In the 1980s, there was a truly staggering amount of choice for a consumer looking to purchase a home computer. On the high end, something like an Apple Lisa, a business-class IBM PC, or a workstation from Sun Microsystems could easily range from $6,000 to $20,000 (not adjusted for inflation). For the time, these mind-blowing prices might have been worth the cost, but for those not willing to mortgage their homes for their computing needs, there were also some entry-level options. One of these was the Sinclair ZX-80, which was priced at an astounding $100, which caused RadioShack to have a bit of a panic and release this version of the TRS-80 computer to compete with it.

As [David] explains in his deep dive into this somewhat obscure machine, the TRS-80 MC-10 was a commercial failure, although not for want of features. It had a color display, a chicklet keyboard, and 4K of RAM, which were all things that the ZX-80 lacked.

Unfortunately, it also had a number of drawbacks compared to some of its other contemporaries that made consumers turn away. Other offerings by Commodore, Atari, Texas Instruments, and even RadioShack themselves were only marginally more expensive and had many more features, including larger memory and better storage and peripheral options, so most people chose these options instead.

The TRS-80 MC-10 is largely a relic of the saturated 80s home computer market. It’s drop in price to below $50, and the price competition between other PC manufacturers at the time was part of the reason for the video game crash of the 1980s, and even led to Steve Jobs getting fired from Apple. There’s not a huge retro scene for these machines either, although there is at least one game developer you can see in the video below from [Spriteworx]. If you want to experiment with some of the standard TRS-80 software, there are emulators that have everything you need.

Thanks to [Stephen] for the tip!

Ever since the invention of the microscope, humanity has gained access to the world of the incredibly small. Scientists discovered that creatures never known to exist before are alive in an uncountable number in spaces as small as the head of a pin. But the microscope unlocked some interesting forms of art as well. Not only could people view and photograph small objects with them, but in the mid-nineteenth century, various artists and scientists used them to shrink photographs themselves down into the world of the microscopic. This article goes into depth on how one man from this era invented the art form known as microphotography.

Compared to photomicroscopy, which uses a microscope or other similar optical device to take normal-sized photographs of incredibly small things, microphotography takes the reverse approach of taking pictures of normal-sized things and shrinking them down to small sizes. [John Benjamin Dancer] was the inventor of this method, which used optics to shrink an image to a small size. The pictures were developed onto photosensitive media just like normal-sized photographs. Not only were these unique pieces of art, which developed — no pun intended — into a large fad, but they also had plenty of other uses as well. For example, since the photographs weren’t at all obvious without a microscope, they found plenty of uses in espionage and erotica.

Although the uses for microphotography have declined in today’s digital world, there are still plenty of unique pieces of art around with these minuscule photographs, as well as a bustling collector culture around preserving some of the antique and historical microphotographs from before the turn of the century. There is also similar technology, like microfilm and microfiche, that were generally used to preserve data instead of creating art, although plenty of these are being converted to digital information storage now.

Although we might all fundamentally recognize that gaming consoles are just specialized computers, we generally treat them, culturally and physically, differently than we do desktops or laptops. But there was a time in the not-too-distant past where the line between home computer and video game console was a lot more blurred than it is today. Even before Microsoft entered the scene, companies like Atari and Commodore were building both types of computer, often with overlapping hardware and capabilities. But they weren’t the only games in town. This video takes a look at the Bally Home Computer System, which was a predecessor of many of the more recognized computers and gaming systems of the 80s.

At the time, Bally as a company was much more widely known in the pinball industry, but they seemed to have a bit of foresight that the computers used in arcades would eventually transition to the home in some way. The premise of this console was to essentially start out as a video game system that could expand into a much more full-featured computer with add-ons. In addition to game cartridges it came with a BASIC interpreter cartridge which could be used for programming. It was also based on the Z80 microprocessor which was used in other popular PCs of the time, so in theory it could have been a commercial success but it was never able to find itself at the top of the PC pack.

