Tiny Tape Cartridge Remembered And A Teardown

If you want to add sound to something these days, you usually store it digitally. Microcontrollers are cheap and fast, and you can hold a lot of audio on a small flash card or in a ROM. But back “in the day,” storing audio was often done with tape. If you wanted something you could automate, you often turned to an endless loop tape. They had the advantage of not needing rewinding and had a way to sense spots on the tape (usually the start). The 8-track, for example, was an endless loop tape, and radio stations used “carts” (technically Fedelipak cartridges). But what if you wanted to build something tiny? Bandai had the answer, and [Tech Moan] shows the 1986-era tiny carts.

In the US, these appear to be mainly in the realm of novelty items. [Tech Moan] has an Elvis figurine that sings thanks to the tape and a diminutive jukebox. He suspects these must have been used in something else, perhaps in the Japanese market.

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A monitoring station as set up in the CEZ, featuring both the legacy (ARMS) and new wireless monitoring system.

How The 2022 CEZ Event Shows The Fragility Of Environmental Sensors In High-Risk Areas

In what reads somewhat like a convoluted detective story, the events unfolding at the Chornobyl Exclusion Zone (CEZ) in Ukraine during late February had the media channels lighting up with chatter about ‘elevated gamma radiation levels’, which showed up on the public CEZ radiation monitoring dashboard for a handful of gamma radiation sensors. This happened right before this reporting system went off-line, leaving outside observers guessing at what was going on. By the time occupying forces had been driven out of the CEZ, the gamma radiation levels were reported as being similar to before the invasion, yet the computer hardware which was part of the monitoring system had vanished along with the occupying forces. After considering many explanations, this left security researchers like [Ruben Santamarta] to consider that the high values had been spoofed.

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Antennas Can Be A Total Mystery

The real action in the world of ham radio is generally in the high frequency bands. Despite the name, these are relatively low-frequency bands by modern standards and the antenna sizes can get a little extreme. After all, not everyone can put up an 80-meter dipole, but ham radio operators have come up with a number of interesting ways of getting on the air anyway. The only problem is that a lot of these antennas don’t seem as though they should work half as well as they do, and [MIKROWAVE1] takes a look back on some of the more exotic radiators.

He does note that for a new ham radio operator it’s best to keep it simple, beginning work with a dipole, but there are still a number of options to keep the size down. A few examples are given using helically-wound vertical antennas or antennas with tuned sections of coaxial cable. From there the more esoteric antennas are explored, such as underground antennas, complex loops and other ways of making a long wire fit in a small space, and even simpler designs like throwing a weight with a piece of wire attached out the window of an apartment building.

While antenna theory is certainly a good start for building antennas, a lot of the design of antennas strays into artistry and even folklore as various hams will have successes with certain types and others won’t. It’s not a one-size-fits-all situation so the important thing is to keep experimenting and try anything that comes to mind as long as it helps get on the air. A good starting point is [Dan Maloney]’s $50 Ham Guide series, and one piece specifically dealing with HF antennas.

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Dial Up A Tune On The Jukephone

What do you do when you find a nice corded phone with giant buttons out in the wild? You could pay $80/month for a landline, use a VOIP or Bluetooth solution instead, or do something a million times cooler and turn it into a jukebox.

Now when the receiver is lifted, [Turi] hears music instead of a dial tone or a voice on the other end. But playback isn’t limited to the handset — there’s a headphone jack around back.

To listen to a track, he can either dial one in directly, or call up a random track using one of the smaller buttons below. A handy directory organizes the tunes by the hundreds, putting children’s tracks between 1-99 and the intriguing category “hits” between 900-999.

The phone’s new guts are commanded by a Raspberry Pi Pico, which is a great choice for handling the key matrix plus the rest of the buttons. As you may have guessed, there’s an DF Player Mini mp3 player that reads the tracks from an SD card. Everything is powered by a rechargeable 18650 battery.

Jukephone is open source, and you’ll find more pictures on [Turi]’s blog post. Be sure to check out the very brief build and demo video after the break.

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Pocket CO2 Sensor Doubles As SMD Proving Ground

While for some of us it’s a distant memory, every serious electronics hobbyist must at some point make the leap from working with through-hole components to Surface Mount Devices (SMD). At first glance, the diminutive components can be quite intimidating — how can you possibly work with parts that are literally smaller than a grain of rice? But of course, like anything else, with practice comes proficiency.

It’s at this silicon precipice that [Larry Bank] recently found himself. While better known on these pages for his software exploits, he recently decided to add SMD electronics to his repertoire by designing and assembling a pocket-sized CO2 monitor. While the monitor itself is a neat gadget that would be worthy of these pages on its own, what’s really compelling about this write-up is how it documents the journey from SMD skeptic to convert in a very personal way.

A fine-tipped applicator will get the solder paste where it needs to go.

