Transmitting Wireless Power Over Longer Distances

Proof-of-concept of the inductive coupling transmitter with the 12V version of the circuitry (Credit: Hyperspace Pirate, YouTube)
Proof-of-concept of the inductive coupling transmitter with the 12V version of the circuitry (Credit: Hyperspace Pirate, YouTube)

Everyone loves wireless power these days, almost vindicating [Nikola Tesla’s] push for wireless power. One reason why transmitting electricity this way is a terrible idea is the massive losses involved once you increase the distance between transmitter and receiver. That said, there are ways to optimize wireless power transfer using inductive coupling, as [Hyperspace Pirate] demonstrates in a recent video.

Starting with small-scale proof of concept coils, the final version of the transmitter is powered off 120 VAC. The system has 10 kV on the coil and uses a half-bridge driver to oscillate at 145 kHz. The receiver matches this frequency precisely for optimal efficiency. The transmitting antenna is a 4.6-meter hexagon with eight turns of 14 AWG wire. During tests, a receiver of similar size could light an LED at a distance of 40 meters with an open circuit voltage of 2.6 V.

Although it’s also an excellent example of why air core transformers like this are lousy for efficient remote power transfer, a fascinating finding is that intermediate (unpowered) coils between the transmitter and receiver can help to boost the range due to coupling effects. Even if it’s not a practical technology (sorry, [Tesla]), it’s undeniable that it makes for a great science demonstration.

Of course, people do charge phones wirelessly. It works, but it trades efficiency for convenience. Modern attempts at beaming power around seem to focus more on microwaves or lasers.

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A Look At The Panasonic FS-A1FM

MSX computers were not very common in the United States, and we didn’t know what we were missing when they were popular. [Re:Enthused] shows us what would have been a fine machine in its day: a Panasonic FS-A1FM. Have a look at the video below to see the like-new machine.

The machine isn’t just an ordinary MSX computer. The keyboard is certainly unique, and it has an integrated floppy drive and a 1200-baud modem. The case proudly proclaims that the floppy is both double-sided and double-density. Like most MSX computers, it had a plethora of ports and, of course, a cartridge slot. Unfortunately, the machine looks great but has some problems that have not been repaired yet, so we didn’t get to see it running properly.

He was able to get to the MSX-DOS prompt to show along with the BIOS menu. We hope he manages to get the keyboard working, and we were glad to see another computer from that era we had not seen before.

We don’t think anyone made one at the time, but we’ve seen a modern take on a luggable MSX. Of course, you can emulate the whole thing on a Pi and focus on the aesthetics.

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A Hacker’s Approach To All Things Antenna

When your homebrew Yagi antenna only sort-of works, or when your WiFi cantenna seems moody on rainy days, we can assure you: it is not only you. You can stop doubting yourself once and for all after you’ve watched the Tech 101: Antennas webinar by [Dr. Jonathan Chisum].

[Jonathan] breaks it all down in a way that makes you want to rip out your old antenna and start fresh. It goes further than textbook theory; it’s the kind of knowledge defense techs use for real electronic warfare. And since it’s out there in bite-sized chunks, we hackers can easily put it to good use.

The key takeaway is that antenna size matters. Basically, it’s all about wavelength, and [Jonathan] hammers home how tuning antenna dimensions to your target frequency makes or breaks your signal. Whether you’re into omnis (for example, for 360-degree drone control) or laser-focused directional antennas for secret backyard links, this is juicy stuff.

If you’re serious about getting into RF hacking, watch this webinar. Then dig up that Yagi build, and be sure to send us your best antenna hacks.

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Repairing A Kodak Picture Maker Kiosk

Photo-printing kiosks are about as common as payphones these days. However, there was a time when they were everywhere. The idea was that if you didn’t have a good printer at home, you could take your digital files to a kiosk, pay your money, and run off some high-quality images. [Snappiness] snagged one, and if you’ve ever wondered what was inside of one, here’s your chance.

