We are always fascinated by bubble memory. In the late 1970s, this was the “Next Big Thing” that, as you may have guessed, was, in fact, not the next big thing at all. But there were a number of products that used it as non-volatile memory at a time when the alternative was tape or disk. [Smbakeryt] has a cool word processor with an acoustic coupler modem made by Teleram. Inside is — you guessed it — bubble memory.

The keyboard was nonfunctional, but fixable. Although we wouldn’t have guessed the problem. Bubble memory was quite high tech. It used magnetic domains circulating on a thin film of magnetic material. Under the influence of a driving field, the bubbles would march past a read-write head that could create, destroy, or read the state of the bubble.

Why didn’t it succeed? Well, hard drives got cheap and fairly rugged. The technology couldn’t compete with the high-density hard drives that could be reached with improved heads and recording strategies. Bubble memory did find use in high-vibration items, but also wound up in things like this terminal, at least one oscilloscope, and a video game.

Bubble memory evolved from twistor memory, one of several pre-disk technologies. While they are hard to come by today, you can find the occasional project that either uses some surplus or steals a part off of a device like this one.

How do you get images downlinked from 30 km up? Hams might guess SSTV — slow scan TV — and that’s the approach [desafloinventor] took. If you haven’t seen it before (no pun intended), SSTV is a way to send images over radio at a low frame rate. Usually, you get about 30 seconds to 2 minutes per frame.

The setup uses regular, cheap walkie-talkies for the radio portion on a band that doesn’t require a license. The ESP32-CAM provides the processing and image acquisition. Normally, you don’t think of these radios as having a lot of range, but if the transmitter is high, the range will be very good. The project steals the board out of the radio to save weight. You only fly the PC board, not the entire radio.

If you are familiar with SSTV, the ESP-32 code encodes the image using Martin 1. This color format was developed by a ham named [Martin] (G3OQD). A 320×256 image takes nearly two minutes to send. The balloon system sends every 10 minutes, so that’s not a problem.

Of course, this technique will work anywhere you want to send images over a communication medium. Hams use these SSTV formats even on noisy shortwave frequencies, so the protocols are robust.

Hams used SSTV to trade memes way before the Internet. Need to receive SSTV? No problem.

Surely by now you’ve at least heard of RTL-SDR — a software project that let’s cheap TV tuner dongles work as a software-defined radios. A number of projects and tools have spun off the original effort, but in his latest video, [Tech Minds] shows off a particularly unique take. It’s a Web browser-based radio application that uses WebUSB, so it doesn’t require the installation of any application software. You can see the program operating in the video below.

There are a few things you should know. First, you need the correct USB drivers for your RTL-SDR. Second, your browser must support WebUSB, of course. Practically, that means you need a Chromium-type browser. You may have to configure your system to allow raw access to the USB port, too.

Watching the video, you can see that it works quite well. According to the comments, it will work with a phone, too, which is an interesting idea. The actual Web application is available as open source. It isn’t going to compete with a full-fledged SDR program, but it looked surprisingly complete.

These devices have grown from a curiosity to a major part of radio hacking over the years. Firefox users can’t use WebUSB — well, not directly, anyway.

Ever heard of VENIX? There were lots of variants of Unix back in the day, and VENIX was one for the DEC Professional 380, which was — sort of — a PDP 11. The 1982 machine normally ran the unfortunately (but perhaps aptly) named P/OS, but you could get VENIX, too. [OldVCR] wanted to put one of these back online and decided the ST-506 hard drive was too risky. A solid-state drive upgrade and doubling the RAM to a whole megabyte was the plan.

It might seem funny to think of a desktop workstation that was essentially a PDP-11 minicomputer, but in the rush to corner the personal computer market, many vendors did the same thing: shrinking their legacy CPUs. DEC had a spotty history with small computers. [Ken Olsen] didn’t think anyone would ever want a personal computer, and the salespeople feared that cheap computers would eat into traditional sales. The Professional 350 was born out of DEC’s efforts to catch up, as [OldVCR] explains. He grabbed this one from a storage unit about to be emptied for scrap.

The post is very long, but you get a lot of history and a great look inside this vintage machine. Of course, the PDP-11 couldn’t actually handle more than 64K without tricks and you’ll learn more about that towards the end of the post, too.

Just as a preview, the story has a happy ending, including a surprising expression of gratitude from the aging computer. DEC didn’t enjoy much success in the small computer arena, eventually being bought by Compaq, which, in turn, was bought by Dell. During their heyday, this would have been unthinkable.