At first, [Larry] admits to being put off by projects using SMD parts, assuming (not unreasonably) that it would require a significant investment in time and money. But eventually he realized that he could start small and work his way up; for less than $100 USD he was able to pick up both a hot air rework station and a hotplate, which is more than enough to get started with a wide range of SMD components. He experimented with using solder stencils, but even there, ultimately found them to be an unnecessary expense for many projects.

While the bulk of the page details the process of assembling the board, [Larry] does provide some technical details on the device itself. It’s powered by the incredibly cheap CH32V003 microcontroller — they cost him less than twenty cents each for fifty of the things — paired with the ubiquitous 128×64 SSD1306 OLED, TP4057 charge controller, and a SCD40 CO2 sensor.

Whether you want to build your own portable CO2 sensor (which judging from the video below, is quite nice), or you’re just looking for some tips on how to leave those through-hole parts in the past, [Larry] has you covered. We’re particularly eager to see more of his work with the CH32V003, which is quickly becoming a must-have in the modern hardware hacker’s arsenal.

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Jenny’s Daily Drivers: SerenityOS, And In Particular, Ladybird

As we continue on with the series in which I take a different OS for a spin every month I am afraid, dear reader, that this month I have a confession to make. Our subject here isn’t a Daily Driver at all, and it’s not the fault of the operating system in question. Instead I’m taking a look at a subject that’s not quite ready for the big time but is interesting for another reason. The OS is SerenityOS, which describes itself as “a love letter to ’90s user interfaces with a custom Unix-like core“, and the reason I’m interested in it comes from its web browser. I know that the OS is very much a work in progress and I’ll have to forgo my usual real hardware and run it in QEMU, but I’ve heard good things about it and I want to try it. The browser in question is called Ladybird, and it’s interesting because it has the aim of creating a modern fully capable cross-platform browser from scratch, rather than being yet another WebKit-based appliance.

A Pleasant Trip Into The 1990s

Part of a Linux desktop with the SerenityOS build instructions in the background, a terminal having built the OS, and the OS itself in a QEMU window.
My first look at SerenityOS after building it.

SerenityOS isn’t ready to be installed on real hardware, and there’s no handy ISO to download. Instead I had to clone the repository to my Linux machine and run the build script to compile the whole thing, something I was very pleased to observe only took about 40 minutes. It creates a hard disk image and opens QEMU for you, and you’re straight into a desktop.

When they mention ’90s user interfaces they definitely weren’t hiding anything, because what I found myself in could have easily been a Windows 9x desktop from the middle of that decade. There are  a bunch of themes including some Mac-like ones, but should you select the “Redmond” one, you’re on very familiar ground if you had a Microsoft environment back then. It’s only skin-deep though, because as soon as you venture into a command line shell there’s no DOS to be found. This is a UNIX-like operating system, so backslashes are not allowed and it’s familiarly similar to an equivalent on my Linux box. The purpose of this review is not to dive too far into the workings of the OS, but suffice it to say that both the underpinnings and the desktop feel stable and as polished as a Windows 95 lookalike can be. The various bundled utilities and other small programs seem to work well, and without any hint of the instabilities I’ve become used to when I’ve experimented with other esoteric operating systems. Continue reading “Jenny’s Daily Drivers: SerenityOS, And In Particular, Ladybird”

Wiring Up 100 Car Batteries So You Don’t Have To

We’re willing to bet most Hackaday readers have accidentally spot welded a few electrical contacts together over the years, complete with the surge of adrenaline that comes with the unexpected pops and sparks. It’s a mistake you’ll usually only make once or twice. But where most of us would look back at such mishaps as cautionary experiences, [Styropyro] sees an opportunity.

Armed with 100 car batteries wired in parallel, his recent video sees him pitting an assortment of household objects against the combined might of eighty-five thousand amps. Threaded rods, bolts, and angle iron all produce the sort of lightshow you’d expect, but [Styropyro] quickly discovered that holding larger objects down was more difficult than anticipated. It turns out that the magnetic fields being generated by the incredible amount of current rushing through the system was pulling the terminals apart and breaking the connection. After reinforcing the business end of his rig, he was able to tackle stouter objects such as crowbars and wrenches with explosive results.

A modified log splitter serves as a remotely operated switch.

We found that his remotely operated switch, built out of a hydraulic log splitter, to be a particular highlight of the video — unfortunately he only briefly goes over its construction at the very start. His side experiment, fashioning an sort of manually-operated carbon arc lamp with a pair of thick graphite electrodes and demonstrating is luminous efficacy compared to modern LEDs was an unexpected treat. As was the off-the-shelf domestic circuit breaker that impressed [Styropyro] by refusing to yield even after repeated jolts.

While the showers of sparks and vaporized metal might trigger some sweaty palms among the audience, we’ve seen [Styropyro] handle far scarier contraptions in the past. Though he may come off as devil-may-care in his videos, we figure there’s no way he could have made it this long without blinding or maiming himself if he didn’t know what he was doing.

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