Although it maintains a bit of a cult following, it’s a limited system even by the standards of the day, as the video’s creator [Vintage Geek] demonstrates. The controllers are fairly cumbersome, and programming in BASIC is extremely tedious without a full keyboard available. But it did make clever use of the technology at the time even if it was never a commercial success. Its graphics capabilities were ahead of other competing systems and would inspire subsequent designs in later systems. It’s also not the last time that a video game system that was a commercial failure would develop a following lasting far longer than anyone would have predicted.

For whatever reason, certain pieces of technology can have a difficult time interacting with the physical world. Anyone who has ever used a printer or copier can attest to this, as can anyone whose robot vacuum failed to detect certain types of non-vacuumable waste in their path, making a simple problem much worse. Farm equipment often falls into this category as well, where often complex machinery needs an inordinate amount of maintenance and repair just to operate normally. Wood chippers specifically seem to always get jammed or not work at all, so [Homemade Inventions] took a shot at building one on their own.

To build this screw-based wood chipper, the first thing to fabricate is the screw mechanism itself. A number of circles of thick steel were cut out and then shaped into pieces resembling large lock washers. These were then installed on a shaft and welded end-to-end, creating the helical screw mechanism. With the “threads” of the screw sharpened it is placed into a cylinder with a port cut out to feed the wood into. Powering the screw is a 3 kW electric motor paired with a custom 7:1 gearbox, spinning the screw at around 200 rpm. With that, [Homemade Inventions] has been able to easily chip branches up to 5 centimeters thick, and theorizes that it could chip branches even thicker than that.

Of course, wood chippers are among the more dangerous tools that are easily available to anyone with enough money to buy one or enough skill to build one, along with chainsaws, angle grinders, and table saws, so make sure to take appropriate safety precautions when using or building any of these things. Of course, knowing the dangers of these tools have led to people attempting to make safer versions like this self-propelled chainsaw mill or the semi-controversial table saw safety standard.

Thanks to [Keith] for the tip!

Some of the largest objects in the night sky to view through a telescope are galaxies and supernova remnants, often many times larger in size than the moon but generally much less bright. Even so, they take up a mere fraction of the night sky, with even the largest planets in our solar system only taking up a few arcseconds and stars appearing as point sources. There are more things to look at in the sky than there are telescopes, regardless of size, so it might almost seem like an impossible task to see everything. Yet that’s what this new telescope in Chile aims to do.

The Vera C. Rubin Observatory plans to image the entire sky every few nights over a period lasting for ten years. This will allow astronomers to see the many ways the cosmos change with more data than has ever been available to them. The field of view of the telescope is about 3.5 degrees in diameter, so it needs to move often and quickly in order to take these images. At first glance the telescope looks like any other large, visible light telescope on the tops of the Andes, Mauna Kea, or the Canary Islands. But it has a huge motor to move it, as well as a large sensor which generates a 3200-megapixel image every 30 seconds.

In many ways the observatory’s telescope an imaging technology is only the first part of the project. A number of machine learning algorithms and other software solutions have been created to help astronomers sift through the huge amount of data the telescope is generating and find new irregularities in the data, from asteroids to supernovae. First light for the telescope was this month, June 2025, and some of the first images can be seen here. There have been a number of interesting astronomical observations underway lately even excluding the JWST. Take a look at this solar telescope which uses a new algorithm to take much higher resolution images than ever before.

For as versatile and inexpensive as switch-mode power supplies are at all kinds of different tasks, they’re not always the ideal choice for every DC-DC circuit. Although they can do almost any job in this arena, they tend to have high parts counts, higher complexity, and higher cost than some alternatives. [Jasper] set out to test some alternative linear chargers called low dropout regulators (LDOs) for small-scale charging of lithium ion capacitors against those more traditional switch-mode options.

The application here is specifically very small solar cells in outdoor applications, which are charging lithium ion capacitors instead of batteries. These capacitors have a number of benefits over batteries including a higher number of discharge-recharge cycles and a greater tolerance of temperature extremes, so they can be better off in outdoor installations like these. [Jasper]’s findings with using these generally hold that it’s a better value to install a slightly larger solar cell and use the LDO regulator rather than using a smaller cell and a more expensive switch-mode regulator. The key, though, is to size the LDO so that the voltage of the input is very close to the voltage of the output, which will minimize losses.

