When Electricity Doesn’t Take The Shortest Path

January 13, 2026 by Maya Posch 53 Comments

Everyone knows that the path of least resistance is the path that will always be taken, be it by water, electricity or the feet of humans. This is where the PCB presented by [ElectrArc240] on YouTube is rather confusing, as it demonstrates two similarly sized traces, one of which is much shorter than the other, yet the current opts to travel via the much longer trace. If you were to measure this PCB between each path, the shorter path has the lowest resistance at 0.44 Ω while the longer path is 1.44 Ω. Did the laws of physics break down here?

Of course, this is just a trick question, as the effective resistance for an electrical circuit isn’t just about ohmic resistance. Instead the relevant phrasing here is ‘path of least impedance‘, which is excellently demonstrated here using this PCB. Note that its return path sneaks on the back side along the same path as the long path on the front. To this is added a 1 MHz high current source that demonstrates the impact of alternating current, with reactance combining with the resistance.

Although for direct current it’s fair to say that impedance is the equivalent of resistance, once the inductance of a trace has to be taken into account – as in the case of AC and high-frequency signaling – the much higher inductance of the short path means that now the long path is actually the shortest.

When you are doing some impedance matching in your favorite EDA software while implementing an Ethernet RMII link or similar, this is basically part of the process, with higher frequencies requiring ever more stringent mechanisms to keep both sides happy. At some point any stray signals from nearby traces and components become a factor, never mind the properties of the PCB material.

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Hacking The Krups Cook4Me Smart Cooking Pot For Doom

January 13, 2026 by Maya Posch 7 Comments

With more and more kitchen utilities gaining touch screens and capable microcontrollers it’d be inconceivable that they do not get put to other uses as well. To this end [Aaron Christophel] is back with another briefly Doom-less device in the form of the Krups Cook4Me pressure cooking pot with its rather sizeable touch screen and proclaimed smarts in addition to WiFi and an associated smartphone app.

Inside is an ESP32 module for the WiFi side, with the brains of the whole operation being a Renesas R7S721031VC SoC with a single 400 MHz Cortex-A9. This is backed by 128 MB of Flash and 128 MB of RAM. The lower touch interface is handled by a separate Microchip PIC MCU to apparently enable for low standby power usage until woken up by touch.

The developers were nice enough to make it easy to dump the firmware on the SoC via SWD, allowing for convenient reverse-engineering and porting of Doom. With the touch screen used as the human input device it was actually quite playable, and considering the fairly beefy SoC, Doom runs like a dream. Sadly, due to the rarity of this device, [Aaron] is not releasing project files for it.

As for why a simple cooking pot needs all of this hardware, the answer is probably along the lines of ‘because we can’.

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Fixing A KS Jive DAB Radio With A Dash Of Fake ICs

January 13, 2026 by Maya Posch 14 Comments

The radio unit after a successful repair. (Credit: Buy it Fix it, YouTube)

The exciting part about repairing consumer electronics is that you are never quite sure what you are going to find. In a recent video by [Mick] of Buy it Fix it on YouTube the subject is a KS Jive radio that throws a few curve balls along the way. After initially seeing the unit not power on with either batteries or external power, opening it up revealed a few loose wires that gave the false hope that it would be an easy fix.

As is typical, the cause of the unit failing appears to have been a power surge that burned out a trace and obliterated the 3.3V LDO and ST TDA7266P amplifier. While the trace was easily fixed, and AMS1117 LDOs are cheap and plentiful, the amplifier chip turned out to be the real challenge on account of being an EOL chip.

The typical response here is to waddle over to purveyors of scrap hardware, like AliExpress sellers. Here [Mick] bought a ‘new’ TDA7266P, but upon receiving his order, he got suspicious after comparing it with the busted original. As can be seen in the top image, the markings, logo and even typeface are wildly different. Thus [Mick] did what any reasonable person does and x-rayed both chips to compare their internals.

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The Distroless Linux Future May Be Coming

January 12, 2026 by Maya Posch 94 Comments

Over the decades the number of Linux distributions has effectively exploded, from a handful in the late ’90s to quite literally hundreds today, not counting minor variations. There lately seems to be a counter-movement brewing in response to this fragmentation, with Project Bluefin’s Distroless project being the latest addition here. Also notable are KDE’s efforts, with KDE Linux as its own top-down KDE-based distro, but now with a switch to BuildStream from Arch likely as a distroless move.

It should be clear that there is no obvious course here yet, and that opinions are very much divided. The idea of ‘Linux’ becoming a more singular OS appeals to some, while to others it’s the antithesis of what ‘Linux’ is about. This much becomes clear in [Brodie Robertson]’s exploration of this topic as well.

