Core memory, magnetized memory using tiny magnetic rings suspended on a grid of wires, is now more than five decades obsolete, yet it exerts a fascination for hardware hackers still. Not least [Andy Geppert], who’s made a nibble, four bits of it, complete with interactive LED illumination to show state. Best of all, it’s on a badge Simple Add-On (SAO) for fun and games at your next hacker con.

Aside from it being a fun project, perhaps the most interesting part comes in the GitHub repository, where can be found the schematic for the device. He’s built all the drive and sense circuitry himself rather than finding an old-stock core memory driver chip, which gives those of us who’ve never worked with this stuff the chance to understand how it works. Beyond that it takes input from the Stemma or SAO ports to a GPIO expander, which provides all the lines necessary to drive it all.

To show it in action he’s posted a video which we’ve placed below. If you’re hungry for more, it’s not [Andy]’s first outing into core memory.

For all the advances in digital photography, there remains a mystique for photographers and filmmakers about chemical film. Using it presents an artistic and technical challenge, and it lends an aesthetic to your work which is difficult to find in other ways. But particularly when it comes to moving pictures, how many of us have ever ventured beyond the Super 8 cartridge? If you’re not lucky enough to have a Spielberg budget, [Stand-Up Maths] is here with a video taking the viewer through the various movie film formats. He claims it’s the first video shot for YouTube in 35mm, and given that his first point is about the costs involved, we can see why.

In particular it serves as an introduction to the various film terms and aspect ratios. We all know what full frame and IMAX are, but do many of us know what they really mean in camera terms. A particularly neat demonstration comes when he has two cameras side by side with the same stock as a split screen, one 35mm and the other 16mm. The cheaper smaller framed format is good quality, but using a profession resolution chart you can see some of the differences clearly. The full film is below the break, and we’d suggest you watch it in the full 4K resolution if you are able to.

Meanwhile, some of us have been known to dabble in 8mm film, and even sometimes shoot footage with it.

Thanks [Jurjen] for the tip.

If you follow the world of clean energy, you will probably have read all about the so-called hydrogen future and the hydrogen economy. The gas can easily be made from water by electrolysis from green solar electricity, contains a lot of stored energy which is clean to recover, and seems like the solution to many of our green energy woes. Sadly the reality doesn’t quite match up as hydrogen is difficult to store and transport, so thus far our hydrogen cars haven’t quite arrived. That hasn’t stopped researchers looking at hydrogen solutions though, and a team from ETH Zurich might just have found a solution to storing hydrogen. They’re using it to reduce iron oxide to iron, which can easily release the hydrogen by oxidation with water.

Their reactor is simplicity itself, a large stainless steel tank filled with powdered iron ore. Pump hydrogen into it and the iron oxide in the ore becomes water and iron which forms the storage medium, and retrieve the hydrogen later by piping steam through the mixture. Hydrogen generated in the summer using solar power can then be released in the winter months. Of course it’s not perfectly efficient, and a significant quantity of energy is lost in heat, but if the heat is recovered and used elsewhere that effect can be mitigated. The hope is that their university might be benefiting from a pilot plant in the coming years, and then perhaps elsewhere those hydrogen grids and cars might become a reality. We can hope.

Meanwhile, in the past we’ve looked at a not quite so green plan for a hydrogen grid.

For almost as long as there have been microcomputers, there have been attempts with varying success to make tiny handheld microcomputers. Sometimes these have been very good, and other times they’ve missed the mark in some way. Latest to find its way to us is the CL-32 from [Moosepr], it’s a handheld computer with an ESP32 as brains, an electronic paper display, and a QWERTY keyboard in its smart printed case.

The hardware is relatively standard, save for the keyboard which is a dome-switch design in which the membrane carrying the domes is hand-made. We like this, and don’t think we’ve seen anyone else doing that. Expansion is taken care of by a novel socket arrangement in which boards nestle in a recess in the surface. Some experimentation was required as always to drive the display, but the result is a functional computer.

Sadly there’s little detail in terms of what the software will be, and no hardware files as yet. But what we can see is promising enough to make this one to watch, so we’ll look forward to what they come up with. If an ESP32 OS is a problem, there’s always badge.team, who have been continuously improving theirs since 2017.