The PDP/11 did have some success because it was put on a chip that ended up in several lower-end machines, like the Heathkit H11. Ever wonder how people programmed the PDP computers with switches and lights?

If you do FDM 3D printing, you know one of the biggest problems is sensing the bed. Nearly all printers have some kind of bed probing now, and it makes printing much easier, but there are many different schemes for figuring out where the bed is relative to the head. [ModBot] had a Voron with a clicky probe but wanted to reclaim the space it used for other purposes. In the video, also linked below, he reviews the E3D PZ probe which is a piezoelectric washer, and the associated electronics to sense your nozzle crashing into your print bed.

There are many options, and it seems like each has its pros and cons. We do like solutions that actually figure out where the tip is so you don’t have to mess with offsets as you do with probes that measure from a probe tip instead of the print head.

Of course, there are other piezo probes we’ve seen. There are also many other kinds of sensors available. The version from E3D is available as a kit you can add to anything, assuming you can figure out how. Or you can do like [ModBot] did and opt for an E3D heatsink with the washer already in place which, presumably, will best fit E3D products.

From the printer’s point of view, the device looks like a normal end stop, so it is simple to configure the printer. There are other ways to sense a head crash, of course. We keep meaning to install one of the “real time” sensors you can get now, but our CR Touch works well enough that we never find the time.

We know how [Techmoan] feels. In the 1980s we had a bewildering array of oddball gadgets and exciting new tech. But as kids we didn’t have money to buy a lot of what we saw. But he had a £5 note burning a hole in his pocket from Christmas and found a Casio RD-10 “card radio” on sale and grabbed it. He’s long-ago lost that one, but he was able to find a new old stock one and shows us the little gadget in the video below.

The card-thin (1.9 mm) FM radio had many odd features, especially for the 1980s. For one thing, it took a coin cell, which was exotic in those days. The headphones had a special flat connector that reminded us of an automotive fuse. Even the idea of an earbud was odd at that time.

It was a good idea not to lose the earbud, as it had that strange connector. The earbud worked as the antenna and power switch, too. Oddly enough, you could get a slightly fatter AM radio version, and they even made one that was AM and FM. Unsurprisingly, Casio even made a version with a calculator built-in. It had a solar cell, but that only powers the calculator. You still needed the coin cell for the radio.

The sound? Meh. But what did you expect? There was a stereo version, too. However, that one had a rechargeable battery, which was not in good health after a few decades. He also shows a Sony card radio that is a bit different. We were hoping for a teardown, especially of the rechargeable since it was toast, anyway, but for now, we’ll have to imagine what’s inside.

We love nostalgic radios, although usually they are a little older. We miss the days when a kid might think it was cool to see an ad touting: “Oh boy! We’re radio engineers!”

We’ve all seen the ads. Some offer “free” solar panels. Others promise nearly free energy if you just purchase a solar — well, solar system doesn’t sound right — maybe… solar energy setup. Many of these plans are dubious at best. You pay for someone to mount solar panels on your house and then pay them for the electricity they generate at — presumably — a lower cost than your usual source of electricity. But what about just doing your own set up? Is it worth it? We can’t answer that, but [Brian Potter] can help you answer it for yourself.

In a recent post, he talks about the rise of solar power and how it is becoming a large part of the power generation landscape. Interestingly, he presents graphs of things like the cost per watt of solar panels adjusted for 2023 dollars. In 1975, a watt cost over $100. These days it is about $0.30. So the price isn’t what slows solar adoption.

The biggest problem is the intermittent nature of solar. But how bad is that really? It depends. If you can sell power back to the grid when you have it to spare and then buy it back later, that might make sense. But it is more effective to store what you make for your own use.

That, however, complicates things. If you really want to go off the grid, you need enough capacity to address your peak demand and enough storage to meet demand over several days to account for overcast days, for example.

There’s more to it than just that. Read the post for more details. But even if you don’t want solar, if you enjoy seeing data-driven analysis, there is plenty to like here.

Building an effective solar power system is within reach of nearly anyone these days. Some of the problems with solar go away when you put the cells in orbit. Of course, that always raises new problems.

If you spend a lot of time at the command line, you probably have either a very basic prompt or a complex, information-dense prompt. If you are in the former camp, or you just want to improve your shell prompt, have a look at Starship. It works on the most common shells on most operating systems, so you can use it everywhere you go, within reason. It has the advantage of being fast and you can also customize it all that you want.

