In a recent video, [Shahriar] from The Signal Path has unveiled the intricate design and architecture of optical HDMI cables, offering a cost-effective solution to extend HDMI 2.0 connections beyond the limitations of traditional copper links. This exploration is particularly captivating for those passionate about innovative hardware hacks and signal transmission technologies.

[Shahriar] begins by dissecting the fundamentals of HDMI high-speed data transmission, focusing on the Transition Minimized Differential Signaling (TMDS) standard. He then transitions to the challenges of converting from twisted-pair copper to optical lanes, emphasizing the pivotal roles of Vertical-Cavity Surface-Emitting Lasers (VCSELs) and PIN photodiodes. These components are essential for transforming electrical signals into optical ones and vice versa, enabling data transmission over greater distances without significant signal degradation.

A standout aspect of this teardown is the detailed examination of the optical modules, highlighting the use of free-space optics and optical confinement techniques with lasers and detectors. [Shahriar] captures the eye diagram of the received high-speed lane and confirms the VCSELs’ optical wavelength at 850 nm. Additionally, he provides a microscopic inspection of the TX and RX chips, revealing the intricate VCSEL and photodetector arrays. His thorough analysis offers invaluable insights into the electronic architecture of optical HDMI cables, shedding light on the complexities of signal integrity and the innovative solutions employed to overcome them.

For enthusiasts eager to take a deeper look into the nuances of optical HDMI technology, [Shahriar]’s comprehensive teardown serves as an excellent resource. It not only gives an insight in the components and design choices involved, but also inspires further exploration into enhancing data transmission methods.

In the near future, imagine a world where your health is continuously monitored, not through bulky devices but through an invisible graphene tattoo. Developed at the University of Massachusetts Amherst, these tattoos could soon detect a range of health metrics, including blood pressure, stress levels, and even biomarkers of diseases like diabetes. This technology, though still in its infancy, promises to revolutionize how we monitor health, making it possible to track our bodies’ responses to everything from exercise to environmental exposure in real-time.

Graphene, a single layer of carbon atoms, is key to the development of these tattoos. They are flexible, transparent, and conductive, making them ideal for bioelectronics. The tattoos are so thin and pliable that users won’t even feel them on their skin. In early tests, graphene electronic tattoos (GETs) have been used to measure bioimpedance, which correlates with blood pressure and other vital signs. The real breakthrough here, however, is the continuous, non-invasive monitoring that could enable early detection of conditions that usually go unnoticed until it’s too late.

While still requiring refinement, this technology is advancing rapidly. Graphene still amazes us, but it’s no longer just science fiction. Soon, these tattoos could be a part of everyday life, helping individuals track their health and enabling better preventative care. Since we’re hackers out here –  but this is a far fetch – combining this knowledge on graphene production, and this article on tattooing with a 3D printer, could get you on track. Let us know, what would you use graphene biosensors for?

Original photo by engin akyurt on Unsplash

Fair warning: watching this hybrid manufacturing method for gear teeth may result in an uncontrollable urge to buy a fiber laser cutter. Hackaday isn’t responsible for any financial difficulties that may result.

With that out of the way, this is an interesting look into how traditional machining and desktop manufacturing methods can combine to make parts easier than either method alone. The part that [Paul] is trying to make is called a Hirth coupling, a term that you might not be familiar with (we weren’t) but you’ve likely seen and used. They’re essentially flat surfaces with gear teeth cut into them allowing the two halves of the coupling to nest together and lock firmly in a variety of relative radial positions. They’re commonly used on camera gear like tripods for adjustable control handles and tilt heads, in which case they’re called rosettes.

To make his rosettes, [Paul] started with a block of aluminum on the lathe, where the basic cylindrical shape of the coupling was created. At this point, forming the teeth in the face of each coupling half with traditional machining methods would have been tricky, either using a dividing head on a milling machine or letting a CNC mill have at it. Instead, he fixtured each half of the coupling to the bed of his 100 W fiber laser cutter to cut the teeth. The resulting teeth would probably not be suitable for power transmission; the surface finish was a bit rough, and the tooth gullet was a little too rounded. But for a rosette, this was perfectly acceptable, and probably a lot faster to produce than the alternative.

In case you’re curious as to what [Paul] needs these joints for, it’s a tablet stand for his exercise machine. Sound familiar? That’s because we recently covered his attempts to beef up 3D prints with a metal endoskeleton for the same project.

Thanks to [Ziggi] for the tip.

As electronics rely more and more on ICs, subtle details about discrete components get lost because we spend less time designing with them. For example, a relay seems like a simple component, but selecting the contact material optimally has a lot of nuance that people often forget. Another case of this is the Miller effect, explained in a recent video by the aptly named [Old Hack EE].