We’re guessing most readers can cite things from their youth which gave them an interest in technology, and spurred on something which became a career or had a profound impact on their life. Public engagement activities for technology or science have a crucial role in bringing forth the next generations of curious people into those fields, and along the way they can provide some fun for grown-ups too.

A case in point is from NASA’s Landsat engagement team, Your Name In Landsat. Type in a text string, and it will spell it out in Earth features seen by the imaging satellites, that resemble letters. Endless fun can be had by all, as the random geology flashes by.

In itself, though fun, it’s not quite a hack. But behind the kids toy we’re curious as to how the images were identified, and mildly sad that the NASA PR people haven’t seen fit to tell us. We’re guessing that over the many decades of earth images there exists a significant knowledge base of Earth features with meaningful or just amusing shapes that will have been gathered by fun-loving engineers, and it’s possible that this is what informed this feature. But we’d also be curious to know whether they used an image classification algorithm instead. There must be a NASA employee or two who reads Hackaday and could ask around — let us know in the comments.

Meanwhile, if LANDSAT interests you, it’s possible to pull out of the air for free.

Switch-mode technology has made inverters which take a low DC voltage and turn it into a usable mains voltage within the reach of everybody. But still, there might be moments when a mains supply is needed and you’re not lucky enough to have AliExpress at your fingertips, and for that, here’s [Rulof] with a mains inverter that is simultaneously awful and awesome. He’s made a rotary converter, from trash and off the shelf parts.

While a switch-mode converter operates using PWM at many times the output frequency for efficiency, we’re guessing that most readers will be familiar enough with how AC works to see how a low frequency converter turns DC into AC. A set of switches repeatedly flip the polarity, and the resulting square wave is fed into a transformer to step up to the final voltage. The switches can be mechanical as with old-style converters that used vibrating reeds or rotary armatures, or they can be electronic using power transistors. In this case they are a set of microswitches actuated by a set of cams on a shaft driven by a small motor, and the transformer comes from a surplus UPS.

We’re guessing that the frequency will be only a few Hz and the microswitches will suffer from switching such an inductive load, but as you can see in the video below the break it does light a mains bulb, and we’re guessing it would be enough to activate most wall-wart switching power supplies. We’re not so sure though about his use of the IEC sockets from the UPS to carry 12 volts, as the current may be a little much for them.

Meanwhile if you thirst for more of this kind of thing, we have you covered.

Beyond the power variant, it sometimes seems as though we rarely encounter a discrete transistor these days, such has been the advance of integrated electronics. But they have a rich history, going back through the silicon era to germanium junction transistors, and thence to the original devices. if you’ve ever looked at the symbol for a transistor and wondered what it represents, it’s a picture of those earliest transistors, which were point contact devices. A piece of germanium as the base had two metal electrodes touching it as the emitter or collector, and as [Marcin Marciniak] shows us, you can make one yourself (Polish language, Google Translate link).

These home made transistors sacrifice a point contact diode to get the small chip of germanium, and form the other two electrodes with metal foil glued to paper. Given that germanium point contact diodes are themselves a rarity these days we’re guessing that some of you will be wincing at that. The video below is in Polish so you’ll have to enable YouTube’s translation if you’re an Anglophone — but we understand that the contact has to be made by passing a current through it, and is then secured with a drop of beeswax.

A slight surprise comes in how point contact transistors are used, unlike today’s devices their gain in common emitter mode was so poor that they took instead a common base configuration. There’s a picture of a project using three of them, a very period radio receiver with bulky transformers between all stages.

If you’re interested in more tales of home made early transistors, read our feature on Rufus Turner.

Thanks [Dr.Q.] for the tip.

The 8-bit home computers of yore that we all know and love, without exception as far as we are aware, had an off the shelf microprocessor at heart. In 1983 you were either in the Z80 camp or the 6502 camp, with only a relatively few outliers using processors with other architectures.

But what if you could have both at once, without resorting to a machine such as the Commodore 128 with both on board? How about a machine with retargetable microcode? No, not the DEC Alpha, but the Isetta from [RoelH]— a novel and extremely clever machine based upon 74-series logic, than can not only be a 6502 or a Z80, but can also run both ZX Spectrum games, and Apple 1 BASIC. We would have done anything to own one of these back in 1983.