What Does It Look Like?

It is hard to explain exactly what the Starship prompt looks like. First, you can customize it almost infinitely, so there’s that. Second, it adapts depending on where you are. So, for example, in a git-controlled directory, you get info about the git status unless you’ve turned that off. If you are in an ssh session, you’ll see different info than if you are logged in locally.

However, here’s a little animation from their site that will give you an idea of what you might expect:

Installation

The web site says you need a Nerd Font in your terminal. I didn’t remember doing that on purpose, but apparently I had one already.

Next, you just have to install using one of the methods they provide, which depends on your operating system. For Linux, you can run the installer:

curl -sS https://starship.rs/install.sh | sh

Sure, you should download it first and look to make sure it won’t reformat your hard drive or something, but it was fine when we did it.

Finally, you have to run an init command. How you do that depends on your shell and they have plenty of examples. There’s even a way to use it with cmd.exe on Windows!

Customization

The default isn’t bad but, of course, you are going to want to change things. Oddly, the system doesn’t create a default configuration file. It just behaves a certain way if it doesn’t find one. You must make your own ~/.config/starship.toml file. You can change where the file lives using an environment variable, if you prefer, but you still have to create it.

The TOML file format has sections like an INI file. Just be aware that any global options have to come before any section (that is, there’s no [global] tag). If you put things towards the bottom of the file, they won’t seem to work and it is because they have become part of the last tag.

There are a number of modules and each module reads data from a different section. For example, on my desktop I have no need for battery status so:

[battery]
disabled = true

Strings

In the TOML file you can use single or double quotes. You can also triple a quote to make a string break lines (but the line breaks are not part of the string). The single quotes are treated as a literal, while double quotes require escape characters for special things.

You can use variables in strings like $version or $git_branch. You can also place part of a string in brackets and then formating for the string in parenthesis immediately following. For example:

'[off](fg:red bold)'

Finally, you can have a variable print only if it exists:

 '(#$id)'

If $id is empty, this does nothing. Otherwise, it will print the # and the value.

Globals and Modules

You can find all the configuration options — and there are many — in the Starship documentation. Of primary interest is the global format variable. This sets each module that is available. However, you can also use $all to get all the otherwise unspecified modules. By default, the format variable starts with $username $hostname. Suppose you wanted it to be different. You could write:

format='$hostname ! $username $all'

You’ll find many modules that show the programming language used for this directory, version numbers, and cloud information. You can shut things off, change formatting, or rearrange. Some user-submitted customizations are available, too. Can’t find a module to do what you want? No problem.

Super Custom

I wanted to show the status of my watercooler, so I created a custom section in the TOML file:

[custom.temp]
command = 'temp-status|grep temp|cut -d " " -f 7'
when = true
format='$output°'

The command output winds up in, obviously, $output. In this case, I always want the module to output and the format entry prints the output with a degree symbol after it. Easy!

Of Course, There are Always Others

There are other prompt helpers out there, especially if you use zsh (e.g., Oh My Zsh). However, if you aren’t on zsh, your options are more limited. Oh My Posh is another cross-shell entry into the field. Of course, you don’t absolutely need any of these. They work because shells give you variables like PS1 and PROMPT_COMMAND, so you can always roll your own to be as simple or complex as you like. People have been doing their own for a very long time.

If you want to do your own for bash, you can get some help online. Or, you could add help to bash, too.

Some slicers have introduced brick layers, and more slicers plan to add them. Until that happens, you can use this new script from [Geek Detour] to get brick layer goodness on Prusa, Orca, and Bambu slicers. Check out the video below for more details.

The idea behind brick layers is that outer walls can be stronger if they are staggered vertically so each layer interlocks with the layer below it. The pattern resembles a series of interlocking bricks and can drastically increase strength. Apparently, using the script breaks the canceling object functionality in some printers, but that’s a small price to pay. Multi-material isn’t an option either, but — typically — you’ll want to use the technique on functional parts, which you probably aren’t printing in colors. Also, the Arachne algorithm option only works reliably on Prusa slicer, so far.

The video covers a lot of detail on how hard it was to do this in an external script, and we are impressed. It should be easier to write inside the slicer since it already has to figure out much of the geometry that this script has to figure out by observation.

If you want more information, we’ve covered brick layers (and the controversy around them) back in November. Of course, scripts that add functions to slicers, tend to get outdated once the slicers catch up.