Put simply, the Miller effect — found in 1919 by [John Milton Miller] — is the change in input impedance of an inverting amplifier due to the gain’s effect on the parasitic capacitance between the amplifier’s input and output terminals. The parasitic capacitance acts like there is an additional capacitor in parallel with the parasitic capacitance that is equivalent to the parasitic capacitance multiplied by the gain. Since capacitors in parallel add, the equation for the Miller capacitance is C-AC where C is the parasitic capacitance, and A is the voltage gain which is always negative, so you might prefer to think of this as C+|A|C.

The example uses tubes, but you get the same effect in any inverting amplification device, even if it is solid state or an op amp circuit. He does make some assumptions about capacitance due to things like tube sockets and wiring.

The effect can be very pronounced. For example, a chart in the video shows that if you had an amplifier with gain of -60 based around a tube, a 10 kΩ input impedance could support 2.5 MHz, in theory. But in practice, the Miller effect will reduce the usable frequency to only 81.5 kHz!

The last part of the video explains why you needed compensation for old op amps, and why modern op amps have compensation capacitors internally. It also shows cases where designs depend on the Miller effect and how the cascade amplifier architecture can negate the effect entirely.

This isn’t our first look at Miller capacitance. If you look at what’s inside a tube, it is a wonder there isn’t more parasitic capacitance.

What would it be like to have to design and build a ventilator, suitable for clinical use, in ten days? One that could be built entirely from locally-sourced parts, and kept oxygen waste to a minimum? This is the challenge [John Dingley] and many others faced at the start of COVID-19 pandemic when very little was known for certain.

Back then it was not even known if a vaccine was possible, or how bad it would ultimately get. But it was known that hospitalized patients could not breathe without a ventilator, and based on projections it was possible that the UK as a whole could need as many as 30,000 ventilators within eight weeks. In this worst-case scenario the only option would be to build them locally, and towards that end groups were approached to design and build a ventilator, suitable for clinical use, in just ten days.

[John] decided to create a documentary called Breathe For Me: Building Ventilators for a COVID Apocalypse, not just to tell the stories of his group and others, but also as a snapshot of what things were like at that time. In short it was challenging, exhausting, occasionally frustrating, but also rewarding to be able to actually deliver a workable solution.

In the end, building tens of thousands of ventilators locally wasn’t required. But [John] felt that the whole experience was a pretty unique situation and a remarkable engineering challenge for him, his team, and many others. He decided to do what he could to document it, a task he approached with a typical hacker spirit: by watching and reading tutorials on everything from conducting and filming interviews to how to use editing software before deciding to just roll up his sleeves and go for it.

We’re very glad he did, and the effort reminds us somewhat of the book IGNITION! which aimed to record a history of technical development that would otherwise have simply disappeared from living memory.

You can watch Breathe for Me just below the page break, and there’s additional information about the film if you’d like to know a bit more. And if you are thinking the name [John Dingley] sounds familiar, that’s probably because we have featured his work — mainly on self-balancing personal electric vehicles — quite a few times in the past.

Car infotainment systems somehow have become a staple in today’s automobiles, yet when it comes down to it they have all the elegance of a locked-down Android tablet. In the case of the Honda infotainment system that [dosdude1] got from a friend’s 2016/2017-era Honda Accord, it pretty much is just that. Powered by a dual-core Cortex-A15 SoC, it features a blazin’ 1 GB of RAM, 2 GB of storage and runs Android 4.2.2. It’s also well-known for crashing a lot, which is speculated to be caused by Out-of-RAM events, which is what the RAM upgrade is supposed to test.

After tearing down the unit and extracting the main board with the (Renesas) SoC and RAM, the SoC was identified as being an automotive part dating back to 2012. The 1 GB of RAM was split across two Micron-branded packages, leaving one of the memory channels on the SoC unused and not broken out. This left removing the original RAM chips to check what options the existing pads provided, specifically potential support for twin-die chips, but also address line 15 (A15). Unfortunately only the A15 line turned out to be connected.

This left double capacity (1 GB) chips as the sole option, meaning a total of 2 GB of RAM. After installation the infotainment system booted up, but only showed 1 GB installed. Cue hunting down the right RAM config bootstrap resistor, updating the boot flags and updating the firmware to work around the LINEOWarp hibernation image that retained the 1 GB configuration. Ultimately the upgrade seems to work, but until the unit is reinstalled in the car and tested it’s hard to say whether it fixes the stability issues.

Thanks to [Dylan] for the tip.

2K y Firaxis Games anunciaron Sid Meier’s Civilization VII VR, la primera entrada de la franquicia a la realidad virtual y mixta, que se lanzará exclusivamente en Meta Quest 3 y 3S en el otoño de 2025 (hemisferio sur).

Desarrollado por PlaySide Studios y publicado por 2K, Civilization VII VR permite a los jugadores experimentar Civilization desde una perspectiva completamente nueva y tomar su lugar en la mesa de mando, sumergiéndose en cada acción mientras construyen un imperio para resistir la prueba del tiempo. Está disponible para incluirlo en la lista de deseos hoy en este enlace y pueden encontrar más información aquí.