If retargetable microcode is new to you, imagine the instruction set of a microprocessor. If you take a look at the die you’ll find what is in effect a ROM on board, a look-up table defining what each instruction does. A machine with said capability can change this ROM, and not merely emulate a different instruction set, but be that instruction set. This is the Isetta’s trick, it’s not a machine with a novel RISC architecture like the Gigatron, but a fairy conventional one for the day with the ability to select different microcode ROMs.

It’s a beautifully designed circuit if you’re a lover of 74 logic, and it’s implemented in all surface mount on a surprisingly compact PCB. The interfaces are relatively modern too, with VGA and a PS/2 keyboard. The write-up is comprehensive and easy to understand, and we certainly enjoyed digging through it to understand this remarkable machine. We were lucky enough to see an Isetta prototype in the flesh over the summer, and we really hope he thinks about making a product from it, we know a lot of you would be interested.

Making microcontrollers produce video has long been a staple of hardware hacking, but as the resolution goes up, it becomes a struggle for less capable silicon. To get higher resolution VGA from an Arduino, [Marcin Chwedczuk] has produced perhaps the most bulletproof solution, to create dual-port RAM with the help of a static RAM chip and a set of 74-series bus transceivers, and let a hardware VGA interface take care of the display. Yes, it’s not a microcontroller doing VGA, but standalone VGA for microcontrollers.

Dual-port memory is a special type of memory with two interfaces than can independently be used to access the contents. It’s not cheap when bought in integrated form, so seeing someone making a substitute with off-the-shelf parts is certainly worth a second look. The bus transceivers are in effect bus-width latches, and each one hangs on to the state while the RAM chip services each in turn. The video card part is relatively straightforward, a set of 74 chips which produce the timings and step through the addresses, and a shift register to push out simple black or white pixel data as a rudimentary video stream. We remember these types of circuits being used back in the days of home made video terminals, and here in 2024 they still work fine.

The display this thing produces isn’t the most impressive picture, but it is VGA, and it does work. We can see this circuit being of interest to plenty of other projects having less capable processing power, in fact we’d say the challenge should lie in how low you can go if all you need is the capacity to talk 74-series logic levels.

Interested in 74-series VGA cards? This isn’t the first we’ve seen.

There’s a joke in the world of radio that all you need for a HF antenna is a piece of wet string, but the truth is that rudimentary antennas rarely perform well. Random pieces of wire may pull in some signal, but along with it comes a ton of unwanted interference and noise. It’s thus worth putting in the effort to make a better antenna, and if you’re not fortunate enough to have a lot of space, your best choice may be a magnetic loop. [Robert Hart] takes us through the design of a receive-only coaxial loop. It’s referred to as a Moebius loop because the conductor takes a “twist” path between the inner and outer halfway around.

The idea of a loop antenna is simple enough. It’s an inductor intended to respond to the magnetic portion of the wave rather than the electric part. They’re normally made of a single turn of wire in a loop of diameter well below half a wavelength, and, in their transmitting versions, they are often tuned to resonance by an air-spaced variable capacitor. Coaxial loops like this one provide enhanced resistance to electrical noise. He’s using some rather expensive Andrews coax for its rigidity, but the less well-heeled can use cheaper stuff without penalty. The result, when put on a frame of PVC pipe and a speaker stand, is an excellent portable receiving antenna, and if we’re being honest, something we might also consider in our own shack.

This isn’t by any means the first magnetic loop we’ve brought you. Have a look at this cleverly concealed one. We recently looked at the YouLoop, a similar Moebius loop antenna.

Through all the generations of computing devices from the era of the teleprinter to the present day, there’s one interface that’s remained universal. Even though its usefulness as an everyday port has decreased in the face of much faster competition, it’s fair to say that everything has a serial port on board somewhere. Even with that ubiquity though, there’s still some scope for variation.

Older ports and those that are still exposed via a D socket are in most case the so-called RS-232, a higher voltage port, while your microcontroller debug port will be so-called TTL (transistor-transistor logic), operating at logic level. That’s not quite always the case though, as [Terin Stock] found out with an older Garmin GPS unit.

