We always look forward to [Stefan’s] CNC Kitchen videos. They are usually useful, but always carefully thought out and backed with experimental data. His latest is about creating transparent and strong FDM prints. You normally don’t associate the FDM process with clear prints even with clear filament. The problem is the filament doesn’t lay down in a particular structure, so light scatters producing a sort of white color. However, [Stefan] found a post on Printables called “How to Print Glass” which changes the structure of the part and, of course, [Stefan] wanted to see if the process also led to stronger parts.
The process is slow and the basic idea is to use no top and bottom layers. The entire part is essentially infill. You also need to set the infill to go in the same direction for each layer. As [Stefan] mentions, there have been other efforts to make transparent parts, especially in vase mode. Of course, you can also get transparent parts using resin printing, although it isn’t always as easy as you might think.
Stored hydrogen is often touted as the ultimate green energy solution, provided the hydrogen is produced from genuinely green power sources. But there are technical problems to be overcome before your average house will be heated with pumped or tank-stored hydrogen. One problem is that the locations that have lots of scope for renewable energy, don’t always have access to plenty of pure water, and for electrolysis you do need both. A team from Melbourne University have come up with a interesting way to produce hydrogen by electrolysis directly from the air.
Redder areas have more water risk and renewable potential
By utilising a novel electrolysis cell with a hygroscopic electrolyte, the so-called direct air electrolysis (DAE) can operate with humidity as low as 4% relative, so perfectly fine even in the most arid areas, after all there may not be clouds but the air still holds a bit of water. This is particularly relevant to regions of the world, such as deserts, where there is simultaneously a high degree of water risk, and plenty of solar potential. Direct electrolysis of saline extracted at coastal areas is one option, but dealing with the liberated chlorine is a big problem.
The new prototype is very simple in construction, with a sponge of melamine or a sintered glass foam soaked in a compatible electrolyte. Potassium Hydroxide (alkaline) was tried as was Potassium Acetate (base) and Sulphuric Acid, but the latter degraded the host material in a short time. Who would have imagined? Anyway, with electrolysis cell design, a key problem is ensuring the separate gasses stay separate, and in this case, are also separate from the air. This was neatly ensured by arranging the electrolyte sponge fully covered both electrodes, so as the hygroscopic material extracted water from the air, the micro-channels in the structure filled up with liquid, with it touching both ends of the cell, forming the circuit and allowing the electrolysis to proceed.
Hydrogen, being very light, would rise upward through holes in the cathode, to be collected and stored. Oxygen simply passed back into the air, after passing though the liquid reservoir at the base. Super simple, and from reading the paper, quite effective too.
You can kind of imagine a future built around this now, where you’re driving your hydrogen fuel cell powered dune buggy around the Sahara one weekend, and you stop at a solar-powered hydrogen fuel station for a top up and a pasty. Ok, possibly not that last bit.
Radioactivity has always been a fascinating phenomenon for anyone interested in physics, and as a result we’ve featured many radioactivity-related projects on these pages over the years. More recently however, fears of nuclear disaster have prompted many hackers to look into environmental radiation monitoring. [Malte] was one of those looking to upgrade the radiation monitor on his weather station, but found the options for wireless geiger counters a bit limited.
So he decided to build himself his own Wifi and LoRa compatible environmental radiation monitor. Like most such projects it’s based on the ubiquitous Soviet-made SBM-20 GM tube, although the design also supports the Chinese J305βγ model. In either case, the tube’s operating voltage is generated by a discrete-transistor based oscillator which boosts the board’s 5 V supply to around 400 V with the help of an inductor and a voltage multiplier.
Data can be visualized in graphs, together with other data from the weather station like temperature and humidity
The tube’s output signal is converted into clean digital pulses to be counted by either an ESP32 or a Moteino R6, depending on the choice of wireless protocol. The ESP can make its data available through a web interface using its WiFi interface, while the Moteino can communicate through LoRa and sends out its data using MQTT. The resulting data is a counts-per-minute value which can be converted into an equivalent dose in Sievert using a simple conversion formula.
Mathematical transforms can be a great help in understanding signals. Imaging trying to look at a complex waveform and figuring out the frequency components without the Fourier transform. [Artem Kirsanov] calls the wavelet transform a “mathematical microscope” and his video gives you a great introduction to the topic. You can see the video below.