With unlimited time or money, good design can become less of an issue. In this case, however, saving a few percentage points in efficiency may not be worth the added cost and complexity of a slightly more efficient circuit, especially if the application will be scaled up for mass production. If switched mode really is required for some specific application, though, be sure to design one that’s not terribly noisy.

As humans we often think we have a pretty good handle on the basics of the way the world works, from an intuition about gravity good enough to let us walk around, play baseball, and land spacecraft on the moon, or an understanding of electricity good enough to build everything from indoor lighting to supercomputers. But zeroing in on any one phenomenon often shows a world full of mystery and surprise in an area we might think we would have fully understood by now. One such area is static electricity, and the way that it forms within certain materials shows that it can impart a kind of memory to them.

The video demonstrates a number of common ways of generating static electricity that most of us have experimented with in the past, whether on purpose or accidentally, from rubbing a balloon on one’s head and sticking it to the wall or accidentally shocking ourselves on a polyester blanket. It turns out that certain materials like these tend to charge themselves positively or negatively depending on what material they were rubbed against, but some researchers wondered what would happen if an object were rubbed against itself. It turns out that in this situation, small imperfections in the materials cause them to eventually self-order into a kind of hierarchy, and repeated charging of these otherwise identical objects only deepen this hierarchy over time essentially imparting a static electricity memory to them.

The effect of materials to gain or lose electrons in this way is known as the triboelectric effect, and there is an ordering of materials known as the triboelectric series that describes which materials are more likely to gain or lose electrons when brought into contact with other materials. The ability of some materials, like quartz in this experiment, to develop this memory is certainly an interesting consequence of an otherwise well-understood phenomenon, much like generating power for free from static electricity that’s always present within the atmosphere might surprise some as well.

The choice between hardware and software for electronics projects is generally a straighforward one. For simple tasks we might build dedicated hardware circuits out of discrete components for reliability and low cost, but for more complex tasks it could be easier and cheaper to program a general purpose microcontroller than to build the equivalent circuit in hardware. Every now and then we’ll see a project that blurs the lines between these two choices like this Pong game built entirely out of discrete components.

The project begins with a somewhat low-quality image of the original Pong circuit found online, which [atkelar] used to model the circuit in KiCad. Because the image wasn’t the highest resolution some guesses needed to be made, but it was enough to eventually produce a PCB and bill of material. From there [atkelar] could start piecing the circuit together, starting with the clock and eventually working through all the other components of the game, troubleshooting as he went. There were of course a few bugs to work out, as with any hardware project of this complexity, but in the end the bugs in the first PCB were found and used to create a second PCB with the issues solved.

With a wood, and metal case rounding out the build to showcase the circuit, nothing is left but to plug this in to a monitor and start playing this recreation of the first mass-produced video game ever made. Pong is a fairly popular build since, at least compared to modern games, it’s simple enough to build completely in hardware. This version from a few years ago goes even beyond [atkelar]’s integrated circuit design and instead built a recreation out of transistors and diodes directly.

Thanks to [irdc] for the tip!

The Portal games were revolutionary not only for their puzzle-based, narrative-driven gameplay, but also for their unique physics engine, which let players open portals anywhere and conserve momentum and direction through them. They’re widely regarded as some of the best video games ever made, but even beyond that they have some extra features that aren’t talked about as much. Namely, there are a number of level editors and mods that allow the in-game components to be used to build things like logic gates and computers, and this project goes even further by building a working NES emulator, all within Portal 2.

The main limitation here is that Portal 2 can only support a certain number of in-game objects without crashing, far lower than what would be needed to directly emulate NES hardware. The creator of the project, [PortalRunner], instead turned to Squirrel, the Portal 2 scripting language, and set about porting an existing NES emulator called smolnes to this scripting language. This is easier said than done, as everything in the code needs to be converted eight bits and then all of the pointers in smolnes need to be converted to use arrays, since Squirrel doesn’t support pointers at all. As can be easily imagined, this led to a number of bugs that needed to be sorted out before the game would run at all.