«Hoy es un verdadero hito para la franquicia Civ, con el anuncio de Civilization VII VR que marca nuestra primera entrada al mundo inmersivo de la realidad virtual y mixta», afirmó Dennis Shirk, productor ejecutivo de franquicias de Firaxis Games. «¡Estamos a sólo unos días del lanzamiento completo de Civilization VII y esperamos marcar el comienzo de una nueva era de excelencia estratégica para nuestros fans!»

«Con el reciente lanzamiento de Meta Quest 3S y nuestra cartera de juegos y entretenimiento más sólida hasta el momento, es un momento increíble para la realidad mixta», dijo Chris Pruett, director de juegos de Meta. «Civilization VII – VR es una prueba más de ese impulso: es una experiencia Civ genuina creada específicamente para los fanáticos de la estrategia profunda».

Acerca de Civilization VII

La galardonada saga de juegos de estrategia regresa con una nueva y revolucionaria entrega. ¡Sid Meier’s Civilization VII te permite construir el mayor imperio que el mundo haya conocido jamás!

En Civilization VII, tus decisiones estratégicas harán que tu imperio en evolución tenga un bagaje cultural único. Gobierna como uno de los líderes legendarios de la historia y dirige el curso de los acontecimientos eligiendo una nueva civilización que represente a tu imperio en cada Era del progreso humano.

Construye ciudades y maravillas arquitectónicas para ampliar tu territorio, mejora tu civilización con nuevos avances tecnológicos y conquista o coopera con civilizaciones rivales a medida que exploras los confines del mundo desconocido. Busca la prosperidad sumergiéndote en el juego en solitario o compite con otros jugadores en el modo multijugador en línea.

Tanto si eliges ser fiel a la historia como si trazas tu propio camino, en Civilization VII puedes construir algo en lo que creas y dejar un legado que se perpetúe.

Características principales:

• CONSTRUYE UN IMPERIO QUE PERDURE EN EL TIEMPO – Dirige tu imperio a través de las diversas Eras de la historia de la humanidad. Cada Era es un viaje único y lleno de matices, con diferentes civilizaciones jugables, recursos disponibles, tierras explorables e incluso sistemas de juego completos. El resultado es un profundo juego de estrategia que te sumerge en la historia. Pugna por conseguir grandes logros científicos, culturales, militares y económicos en cada Era y desbloquear ventajas decisivas en la siguiente.
• HAZ EVOLUCIONAR TU IMPERIO CON CADA NUEVA ERA – Para construir un legado que resista el paso del tiempo, debes adaptarte. Forja tu propio camino a través de la historia mientras remodelas tu imperio en cada nueva Era. Elige entre nuevas opciones de civilización relevantes para cada Era que vienen determinadas por tus logros anteriores en el juego. A medida que tu imperio evoluciona, accedes a nuevas bonificaciones de juego y unidades únicas, para que tu civilización actual esté siempre en su máximo esplendor.
• JUEGA CON LOS LÍDERES MÁS VISIONARIOS – Elige al líder ilustre que quieres encarnar entre la mayor variedad de opciones disponible hasta la fecha en Civilization: desde jefes de estado tradicionales conocidos por su poderío militar o sus proezas políticas, hasta líderes visionarios que tuvieron un impacto imperecedero en la filosofía, la ciencia, los derechos humanos y otros ámbitos. Cada líder posee una habilidad única y puedes mejorarlo con atributos personalizables que obtienes a medida que avanzas en el juego, y todo para que puedas reforzar o cambiar tu estrategia en cada nueva Era. Por primera vez en la historia de la saga, puedes elegir a un líder que no pertenezca a la civilización con la que juegas, lo que te da libertad para crear estrategias totalmente nuevas mezclando y combinando bonificaciones de juego.
• EXPLORA UN MUNDO RECREADO COMO NUNCA ANTES – ¡Deja tu huella en un planeta magníficamente detallado! Tu imperio cobra vida con una amplia y diversa gama de estilos culturales, representados en la arquitectura de los edificios y el diseño de las unidades. Las interacciones cara a cara con otros líderes históricos te harán sentir como si estuvieras presente en cada acto de diplomacia y declaración de guerra. A medida que tu territorio se expande y tus ciudades siguen desarrollándose, las espléndidas vistas de tu imperio se conectan a la perfección para crear una vibrante metrópolis.
• PON A PRUEBA TU ESTRATEGIA EN EL MODO MULTIJUGADOR – Compite contra otros jugadores en línea y demuestra tu destreza como gran líder. Las partidas multijugador pueden ser épicas campañas que abarcan varias Eras, o desarrollarse en una sola Era para disfrutar de una partida entera en una sesión. Es totalmente compatible con el juego cruzado entre PC y consolas, por lo que podrás jugar con tus amigos estén donde estén.
• UNA EXPERIENCIA DE ESTRATEGIA PARA TODOS – Con más de 30 años de trayectoria de la saga, Civilization VII incorpora una gran cantidad de mejoras en la jugabilidad que entusiasmarán tanto a los veteranos de la serie como a los recién llegados. El renovado tutorial y los refinados sistemas de juego hacen que sea más fácil que nunca iniciarse en Civilization, mientras que los jugadores veteranos apreciarán las numerosas mejoras en la jugabilidad. Mueve todo tu ejército a la vez bajo el liderazgo de un comandante, desbloquea bonificaciones de progresión para tus líderes a medida que avanzas en el juego, surca ríos navegables, ¡y mucho, mucho más!

