Usually, an oscilloscope lets you visualize what a signal looks like. [Mitxela]’s reverse oscilloscope lets you set what you want an audio waveform to look like, and it will produce it. You can see the box in the video below.
According to [Mitxela] part of the difficulty in building something like this is making the controls manageable for mere mortals. We really like the slider approach, which seems pretty obvious, but some other controls are a bit more subtle. For example, the interpolation control can create a squarish wave or a smooth waveform, or anything in between.
This is sort of an artistic take on an arbitrary waveform generator but with a discrete-panel user interface. The device contains a Teensy, a Raspberry PI Pico, a 16-bit ADC, and an external DAC. The Pico is little more than an I/O controller, reading the user interface and transmitting it on a serial port.
The outside construction looks excellent (we assume the tape is temporary). The inside is a bit messier, but still nicely done. There are many photos of the construction and details of problems along the way with 12-bit ADCs and power supply experiments.
When you’ve been a fact-sponge for electronics trivia for over four decades, it’s not often that an entire class of parts escapes your attention. But have you seen the Skiatron? It’s a CRT that looks like a normal mid-20th-century tube, until it’s switched on. Then its secret is revealed; instead of the glowing phosphor trace we’d expect, the paper-white screen displays a daylight-readable and persistent black trace. They’re invariably seen in videos of radar installations, with the 360 degree scans projected onto large table-top screens which show the action like a map. It’s like e-ink, but from the 1940s. What’s going on?
The tenebrescent mineral Hackmanite, before and after UV exposure. Leland Green…, CC BY-SA 2.0 and CC BY-SA 2.0.
The phosphor coating on a traditional CRT screen is replaced by a halide salt, and the property on which the display relies is called tenebrescence, changing colour under the influence of radiation. This seems most associated online with UV treatment of some minerals and gemstones to give them a prettier look, and its use a s a display technology is sadly forgotten.
A high-school physics understanding of the phenomenon is that energy from the UV light or the electron beam in the case of the tube, places some electrons in the crystal into higher energy levels, at which they absorb some visible light wavelengths. This is reversible through heat, in some substances requiring the application of heat while in others the heat of room temperature being enough. Of course here at Hackaday we’re hands-on people, so into the EPROM eraser went a small amount of table salt in a makeshift dish made of paper, but sadly not to be rewarded by a colour change.
On a real dark-trace CRT the dark trace would be illuminated from behind by a ring light round the glass neck of the tube. An interesting aside is that, unlike phosphor CRTs, they were more suitable for vertical mounting. It seems that small amounts of phosphor could detach themselves from a vertically mounted screen and drop into the electron gun, something that wasn’t a problem for tenebrescent coatings.
This display tech has shuffled off into the graveyard of obsolescence, we’re guessing because CRT technology became a lot better over the 1950s, and radar technologies moved towards a computerised future in which the persistence of the display wasn’t the only thing keeping the information on the screen. It seems at first sight to be a surprise that tenebrescent coatings have never resurfaced in other displays for their persistence, but perhaps there was always a better alternative whether it was ultra-low-power LCDs or more recently e-ink style devices.
For more bleeding-edge 1950s radar displays, we’ve previously brought you Volscan, a radar with an early form of GUI, which no doubt was one of those which consigned dark-trace CRTs to history.
When you think about it, wiggling your fingers over a bunch of magic chiclets is a pretty strange gateway to the written word. And yet, here we sit a hundred-odd years after someone first decided that the same basic interface used to run pianos and harpsichords for centuries would be a fantastic model for mechanizing the whole writing thing. Just because it makes perfect sense thanks to the outsized portion of our brains dedicated to the motor and sensory functions of our wonderfully complex and versatile hands doesn’t mean it’s not weird.
Still and all, it seems like there could be some room for improvement in the basic design of keyboards. We could probably do with something that makes typing easier, results in less repetitive strain, or is just more fun to do. Pushing back on the traditional and boring designs of the past is where we find the strange breed of keyboard builders and modders that our very own Kristina Panos counts herself part of. You know here from her popular “Keebin’ with Kristina” series, and now we’ve coaxed her into checking into the Hack Chat to talk to all the rest of us keyboard-minded individuals. If you’ve ever thought that there has to be a better way to enter text, or even just something a little bit different, you’ll want to come along and join the conversation.