For those interested in code golfing, porting, or cross-compatibility, this project is a master class not only in the intricacies of the Portal 2 scripting language but in the way the NES behaves as well, not to mention the coding skill needed to recognize unique behaviors of the C language and the Squirrel scripting language. But eventually [PortalRunner] is able to get Super Mario Bros. running in Portal 2, albeit with low resolution and frame rate. Since we heard you like games within games, someone else put DOOM inside DOOM so you can DOOM while you DOOM.

Thanks to [Mahdi] for the tip!

Electric cars are everywhere these days, but what about boats? Looking to go green on the water, [NASAT] put together this impressively nimble boat propelled by a pair of brushless motors.

The boat itself has a completely custom-built hull, using plywood as a mold for the ultimate fiberglass body. It’s a catamaran-like shape that seems to allow it to get on plane fairly easily, increasing its ultimate speed compared to a displacement hull. It gets up to that speed with two electric motors totaling 4 kW, mated to a belt-driven drivetrain spinning a fairly standard prop. Power is provided by a large battery, and the solar panel at the top can provide not only shade for the operator, but 300 W to charge the battery when the motors are not being used.

With the finishing touches put on, the small single-seat boat effortlessly powers around the water with many of the same benefits of an electric car: low noise, low pollution, a quiet ride, and a surprisingly quick feel. Electrification has come for other boats as well, like this sailing catamaran converted to electric-only. Even some commercial boats have begun to take the plunge.

The advent of affordable computing over the last few decades has certainly been a boon for many people with disabilities, making it easier to access things like text-to-speech technology, automation, or mobility devices, and even going as far as making it easier to work in general by making remote work possible. Some things still lag behind, though, like user interfaces that don’t take the colorblind into account, or appliances that only use an audio cue to signal to their users. This doorbell, for example, is one such device and [ydiaeresis] is adding features to it to help their mother with some hearing issues.

The first thing up for this off-the-shelf remote doorbell is a “brain transplant” since the built-in microcontroller couldn’t be identified. There are only a few signals on this board though so an ATtiny412 made for a suitable replacement. A logic analyzer was able to decode the signals being fed to the original microcontroller, and with that the push of the doorbell can be programmed to do whatever one likes, including integrating it with home automation systems or other assistive technology. In [ydiaeresis]’s case there’s an existing LED lighting system that illuminates whenever the phone rings.

Although it would be nice if these inexpensive electronics came with the adaptive features everyone might need from them, it’s often not too hard to add it in as was the case with this set of digital calipers. To go even further, some other common technology can be used to help those with disabilities like this hoverboard modified to help those with mobility issues.

Thanks to [buttim] for the tip!

It’s sometimes easy to forget that the light in the sky is an actual star. With how reliable it is and how busy we tend to be as humans, we can take that incredible fact and stow it away and largely go on with our lives unaffected. But our star is the thing that gives everything on the planet life and energy and is important to understand. Humans don’t have a full understanding of it either; there are several unsolved mysteries in physics which revolve around the sun, the most famous of which is the coronal heating problem. To help further our understanding a number of scientific instruments have been devised to probe deeper into it, and this adaptive optics system just captures some of the most impressive images of it yet.

Adaptive optics systems are installed in terrestrial telescopes to help mitigate the distortion of incoming light caused by Earth’s atmosphere. They generally involve using a reference source to measure these distortions, and then make changes to the way the telescope gathers light, in this case by making rapid, slight changes to the telescope’s mirror. This system has been installed on the Goode Solar Telescope in California and has allowed scientists to view various solar phenomena with unprecedented clarity.

The adaptive optics system here has allowed researchers to improve the resolution from the 1000 km resolution of other solar telescopes down to nearly the theoretical limit of this telescope—63 km. With this kind of resolution the researchers hope that this clarity will help shine some light on some of the sun’s ongoing mysteries. Adaptive optics systems like this aren’t just used on terrestrial telescopes, either. This demonstration shows how the adaptive optics system works on the James Webb Space Telescope.

Thanks to [iliis] for the tip!

