peak?

September 2, 2026 by Jenny List 30 Comments

Over the time Hackaday has been in existence, the art of 3D printing has evolved from a relatively crude hit-and-miss affair to something approaching what we all imagined back then. You can’t yet walk up to a Star Trek replicator and ask for a part, but a modern state of the art consumer or prosumer grade printer will deliver consistent high-resolution parts, and in a surprisingly short time. [The Next Layer] asks whether consumer FDM printers have now reached the point at which they’re about as good as they’re going to get, and whether other technologies hold the future.

It’s a fair point to make that the resolution of a consumer FDM printer may be close to its mechanical limit. Techniques such as input shaping and the adoption of better CoreXY mechanisms mean that prints which once might have relied on SLA can be done in FDM. Healthy competition in the marketplace has delivered high quality colour printing, with tool-changing printers being no longer solely the preserve of the professional. He uses the example of a mobile phone to make the point that new machines have less of a wow factor to deliver, as increments have become less grand.

It’s a persuasive argument, and looking at the printers around us we can see it in action. The difference in ability between a 2020-ish and a 2026 FDM printer are far smaller than those between the same time periods in the last decade. Compare a MakerBot Cupcake and an Ultimaker II, or the Ultimaker and a Prusa Mini, and each is light years ahead of the last. But the best the Mini can do is surprisingly not as far behind as you’d expect to that of their latest, or of the equivalent from Bambu Labs.

Does this means that nothing new is coming in 3D printing? Of course not. UV printing is coming through and will deliver incredible results, as will SLS printing. It’s interesting he devotes little time to SLA printing, perhaps because it’s not as easy a process as FDM. He makes the point that we’ve never had it so good, as the high-end FDM features will appear in modestly priced machines, and we have those other technologies to look forward to.

It’s an interesting discussion, and you can see it below the break.

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