Full-color 3D printing is something of a holy grail, if nothing else just because of how much it impresses the normies. We’ve seen a lot of multi-material units the past few years, and with Snapmaker’s U1 and the Prusa XL it looks like tool changers are coming back into vogue. Just in time, [Radoux] has a fork of OrcaSlicer called FullSpectrum that brings HueForge-like color mixing to tool changing printers.

The hook behind FullSpectrum is very simple: stacking thin layers of colors, preferably with semi-translucent filament, allows for a surprising degree of mixing. The towers in the image above have only three colors: red, blue, and yellow. It’s not literally full-spectrum, but you can generate surprisingly large palettes this way. You aren’t limited to single-layer mixes, either: A-A-B repeats and even arbitrary patterns of four colors are possible, assuming you have a four-head tool changing printer like the Snapmaker U1 this is being developed for.

FullSpectrum is in fact a fork of Snapmaker’s fork of OrcaSlicer, which is itself forked from Bambu Slicer, which forked off of PrusaSlicer, which originated as a fork of Slic3r. Some complain about the open-source chaos of endless forking, but you can see in that chain how much innovation it gets us — including this technique of color mixing by alternating layers.

[Wombly Wonders] shows the limits of this in his video: you really want layer heights of 0.8 mm to 0.12 mm, as the standard 0.2 mm height introduces striping, particularly with opaque filaments. Depending on the colors and the overhang, you might get away with it, but thinner layers generally going to be a safer bet. Fully translucent filaments can blend a little too well at the edges, but the HueForge community — that we’ve covered previously — has already got a good handle on characterizing translucency and we’ll likely see a lot of that knowledge applied to FullSpectrum OrcaSlicer as time goes on.

Now, you could probably use this technique with an multi-material unit (MMU), but the tool-changing printers are where it is going to shine because they’re so much faster at it. With the right tool-changer, it’s actually faster to run off a model mixing colors from the cyan-yellow-magenta color space that it is to print the same model with the exact colors needed loaded on an MMU. That’s unexpected, but [Wombly] does demonstrate in his video with a chicken that’s listed as taking nineteen hours on Bambu’s MakerWorld as taking under seven hours.

Could this be the killer app that pushes tool-change printers into the spotlight? Maybe! Tool changing printers are nothing new, after all. We’ve even seen it done with a delta, and lots of other DIY options if you don’t fancy buying the big Prusa. If you’ve been lusting after such a beast, though, you might finally have your excuse.

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If you’re a diehard fan of the chiptune scene, you’ve probably heard endless beautiful compositions on the Nintendo Game Boy, Commodore 64, and a few phat FM tracks from Segas of years later. What the scene is yet to see is a breakout artist ripping hot tracks on the Sharp PC-E500. If you wanted to, though, you’d probably find use in this 3-voice music driver for the ancient 1993 mini-PC.

This comes to us from [gikonekos], who dug up the “PLAY3” code from the Japanese magazine “Pocket Computer Journal” published in November 1993. Over on GitHub, the original articles have been scanned, and the assembly source code for the PLAY3 driver has been reconstructed. There’s also documentation of how the driver actually works, along with verification against RAM dumps from actual Sharp PC-E500 hardware. The driver itself runs as a machine code extension to the BASIC interpreter on the machine. The “PLAY” command can then be used to specify a string of notes to play at a given tempo and octave. Polyphony is simulated using time-division sound generation, with output via the device’s rather pathetic single piezo buzzer.

It’s very cool to see this code preserved for the future. That said, don’t expect to see it on stage at the next Boston Bitdown or anything—as this example video shows, it’s not exactly the punchiest chiptune monster out there. We’ll probably stick to our luscious fake-bit creations for now, while Nintendo hardware will still remain the bedrock of the movement.

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Did you ever wonder how the mechanical voltage regulator — that big black box wired up to the generator on a car from the ’60s or before — worked? [Jonelsonster] has some answers.