While later models used a Windows PC inside, this one is old enough to have a Sun computer. That also means that it had things like PCMCIA slots and a film scanner. Unfortunately, it wasn’t working because of a bad touch screen. The box was looking for a network on boot, which required some parameter changes. The onboard battery is dead, too, so you have to change the parameters on every boot. However, the real killer was the touchscreen, which the software insists on finding before it will start.

The monitor is an old device branded as a Kodak monitor and, of course, is unavailable. [Snappiness] found pictures of another kiosk online and noted that the monitor was from Elo, a common provider of point-of-sale screens. Could the “Kodak” monitor just be an Elo with a new badge? It turns out it probably was because a new Elo monitor did the trick.

Of course, what excited us was that if we found one of these in a scrap pile, it might have a Sun workstation inside. Of course, you can just boot Solaris on your virtual PC today. You might be surprised that Kodak invented the digital camera. But they failed to understand what it would mean to the future of photography.

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Building A Fully Automatic Birkeland-Eyde Reactor

Ever wanted to produce nitrogen fertilizer like they did in the 1900s? In that case, you’re probably looking at the Birkeland-Eyde process, which was the first industrial-scale atmospheric nitrogen fixation process. It was eventually replaced by the Haber-Bosch and Ostwald processes. [Markus Bindhammer] covers the construction of a hobbyist-sized, fully automated reactor in this video.

It uses tungsten electrodes to produce the requisite arc, with a copper rod brazed onto both. The frame is made of aluminium profiles mounted on a polypropylene board, supporting the reaction vessel. Powering the whole contraption is a 24 VDC, 20 A power supply, which powers the flyback transformer for the high-voltage arc, as well as an air pump and smaller electronics, including the Arduino Uno board controlling the system.

The air is dried by silica gel before entering the reactor, with the airflow measured by a mass air flow sensor and the reaction temperature by a temperature sensor. This should give the MCU a full picture of the state of the reaction, with the airflow having to be sufficiently high relative to the arc to extract the maximum yield for this already very low-yield (single-digit %) process.

Usually, we are more interested in getting our nitrogen in liquid form. We’ve also looked at the Haber-Bosch method in the past.

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Firefox logo displayed on screen

Add WebUSB Support To Firefox With A Special USB Device

RP2040-based Pico board acting as U2F dongle with Firefox. (Credit: ArcaneNibble, GitHub)
RP2040-based Pico board acting as U2F dongle with Firefox. (Credit: ArcaneNibble, GitHub)

The WebUSB standard is certainly controversial. Many consider it a security risk, and, to date,  only Chromium-based browsers support it. But there is a workaround that is, ironically, supposed to increase security. The adjacent Universal 2nd Factor (U2F) standard also adds (limited) USB support to browsers. Sure, this is meant solely to support U2F USB dongles for two-factor authentication purposes, but as [ArcaneNibble] demonstrates using U2F-compatible firmware on a Raspberry Pi RP2040, by hijacking the U2F payload, this API can be used to provide WebUSB-like functionality.

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You Too Can Do The Franck-Hertz Experiment

We talk about quantum states — that is, something can be at one of several discrete values but not in between. For example, a binary digit can be a 1 or a 0, but not 0.3 or 0.5. Atoms have quantum states, but how do we know that? That’s what the Franck-Hertz experiment demonstrates, and [stoppi] shows you how to replicate that famous experiment yourself.

You might need to translate the web page if your German isn’t up to speed, but there’s also a video you can watch below. The basic idea is simple. A gas-filled tube sees a large voltage across the cathode and grid. A smaller voltage connects to the grid and anode. If you increase the grid voltage, you might expect the anode current to increase linearly. However, that doesn’t happen. Instead, you’ll observe dips in the anode current.

When electrons reach a certain energy they excite the gas in the tube. This robs them of the energy they need to overcome the grid/anode voltage, which explains the dips. As the energy increases, the current will again start to rise until it manages to excite the gas to the next quantum level, at which point another dip will occur.

Why not build a whole lab? Quantum stuff, at a certain level, is weird, but this experiment seems understandable enough.

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