Hackaday Podcast Episode 362: Compression Molding, IPv4x, And Wired Headphones

As the sun goes down on a glorious spring evening on the western edge of Europe, Elliot Williams is joined by Jenny List for a look at the week in all things Hackaday.

First up: Hackaday Europe tickets are on sale! Bad luck folks, the early bird tickets disappeared in an instant, but regular ones are still available for now. We’re really looking forward to making our way to Lecco for a weekend of hacks, and it would be great to see you there too.

Then we have a new feature for the podcast, the Hackaday Mailbag. This week’s contribution comes from [Kenny], a longtime friend of Hackaday and probably our most regular conference attendee.

To the hacks, and we have some good ones. An air hockey robot might not seem like a challenge, but the engineering which went into [BasementBuilds’] one proves it’s not a job for the faint hearted. Then we look at compression molding of recycled plastic using 3D-printed molds, something that seems surprisingly accessible and we’d like to try, too. We’ve got a new DOS, a 3D-printed zipper repair, the IPv4 replacement we didn’t get, and the mind-bending logic of ternary computing. It’s one of those weeks where the quick hacks could all deserve their own in-depth look, but perhaps the stand-outs are and Arduino style compiler that includes the source code compressed within the binary, and a beautifully-done revival of a 1980s brick cellphone as a modern 5G unit.

Finally in the longer reads we’ve got an examination of wired versus Bluetooth headphones — we’re both in the wired camp — and a look back at the age of free dialup. As is so often the case, the experience there differed between Brits and Americans. Anyway, enjoy the episode, and we have another week to look forward to.

Download your own personal copy of the Podcast in glorious 192 kB MP3.

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Modular 18650 Packs, No Spot Welding Required

Building a battery pack from 18650 cells traditionally requires patience, a spot welder, and a supply of nickel strip. But what if there was another way? [Ben] is here with Cell-Lock, a modular battery assembly system.

At the system’s heart are a set of interlocking end caps and connection pieces that function as locking cams as well as the electrical connections where needed. They were inspired by the cam systems used for furniture assembly, and are activated by rotation with a screwdriver. The result is a mechanically stable battery system in which different configurations can easily be assembled.

We like that it doesn’t involve any heat near those cells; in part because we’ve seen our share of dodgy connections overheating. But we do have a few concerns. These include how reliable a connection those cams would make, as well as how much current they could safely take without overheating. If both of those could be addressed, we can see that this is an idea with a future.

You can see plenty of examples on the linked project, including an e-bike pack which seems to return no problems. Meanwhile this is by no means the first modular battery pack system we’ve seen.

Teardown Of A 2026 LEGO SMART Brick

LEGO SMART brick from its side. (Credit: EvilmonkeyzDesignz, YouTube)
LEGO SMART brick from its side. (Credit: EvilmonkeyzDesignz, YouTube)

At the beginning of March this year LEGO released their new SMART brick, which looks like a 2×4 stud brick and is filled to the brim with sensors, LEDs, NFC and Bluetooth functionality, as well as a purported custom ASIC. The central idea behind it appears to be to add a lot of interactivity to LEGO builds while allowing for mesh-style communication with other SMART bricks. Naturally, this makes it a great subject for a teardown, which is what [EvilmonkeyzDesignz] over on YouTube did in a recent video.

Normally the only way you can purchase one of these new bricks is by buying them as part of a ‘Smart Play’ set, but someone was selling singular bricks on EBay. As the brick is inductively recharged, it’s pretty well-sealed, requiring a fairly destructive opening method.

Directly below the transparent top is a speaker, with the opposing PCB on the main body containing a microphone as well as a number of RGB LEDs. On the opposite side of this PCB we find the photo sensor, but to get to this part of the PCB the copper wires that wrap around the entire main assembly have to be disconnected from the PCB’s side pads with some force as they’re apparently pressed in place without the use of solder.