Nota: El juego en línea y las funciones (incluidas las bonificaciones por progresión) requieren una conexión a Internet y una Cuenta de 2K (la edad mínima varía). Las Eras de la Antigüedad y la Exploración admiten hasta cinco jugadores. La Era Moderna admite hasta ocho jugadores. El juego en línea para consola requiere una suscripción de pago aparte. Es posible que se apliquen restricciones al tamaño de los mapas en algunas partidas multijugador cruzadas. Se aplican términos.

Requisitos Mínimos:

• Requiere un procesador y un sistema operativo de 64 bits
• SO: Win 10 64 Bit
• Procesador: Intel i5-4690 / Intel i3-10100 / AMD Ryzen 3 1200
• Memoria: 8 GB de RAM
• Gráficos: NVIDIA GTX 1050 / AMD RX 460 / Intel Arc A380
• DirectX: Versión 12
• Almacenamiento: 20 GB de espacio disponible

Requisitos Recomendados:

• Requiere un procesador y un sistema operativo de 64 bits
• SO: Win 10 64 Bit
• Procesador: Intel Core i5-10400 / AMD Ryzen 5 3600X
• Memoria: 16 GB de RAM
• Gráficos: NVIDIA RTX 2060 / AMD RX 6600 / Intel Arc A750
• DirectX: Versión 12
• Almacenamiento: 20 GB de espacio disponible

Reserva Sid Meier’s Civilization VII y recibe el Pack de Tecumseh y los shawnees en el lanzamiento. El Pack de Tecumseh y los shawnees se incluye en las ediciones Deluxe y Fundadores.

¡Amplía los horizontes estratégicos de tu imperio y disfruta de más opciones para tu reinado con Sid Meier’s Civilization VII Deluxe Edition!

La Edición Deluxe incluye:

• Juego base completo
• Acceso avanzado: accede al juego con antelación el 6 de febrero de 2025
• Pack de Tecumseh y los shawnees
• Colección Encrucijadas del mundo con contenido posterior al lanzamiento que incluye 2 nuevos líderes, 4 nuevas civilizaciones, 4 nuevas maravillas, una bonificación de estilo especial ¡y mucho más!
• Pack de contenido Deluxe, que incluye:

• 2 personalidades de líder
• 4 personalizaciones de perfil
• 1 aspecto de batidor alternativo

Amplía los horizontes estratégicos de tu imperio y disfruta de más opciones para tu reinado con Sid Meier’s Civilization VII Edición Fundadores. Esta edición digital solo estará disponible hasta el 28 de febrero de 2025; consíguela antes de que pase a la historia.

La Edición Fundadores incluye:

• Juego base completo
• Acceso avanzado: accede al juego 5 días antes (el 6 de febrero de 2025)
• Pack de Tecumseh y los shawnees
• Colección Encrucijadas del mundo, con contenido posterior al lanzamiento que incluye 2 nuevos líderes, 4 nuevas civilizaciones, 4 nuevas maravillas, una bonificación de estilo especial, ¡y mucho más!
• Colección Derecho a gobernar, con contenido posterior al lanzamiento que incluye 2 nuevos líderes, 4 nuevas civilizaciones, 4 nuevas maravillas, una bonificación de estilo especial, ¡y mucho más!*
• Pack de contenido Deluxe, que incluye:

• 2 personalidades de líder
• 4 personalizaciones de perfil
• 1 aspecto de batidor alternativo

• Pack de contenido Fundadores, que incluye:

• 2 personalidades de líder
• 4 personalizaciones de perfil
• 1 conjunto de casillas de niebla de guerra
• 1 aspecto de palacio de Fundadores

Consigue a Napoleón y su personalidad de Emperador en Sid Meier’s Civilization VII*

Crea una Cuenta de 2K gratuita y podrás añadir a Napoleón Bonaparte con su personalidad de Emperador a tu selección de líderes en Civilization VII en el momento del lanzamiento.

