Although GNSS systems like GPS have made pin-pointing locations on Earth’s sphere-approximating surface significantly easier and more precise, it’s always possible to go a bit further. The latest innovation involves strapping laser retroreflector arrays (LRAs) to newly launched GPS satellites, enabling ground-based lasers to accurately determine the distance to these satellites.
Similar to the retroreflector array that was left on the Moon during the Apollo missions, these LRAs will be most helpful with scientific pursuits, such as geodesy. This is the science of studying Earth’s shape, gravity and rotation over time, which is information that is also incredibly useful for Earth-observing satellites.
Laser ranging is also essential for determining the geocentric orbit of a satellite, which enables precise calibration of altimeters and increasing the accuracy of long-term measurements. Now that the newly launched GPS III SV-09 satellite is operational this means more information for NASA’s geodesy project, and increased accuracy for GPS measurements as more of its still to be launched satellites are equipped with LRAs.
Unless you’re into circuit sculptures, generally speaking, a working circuit isn’t the end-point of a lot of electronics projects. To protect your new creation from grabby hands, curious paws, and the ravages of nature, you’ll probably want some kind of enclosure. These days a lot of us would probably run it off on the 3D printer, but some people would rather stay electronics hobbiests without getting into the 3D printing hobby. For those people, [mircemk] shares how he creates professonal-looking enclosures with handtools.
The name [mircemk] will seem familiar to longtime readers– we’ve featured many of his projects, and they’ve always stood out for the simple but elegant enclosures he uses. The secret, it turns out, is thin PVC sheeting from a sign shop. At thicknesses upto and including 5 mm, the material can be bent by hand and cut with hobby knives. It’s obviously also amenable to drilling and cutting with woodworking tools as well. Drilling is especially useful to make holes for indicator LEDs. [mircemk] recommends cyanoacrylate ‘crazy’ glue to hold pieces together. For holding down the PCB, the suggestion of double-sided tape will work for components that won’t get too hot.
Rather than paint, the bold contrasting colours we’ve become used to are applied using peel-and-stick wallpaper, which is a great idea. It’s quick, zero mess, and the colour is guaranteed to be evenly applied. It might even help hold the PVC enclosure together ever so slightly. You can watch him do it in the video embedded below.
We hate to say it, but for a one-off project, this technique probably does beat a 3D printed box for professional looks, assuming you have [mircemk]’s motorskills. If you don’t have said motor skills, check out this parametric project box generator. If you’d rather avoid PVC while making a square box to hold a PCB, have you considered using PCBs?
Thanks to [mircemk] for the tip! If you have a tip or technique you want to share, please box it up and send it to the tipsline
Ionizing radiation damage from electrons, protons and gamma rays will over time damage a CMOS circuit, through e.g. degrading the oxide layer and damaging the lattice structure. For a space-based camera that’s inside a probe orbiting a planet like Jupiter it’s thus a bit of a bummer if this will massively shorted useful observation time before the sensor has been fully degraded. A potential workaround here is by using thermal energy to anneal the damaged part of a CMOS imager.
The first step is to detect damaged pixels by performing a read-out while the sensor is not exposed to light. If a pixel still carries significant current it’s marked as damaged and a high current is passed through it to significantly raise its temperature. For the digital logic part of the circuit a similar approach is used, where the detection of logic errors is cause for a high voltage pulse that should also result in annealing of any damage.
During testing the chip was exposed to the same level of radiation to what it would experience during thirty days in orbit around Jupiter, which rendered the sensor basically unusable with a massive increase in leakage current. After four rounds of annealing the image was almost restored to full health, showing that it is a viable approach.
Naturally, this self-healing method is only intended as another line of defense against ionizing radiation, with radiation shielding and radiation-resistant semiconductor technologies serving as the primary defenses.
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’ 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 speak for themselves: a full three-color double helix, involving 830 tool changes, could be printed with as little as six grams of purge waste.
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.
[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.
A one-line, twenty-character wide display was a fantastic feature, but certainly lacking for development work.
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.
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.