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FLOSS Weekly Episode 866: BreezyBox And Embedded Compilers

This week Jonathan chats with Valentyn Danylchuk about BreezyBox — an interactive shell and toolkit that provides various tools and a compiler on an ESP32 microcontroller. What was the inspiration for this impressive project, and what direction is it heading? Watch to find out!

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From 8086 To Z80: Building A NASM-Inspired SDK For 8-Bit Retro Computing

Assembler syntax is a touchy subject, with many a flamewar having raged over e.g. Intel vs AT&T style syntax. Thus when [Humberto Costa] recently acquired an MSX system for some fun retro-style ASM programming, he was dismayed to see that the available Z80 assemblers did not support the syntax of his favorite ASM tool, NASM. Thus was born the HC SDK project, which seeks to bring more NASM to the Z80, 8085 and a slew of other processors.

There’s both a project site and a GitHub repository, from where both source and pre-compiled releases can be obtained. Supported host platforms are macOS, Windows, OpenBSD, FreeBSD, and Linux, with currently supported targets the 8080, 8085, 8086 and Z80. Support for the 6502 is currently in progress.

The Netwide Assembler (NASM), targets only the x86 architecture, being one of the most popular assemblers for Linux and x86. It uses a variant of the Intel ASM syntax, which contrasts it strongly with the GNU Assembler (GAS) that uses AT&T syntax. Of course, in an ironic twist of fate NASM now also supports AT&T syntax and vice versa, albeit with some subtle gotchas.

Regardless, if ASM for these retro architectures is your thing, then the HC SDK may be worth checking out. [Humberto] also says that he’s looking at adding higher-level language support to make it a more complete development environment for these old systems and new takes on them.

Thanks to [Albert Wolf] for the tip.

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Hackaday Links: March 15, 2026

Some days, it feels like we’re getting all the bad parts of cyberpunk and none of the cool stuff. Megacorps and cyber warfare? Check. Flying cars and holograms? Not quite yet. This week, things took a further turn for the dystopian with the news that a woman was hospitalized after an altercation with a humanoid robot in Macau. Police arrived on scene, took the bot into custody, and later told the media they believed this was the first time Chinese authorities had been called to intervene between a robot and a human.

The woman, reportedly in her seventies, was apparently shocked when she realized the robot was standing behind her. After the dust settled, the police determined it was being operated remotely as part of a promotion for a local business. We’ve heard there’s no such thing as bad publicity, but we’re not sure the maxim holds true when you manage to put an old lady into the hospital with your ad campaign.

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The Shockley 4-Layer Diode In 2026

The physicist William Shockley is perhaps today best known for three things: his role in the invention of the transistor, his calamitous management of Shockley Semiconductor which led to a mass defection of employees and precipitated the birth of the Silicon Valley we know, and his later descent into promoting eugenics. This was not the sum of his work though, and [David Prutchi] has been experimenting with a now-mostly-forgotten device that bears the Shockley name (PDF), after finding one used in an early heart pacemaker circuit.  His findings are both comprehensive and fascinating.

The Shockley diode, or 4-layer diode as it later became known, is as its name suggests a two terminal device with a 4-layer NPNP structure. It can be modeled as a pair of complementary transistors in parallel with a reverse biased diode, and the avalanche breakdown characteristics of that diode when a particular voltage is applied to it provide the impetus to turn on the two transistors. This makes it a voltage controlled switch, that activates when the voltage across it reaches that value.

The PDF linked above goes into the Shockley diode applications, and in them we find a range of relaxation oscillators, switches, and logic circuits. The oscillators in particular could be made with the barest minimum of components, important in a time when each semiconductor device could be very expensive. It may have faded into obscurity as it was superseded by more versatile 4-layer devices such as the PUJT or silicon-controlled switch and then integrated circuits, but he makes the point that its thyristor cousin is still very much with us.

This appears to be the first time we’ve featured a 4-layer diode, but we’ve certainly covered the genesis of the transistor in the past.