Pleasingly for a three decade old device, given a fresh set of batteries it worked. The time was wrong, but after some fiddling and a Windows 98 machine spun up it applied a Garmin update from 1999 that fixed it. When hooked up to a Flipper Zero though, and after a mild panic about voltage levels, the serial port appeared to deliver garbage. There followed some investigation, with an interesting conclusion that TTL serial is usually the inverse of RS-232 serial, The Garmin had the RS-232 polarity with TTL levels, allowing it to work with many PC serial ports. A quick application of an inverter fixed the problem, and now Garmin and Flipper talk happily.

The laptop to have here in the 2020s varies depending on who you ask, perhaps a Framework, or maybe a ThinkPad. Back in the 1990s the answer might have included a now-forgotten contender, because in that decade Toshiba made a range of legendarily tough chunky grey machines. Of these the smallest was the Libretto, a paperback book sized clamshell design which was an object of desire. It’s one of these that [Robert’s Retro] has upgraded to use USB-C power instead of the original power brick.

The full video is below the break, and while it first deals with replacing a defective screen, the power part starts just before 22 minutes in. As you’d expect it involves a USP-C PD trigger board, this time at 15 volts. It’s mounted in a small 3D printed adapter to fill the space of the original jack, and requires a tiny notch be removed from the corner of its PCB to fit round the motherboard. The rest of the video deals with reassembling the machine and tending to mishaps with the ageing plastic, but the result is a Libretto with a modern charging port.

Naturally a machine with a Pentium CPU and 32 megabytes of RAM is in of limited use in modern terms, but these Librettos remain very well-designed tiny PCs to this day. It’s great to see them still being modified and upgraded, even if perhaps there’s a limit to how far you can push their computing power. We’ve encountered the Libretto before a few times, such as when one was used to retrieve data from an old Flash card.

There may not be many radio astronomy printouts that have achieved universal fame, but the one from Ohio State University’s Big Ear telescope upon which astronomer [Jerry R. Ehman] wrote “WOW!” is definitely one of them. It showed an intense one-off burst that defied attempts to find others like it, prompting those who want to believe to speculate that it might have been the product of an extraterrestrial civilization. Sadly for them the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo has provided an explanation by examining historical data from the Arecibo telescope.

The radio signal in question lay on the hydrogen line frequency at 1420 MHz, and by looking at weaker emissions from cold hydrogen clouds they suggest that the WOW! signal may have come from a very unusual stimulation of one of these clouds. A magnetar is a type of neutron star which can create an intense magnetic field, and their suggestion is that Big Ear was in the lucky position of being in the right place at the right time to see one of these through a hydrogen cloud. The field would excite the hydrogen atoms to maser-like emission of radiation, leading to the unexpected blip on that printout.

There’s a question as to whether speculation about aliens is helpful to the cause of science, but in answer to that we’d like to remind readers that we wouldn’t be talking about magnetars now without it, and that the WOW! signal was in fact part of an early SETI experiment. Better keep on searching then!

Meanwhile readers with long memories will recollect us looking at the WOW! signal before.

The new Raspberry Pi Pico 2 with its RP2350 microcontroller has only been with us for a short time, and thus its capabilities are still being tested. One of the new peripherals is HSTX, for which the description “High speed serial port” does not adequately describe how far it is from the humble UART which the name might suggest. CNX Software have taken a look at its capabilities, and it’s worth a read.

With a 150 MHz clock and 8 available pins, it’s a serial output with a combined bandwidth of 2400 Mbps, which immediately leaves all manner of potential for streamed outputs. On the RP2040 for example a DVI output was made using the PIO peripherals, while here the example code shows how to use these pins instead. We’re guessing it will be exploited for all manner of pseudo-analogue awesomeness in the manner we’re used to with the I2S peripherals on the EP32. Of course, there’s no corresponding input, but that still leaves plenty of potential.

Have a quick read of our launch coverage of the RP2350, and the Pico 2 board it’s part of.

A feature of many modern network-connected entertainment devices is that they will play streamed music while on standby mode. This so-called “network standby”is very useful if you fancy some gentle music but don’t want the Christmas lights or the TV. It was a feature [Caramelfur] missed on their Sony AV receiver, something especially annoying because it’s present on the US-market equivalent of their European model. Some gentle hackery ensued, and now the rece3iver follows its American cousin.

