Multi-Divi book with hand thumbing through it

Math, Optimized: Sweden’s Maximal Multi-Divi

March 28, 2025 by 30 Comments

Back in the early 1900s, before calculators lived in our pockets, crunching numbers was painstaking work. Adding machines existed, but they weren’t exactly convenient nor cheap. Enter Wilken Wilkenson and his Maximal Multi-Divi, a massive multiplication and division table that turned math into an industrialized process. Originally published in Sweden in the 1910’s, and refined over decades, his book was more than a reference. It was a modular calculating instrument, optimized for speed and efficiency. In this video, [Chris Staecker] tells all about this fascinating relic.

What makes the Multi-Divi special isn’t just its sheer size – handling up to 9995 × 995 multiplications – but its clever design. Wilkenson formatted the book like a machine, with modular sections that could be swapped out for different models. If you needed an expanded range, you could just swap in an extra 200 pages. To sell it internationally, just replace the insert – no translation needed. The book itself contains zero words, only numbers. Even the marketing pushed this as a serious calculating device, rather than just another dusty math bible.

While pinwheel machines and comptometers were available at the time, they required training and upkeep. The Multi-Divi, in contrast, required zero learning curve – just look up the numbers for instant result. And it wasn’t just multiplication: the book also handled division in reverse, plus compound interest, square roots, and even amortizations. Wilkenson effectively created a pre-digital computing tool, a kind of pocket calculator on steroids (if pockets were the size of briefcases).

Of course, no self-respecting hacker would take claims of ‘the greatest invention ever’ at face value. Wilkenson’s marketing, while grandiose, wasn’t entirely wrong – the Multi-Divi outpaced mechanical calculators in speed tests. And if you’re feeling adventurous, [Chris] has scanned the entire book, so you can try it yourself.

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An Artificial Sun In A Manageable Size

March 28, 2025 by 8 Comments

The sun is our planet’s source of natural illumination, and though we’ve mastered making artificial light sources, it remains extremely difficult to copy our nearby star. As if matching the intensity wasn’t enough, its spectral quality, collimation, and atmospheric scattering make it an special challenge. [Victor Poughon] has given it a go though, using a bank of LEDs and an interesting lens system.

We’re used to lenses being something that can be bought off-the-shelf, but this design eschews that convenience by having the lenses manufactured and polished as an array, by JLC. The scattering is taken care of by a sheet of inkjet printer film, and the LEDs are mounted on a set of custom PCBs.

The result is certainly a very bright light, and one whose collimation delivers a sun-like effect of coming from a great distance. It may not be as bright as the real thing, but it’s certainly something close. If you’d like something to compare it to, it’s not the first such light we’ve featured.

Take A Little Bit Of Acorn To Work

March 28, 2025 by 5 Comments

When we think of 8-bit computers, it’s natural to start with home computers. That’s where they live on in the collective memory. But a Z80, a 6502, or similar was more likely to be found unseen in a piece of industrial machinery, doing the job for which we’d today reach for a microcontroller. Sometimes these two worlds intersected, and thus we come to the EuroBEEB, a derivative of Acorn’s BBC Micro on a Eurocard. [Steve Crozier] has performed extensive research into this system and even produced a recreated PCB, providing a fascinating window into embedded computing in the early 1980s.

The EuroBEEB was the work of Control Universal, a Cambridge-based company specialising in embedded computers. They produced systems based upon 6502 and 6809 processors, and joining their product line to the then-burgeoning BBC Micro ecosystem would have been an obvious step. The machine itself is a Eurocard with a simple 6502 system shipped with ACORN BBC Basic on ROM, and could be seen as a cut-down BBC Micro with plenty of digital I/O, accesible through a serial port. It didn’t stop there though, as not only could it export its graphics to a “real” BBC Micro, it had a range of expansion Eurocards that could carry the missing hardware such as analogue input, Teletext, or high-res graphics.

The reverse-engineered PCB comes from analysis of surviving schematics, and included a couple of gate array logic chips to replace address decoding ROMs in the original. If it seems overkill for anyone used to a modern microcontroller, it’s worth remembering that by the standards of the time this was a pretty simple system. Meanwhile if you only fancy trying BBC BASIC, there’s no need to find original hardware.

Hackaday Podcast Episode 314: It’s Pi, But Also PCBs In Living Color And Ultrasonic Everything

March 28, 2025 by 3 Comments

It might not be Pi Day anymore, but Elliot and Dan got together for the approximately 100*Pi-th episode of the Podcast to run through the week’s coolest hacks. Ultrasound seemed to be one of the themes, with a deep dive into finding bugs with sonar as well as using sound to cut the cheese — and cakes and pies, too.