For most people in 2026 an old car perhaps means one from the 20th century, now that vehicles from the 1990s and 2000s have become the beloved jalopies of sallow youths with a liking for older cars and a low budget. But even a 1990s vehicle is modern in terms of its technology, because a computer controls the show. It has electronic fuel injection (EFI), anti-lock braking system (ABS), closed loop emissions control, and the like.

Go back in time to the 1970s, and you’ll find minimal electronics in the average car. The ABS is gone, and the closest thing you might find to EFI is an electronic ignition where the points in the distributor have been replaced with a simple transistor. Perhaps an electronic voltage regulator on the alternator. Much earlier than that and everything was mechanical, be that the ignition, or that regulator.

The video below the break has a pair of units, it seems from 1940s tractors. They would have had a DC generator, a spinning coil with a commutator and brushes, in a magnetic field provided by another coil. These things weren’t particularly powerful by today’s standards and sometimes their charging could be a little lackluster, but they did work. We get to see how, as he lifts the lid off to reveal what look like a set of relays.

We’re shown the functions of each of the three coils with the aid of a lab power supply; we have a reverse current relay that disconnects the generator if the battery tries to power it, an over-current relay that disconnects the field coil if the current is too high, and an over-voltage relay that does the same for voltage. The regulating comes down to the magnetic characteristics, and while it’s crude, it does the job.

We remember European devices with two coils and no field terminal, but the principle is the same. There is never a dull moment when you own an all mechanical car.

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You would be very hard pressed to find any sort of CPU or microcontroller in a commercial product that uses anything but binary to do its work. And yet, other options exist! Ternary computing involves using trits with three states instead of bits with two. It’s not popular, but there is now a design available for a ternary processor that you could potentially get your hands on.

The device in question is called the 5500FP, as outlined in a research paper from [Claudio Lorenzo La Rosa.] Very few ternary processors exist, and little effort has ever been made to fabricate such a device in real silicon. However, [Claudio] explains that it’s entirely possible to implement a ternary logic processor based on RISC principles by using modern FPGA hardware. The impetus to do so is because of the perceived benefits of ternary computing—notably, that with three states, each “trit” can store more information than regular old binary “bits.” Beyond that, the use of a “balanced ternary” system, based on logical values of -1, 0 , and 1, allows storing both negative and positive numbers without a wasted sign bit, and allows numbers to be negated trivially simply by inverting all trits together.

The research paper does a good job of outlining the basis of this method of computing, as well as the mode of operation of the 5500FP processor. For now, it’s a 24-trit device operating at a frequency of 20MHz, but the hope is that in future it would be possible to move to custom silicon to improve performance and capability. The hope is that further development of ternary computing hardware could lead to parts capable of higher information density and lower power consumption, both highly useful in this day and age where improvements to conventional processor designs are ever hard to find.

Head over to the Ternary Computing website if you’re intrigued by the Ways of Three and want to learn more. We perhaps don’t expect ternary computing to take over any time soon, given the Soviets didn’t get far with it in the 1950s. Still, the concept exists and is fun to contemplate if you like the mental challenge. Maybe you can even start a rumor that the next iPhone is using an all-ternary processor and spread it across a few tech blogs before the week is out. Let us know how you get on.

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Recycling plastic at home using 3D printed molds is relatively accessible these days, but if you do not wish to invest a lot of money into specialized equipment, what’s the most minimal setup that you can get away with? In a recent [future things] video DIY plastic recycling is explored using only equipment that the average home is likely to have around.

Lest anyone complain, you should always wear PPE such as gloves and a suitable respirator whenever you’re dealing with hot plastic in this manner, just to avoid a trip to the emergency room. Once taken care of that issue, there are a few ways of doing molding, with compression molding being one of the most straightforward types.

With compression molding you got two halves of a mold, of which one compresses the material inside the other half. This means that you do not require any complex devices like with injection molding, just a toaster oven or equivalent to melt the plastic, which is LDPE in this example. The scrap plastic is placed in a silicone cup before it’s heated so that it doesn’t stick to the container.