Since the tail end of World War II, humanity has struggled to deal with its newfound ability to harness the tremendous energy in the nucleus of the atom. Of course there have been some positive developments like nuclear power which can produce tremendous amounts of electricity without the greenhouse gas emissions of fossil fuels. But largely humanity decided to build a tremendous nuclear weapons arsenal instead, which has not only cause general consternation worldwide but caused specific problems for one scientist in particular.

[Steve Weintz] takes us through the tale of [Dr. John C. Clark] who was working with the Atomic Energy Commission in the United States and found himself first at a misfire of a nuclear weapons test in the early 1950s. As the person in charge of the explosive device, it was his responsibility to safely disarm the weapon after it failed to detonate. He would find himself again in this position a year later when a second nuclear device sat on the test pad after the command to detonate it was given. Armed with only a hacksaw and some test equipment he was eventually able to disarm both devices safely.

One note for how treacherous this work actually was, outside of the obvious: although there were safety devices on the bombs to ensure the nuclear explosion would only occur under specific situations, there were also high explosives on the bomb that might have exploded even without triggering the nuclear explosion following it. Nuclear bombs and nuclear power plants aren’t the only things that the atomic age ushered in, though. There have been some other unique developments as well, like the nuclear gardens of the mid 1900s.

In the early years of electrification, when electricity was beginning to shape the modern world, this new technology was being put to use in many more places than turning motors and providing lighting. Some things we can see as obvious missteps like electrified corsets marketed as health tonics or x-ray treatments for eye strain, but others ended up being fascinating bits of technology with interesting uses, many of which have been largely forgotten since. This 100-year-old musical instrument is squarely in the latter category, and this build brings the sound of it back to life.

The instrument was called the Luminaphone and was originally built by [Harry Grindell Matthews]. Of course, this was an age before transistors and many other things we take for grated, so it has some quirks that we might not otherwise expect from a musical instrument. The device generated sound by shining a series of lights through a perforated rotating disc at a selenium cell. The selenium cell was an early photoresistor, generating current corresponding to the amount of light falling on it. A keyboard activated different lights, shining on areas of the disc with different numbers of holes, causing differing sounds to be produced by the instrument.

The recreation was built by [Nick Bild] and uses a laser diode as a stand-in for the rotating disc, but since it can be modulated in a similar way the idea is that the photodiode used as a receiver would generate a similar sound. The recreation sounds a bit like a video game from the 8-bit era, but with no recordings or original Luminaphones surviving to the present day we may never know how accurate it is. There are some other electronic instruments still around today, though, and plenty of ways of DIY-ing their sound like this project which recreates the tonewheels of the classic Hammond organ.

For those motorcyclists looking to get a classic American-style cruiser, often the go-to brand is Harley-Davidson. However, these bikes not only have reputations for being stuck in the past, both in terms of design and culture, but they also tend to be extremely expensive—not only upfront, but in maintenance as well. If you want the style without all of that baggage, you might want to try out something like this custom motorcycle which not only looks the part, it reduces those costs by being built around a hand truck.

By the end of the project, though, the hand truck does not retain much of its original form or function. [Garage Avenger] has cut and welded it essentially into a custom frame for the diminutive motorcycle, while retaining much of its original look and feel. Keeping up with the costs savings aspect of this project, the four-stroke engine was free, although it did take some wrenching to get it running and integrated into the frame. A custom axle, a front end from another bike, a gas tank from an online retailer (that needed re-welding), and some wiring finishes out the build.

With a fresh paint job to match the original color of the hand truck, it’s off to the track. Of course it doesn’t have quite the performance of most street legal motorcycles, including some quirks with the handling and braking, but for the trails around [Garage Avenger]’s home it’s certainly a fun transportation mode he can add to his repertoire. If this is your first time seeing one of his projects, be sure to check out his other work including this drifting shopping cart and this turbine-powered sled.

To some, an operating system is a burden or waste of resources, like those working on embedded systems and other low-power applications. To others it’s necessary, abstracting away hardware so that higher-level programming can be done. For most people it’s perhaps not thought of at all. But for a few, the operating system is the most interesting piece of software running on a computer and if you’d like to investigate what makes this often overlooked aspect of computer science interesting, take a look at this course on operating systems from Cornell University.