The aesthetics of PCBs were much on our minds, too, from full-color graphics on demand to glow-in-the-dark silkscreens. Is automation really needed to embed fiber optics in concrete? Absolutely! How do you put plasma in a bottle? Apparently, with kombucha, Nichrome, and silicone. If you need to manage your M:TG cards, scribble on the walls, or build a mechanical chase light, we’ve got the details. And what exactly is a supercomputer? We can’t define it, but we know one when we see it.

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Keep Tabs On Your Vehicle’s Needs With LubeLogger

March 28, 2025 by 21 Comments

It doesn’t matter if its a Vespa or a Peterbilt truck — if you ignore the maintenance needs of your vehicle, you do so at your own peril. But it can be difficult enough to keep track of basic oil changes, to say nothing of keeping records on what parts were changed when. Instead of cramming more receipts into your glove box, maybe give LubeLogger a try.

This free and open source software tool is designed to make it easy for individuals to keep track of both the routine maintenance needs of their vehicles, as well as keep track of any previous or upcoming repairs and upgrades. Released under the MIT license, LubeLogger is primarily distributed as a Docker image that makes it easy to self-host the tool should you wish to keep your data safe at home rather than on somebody’s server out in the Wild West of the modern Internet.

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This Week In Security: IngressNightmare, NextJS, And Leaking DNA

March 28, 2025 by 9 Comments

This week, researchers from Wiz Research released a series of vulnerabilities in the Kubernetes Ingress NGINX Controller  that, when chained together, allow an unauthorized attacker to completely take over the cluster. This attack chain is known as IngressNightmare, and it affected over 6500+ Kubernetes installs on the public Internet.

The background here is that web applications running on Kubernetes need some way for outside traffic to actually get routed into the cluster. One of the popular solutions for this is the Ingress NGINX Controller. When running properly, it takes incoming web requests and routes them to the correct place in the Kubernetes pod.

When a new configuration is requested by the Kubernetes API server, the Ingress Controller takes the Kubernetes Ingress objects, which is a standard way to define Kubernetes endpoints, and converts it to an NGINX config. Part of this process is the admission controller, which runs nginx -t on that NGINX config, to test it before actually deploying.

As you might have gathered, there are problems. The first is that the admission controller is just a web endpoint without authentication. It’s usually available from anywhere inside the Kubernetes cluster, and in the worst case scenario, is accessible directly from the open Internet. That’s already not great, but the Ingress Controller also had multiple vulnerabilities allowing raw NGINX config statements to be passed through into the config to be tested. Continue reading “This Week In Security: IngressNightmare, NextJS, And Leaking DNA” →

Dwingeloo telescope with sun shining through

Dwingeloo To Venus: Report Of A Successful Bounce

March 28, 2025 by 14 Comments

Radio waves travel fast, and they can bounce, too. If you are able to operate a 25-meter dish, a transmitter, a solid software-defined radio, and an atomic clock, the answer is: yes, they can go all the way to Venus and back. On March 22, 2025, the Dwingeloo telescope in the Netherlands successfully pulled off an Earth-Venus-Earth (EVE) bounce, making them the second group of amateurs ever to do so. The full breakdown of this feat is available in their write-up here.

Bouncing signals off planets isn’t new. NASA has been at it since the 1960s – but amateur radio astronomers have far fewer toys to play with. Before Dwingeloo’s success, AMSAT-DL achieved the only known amateur EVE bounce back in 2009. This time, the Dwingeloo team transmitted a 278-second tone at 1299.5 MHz, with the round trip to Venus taking about 280 seconds. Stockert’s radio telescope in Germany also picked up the returning echo, stronger than Dwingeloo’s own, due to its more sensitive receiving setup.

Post-processing wasn’t easy either. Doppler shift corrections had to be applied, and the received signal was split into 1 Hz frequency bins. The resulting detections clocked in at 5.4 sigma for Dwingeloo alone, 8.5 sigma for Stockert’s recording, and 9.2 sigma when combining both datasets. A clear signal, loud and proud, straight from Venus’ surface.

The experiment was cut short when Dwingeloo’s transmitter started failing after four successful bounces. More complex signal modulations will have to wait for the next Venus conjunction in October 2026. Until then, you can read our previously published article on achievements of the Dwingeloo telescope.