The wad of goopy plastic is then put inside the bottom part of the mold before the top part is put in place and squeezed by hand until molten plastic comes out of the overflow opening(s). After letting it fully cool down, the mold is opened and the part released. Although the demonstrated process can be improved upon, it seems to work well enough if you are aware of the limitations. In terms of costs and parts required it’s definitely hard to come up with a cheaper way to do plastic molding.

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Every ham radio shack needs a clock; ideally one with operator-friendly features like multiple time zones and more. [cburns42] found that most solutions relied too much on an internet connection for his liking, so in true hacker fashion he decided to make his own: the operator-oriented Ham Clock CYD.
A tabbed interface goes well with the touchscreen LCD.
The Ham Clock CYD is so named for being based on the Cheap Yellow Display (CYD), an economical ESP32-based color touchscreen LCD which provides most of the core functionality. The only extra hardware is a BME280 temperature and humidity sensor, and a battery-backed DS3231 RTC module, ensuring that accurate time is kept even when the device is otherwise powered off.

It displays a load of useful operator-oriented data on the touchscreen LCD, and even has a web-based configuration page for ease of use. While the Ham Clock is a standalone device that does not depend on internet access in order to function, it does have the ability to make the most of it if available. When it has internet access over the built-in WiFi, the display incorporates specialized amateur radio data including N0NBH solar forecasts and calculated VHF/HF band conditions alongside standard meteorological data.

The CYD, sensor, and RTC are very affordable pieces of hardware which makes this clock an extremely economical build. Check out the GitHub repository for everything you’ll need to make your own, and maybe even put your own spin on it with a custom enclosure. On the other hand, if you prefer your radio-themed clocks more on the minimalist side, this Morse code clock might be right up your alley.

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Kitchen scales are plentiful and cheap, but their accuracy and measuring speed often leave a lot to be desired. In particular the filtering out of noise can make small changes a nightmare as e.g. adding a little bit of weight slowly can result in the result never updating. This frustrated [Mark Furneaux] enough that he dug up the load cell and metal base of a scrapped laboratory scale and added a strain gauge amplifier to build a better kitchen scale around it.

The only purpose-bought part was an HX710-based strain gauge amplifier module for $7 with LED display, with the metal base getting some metal bits welded onto it to hold said module as well as a push button and toggle switch. Existing wiring from the load cell was wired into the HX710 module, with power provided from a single 18650 Li-ion cell. This was paired with the standard TP4056-based module and its protection IC.

Ultimately the entire assembly looks very much bodged together, with plentiful zip ties, hot glue and messy welding, but it’s hard to deny that it seems to work well. A plastic cutting board makes for a good surface for the items being weighed, and measured drift across the range was about 200 mg, while the amplifier module updates the output in real-time so that you can see even the smallest changes and noise.

Even if you’re not lucky enough to have such a nice load cell and base kicking around, strain gauges are everywhere, and you can absolutely hack an existing (kitchen) scale to be better with some custom hard- and software.

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Lego train sets have been available for decades, now. The Danish manufacturer long ago realized the magic of combining its building block sets with motors and plastic rails to create real working railways for children and adults to enjoy. Over the years, Lego has innovated through several generations of trains, from classic metal-rail systems to the more modern IR and later Bluetooth-controlled versions. The only thing largely missing over all that time, though…? A bridge!

Yes, Lego has largely neglected to build any bridges for its mainstream train lineup. There are aftermarket solutions, and innovative hacks invented by the community, all with their own limitations and drawbacks. This glaring oversight, though, seemed like a perfect opportunity to me. It was time to fire up the 3D printer and churn out a fully-realized Lego rail bridge of my very own.