The Amiga has a lot of fans, and rightly so. The machine broke a lot of ground. However, according to [Dave Farquhar], one of the most popular models today — the Amiga 600 — was reviled in 1992 by just about everyone. One of the last Amigas, it was supposed to be a low-cost home computer but was really just a repackaged Amiga 1000, a machine already seven years old which, at the time, might as well have been decades. The industry was moving at lightspeed back then.

[Dave] takes a look at how Commodore succeeded and then lost their way by the time the 600 rolled out. Keep in mind that low-cost was a relative term. A $500 price tag was higher than it seems today and even at that price, you had no monitor or hard drive. So at a $1,000 for a practical system you might as well go for a PC which was taking off at the same time.

By the time Commodore closed down, they had plenty of 600s left, but they also had refurbished 500s, and for many, that was the better deal. It was similar to the 500 but had more features, like an external port and easy memory expansion. Of course, both machines used the Motorola 68000. While that CPU has a lot of great features, by 1992, the writing was on the wall that the Intel silicon would win.

Perhaps the biggest issue, though, was the graphics system. The original Amiga outclassed nearly everything at the time. But, again, the industry was moving fast. The 600 wasn’t that impressive compared to a VGA. And, as [Dave] points out, it couldn’t run DOOM.

There’s more to the post. Be sure to check it out. It is a great look into the history of the last of a great line of machines. Maybe if Commodore had embraced PC interfaces, but we’ll never know. [Dave’s] take on the end of the Amiga echos others we’ve read. It wasn’t exactly Doom that killed the Amiga. It was more complicated than that. But Doom would have helped.

If you think of old recording technology, you probably think of magnetic tape, either in some kind of cassette or, maybe, on reels. But there’s an even older technology that recorded voice on hair-thin stainless steel wire and [Mr. Carlson] happened upon a recorded reel of wire. Can he extract the audio from it? Of course! You can see and hear the results in the video below.

It didn’t hurt that he had several junk wire recorders handy, although he thought none were working. It was still a good place to start since the heads and the feed are unusual to wire recorders. Since the recorder needed a little work, we also got a nice teardown of that old device. The machine was missing belts, but some rubber bands filled in for a short-term fix.

The tape head has to move to keep the wire spooled properly, and even with no audio, it is fun to watch the mechanism spin both reels and move up and down. But after probing the internal pieces, it turns out there actually was some audio, it just wasn’t making it to the speakers.

The audio was noisy and not the best reproduction, but not bad for a broken recorder that is probably at least 80 years old. We hope he takes the time to fully fix the old beast later, but for now, he did manage to hear what was “on the wire,” even though that has a totally different meaning than it usually does.

It is difficult to recover wire recordings, just as it will be difficult to read modern media one day. If you want to dive deep into the technology, we can help with that, too.

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.

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.

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.

[Project 326] has a cheap thermal camera that plugs into a smart phone. Sure they are handy, but what if you could hack one into a microscope with a resolution measured in microns? It is easier than you might think and you can see how in the video below.

Of course, microscopes need lenses, but glass doesn’t usually pass IR very well. This calls for lenses made of exotic material like germanium. One germanium lens gives some magnification. However, using a 3D printed holder, three lenses are in play, and the results are impressive.

The resolution is good enough to see the turns of wire in an incandescent light bulb. A decapsulated power transistor was interesting to view, too. Imaging heat at that much resolution gives you a lot of information. At the end, he teases that using first surface mirrors, he may show how to build an IR telescope as well.

Presumably, this will work with just about any IR camera if you adapt the lens holder. The unit in the video is a UNI-T UTi-260M. So when he says he spent about $35 on the build, that’s not including the $400 or so camera module.

IR imaging can pull off some amazing tricks, like looking inside an IC. If the thermal camera used in the video isn’t to your liking, there are plenty of others out there.

[Tech Minds] built one of those cheap automatic antenna tuners you see everywhere — this one scaled up to 350 watt capability. The kit is mostly built, but you do have to add the connectors and a few other stray bits. You can see how he did it in the video below.

What was very interesting, however, was that it wasn’t able to do a very good job tuning a wire antenna across the ham bands, and he asks for your help on what he should try to make things better.

It did seem to work in some cases, and changing the length of the wire changed the results, so we would guess some of it might be a resonance on the antenna wire. However, you would guess it could do a little better. It is well known that if a wire is one of a number of certain lengths, it will have extremely high impedence in multiple ham bands and be challenging to tune. So random wires need to not be exactly random. You have to avoid those lengths.

