2026-03-29 19:00:36
Usually, when we see non-planar 3D printers, they’re rather rudimentary prototypes, intended more as development frames than as workhorse machines. [multipoleguy]’s Archer five-axis printer, on the other hand, breaks this trend with automatic four-hotend toolchanging, a CoreXY motion system, and print results as good-looking as any Voron’s.
The print bed rests on three ball joints, two on one side and one in the center of the opposite side. Each joint can be raised and lowered on an independent rail, which allows the bed to be tilted on two axes. The dimensions of the extruders their motion system limit how much the bed can be angled when the extruder is close to the bed, but it can reach sharp angles further out.
The biggest difficulty with non-planar printing is developing a slicer; [multipoleguy] is working on a slicer (MaxiSlicer), but it’s still in development. It looks as though it’s already working rather well, to the point that [multipoleguy] has been optimizing purge settings for tool changes. It seems that when a toolhead is docked, the temperature inside the melt chamber rises above the normal temperature in use, which causes stringing. To compensate for this, the firmware runs a more extensive purge when a hotend’s been sitting for a longer time. The results for themselves: a full three-color double helix, involving 830 tool changes, could be printed with as little as six grams of purge waste.
As three-axis 3D printers become consumer products, hackers have kept looking for further improvements to make, which perhaps explains the number of non-planar printing projects appearing recently, including a few five-axis machines. Alternatively, some have experimented with non-planar print ironing.
2026-03-29 16:00:36
Until the fall of the Soviet Union around 1990 you’d be forgiven as a proud Soviet citizen for thinking that the USSR’s technology was on par with the decadent West. After the Iron Curtain lifted it became however quite clear how outdated especially consumer electronics were in the USSR, with technologies like digital audio CDs and their players being one good point of comparison. In a recent video by a railways/retro tech YouTube channel we get a look at one of the earliest Soviet CD players.
A good overall summary of how CD technology slowly developed in the Soviet Union despite limitations can be found in this 2025 article by [Artur Netsvetaev]. Soviet technology was characterized mostly by glossy announcements and promises of ‘imminent’ serial production prior to a slow fading into obscurity. Soviet engineers had come up with the Luch-001 digital audio player in 1979, using glass discs. More prototypes followed, but with no means for mass-production and Soviet bureaucracy getting in the way, these efforts died during the 1980s.
During the 1980s CD players were produced in Soviet Estonia in small batches, using Philips internals to create the Estonia LP-010. Eventually sanctions on the USSR would strangle these efforts, however. Thus it wouldn’t be until 1991 that the Vega PKD-122 would become the first mass-produced CD player, with one example featured in this video.
The video helpfully includes a teardown of the player after a rundown of its controls and playback demonstration, so that we can ogle its internals. This system uses mostly localized components, with imported components like the VF display and processors gradually getting replaced over time. The DAC and optical-mechanical assembly would still be imported from Japan until 1995 when the factory went bankrupt.
This difference between the imported and localized part is captured succinctly in the video with the comparison to Berlin in 1999, in that you can clearly see the difference between East and West. The CD mechanism is produced by Sanyo, with a Sanyo DAC IC on the mainboard. The power supply, display and logic board (using Soviet TTL ICs) are all Soviet-produced. A sticker inside the case identifies this unit as having been produced in 1994.
Amusingly, the front buttons are directly coupled into the mainboard without ESD protection, which means that in a Siberian winter with practically zero relative humidity inside you’d often fry the mainboard by merely using these buttons.
After this exploration the video goes on to explain how Soviet CD production began in the 1989, using imported technology and know-how. This factory was set up in Moscow, using outdated West-German CD pressing equipment and makes for a whole fascinating topic by itself.
Finally, the video explores the CD player’s manual and how to program the player, as well as how to obtain your own Soviet CD player. Interestingly, a former employee of the old factory has taken over the warehouse and set up a web shop selling new old stock as well as repaired units and replacement parts.
2026-03-29 13:00:56
[Casey Bralla] got his hands on a Rockwell AIM 65 microcomputer, a fantastic example of vintage computing from the late 70s. It sports a full QWERTY keyboard, and a twenty character wide display complemented by a small thermal printer. The keyboard is remarkably comfortable, but doing software development on a one-line, twenty-character display is just not anyone’s idea of a good time. [Casey] made his own tools to let him write programs on his main PC, and transfer them easily to the AIM 65 instead.
Moving data wasn’t as straightforward in 1978 as it is today. While the Rockwell AIM 65 is a great machine, it has no disk drive and no filesystem. Programs can be written in assembler or BASIC (which had ROM support) but getting them into running memory where they could execute is not as simple as it is on modern machines. One can type a program in by hand, but no one wants to do that twice.
Fortunately the AIM 65 had a tape interface (two, actually) and could read and store data in an audio-encoded format. Rather than typing a program by hand, one could play an audio tape instead.
This is the angle [Casey]’s tools take, in the form of two Python programs: one for encoding into audio, and one for decoding. He can write a program on his main desktop, and encode it into a .wav file. To load the program, he sets up the AIM 65 then hits play on that same .wav file, sending the audio to the AIM 65 and essentially automating the process of typing it in. We’ve seen people emulate vintage tape drive hardware, but the approach of simply encoding text to and from .wav files is much more fitting in this case.