The video starts with a discussion about how the time domain and frequency domain have a dual relationship — not big news if you’ve dealt with Fourier transforms and — in fact — that’s the next topic in the video. However, there are limitations to the transformation — you lose time domain information in the process.
One of the global news stories this week has been the passing of the British monarch, Queen Elizabeth II. Since she had recently celebrated 70 years on the throne, the changing of a monarch is not something that the majority of those alive in 2022 will have seen. But it’s well known that there are a whole suite of “London Bridge has fallen” protocols in place for that eventuality which the various arms of the British government would have put in motion immediately upon news from Balmoral Castle. When it became obvious that the Queen’s health was declining, [Hackerfantastic] took to the airwaves to spot any radio signature of these plans. [Update 2022-09-11] See the comments below and a fresh Tweet to clarify, it appears these were not the signals they were at first suspected to be.
What he found in a waterfall view of the 4 MHz military band was an unusual transmission, a set of strong QPSK packets that started around 13:40pm on the 8th of September, and continued on for 12 hours before disappearing. The interesting thing about these transmissions is not that they were a special system for announcing the death of a monarch, but that they present a rare chance to see one of the country’s Cold War era military alert systems in action.
It’s likely that overseas embassies and naval ships would have been the intended recipients and the contents would have been official orders to enact those protocols, though we’d be curious to know whether 2022-era Internet and broadcast media had tipped them off beforehand that something was about to happen. It serves as a reminder: next time world news stories happen in your part of the world, look at the airwaves!
We know the pandemic has screwed with a lot of people’s sense of time, but we doubled checked, and it has indeed been more than two years since the Internet first laid eyes upon the incredible rotary cell phone put together by [Justine Haupt]. We’re happy to report that not only has she continued to develop and improve the phone since the last time it made the rounds, but that the kits for this open source marvel are currently available for preorder.
A lot has happened since this phone last graced the pages of Hackaday. For one thing, it’s now officially known as the Rotary Un-Smartphone. [Justine] has also spun up a small company for the express purposes of putting these kits into production, which clearly speaks to just how much attention the project picked up in mainstream circles.
The new rotary mechanism is based on modern components.
In terms of hardware, while the phone might look more or less the same externally, [Justine] says that there’s not a single unchanged component from the previous version. The 3D printed case has given way to a beautiful injection molded enclosure offered in several retro colors, and the rather incongruous rubber ducky antenna has been replaced with an articulated aerial that serves as a kickstand.
Speaking of reception, the original 3G cellular modem has been upgraded to a LTE-compatible model from uBlox, so it should still get a signal for a decade or so before your carrier kicks it off the network. When ordering the kit you can choose between a global version using the TOBY-R200 modem, or a North American variant with the TOBY-R202.
Even the user interface has been spruced up — while the previous model featured a simple LED indicator on the front to show when you were in a call, the new version features an OLED display that will show you the currently dialed number as well as status information such as battery life and signal strength. Some may be disappointed to hear that the authentic Western Electric model 10A rotary dial has been deleted in favor of a custom designed mechanism that uses all modern components, but we can certainly understand why the change had to be made from a production standpoint.
The trend for cyberdecks has brought us many takes on the home-made portable computers, but it’s fair to say that some of them can be rather unwieldy. This is not an accusation you can point at [Smeef] with the Mini-Deck though, because its Raspberry Pi Zero, Adafruit miniature display, and tiny keyboard make the whole unit able to fit in the palm of a hand. We’re not sure we’ve seen one so compact!
The most obvious feature is the keyboard, it’s a DreamGear MiniKey miniature USB keyboard. It doesn’t have all the useful buttons a PC board has, so there’s also a separate set of buttons to cover those. Then there’s an analog stick connected to an Arduino Pro Micro that takes the functionality of a mouse, and an Adafruit Mini PiTFT 1.3″ Display. While a fully-functional display for the Pi, we do wonder if this tiny screen might actually be a bit too tiny to be practical. Power for the unit comes via an 18650 battery, which also functions as a pin for a folding mechanism.
The result is something that looks, feels, and works like a cyberdeck, but all in miniature. It might be a stretch to write a Hackaday piece on a machine like it, but we’re guessing that merely having built something like this is cool enough in itself. Certainly it’s considerably smaller than previous contenders for the smallest build.
sponge fully covered both electrodes, so as the hygroscopic material extracted water from the air, the micro-channels in the structure filled up with liquid, with it touching both ends of the cell, forming the circuit and allowing the electrolysis to proceed.