Bridges Are Hard

I’ve experimented with building Lego rail bridges before, using standard track and household objects like cardboard, books, and beer. Unfortunately, it can be very difficult to support the track evenly at the joints which occur every 150mm, and derailments are common. Credit: author
There’s actually a good reason Lego bridges aren’t a big thing in the company’s own product lineup, beyond a few obscure historical parts. This is probably because they aren’t very practical. Lego locomotives are not particularly strong haulers, nor do they have excellent grip on the rails, and this makes them very poor at climbing even mild grades. Any official Lego bridge would have to be very long with a shallow slope just to allow a train to climb high enough to clear a locomotive on a track below. This would end up being an expensive set that would probably prove unpopular with the casual Lego train builder, even if the diehard enthusiasts loved it.

There are third-party options available out there. However, most rely on standard Lego track pieces and merely combine them with supports that hold them up at height. This can work in some cases, but it can be very difficult to do cool things like passing a Lego train under a bridge, for example. It can be hard to gain enough height, and the short length of Lego track pieces makes it hard to squeeze a locomotive between supports.

However, none of these problems are insurmountable if you’re dedicated to the task. The trick is in being able to make entire pieces of Lego track with custom geometry to suit your exact needs. I’ve always tried to add bridges to my Lego railways, and I’ve found that trying to do so with the standard track pieces is often difficult. At just 150 mm long, they require a lot of supports, particularly at the joints, and it can be difficult to build any sort of structure that is stable enough to hold together without a train derailing across it. After many prior experiments, I figured that 3D printing bespoke bridge pieces would probably be the way to go to build a stable Lego train bridge that actually works.

Research And Development

Recreating basic Lego rail geometry was task 1. Credit: author
I started my work by recreating the track geometry so that my 3D printed parts would work with official Lego track. I was able to recreate the rails and the inter-track coupler design, based on a drawing available at the L-Gauge website. From there, I began my bridge design, starting with picking the most critical number—the grade of the bridge. Having done some research on Lego trains online, combined with my own prior tests, I figured a 10 degree grade would be low enough for a Lego train to climb without too much trouble. I also wanted to make the individual bridge pieces as long as possible to reduce the number of joints involved. I landed on a figure of approximately 290 mm, as this was the largest track length I could fit by printing diagonally on my printer.
The basic bridge design. The three ramp pieces repeat on the other side. Credit: author
I quickly worked up a design that involved seven separate pieces to create a whole bridge. Three individual ramp pieces on each side, plus a central flat bridge piece that has a piece of track passing at a perpendicular angle underneath. In total, the whole bridge measures almost two meters long, mostly because Lego locomotives only like a gentle climb and it’s quite a hike to get high enough to clear a train passing below.
The arches and pillars are probably excessive but they allow the bridge to be printed without support. Credit: author
From the get go, I wanted to print without supports—both for speed and to save plastic. This took some experimentation, but I mostly achieved success by using arches and subtle curves to keep overhangs in check and create a structure that would print cleanly.

With that said, one might argue that the excessive amount of arches and pillars used in my design might have wasted more plastic than just using standard supports generated by the slicer. Regardless, I think the choice to go with arches gave the bridge a nice aesthetic befitting a good railway. I printed the bridge pieces in PLA at a layer height of 0.20 mm, using two-colored filament just because I could, and it was cheap at the store. While some of the diagonal stretches of the rails featured obvious layer lines, this didn’t seem to have any negative effect on performance. It did, however, give the trains a zippy sound when they climbed and descended the bridge.
The completed bridge, prior to construction of supporting railway infrastructure. Credit: authorShorter carriages work best due to the relatively sudden transition between the 10-degree grade and flat running. Credit: author
I set about testing the bridge design by inviting some friends over and building a railway in my living room. We set up a simple S-shaped loop that would allow a single train to test both the bridge itself and the passthrough track underneath. Early testing revealed some fun unexpected problems. Right off the bat, we found that one Lego locomotive had a low-slung piece that would smash into the track coupler as it came down off the bridge back on to the flat rails at ground level. Removing that piece barely compromised the look of the locomotive but enabled it to pass the bridge more easily.

