Figuring Out What James Webb’s Mysterious Little Red Dots Are

May 26, 2026 by Maya Posch 15 Comments

After the James Webb Space Telescope (JWST) began operations in 2022, it soon made a tantalizing discovery in the form of mysterious red dots: small, red-tinted astronomical objects of unknown origin and composition. So far well over 300 of such little red dots (LRDs) have been identified, with many theories on what they are. Fortunately the Chandra X-ray Observatory recently added some more clues as detailed in an accompanying paper.

Current theories include them being a form of primordial galaxy, or a supermassive black holes embedded in a dense gas cloud. The LRD discussed in the paper with the designation 3DHST-AEGIS-12014 was found to emit X-rays unlike other LRDs. By comparing the data between JWST and Chandra for this LRD it lends credence to the theory that these LRDs are a transitional phase as a supermassive black hole ingests the material of said gas cloud.

X-rays produced during this can sometimes make it out of the gas cloud, after which we can observe it. If that’s the case, these LRDs should cease to exist the moment the black hole has consumed enough of the cloud, which is something that we may be able to find evidence for if we’re lucky.

This adds just another reason why keeping the Chandra X-ray Observatory mission funded, after it narrowly got saved in 2024.

Through-Glass Vias And The Long Road To Glass Substrates

May 25, 2026 by Maya Posch 13 Comments

Glass-based substrates are slowly beginning to push out organic substrates – as also commonly used in PCBs – due to often superior material properties for packaging. One area where glass substrates have however struggled is with through-hole vias and providing the conductive copper path through them. A 2024 article by [Keith Best] gives a good overview of the topic, with recent news showing how much companies like Intel are pushing for glass substrates, specifically for the packaging of dies.

One major advantage with vias in glass substrates is that they can be much smaller, enabling smaller than 0.1 mm diameter holes with far finer pitch. The challenge here is to make perfect holes with a laser that are defect-free, as well as have the intended diameter.

After that this through-glass via (TGV) has to be coated or filled with copper, much like their organic equivalent. Said TGV can be fully filled with copper, or use plating and add dielectric filler. Detecting flaws in such a finished TGV is important.

In a 2025 review article of glass substrate technologies by [Pratik Nimbalkar] et al. published in Chips the state of the art at the time was covered. The need for ever higher-density integration options with ASICs is highlight here, especially now that many chips today consist of multiple interconnected dies inside a single package.

The complications of creating TGVs with femtosecond laser pulses in Borofloat 33 glass are highlighted by [Daniel Franz] et al. in a 2025 research article, with microcracks and backside ablation observed without proper precautions, something which previously was often resolved by an etching step following said laser drilling. The main issue here is the post-drilling residual stress from the thermal shock, which the authors demonstrate can be largely prevented with careful tweaking of the laser drilling parameters.

As pointed out in a 2024 review article by [Chen Yu] et al. glass substrates are useful for far more than just high-density chip packaging. Glass substrates are also chemically resistant, have a higher heat resistance, are largely transparent to RF and can be hermetically sealed against outside influences. This makes them great for various advanced sensors and communication devices.

Meanwhile, if you wanted to do some metal-depositing on glass at home, we covered this recently.

Z386: An Open-Source 80386 Built Around Original Microcode

May 25, 2026 by Maya Posch 10 Comments

There are many ways you can implement an Intel i386 CPU on an FPGA, with the use of original microcode probably being one of the most interesting approaches. This is what [nand2mario]’s z386 project does, with a recent blog post summarizing the development so far.

This effort is similar to the previously developed z8086 project, which as one may guess does something similar, except for the Intel 8086 CPU. By executing the original microcode you’re basically guaranteeing close compatibility with the original hardware, though of course the sheer scale of this microcode between an 8086 and 80386 is quite different.

There’s a much larger instruction set with a correspondingly much more complicated internal state to keep track of, including all those newfangled features like memory management, paging and register debugging, as well extensions to protected mode that began with the i286.

Currently z386 runs on a number of FPGAs, including the Altera Cyclone V and Gowin GW5A, with performance equivalent to a ~70 MHz i386 albeit with slightly worse cycle efficiency, some of which could be due to the limited 16 kB cache compared to the 32+ kB cache in the fastest i386 CPUs. Either way, it’s more than enough to run all kinds of software, including games like DOOM.

Important to note is that the goal here isn’t to be more performant than cores such as for example ao486, but more as an archaeological reconstruction of the original hardware and its interaction with said microcode.