Para conseguir esta recompensa, regístrate o inicia sesión en 2K Account y luego vincula la cuenta y la plataforma que usas para jugar a Civilization VII mediante la pestaña “Contactos” situada debajo de “Resumen de la cuenta”, a la izquierda de la pantalla. Una vez que esté disponible Civilization VII, solo tienes que iniciar sesión con tu Cuenta de 2K en el juego para acceder a Napoléon Bonaparte y su personalidad de Emperador.

Como todas las Personalidades de líder, la personalidad de Emperador de Napoleón tiene un atuendo y un trasfondo únicos, nuevas bonificaciones de juego y una agenda alternativa cuando juega la IA. La personalidad de Emperador de Napoleón busca ser una potencia comercial y militar.

Para ello, cuenta con una habilidad exclusiva: Empereur des Français, una Acción diplomática que reduce la capacidad de la ruta comercial de una civilización y genera enormes quejas entre su pueblo. Por otro lado, obtiene bonificaciones de oro en todas las Eras por cada líder con el que mantenga una relación de amistad u hostilidad.

Nota: Requiere una conexión a Internet y una Cuenta de 2K vinculada a la cuenta de la plataforma utilizada para jugar a Sid Meier’s Civilization VII. Las Cuentas de 2K son gratuitas. Una por cuenta. La recompensa se entregará automáticamente en el juego. Nulo donde esté prohibido. Se aplican las condiciones.

La entrada Civilization VII VR llegará a Meta Quest 3 (S) en Q2 2025 – Primeros Detalles y Teaser Trailer apareció primero en PC Master Race Latinoamérica.

If you’re like most makers, you have a few product ideas kicking about, but you may not have made it all the way to production of those things. If you’re thinking about making the leap, [Simone Giertz] recently discussed all the perils and pitfalls of the process from idea to reality.

The TLDR is that there’s a big difference between making one item and making hundreds or thousands of them, which you probably already knew, but it is nice to see what sort of issues can crop up in this seemingly simple example of the Yetch Screwdriver Ring. It turns out that the metalworking skills of tool making and jewelry making rarely overlap in the contract manufacturing world.

[Giertz] also shares some of the more mundane, yet terrifying, parts of business like finally committing to bulk orders and whether it’s wise to go with intermediaries when working with suppliers overseas. She also keys us into parts of the process where things can go wrong, like how product samples typically use a different manufacturing process than bulk for practical reasons and how you need to have very specific quality control requirements not just decide if a product is good enough based on vibes.

If you’d like some more advice on making your own products, check out [Carrie Sundra]’s Supercon talk about Manufacturing on a Shoestring Budget.

The invention of the computer is a tricky thing to pinpoint. There were some early attempts that were not well known and some early attempts that were deliberately secret. [Alan Turing]’s efforts with Colossus were top secret for years, and while that work built on earlier efforts in Poland, [Turing] has as much claim to be the father of computers as anyone. But [Jack Copland] points out in a recent post that the famous computer scientist was also involved in another secret project: Delilah.

While [Turing] is best known for his work breaking ciphers at Bletchley Park, he also put time in on a second project about ten miles away in a secret electronics lab at Hanslope Park. There he worked with an assistant, [Donald Bayley] on Delilah — a portable system for encrypting voice transmissions.

The keyword is “portable.” In 1942, Bell Labs created SIGSALY for the U.S. Army to encrypt voice. It took up an entire room and weighed about 25 metric tons. [Turing] found a way to get the job done in a box that, including power, weighed in at 39 kilograms — not a cellphone, but portable in a truck. For comparison, an SCR-300 (the backpack radio used in the war, carried by “the lucky soldier”) weighed about 17 kilos with a full-sized battery.

The machine worked by generating a pseudo-random number sequence, synchronized with a similar unit on the other end of the transmission. Voice input was converted to digital, the numbers added on one end were transmitted, and the same numbers were subtracted from the other end. The result was not perfect for a number of reasons, but you could understand it, reportedly. But with the end of the war, interest in voice encryption wore off, and [Turing] and [Bayley] went on to other projects.

Luckily, [Bayley] saved his papers, which were auctioned off after his death for nearly half a million dollars. Without those papers, we wouldn’t know much about Delilah outside of a previously classified report (paywalled) and a few other notes.

The British National Museum of Computing rebuilt the device back in 2024, and you can see a video about it below. You can also see an interview in the video below with [Turing’s] nephew that mentions Delilah at the very end.

Title photo from The National Archives, London.

Ever stopped at a red light and noticed something odd about the poles holding up the traffic lights? Look closer next time—many of them appear to hover just above the concrete, anchored by visible bolts. This video below explains it all. It’s not a job left unfinished. It is actually clever design, and all about functionality and easy maintenance. Let’s break down why engineers prefer this so-called ‘floating’ base plate setup.