The way to think about ‘distroless’ is that there is a common base using the Freedesktop SDK on which the customization layer is applied, such as Bluefin, KDE or Gnome’s environments. You could think of this base as the common runtime, using the Freedesktop standards for interoperability for a user-selected layer that’s installed on top. This way the idea of basing a distro on a specific distro is tossed out in favor of something that’s vaguely reminiscent of the Linux Standard Base attempt at standardization.

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The Intel 8087 And Conditional Microcode Tests

January 11, 2026 by Maya Posch 19 Comments

Continuing his reverse-engineering of the Intel 8087, [Ken Shirriff] covers the conditional tests that are implemented in the microcode of this floating point processing unit (FPU). This microcode contains the details on how to perform the many types of specialized instructions, like cos and arctan, all of which decode into many microcode ops. These micro ops are executed by the microcode engine, which [Ken] will cover in more detail in an upcoming article, but which is effectively its own CPU.

Conditional instructions are implemented in hardware, integrating the states of various functional blocks across the die, ranging from the instruction decoder to a register. Here, the evaluation is performed as close as possible to the source of said parameter to save on wiring.

Implementing this circuitry are multiplexers, with an example shown in the top die shot image. Depending on the local conditions, any of four pass transistors is energized, passing through that input. Not shown in the die shot image are the inverters or buffers that are required with the use of pass transistors to amplify the signal, since pass transistors do not provide that feature.

Despite how firmly obsolete the 8087 is today, it still provides an amazing learning opportunity for anyone interested in ASIC design, which is why it’s so great that [Ken] and his fellow reverse-engineering enthusiasts keep plugging away at recovering all this knowledge.

Reverse-Engineering The Tamagotchi IR Connection

January 10, 2026 by Maya Posch 7 Comments

The Tamagotchi Connection is a series of Tamagotchi toys that took the original portable pet concept and mixed things up with a wireless connection, which allowed you to interact with the pets of other proud Tamagotchi owners. This wireless connection is implemented using an infrared transceiver, somewhat like IrDA, but as [Zach Resmer] discovered while reverse-engineering this connection, it’s actually what is called ‘Nearly NEC’ by [Natalie Silvanovich], who has a GitHub repository full of related Tamagotchi hacking tools and ROM dumps.

With the protocol figured out, creating a transceiver for low-bitrate infrared communication isn’t particularly hard. In this case, it was implemented using an RP2040 MCU and an appropriate IR LED and receiver pair. This Tamagometer project was also implemented as an app for the Flipper Zero, and a custom PCB called the Pico TamaBadge by [Daniel Weidman].

There’s a web application associated with [Zach]’s project using a Web Serial-enabled browser (i.e. Chrome). The serial protocol is somewhat documented in the patent for the device’s connection feature, which makes it relatively easy to implement yourself.

Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion

January 10, 2026 by Maya Posch 78 Comments

Although the humble propeller and its derivatives still form the primary propulsion method for ships, this doesn’t mean that alternative methods haven’t been tried. One of the more fascinating ones is the magnetohydrodynamic drive (MHDD), which uses the Lorentz force to propel a watercraft through the water. The somewhat conductive seawater is thus the working medium, with no moving parts required.

The end of the MHD thruster from the Yamato 1. It has six smaller green tubes surrounding a central circle. All of these pieces are coming through a grey metal fixture that is a circular shape. Small labels are affixed with Japanese writing on them. It is inside a sky blue metal frame. — The end of the MHD thruster from the *Yamato-1*.

Although simple in nature, only the Japanese Yamato-1 full-scale prototype ever carried humans in 1992. As covered in a recent video by [Sails and Salvos], the prototype spent most of its time languishing at the Kobe Maritime Museum, until it was scrapped in 2016.

There are two types of MHDD, based around either conduction – involving electrodes – or induction, which uses a magnetic field. The thrusters used by the Yamato-1 used the latter type of MHDD, involving liquid helium-cooled, super-conducting coils. The seawater with its ions from the dissolved salts responds to this field by accelerating according to the well-known right-hand rule, thus providing thrust.

The main flaw with an MHDD as used by the Yamato-1 is that it’s not very efficient, with a working efficiency of about 15%, and a top speed of about 15 km/h (8 knots). Although research in MHDDs hasn’t ceased yet, the elemental problem of seawater not really being that great as the fluid without e.g. adding more ions to it has meant that ships like the Yamato-1 are likely to remain an oddity like the Lun-class ekranoplan ground effect vehicle.

For as futuristic as this technology sounds, it’s suprisingly straightforward to build a magnetohydrodynamic drive of your own in the kitchen sink. Continue reading “Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion” →