Dial-up modems used to be the default way of accessing the Internet, but times have moved on. They’re now largely esoteric relics from a time gone by. With regular old phone lines rather hard to come by these days, [Peter Mount] decided to try getting a pair of dial-up modems working over VoIP instead.
The build started with a pair of Linksys PAP2T VoIP phone adapters, which were originally designed for hooking regular phones up to VoIP systems. He paired each US Robotics modem with a PAP2T, and then hooked both into a VoIP Private Branch Exchange which he set up using 3cx on a Raspberry Pi 3B+. The Pi also acted as a server for the modems to connect to. It took a lot of fiddly configuration steps, but he found success in the end. On YouTube, he demonstrates the setup—with that glorious modem sound—communicating successfully at a rate of 9600 baud.
It’s nice to see this vintage hardware communicating in a what is effectively a simulated world created entirely within modern hardware. We’ve seen similar projects before, like this attempt to get dial-up going over Discord. If you’re doing your own odd-ball screechy communications experiments, don’t hesitate to drop us a line!
We talk a lot about patent disputes in today’s high-tech world. Whether it’s Wi-Fi, 3D printing, or progress bars, patent disputes can quickly become big money—for lawyers and litigants alike.
Where we see less of this, typically, is the world of sports. And yet, a recent football innovation has seen plenty of conflict in this very area. This is the controversial story of vanishing spray.
Patently Absurd
Vanishing spray has quickly become a common sight on the belts of professional referees. Credit: Balkan Photos, CC BY-SA 2.0
You might have played football (soccer) as a child, and if that’s the case, you probably don’t remember vanishing spray as a key part of the sport. Indeed, it’s a relatively modern innovation, which came into play in international matches from 2013. The spray allowed referees to mark a line with a sort of disappearing foam, which could then be used to enforce the 10-yard distance between opposing players and the ball during a free kick.
The product is a fairly simple aerosol—the cans contain water, butane, a surfactant, vegetable oil, and some other minor constituents. When the aerosol nozzle is pressed, the liquified butane expands into a gas, creating a foam with the water and surfactant content. This creates an obvious white line that then disappears in just a few minutes.
The spray was created by Brazilian inventor Heine Allemagne in 2000, and was originally given the name Spuni. He filed a patent in 2000, which was then granted in 2002. It was being used in professional games by 2001, and quickly adopted in the mainstream Brazilian professional competition.
The future looked bright for Allemagne and his invention, with the Brazilian meeting with FIFA in 2012 to explore its use at the highest level of international football. In 2013, FIFA adopted the use of the vanishing spray for the Club World Cup. It appeared again in the 2014 World Cup, and many competitions since. By this time, it had been renamed “9.15 Fair Play,” referring to the metric equivalent of the 10-yard (9.15 meter) distance for free kicks.
After its first use by FIFA, the use of vanishing spray quickly spread to other professional competitions, making its first appearance in the Premier League in 2014. Credit: Egghead06, CC BY-SA 4.0
The controversy came later. Allemagne would go on to publicly claim that the global sporting body had refused to pay him the agreed price for his patent. He would go on to tell the press he’d knocked back an initial offer of $500,000, with FIFA later agreeing to pay $40 million for the invention. Only, the organization never actually paid up, and started encouraging the manufacture of copycat products from other manufacturers. In 2017, the matter went to court, with a Brazilian ruling acknowledging Allemagne’s patent. It also ordered FIFA to stop using the spray, or else face the risk of fines. However, as is often the way, FIFA repeatedly attempted to appeal the decision, raising questions about the validity of Allemagne’s patent.
The case has languished in the legal system for years since. In 2020, one court found against Allemagne, stating he hadn’t proven that FIFA had infringed his products or that he had suffered any real damages. By 2022, that had been overturned on appeal to a higher court, which found that FIFA had to pay material damages for their use of vanishing spray, and for the loss of profits suffered by Allemagne. The latest development occurred earlier this year, with the Superior Court of Justice ruling that FIFA must compensate Allemagne for his invention. In May, CNN reported that he expected to receive $40 million as a result of the case, with all five ministers on the Superior Court ruling in his favor.
Ultimately, vanishing spray is yet another case of authorities implementing ever-greater control over the world of football. It’s also another sad case of an inventor having to fight to receive their due compensation for an innovative idea. What seems like an open-and-shut case nevertheless took years to untangle in the courts. It’s a shame, because what should be a simple and tidy addition to the world of football has become a mess of litigation that cost time, money, and a great deal of strife. It was ever thus.