At first, you might think mounting poles directly into concrete would be more stable—after all, that’s how heavy columns are often installed. But traffic light poles are lightweight, hollow, and face constant wind pressure. Instead of brute stability, they need flexibility and precise alignment. Enter the standoff base plate. By resting on leveling nuts, these poles can be fine-tuned for perfect verticality, even when the ground shifts slightly over time. That’s critical for keeping your 30-foot pole from leaning like the Tower of Pisa.

The open design also simplifies maintenance. If the pole tilts after years of wear, it takes just a few nut adjustments to fix it—no heavy cranes required. Plus, the gap helps prevent moisture buildup, reducing corrosion. So next time you’re waiting at an intersection, you’ll know it’s not just clever engineering—it’s practical street smarts. If you’re an infrastructure nut, this slightly older article might spark your interest.

Was your 3D printer working fine over the summer, and now it’s not? With colder temperatures comes an overall surge in print failure reports — particularly with resin-based printers that might reside in outbuildings, basements, or garages. If you think this applies to you, don’t miss [Jan Mrázek]’s tips on improving cold-weather print results. His tips target the main reasons prints fail, helping to make the process a little more resilient overall. [Jan]’s advice is the product of long experience and experimentation, so don’t miss out.

With environmental changes comes the possibility that things change just enough to interfere with layers forming properly. The most beneficial thing overall is to maintain a consistent resin temperature; between 22 and 30 degrees Celsius is optimal. A resin heater is one solution, and there are many DIY options using simple parts. Some of the newer (and more expensive) printers have heaters built in, but most existing hobbyist machines do not.

Temperature control isn’t the only thing, either. Layer formation and build plate adhesion can all be improved by adding rest times between layers. Yes, this increases print time. It also allows resin to settle before the next layer, improving adhesion and preventing blooming (a rough texture caused by an imperfect cure.) Since resin flows less readily at lower temperatures, rest times can help improve results. The best setting depends heavily on your particular setup, so [Jan] gives tips on finding optimal rest times.

Most common knowledge and advice from well-meaning communities online focuses on increasing exposure time or blaming the build plate. [Jan] feels that these are ultimately the wrong way to go about addressing failures. Usually, an environmental change (like the arrival of winter) has simply pushed a printer that was not optimized in the first place outside of its narrow comfort zone. A little optimization can set things back on track, making the printer more resilient and reliable overall.

Although much diminished now, the public switched telephone network was one of the largest machines ever constructed. To make good on its promise of instant communication across town or around the world, the network had to reach into every home and business, snake along poles to thousands of central offices, and hum through the ether on microwave links. In its heyday it was almost unfathomably complex, with calls potentially passing through thousands of electronic components, any of which failing could present anything from a minor annoyance to a matter of life or death.

The brief but very interesting film below deals with “The Tyranny of Large Numbers.” Produced sometime in the 1960s by Western Electric, the manufacturing arm of the Bell System, it takes a detailed look at the problems caused by scaling up systems. As an example, it focuses on the humble carbon film resistor, a component used by the millions in various pieces of telco gear. Getting the manufacturing of these simple but critical components right apparently took a lot of effort. Initially made by hand, a tedious and error-prone process briefly covered in the film, Western Electric looked for ways to scale up production significantly while simultaneously increasing quality.

While the equipment used by the Western engineers to automate the production of resistors, especially the Librascope LGP-30 computer that’s running the show, may look quaint, there’s a lot about the process that’s still used to this day. Vibratory bowl feeders for the ceramic cores, carbon deposition by hot methane, and an early version of a SCARA arm to sputter gold terminals on the core could all be used to produce precision resistors today. Even cutting the helical groove to trim the resistance is similar, although today it’s done with a laser instead of a grinding wheel. There are differences, of course; we doubt current resistor manufacturers look for leaks in the outer coating by submerging them in water and watching for bubbles, but that’s how they did it in the 60s.

The productivity results were impressive. Just replacing the silver paint used for terminal cups with sputtered gold terminals cut 16 hours of curing time out of the process. The overall throughput increased to 1,200 pieces per hour, an impressive number for such high-reliability precision components, some of which we’d wager were still in service well into the early 2000s. Most of them are likely long gone, but the shadows cast by these automated manufacturing processes stretch into our time, and probably far beyond.

We’re used to those high voltage projects which use a self-oscillating transformer circuit with a TV flyback winding, and we have even at times railed against them for their inefficiency compared to a real flyback circuit using the same parts. But what happens if the same idea is used to create a low voltage instead of a high one? [D. Creative] has a soldering gun project doing just this, making a low voltage at a very high current.

The video of the project is below the break, and while electrically it’s nothing unexpected, we’re taken by the quality of the build. All the parts come from scrap electronics, the main transformer is three ferrite cores with a piece of copper busbar as the secondary. The circuitry is built dead bug style, and it’s housed in a gun-style case made by hand from sheet Perspex. It takes 12 volt power from a laptop power supply, and feeds it to the oscillator which is perched up at the back of the device. The transformer fits in the “barrel”, and a pair of large capacitors fit in the handle. We expect it to get hot, but the duty cycle on these devices in use is probably low enough to keep it from melting.