In addition, we were surprised there wasn’t more RF protection on the power lines. We would probably have suggested winding some coax to act as a shield choke, RF beads, and even extra bypass capacitors.

Another possible problem is that the diodes in these units are often not the best. [PU1OWL] talks about that in another video and bypasses some of the power lines against RF, too.

If you have any advice, we are sure he’d love to hear it. As [PU1OWL] points out, a tuner like this can’t be any better than its SWR measurement mechanism. Of course, all of these tuners take a few watts to light them up. You can, however, tune with virtually no power with a VNA.

Science fiction authors and readers dream of travelling at the speed of light, but Einstein tells us we can’t. You might think that’s an arbitrary rule, but [FloatHeadPhysics] shows a different way to think about it. Based on a book he’s been reading, “Relativity Visualized,” he provides a graphic argument for relativity that you can see in the video below.

The argument starts off by explaining how a three-dimensional object might appear in a two-dimensional world. In this world, everything is climbing in the hidden height dimension at the exact same speed.

Our 2D friends, of course, can only see the shadow of the 3D object so if it is staying in one place on the table surface, the object never seems to move. However, just as we can measure time with a clock, the flat beings could devise a way to measure height. They would see that the object was moving “through height” at the fixed speed.

Now suppose the object turns a bit and is moving at, say, a 45 degree angle relative to the table top. Now the shadow moves and the “clock speed” measuring the height starts moving more slowly. If the object moves totally parallel to the surface, the shadow moves at the fixed speed and the clock speed shadow doesn’t move at all.

This neatly explains time dilation and length contraction. It also shows that the speed of light isn’t necessarily a rule. It is simply that everything in the observable universe is moving at the speed of light and how moving through space affects it.

Doesn’t make sense? Watch the video and it will. Pretty heady stuff. We love how passionate [FloatHeadPhysics] gets about the topic. If you prefer a funnier approach, turn to the BBC. Or, if you like the hands-on approach, build a cloud chamber and measure some muons.

If you’ve ever been configuring a router or other network device and noticed that you can set up IPv4 and IPv6, you might have wondered what happened to IPv5. Well, thanks to [Navek], you don’t have to wonder anymore. Just watch the video below.

We will warn you of two things. First, the video takes a long time to get around to what IPv5 was. In addition, if you keep reading, there will be spoilers.

The first part of the video covers the general differences between IPv4 and IPv6, especially surrounding addressing. Then, it talks about how IP alone can’t do things you like to do for handling things like voice. For example, the IP layer doesn’t understand how much bandwidth exists between two points. It is only concerned with moving data from one point to another point.

To foster voice communications, there was a proposal for something called the stream protocol. It didn’t catch on. In fact, it was reincarnated as a proposal to move video, too, but it still didn’t catch on. However, the network header used the next number in sequence, which was… five!

So, really, the video title is a bit of a red herring. You didn’t forget IPv5; there simply was never an IPv5. There is, however, network protocol #5, which has little to do with IP and never caught on.

Still, an interesting walk down memory lane to a time when moving voice and video over the network was exotic high-tech. We love diving into the old network stuff like finger and UUCP.

You’ve doubtless seen those ubiquitous clock modules, especially when setting clocks for daylight savings time. You know the ones: a single AA battery, a wheel to set the time, and two or three hands to show the time. They are cheap and work well enough. But [Playful Technology] wanted to control the hands with an Arduino directly and, in the process, he shows us how these modules work.

If you’ve never studied the inside of these clock modules, you may be surprised about how they actually work. A crystal oscillator pulses a relatively large electromagnet. A small plastic gear has a magnetic ring and sits near the electromagnet.

Each time the polarity of the electromagnet flips, the ring turns 180 degrees to face the opposite magnetic pole to the electromagnet. This turns the attached gear which is meshed with other gears to divide the rotation rate down to once per 24 hours, once per hour, and once per minute. Pretty clever.

That makes it easy to control the hands. You simply detach the electromagnet from the rest of the circuit and control it yourself. The module he used had a mechanical limitation that prevents the hands from moving well at more than about 100 times normal speed.

We wondered how he made the hands reverse and, apparently, there is a way to get the drive gear to move in reverse, but it isn’t always reliable. Of course, you could also replace the drive mechanism with something like an RC servo or other motor and it sounds like he has done this and plans to show it off in another video.

We’ve seen the opposite trick before, too. If you really want an easy-to-control analog clock, try this one