If you want to build semiconductors at home, it seems like the best place to start might be to find a used scanning electron microscope on eBay. At least that’s how [Peter Bosch] kicked off his electron beam lithography project, and we have to say the results are pretty impressive.
Now, most of the DIY semiconductor efforts we’ve seen start with photolithography, where a pattern is optically projected onto a substrate coated with a photopolymer resist layer so that features can be etched into the surface using various chemical treatments. [Peter]’s method is similar, but with important differences. First, for a resist he chose poly-methyl methacrylate (PMMA), also known as acrylic, dissolved in anisole, an organic substance commonly used in the fragrance industry. The resist solution was spin-coated into a test substrate of aluminized Mylar before going into the chamber of the SEM.
As for the microscope itself, that required a few special modifications of its own. Rather than rastering the beam across his sample and using a pattern mask, [Peter] wanted to draw the pattern onto the resist-covered substrate directly. This required an external deflection modification to the SEM, which we’d love to hear more about. Also, the SEM didn’t support beam blanking, meaning the electron beam would be turned on even while moving across areas that weren’t to be exposed. To get around this, [Peter] slowed down the beam’s movements while exposing areas in the pattern, and sped it up while transitioning to the next feature. It’s a pretty clever hack, and after development and etching with a cocktail of acids, the results were pretty spectacular. Check it out in the video below.
It’s pretty clear that this is all preliminary work, and that there’s much more to come before [Peter] starts etching silicon. He says he’s currently working on a thermal evaporator to deposit thin films, which we’re keen to see. We’ve seen a few sputtering rigs for thin film deposition before, but there are chemical ways to do it, too.
When you hear the cry of “Man Overboard!” on a ship, it’s an emergency situation. The sea is unkind to those that fall from their vessel, and survival is never guaranteed—even in the most favorable conditions. Raging swell and the dark of night can only make rescue more impossible.
Over the centuries, naval tradition has included techniques to find and recover the person in the water as quickly and safely as possible. These days, though, technology is playing an ever-greater role in such circumstances. Modern man-overboard (MOB) systems are designed to give crews of modern vessels a fighting chance when rescuing those in peril.
Air hockey is a fun game, but it’s one you can’t play by yourself. That is, unless you have a smart robot hockey player to act as your rival. [Zeroshot] built exactly that.
The build is based around a small 27-inch air hockey table—not exactly arcade-spec, but big enough to demonstrate the concepts at play. The robot player moves its mallet in the X and Y axes using a pair of NEMA17 stepper motors and an H-belt configuration. To analyze the game state, there’s a Raspberry Pi 3B fitted with a camera, and it has a top-down view of the board. The Pi gives the stepper motors commands on how to move the mallet via an Arduino that communicates with the stepper drivers. The Pi doesn’t just aim for the puck itself, either. With Python and OpenCV, it tries to predict your own moves by tracking your mallet, and the puck, too. It predicts the very-predictable path of the puck, and moves itself to the right position for effective defence.
As part of a phosphorescence detector, [lcamtuf] has been working with photodiodes. The components, like all diodes, have some capacitance at the junction, and this can limit performance. That’s why [lcamtuf] turned to bootstrapping to make that parasitic capacitance almost disappear.
The technique appears in several Analog Devices datasheets that presents a mystery. An op amp circuit that would normally limit changes to about 52 kHz has an unusually-placed JFET and claims to boost the bandwidth to 350 kHz.
If you’re a fan of the Fallout series of games, you’ve probably come across a Radiation King radio before. In the game, that is, they don’t exist in real life. Which is precisely why [zapwizard] built one!
Externally, the design faithfully recreates the mid-century design of the Radiation King. It’s got the louvered venting on the front panel, the chunky knobs, and a lovely analog needle dial, too. Inside, it’s got a Raspberry Pi Zero which is charged with running the show and dealing with audio playback. It’s paired with a Pi Pico, which handles other interface tasks.
It might seem simple, but the details are what really make this thing shine. It doesn’t just play music, it runs a series of simulated radio stations which you can “tune into” using the radio dial. [zapwizard dives into how it all works—from the air core motor behind the simulated tuning dial, to the mixing of music and simulated static. It’s really worth digging into if you like building retro-styled equipment that feels more like the real thing.
It’s not just a prop—it’s a fully-functional item from the Fallout universe, made manifest. You know how much we love those. If you’re cooking up your own post-apocalyptic hacks, fictional or non-fictional, don’t hesitate to let us know.