We like anything that uses scrap parts to make something useful, and we’re particularly taken with the casing of this one. It looks as though the parts come from old switch mode power supplies, something we’ve been known to rob ourselves.

There are a huge number of manufacturers building awesome radio-controlled cars these days. However, sometimes you just have to go your own way. That’s what [snamle] did with this awesome 3D-printed RC car—and the results are impressive.

This build didn’t just aim to build something that looked vaguely car-like and whizzed around on the ground. Instead, it was intended to give [snamle] the opporunity to explore the world of vehicle dynamics—learning about weight distribution, suspension geometry, and so many other factors—and how these all feed into the handling of a vehicle. The RC side of things is all pretty straightforward—transmitter, receiver, servos, motors, and a differential were all off-the-shelf. But the chassis design, the steering, and suspension are all bespoke—designed by [snamle] to create a car with good on-road handling and grip.

It’s a small scale testbed, to be sure. Regardless, there’s no better way to learn about how a vehicle works on a real, physical level—you can’t beat building one with your own two hands and figuring out how it works.

It’s true, we see a lot of 3D printed RC cars around these parts. Many are built with an eye to robotics experimentation or simply as a learning exercise. This one stands out for its focus on handling and performance, and of course that nicely-designed suspension system. Video after the break.

This week, we witnessed a couple of space oopsies as both Starship and New Glenn suffered in-flight mishaps on the same day. SpaceX’s Starship was the more spectacular, with the upper stage of the seventh test flight of the full stack experiencing a “rapid unscheduled disassembly” thanks to a fire developing in the aft section of the stage somewhere over the Turks and Caicos islands, about eight and a half minutes after takeoff from Boca Chica. The good news is that the RUD happened after first-stage separation, and that the Super Heavy booster was not only able to safely return to the pad but also made another successful “chopsticks” landing on the tower. Sorry, that’s just never going to get old.

On the Bezos side of the billionaire rocket club, the maiden flight of Blue Origin’s New Glenn ended with the opposite problem. The upper stage reached orbit, but the reusable booster didn’t make it back to the landing barge parked off the Bahamas. What exactly happened isn’t clear yet, but judging by the telemetry the booster was coming in mighty fast, which may indicate that the engines didn’t restart fully and the thing just broke up when it got into the denser part of the atmosphere.

While we’re not huge fans of doorbell cameras, mainly on privacy grounds but also because paying a monthly fee for service just seems silly, we might reconsider our position after one captured video of a meteorite strike. The impact, which occurred at the Prince Edward Island home of Joe Velaidum, happened back in July but the video was only just released; presumably the delay was for confirmation that the object was indeed a meteorite. Joe’s Ring camera captured video of something yeeting out of the sky and crashing into the sidewalk next to the driveway, in the exact spot he’d been standing only moments before. It’s hard to say if he would have been killed by the impact, but it sure wouldn’t have been fun.

While we’re on space-adjacent topics, we saw an interesting story about a satellite that was knocked out of service for a couple of days thanks to 2024 being a leap year. The Eutelsat OneWeb communications satellite went offline on the last day of the year, apparently because some software wasn’t prepared for the fact that 2024 had 366 days. It’s not clear if this caused any problems with the satellite itself, although the company said the problem was with the “ground segment” so it likely wasn’t. Engineers were able to work through the problem and get it back online within 48 hours, but we’re left wondering how something like this could happen with so many standard libraries out there that specifically deal with leap day calculations.

It’s that time of year again — HOPE_16 is gearing up, and tickets for the August 15-17 conference at St. John’s University in Queens are already on sale. It looks like the Call for Proposals is active now too, so if you’ve got a talk you’d like to give, get going.

And finally, sad news for a hapless early adopter of Bitcoin, whose eleven-year effort to locate a hard drive with 8,000 Bitcoin on it has reached a legal end. Back in 2013, a hard drive owned by James Howells containing the Bitcoin wallet was accidentally disposed of, ending up in a landfill in Newport, Wales. Howells immediately asked for permission to search for the missing fortune, which at the time was worth about $7.5 million. This seems to us like his first mistake; in light of the potential payout, we’d probably have risked a trespassing charge. Howells spent the next couple of years trying to get access while assembling a recovery team, with the effort driven by the ever-increasing price of Bitcoin. Howells also brought suit against the council to get access, an effort that a High Court judge brought to an end last week. So Howells is out of luck, and the hard drive, now worth $765 million, still lies in the landfill.

Officially, the term “taser” refers to a particular brand of projectile-firing electric stun gun. However, the word is also colloquially used to refer to just about any device intended for delivering electric shocks to an adversary. The taser ring from [Penguin DIY] definitely fits that description, though we’d strictly advise you not to consider building this at home.