We also soon found issues with carriages. Even at a subtle 10-degree grade, most Lego locomotives struggled to pull more than a single carriage up the slope. Further compounding the problem was that the momentum from the extra carriages on the downhill tended to overspeed the train and derail it at an immediately-following turn. Some carriages and locomotives were also simply incompatible with the bridge due to my design decisions. I had not paid much attention to the transitions on and off the sloped ramps. This meant that some longer carriages with wider-spread bogies would find themselves derailing as one set of wheels left the track while passing over the bridge. There were also some minor issues with the bridge pieces themselves and how they couple together. The Lego track coupling design is pretty good at snapping pieces together when they’re injection molded. It doesn’t work as well with softer 3D-printed PLA, nor is it good at locking together big heavy pieces of bridge that weigh many hundreds of grams each.
The custom bridge allows for the construction of fun new layouts that aren’t readily achievable with standard Lego parts. Credit: author
Nevertheless, the bridge design did mostly work if you were careful and only ran the right trains. With a layout built to suit the vagaries of over-bridge travel, with lots of straights for run-up and run-off, it was possible to climb and descend without too much trouble. The underpass track was also perfectly serviceable and presented precisely no problems during hours of play.

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This bridge design could be easily improved. I’d probably rework the design with a lower grade—maybe 7 degrees, maybe 5—and really smooth out the transitions on and off the slope to allow as many different Lego trains to use the bridge as possible. Beyond that, it would simply be a matter of improving printability and reducing plastic use to really make this project shine. For those eager to try printing what I built, the files are available, but just be wary that your mileage, and your train’s mileage, may vary.

The fun thing about 3D printers is that they are perfect for jobs like this. If you need to make a plastic part with specific geometry, it’s now almost trivial to do. That makes recreating or innovating on things like toys or home appliances really easy, and also very fun. I had a blast designing this bridge and putting it together, and even more fun playing trains with my friends. I’d highly recommend taking a shot yourself if you feel like tinkering with Lego railways at home!

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Tic-Tac-Toe is a relatively simple game, and one of the few which has effectively been solved for perfect play. The nature of the game made it possible for [Joost van Velzen] to create a LEGO machine that can play the game properly in an entirely mechanical fashion.

The build features no electronics to speak of. Instead, it uses 52 mechanical logic gates and 204 bits of mechanical memory to understand and process the game state and respond with appropriate moves in turn. There are some limitations to the build, however—the game state always begins with the machine taking the center square. Furthermore, the initial move must always be played on one of two squares—given the nature of the game though, this doesn’t really make a difference.

It’s also worth heading over to the Flickr page for the project just to appreciate the aesthetics of the build. It’s styled in the fashion of an 18th-century automaton or similar. It’s also been shared on LEGO Ideas where it’s raised quite a profile.

If you’ve ever wanted to think about computing in a mechanical sense, this build is a great example of how it can be done. We often see some fun LEGO machines around these parts, from massive parts sorters to somewhat-functional typewriters.

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They say you should never throw out old clothes because they will come back in style one day. Maybe they are right. We noted in a recent BBC post that, apparently, wired headphones are making a comeback. Like many people, we were dismayed when Apple took the headphone jack out of the iPhone and, as [Thomas Germain] notes, even Google eventually ejected the normal headphone jack. (Although, in fairness, most of the Pixel phones we’ve seen come with a pair of USB-C earbuds.)

On the face of it, though, wireless seems to be a good idea. You can get cheap Bluetooth earbuds now, although maybe still not as cheap as wired buds. Sure, they sound terrible, but so do cheap buds. It is a pain to charge them, of course, but not having to untangle wires is a benefit. On the other hand, you never have to charge your wired headphones.

So why are people suddenly going back to wires? According to the BBC and analytics firm Circana, the second half of 2025 saw an explosion in wired headphone sales, and sales continued to rise in 2026.