A little over a year ago, and about 150 million kilometers (93 million miles) from where you’re currently reading this, NASA’s Parker Solar Probe quietly made history by safely flying through one of the most powerful coronal mass ejections (CMEs) ever recorded. Now that researchers have had time to review the data, amateur space nerds like ourselves are finally getting details about the probe’s fiery flight.
Launched in August 2018, the Parker Solar Probe was built to get up close and personal with our local star. Just two months after liftoff, it had already beaten the record for closest approach to the Sun by a spacecraft. The probe, with its distinctive solar shield, has come within 8.5 million kilometers (5.3 million miles) of its surface, a record that it’s set to break as its highly elliptical orbit tightens.
The fury of a CME at close range.
As clearly visible in the video below, the Parker probe flew directly into the erupting CME on September the 5th of 2022, and didn’t get fully clear of the plasma for a few days. During that time, researchers say it observed something that had previously only been theorized — the interaction between a CME and the swirling dust and debris that fills our solar system.
According to the Johns Hopkins Applied Physics Laboratory (APL), the blast that Parker flew through managed to displace this slurry of cosmic bric a brac out to approximately 9.6 million km (6 million miles), though the void it created was nearly instantly refilled. The researchers say that better understanding how a CME propagates through the interplanetary medium could help us better predict and track potentially dangerous space weather.
It’s been a busy year for the Parker Solar Probe. Back in June it announced that data from the craft was improving our understanding of high-speed solar winds. With the spacecraft set to move closer and closer to the Sun over the next two years, we’re willing to bet this isn’t the last discovery to come from this fascinating mission.
Autoimmune diseases occur when the immune system starts attacking the body’s own cells. They can cause a wide range of deleterious symptoms that greatly reduce a patient’s quality of life. Treatments often involve globally suppressing the immune system, which can lead to a host of undesirable side effects.
However, researchers at the University of Chicago might have found a workaround by tapping into the body’s own control mechanisms. It may be possible to hack the immune system and change its targeting without disabling it entirely. The new technique of creating “inverse vaccines” could revolutionize the treatment of autoimmune conditions.
If you ask your neighbor who Bill Gates or Steve Jobs is, they’d probably know. But mention Gary Kildall, and you are likely to get a blank stare unless you live next door to another Hackaday reader. [Al’s Geek Lab] has a great three-part documentary on Gary Kildall who, in case you didn’t know, was the man behind CP/M, a very influential operating system in the early days of computing and one that set the stage for the PC revolution.
You probably know the folktale that when IBM was looking for an operating system, Bill Gates took the meeting, and Gary Kildall went surfing instead. But like most capsule histories, there is plenty more to the story, and it isn’t as simple as people make it out.
We forget, sometimes, how innovative Digital Research — Kildall’s company — was for the time. We think of CP/M as the venerable CP/M 2.2, which was fine. But there was multitasking CP/M and GEM — a precursor to the graphical user interface found everywhere today. Sure, it looks antiquated now, but it was light years in front of everyone else.
If you watch the whole series, you’ll learn that the IBM story isn’t totally apocryphal, but the truth is much different. Kildall didn’t want the IBM deal, and for what seemed like good reasons at the time. Of course, Gates negotiated a deal with IBM that would build a huge company, so it is easy to look back and say that not taking the deal was a mistake, but we would have probably made the same decision as Kildall at that time.
This isn’t the first time we’ve wondered what a world where CP/M won would have looked like. If you want to look inside CP/M, you can. Of course, it still powers many retrocomputers and even has some surprising clones.
A Rogowski coil is a device for measuring AC current that differs from a conventional current transformer in that it has no need to encircle the conductor whose current it measures. They’re by no means cheap though, so over time we’ve seen some interesting variations on making one without the pain in the wallet. We particularly like [Stephen]’s one, because he eschews exotic devices for an interesting hack on a familiar chip. He’s taken the venerable TL431 voltage reference chip and turned it into an op-amp.
We had to look at the TL431 data sheet for this one and shamefacedly admit that since we’d only ever used the chip as a voltage reference, we hadn’t appreciated this capability. In this mode, it’s a op-amp with the inverting input connected to a fixed rail, so it can accept a feedback network to its non-inverting input just like any other. He’s using it as both integrator and amplifier, as well as, of course, in a more conventional power supply.