The build is a hacky one. An arc generator circuit was pulled out from a jet cigarette lighter, and reconfigured to fit in a small ring-based form factor. It was hooked up with a power switch and a small bank of 30 mAh lithium polymer cell for power, and a compact USB-C charger board was installed to keep the batteries juiced. The electronics were then delicately assembled into a ring-shaped mold, which was injected with resin to produce the final ring. Once cast, a pair of small metal electrodes were installed on the outside. Activating the taser function is as simple as squeezing the ring—easy to do just by making a fist.

We’ve seen projects like these before; our advice is usually to avoid them unless you really know what you’re doing. Whether you end up shocking someone else or accidentally shocking yourself, the results tend to be bad. The latter seems particularly easy to do if you’re wearing this thing on your finger. Given it’s a ring, don’t expect to be able to pull it off in a hurry, either. It’s hard to see how that ends well.

Sometimes it’s the simplest hacks that make the biggest impact.

Take these DIY magnetic PCB vises for example. Sure, you can go out and buy purpose-built tools, but [Dylan Radcliffe] just made a trip to the hardware store for some nuts and bolts. He chose 3/8″-16 bolts, which would probably be around M10 for the rest of the world. The head of each bolt is ground flat so a ceramic disc magnet can be attached to it with CA glue, while the head of the bolt gets a plastic washer glued to it. Another plastic washer gets glued to a nut, which when threaded onto the bolt provides the light clamping force needed to hold a PCB. Make four of those and stick them to a steel plate with the magnets, and you can stop chasing your boards around the bench with a soldering iron.

As much as we like this idea — and we do; we’re heading to Home Depot to buy the needed parts this very evening — we can think of a few useful modifications. With a long bolt and two nuts rather than one, you could make a set of vises that are easily adjustable along the Z-axis. This could prove useful to those of us working under a microscope. Also, rather than making the bolts the magnetic part we bet you could lay down a flexible magnetic sheet, the kind you can feed into a printer to roll your own fridge magnets. We suspect that would hold the bolts firmly enough for most work while still allowing easy repositioning. We’d also favor flange nuts over plain hex nuts, to give a larger clamping area. We’d still include the plastic washers, though, or possibly switch to rubber ones.

There’s more than one way to skin this cat, of course, especially if you’ve got a Harbor Freight nearby and a well-stocked Lego bin.

When it comes to DIY projects, nothing beats the thrill of crafting something that rivals expensive commercial products. In the microphone build video below, [Electronoobs] found himself inspired by DIY Perks earlier efforts. He took on the challenge of building a $20 high-quality microphone—a budget-friendly alternative to models priced at $500. The result: an engaging and educational journey that has it’s moments of triumph, it’s challenges, and of course, opportunities for improvement.

The core of the build lies in the JLI-2555 capsule, identical to those found in premium microphones. The process involves assembling a custom PCB for the amplifier, a selection of high-quality capacitors, and designing lightweight yet shielded wiring to minimize noise. [Electronoobs] also demonstrates the importance of a well-constructed metal mesh enclosure to eliminate interference, borrowing techniques like shaping mesh over a wooden template and insulating wires with ultra-thin enamel copper. While the final build does not quite reach the studio-quality level and looks of the referenced DIY Perks’ build, it is an impressive attempt to watch and learn from.

The project’s key challenge here would be achieving consistent audio quality. The microphone struggled with noise, low volume, and single-channel audio, until [Electronoobs] made smart modifications to the shielded wiring and amplification stages. Despite the hurdles, the build stands as an affordable alternative with significant potential for refinement in future iterations.

You never know when inspiration is going to strike, and for [Ekaggrat Singh Kalsi], it struck while he was playing with one of his daughter’s hair ties. The result is a clock called “Bezicron” and it’s a fascinating study in mechanical ingenuity.

The hair ties in question are simple objects, just a loose polymer coil spring formed into a loop that can be wrapped around ponytails and the like. In Bezicron, though, each digit is formed by one of these loops fixed to the ends of five pairs of arms. Each pair moves horizontally thanks to a cam rotating between them, changing the spacing between them and moving the hair tie. This forms each loop into an approximation of each numeral, some a little more ragged than others but all quite readable. The cams move thanks to a geared stepper motor on the rightmost digit of the hours and minutes section of the clock, with a gear train carrying over to the left digit. In between is the colon, also made from springy things pulsing back and forth to indicate seconds. The video below shows the clock going through its serpentine motions.

For our money, the best part of this build is the cams. Coming up with the proper shape for those had to be incredibly tedious, although we suspect 3D printing and rapid iterative design were a big help here. Practice with cam design from his earlier Eptaora clock probably helped too.

Thanks to [Hari Wiguna] for the tip.