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Quality of Sound

The biggest reason cited was sound quality. While Bluetooth has made huge strides in sound quality, you are still trading something for wireless. We have to admit, we get annoyed when the Bluetooth drops out, but we wonder how many people can really hear much difference in audio quality? If you care about latency, maybe that’s a point in the wired gear’s favor. But if your song starts 250 milliseconds late, you probably don’t care. It is only an issue when you have video or games.

Many people, when using a modern Bluetooth stack, can’t tell the difference in audio quality between wired and wireless, especially with normal source material and in typical listening environments.

According to [SoundGuys], while Bluetooth is technically worse, if you are over 24 or not in a perfectly quiet environment, you probably can’t tell the difference. Another study found that casual listeners could only guess which headphones were wireless 50% of the time. Even two pro audio people got it wrong 30% of the time.

It Got Better

The problem historically with Bluetooth is that it creates a digital stream to the headphones, which is compressed and decompressed using a codec. The original codec was SBC (Subband Codec), and it didn’t sound that great.

However, as technology gets better, so do the codecs. AAC, LDAC, and others sound great. LDAC, for example, transmits audio at roughly 990 kbps and with very little distortion.

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So when you are looking at Bluetooth sound, you have to account for several things. If your source or destination doesn’t support modern codecs, it might not sound as good as it could. In addition, you are dealing with the headphone’s internal digital-to-analog converter. If you think your $10 earbuds have a converter that matches the audio output from your phone or motherboard, you will probably be disappointed. But that’s not a fault inherent with Bluetooth. Cheap sound devices sound worse than expensive ones, in general.

Other Reasons

There are other reasons to go wired. Apparently, some social media influencers have decided that the right pair of wires dangling from your ears is a fashion accessory. Maybe some of it is like the resurgence of vinyl records or typewriters: nostalgia. Or, perhaps it is just a fad. As a practical matter, it does help people see that you are just sitting at your desk swaying for no reason.

Apparently, even the brand and design of headphones are important to fashionistas. For example, the three-year-old video below shows how old Koss headphones with some color changes went viral. (Although of course you can also get a Bluetooth variant.)

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While this might not make sense to a Hackaday crowd, headphones have long been a fashion accessory, and headphones like Beats were, at least at one point, the must-have accessory for some people.

Of course, if you really want to make a statement, you can check whether any of the 10 $135,000 headphones are in stock. Or, try a $750,000 pair of Beats, which probably don’t sound as good as you would hope for that price.

Back to Reality

There are people who swear they need gold-plated cables or ones with no oxygen or whatever to get the perfect sound. Tests involving sending audio through a banana don’t back that up.

So, sure, you need to invest in good-quality gear. You really need to make sure the whole setup supports something like aptX, LDAC, or even AAC. You also need a good source. Old movies don’t look better on an 8K TV; after all, why should your headphones improve your 1979 mix tape digitized at 32k?

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Unless you are worried about latency or you experience dropouts for some reason, there is very little difference for most people. Of course, if you want to use a wired headphone on a modern phone, you probably need an adapter or USB headphones, which basically have the adapter built in. And your audio will only be as good as that adapter, too, so choose wisely. Don’t forget to pick the right cables, too.

If you are experiencing dropouts, you may need better equipment. Or maybe just take your phone out of your pocket with the keys and the RFID-blocking wallet. Bluetooth can, in theory, travel 30 ft, but reality is something else, and interference from other devices can also be a problem, especially if you have a dual WiFi/Bluetooth device in your computer. We’ve heard, too, that unpairing and repairing can sometimes help, although you wouldn’t think it should matter.

One thing we do suggest. As long as wired headphones are a fad, it is probably a great time to list your old wired gear on eBay, Facebook Marketplace, or a similar site. Fads drive prices up, and the old cans may never be worth so much again.

Your Turn

So what do you think? Can you really tell the difference? What’s your daily driver? Let us know in the comments.

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