A first examination of the firmware found the two downloads to be identical, so whatever differences had to be in some form of configuration. Investigating what it exposed to the network led to a web server with device configuration parameters. Some probing behind the scenes and a bit of lucky guesswork identified the endpoint to turn on network standby, and there it was, the same as the US market model. Should you need it, the tooling is in a GitHub repository.

This isn’t the first time we’ve seen identical hardware being shipped with different firmwares in Europe from that in the USA, perhaps our most egregious example was a Motorola phone with a much earlier Android version for Europeans. We don’t understand why manufacturers do it, in particular with such an innocuous feature as network standby. If you have a Sony receiver you can now fix it, but you shouldn’t have to.

RJ45, Devcore, CC0.

When we think of fishing rods, the image brought to mind is one of a tweed-clad fisherman in his waders in a wild salmon stream, his line whipping about as it guides the fly over the surface of the water. Angling is a pursuit with a heritage, and having a lengthy rod seems an essential for its enjoyment. But perhaps your tackle needn’t be such an important factor, and in that spirit here’s [3dcreation] with a tiny but fully functional 3D printed fishing rod.

If you’ve ever seen a fisherman working through a hole in the ice, you may have some idea of the type of rod in question, it’s a stubby affair half handle and half rod, with a rudimentary reel in the middle. In the pictures it’s loaded up with line, weight ready to go, so we can see how it’s supposed to work. We’re not anglers here though, so the question of whether it would indeed work is one for your imagination.

Perhaps surprisingly, few anglers find their way onto these pages. One of the few that has, used a drone.

Some time over a year ago, we told you about a camera. Not just any camera, but a fully-functional 35mm film camera made entirely of LEGO, and with a pleasingly retro design into the bargain. It’s the work of [Zung92], and it can be found on the LEGO Ideas website.

You might now be asking why we’re talking about it again so soon, and the answer comes in its approaching the deadline for being considered by LEGO for a set. Projects on the Ideas website move forward when they achieve 10,000 supporters, and this one’s just shy of 8,000 with a month to go. We like this project and we think it deserves to see the light of day, and perhaps with your help it can.

When we covered this project last time we lamented the lack of technical detail, so we’re pleased to see a glimpse inside it as part of a manual uploaded to the updates page. We’d be the first to remark that with its LEGO part plastic lens and quarter-frame pictures it won’t be the best camera ever, but that’s hardly the point. Cameras like this one are a challenge, and it seems as though this one is perfect for the competition with a difference.

The decline of AM broadcast radio is a slow but inexorable process over much of the world, but for regions outside America there’s another parallel story happening a few hundred kilohertz further down the spectrum. The long wave band sits around the 200kHz mark and has traditionally carried national-level programming due to its increased range. Like AM it’s in decline due to competition from FM, digital, and online services, and one by one the stations that once crowded this band are going quiet. In the middle of all this it’s a surprise then to find a new long wave station in the works in the 2020s, bucking all contemporary broadcasting trends. Arctic 252 is based in Finland with programming intended to be heard across the Arctic region and aims to start testing in September.

The hack in this is that it provides an opportunity for some low-frequency DXing, and given the arctic location, it would be extremely interesting to hear how far it reaches over the top of the world into the northern part of North America. The 252KHz frequency is shared with a station in North Africa that may hinder reception for some Europeans, but those with long memories in north-west Europe will find it fairly empty as it has been vacated in that region by the Irish transmitter which used to use it.

So if you have a receiver capable of catching long wave and you think you might be in range, give it a listen. Closer to where this article is being written, long wave stations are being turned off.

Harris & Ewing, photographer, Public domain.

There are many forms of human interface device beyond the ubiquitous keyboard and mouse, but when it comes to fine-tuning a linear setting such as a volume control there’s nothing quite like a knob. When it comes to peripherals it’s not the size that matters, as proven by  [Stefan Wagner] with the Tiny Knob. It’s a very small PCB with a rotary encoder and knob, an ATtiny85, a USB port, and not much else.

It uses the V-USB software implementation of USB HID, and should you have a need for a Tiny Knob of your own you can find all the files for it in a GitHub repository. There’s even a very professional-looking 3D-printed enclosure for the finishing touch. We like this project for its simplicity, and we think you might too.

Over the years we’ve brought you more than one knob, they appear to be a popular subject for experimentation. If you’re up for more, have a look at this one.