The audio encoding format Rockwell used for the AIM is very well-documented but no tools existed that [Casey] could find, so he made his own with the help of Anthropic’s Claude AI. The results were great, as Claude was able to read the documentation and, with [Casey]’s direction, generate working encoding and decoding tools that implemented the spec perfectly. It went so swimmingly he even went on to also make a two-pass assembler and source code formatter for the AIM, as well. With them, development is far friendlier.
Watch a demonstration in the video [Casey] made (embedded under the page break) that shows the encoded data being transferred at a screaming 300 baud, before being run on the AIM 65.
2026-03-29 10:00:50
It’s one thing to learn about transmission lines in theory, and quite another to watch a voltage pulse bounce off an open connector. [Alpha Phoenix] bridges the gap between knowledge and understanding in the excellent videos after the break. With a simple circuit, he uses an oscilloscope to visualize the propagation of electricity, showing us exactly how signals travel, reflect, and interfere.
The experiment relies on a twisted-pair Y-harness, where one leg is left open and the other is terminated by a resistor. By stitching together oscilloscope traces captured at regular intervals along the wire, [Alpha Phoenix] constructs a visualization of the voltage pulse propagating. To make this intuitive, [Alpha Phoenix] built a water model of the same circuit with acrylic channels, and the visual result is almost identical to the electrical traces.
For those who dabble in the dark art of RF and radio, the real payoff is the demonstration of impedance matching in the second video. He swaps resistors on the terminated leg to show how energy “sloshes” back when the resistance is too high or too low. However, when the resistor matches the line’s characteristic impedance, the reflection vanishes entirely—the energy is perfectly dissipated. It really makes it click how a well-matched, low SWR antenna is crucial for performance and protecting your radio.
[Alpha Phoenix] is a genius at making physics visible. He even managed “film” a laser beam traveling at light speed.
2026-03-29 07:00:53
[Tommy] at Oskitone has been making hardware synth kits for years, and his designs are always worth checking out. His newest offering Space Dice is an educational kit that is a combination vintage sci-fi space laser sound generator, and six-sided die roller. What’s more, as a kit it represents an effort to be genuinely educational, rather than just using it as a meaningless marketing term.
There are several elements we find pretty interesting in Space Dice. One is the fact that, like most of [Tommy]’s designs, there isn’t a microcontroller in sight. Synthesizers based mostly on CMOS logic chips have been a mainstay of DIY electronics for years, as have “electronic dice” circuits. This device mashes both together in an accessible way that uses a minimum of components.
There are only three chips inside: a CD4093 quad NAND with Schmitt-trigger inputs used as a relaxation oscillator, a CD4040 binary counter used as a prescaler, and a CD4017 decade counter responsible for spinning a signal around six LEDs while sound is generated, to represent an electronic die. Sound emerges from a speaker on the backside of the PCB, which we’re delighted to see is driven not by a separate amplifier chip, but by unused gates on the CD4093 acting as a simple but effective square wave booster.
In addition, [Tommy] puts effort into minimizing part count and complexity, ensuring that physical assembly does not depend on separate fasteners or adhesives. We also like the way he uses a lever assembly to make the big activation button — mounted squarely above the 9 V battery — interface with a button on the PCB that is physically off to the side. The result is an enclosure that is compact and tidy.
We recommend checking out [Tommy]’s concise writeup on the design details of Space Dice for some great design insights, and take a look at the assembly guide to see for yourself the attention paid to making the process an educational one. We love the concept of presenting an evolving schematic diagram, which changes and fills out as each assembly step is performed and tested.
Watch it in action in a demo video, embedded just below. Space Dice is available for purchase but if you prefer to roll your own, all the design files and documentation are available online from the project’s GitHub repository.
2026-03-29 04:00:37
The common narrative around device design is that you can have repairability or a low price, but that they are inversely proportional to each other. Apple’s new budget MacBook Neo seems to attempt a bit of both.
Brittle snap-fit enclosures or glue can make a device pop together quickly during manufacture, but are a headache when it comes time to repair or hack it. Our friends at iFixit tore down the Neo and found it to be the most repairable MacBook since the 2012 unibody model. A screwed in battery, and modules for many of the individual components including the USB ports and headphone jack make it fairly simple to replace individual components. Most of those components are even accessible as soon as you pop the bottom cover instead of requiring major surgery.
As someone who has done a keyboard replacement on a 2010 MacBook, the 41 screws holding the keyboard in brought back (bad) memories. While this is a great improvement over Apple’s notoriously painful repair processes, we’re still only looking at an overall 6/10 score from iFixit versus a 10/10 from Framework or Lenovo.
The real story here is that these improvements from Apple were spurred by Right-to-Repair developments, particularly in the EU, that were the result of pressure from hackers like you.
If you want to push a Neo even further, how about water cooling it? If you’d rather have user-upgradeable RAM and storage too in a Mac, you’ve got to go a bit older.