Top image: line-up of Intel 286, 386 and 486 CPUs. (Credit: Sgroey, Wikimedia)

Hacking A Video Walkie Talkie’s TXW818 MCU And Running DOOM

May 24, 2026 by Maya Posch 10 Comments

Recently cheapo video walkie-talkies popped up on everyone’s favorite online retailers, which naturally lured in the usual gaggle of reverse-engineering enthusiasts of cheap tat to see what’s inside these devices, as well as what more they can be made to do. Cue [Aaron Christophel] doing just that, with the typical DOOM demo as proof of concept.

Inside these cheerful little devices is a TXW818 MCU, made by TaiXin Semiconductor. It provides its own CK803 CPU core at 240 MHz with 272 kB of SRAM, as well as BLE and 2.4 GHz Wi-Fi support. For these walkie-talkies an additional 4 MB of PSRAM is provided as well as 2-4 MB of SPI Flash.

The display is a glorious 240×320 LCD, which actually fits rather well with a game like DOOM. As also explained on the GitHub project page, to build the project you simply have to fetch the CDK IDE and build the binary. After that it can be flashed with an STM32F103 ‘Blue Pill’ based board.

According to [Aaron] the SDK is rather convoluted and not that nice to work with, so it’s not a sleeper ESP32 alternative, but these cheap walkie-talkies could be nice to tinker with anyway. Other than playing games, of course, as the side buttons aren’t very conducive to gaming, and the limited Flash space required compressing the WAD game file.

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Meet The Raven: An Atari Clone Computer Based On The Motorola 68060

May 24, 2026 by Maya Posch 9 Comments

Some people who have a hankering to run GEM/TOS applications might just fire up an emulator, or maybe coax an old Motorola 68k-based Atari ST system back to life. Then there are people like [Anders Granlund], for whom hard mode is a way of life and making a custom mainboard around a genuine 68060 CPU and associated peripherals is a reasonable approach to pick. Thus quoth the Raven project.

The project commenced in 2024, when [Anders] started a thread on it over at the Exxos Forum which thus became pretty much the project log for the endeavor.

Both RAM and ROM ICs are on SIMM sticks, which seems like a pretty nifty idea compared to the typical socketed or soldered-in approach here, allowing for up to 48 MB of RAM and 16 MB of ROM.

On the custom ATX-compatible mainboard you get a total of 4 ISA slots, as well as everything from YM2149 audio, IDE HDD and legacy Atari peripheral support. All of which fits in a standard ATX case with an ATX power supply. If this tickles your fancy, you can find the design files for the current A1 board revision, though you will have to source your own ICs.

With all of it assembled you can run Atari’s TOS with its GEM UI, or the modern equivalent in the form of FreeMiNT.

Designing A Printable Cyclone Dust Separator For 99.95% Efficiency

May 24, 2026 by Maya Posch 14 Comments

Filtering sawdust out of an airflow is easy until you try to do it with cyclone separation, but the obvious appeal here is of course not spending a fortune on filters. Over the years we have thus seen a lot of DIY takes on this concept alongside commercial offerings. Recently [Ruud] of the [Capturing Dust] YouTube channel gave it a fresh shake with a claimed 99.95% filtering efficiency that outperforms a commercial solution.

As a starting point the commercial and very succinctly named Oneida Air Super Dust Deputy Cyclone Separator was used, which retails for about $179 and claims a 99.9% filtrating rate of fine dust and debris. Based on its design a 3D model was created and printed with an FDM printer.

Initially only about a 98% rate was measured, but after some investigation this appeared to be due to the incoming and exciting airflows interfering. One tweak later to add some separation between the flows and a lot of testing of different configurations a final design was settled on that would seem to be rather quite efficient compared to the commercial option.

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Putting Version 7.1 Of The Direct Granules FDM Extruder Through Its Paces

May 23, 2026 by Maya Posch 11 Comments

Whether you’re using granules or filament, FDM printing relies heavily on a consistent flowrate of the extruder. This is also the challenge with [HomoFaciens]’s direct granule extruder. Version 7.1 here refines some parameters before being put through a number of printing tests to see how close it comes to something you’d want to use for production.

There’s also an accompanying blog post, on which the project files can be found for those who are playing along at home.

A big part of this V7.1 change was to simplify the design for manufacturing, removing the brass insert of V7.0, instead requiring some manual labor using a drill bit and a hand reamer to get the inside of the extruder tube just right.

The section with the heating element was also extended, though this didn’t have as much of an effect as expected. During testing the overall results were actually pretty good, with the extruder able to keep up with bridging tests while the feared air bubbles from air intruding into the tube remained absent.

On the Prusa Mk4 FDM printer, there are some definite limitations on testing features like input shaping resulting in wavy patterns in some rest prints, but for upcoming tests a different FDM printer will be used which should more clearly show the potential of this extruder design.

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