The operating system itself is called Earth and Grass Operating System because it splits the functionality of the operating system into three separate parts. The Earth layer involves dealing with hardware, the Grass layer involves hardware-independent aspects, and a third application layer implements other key operating system features. It’s built for a RISC-V processor, since that instruction set is completely open source and transparent about what it’s doing. It’s also incredibly small, coming in at around 2000 lines of code. The course covers nine areas, with the first six being core operating system functions and the remaining three covering more advanced operating system concepts.

For understanding the intricacies and sometimes mysterious ways that operating systems work, a course like this can go a long way into unraveling those mysteries and developing a deeper understanding of how it brings the hardware to work for higher-level software. We actually featured this operating system two years ago, before this course was created, which covers this project for those who like to take a more self-directed approach, or simply want a lightweight OS for a RISC-V system.

The MP3 file type has been around for so long, and is supported by essentially all modern media software and hardware, that it might be surprising to some to learn that it’s actually a proprietary format. Developed in the late 80s and early 90s, it rose to prominence during the Napster/Limewire era of the early 00s and became the de facto standard for digital music, but not all computers in these eras could play this filetype. This includes the Amigas of the early 90s, with one rare exception: this unreleased successor to the A3000 with a DSP chip, which now also has the software to play back these digital tunes.

The AA3000, developed as a prototype by Amiga, was never released to the general public. Unlike the original A3000 this one would have included a digital signal processing chip from AT&T called the DSP3210 which would have greatly enhanced its audio capabilities. A few prototype boards did make it out into the hands of the public, and the retrocomputing scene has used them to develop replicas of these rare machines. [Wrangler] used one to then develop the software needed for the MPEG layer 2 and 3 decoder using this extra hardware, since the original Amiga 3000 was not powerful enough on its own to play these files back.

If you want to follow along with the community still developing for this platform there’s a form post with some more detail for this specific build (although you may need to translate from German). [Wrangler] additionally points out that there are some limitations with this implementation as well, so you likely won’t get Winamp-level performance with this system, but for the Amiga fans out there it’s an excellent expansion of this computer’s capabilities nonetheless.

Thanks to [Andy] for the tip!

Plenty of consumer goods, from passenger vehicles to toys to electronics, get tossed out prematurely for all kinds of reasons. Repairable damage, market trends, planned obsolescence, and bad design can all lead to an early sunset on something that might still have some useful life in it. This was certainly the case for a sound system that [Bill] found — despite a set of good speakers, the poor design of the hardware combined with some damage was enough for the owner to toss it. But [Bill] took up the challenge to get it back in working order again.

The main problem with this unit is that of design. It relies on a remote control to turn it on and operate everything, and if that breaks or is lost, the entire unit won’t even power on. Tracing the remote back to the control board reveals a 15-pin connector, and some other audio sleuths online have a few ways of using this port to control the system without the remote.

[Bill] found a few mistakes that needed to be corrected, and was eventually able to get an ESP8266 (and eventually an ESP32) to control the unit thanks largely to the fact that it communicates using a slightly modified I2C protocol.

There were a few pieces of physical damage to correct, too. First, the AC power cable had been cut off which was simple enough to replace, but [Bill] also found that a power connector inside the unit was loose as well. With that taken care of he has a perfectly functional and remarkably inexpensive sound system ready for movies or music. There are some other options available for getting a set of speakers blasting tunes again as well, like building the amplifier for them from scratch from the get-go.

Although there are some ferries and commercial boats that use a multi-hull design, the most recognizable catamarans by far are those used for sailing. They have a number of advantages over monohull boats including higher stability, shallower draft, more deck space, and often less drag. Of course, these advantages aren’t exclusive to sailboats, and plenty of motorized recreational craft are starting to take advantage of this style as well. It’s also fairly straightforward to remove the sails and add powered locomotion as well, as this electric catamaran demonstrates.

Not only is this catamaran electric, but it’s solar powered as well. With the mast removed, the solar panels can be fitted to a canopy which provides 600 watts of power as well as shade to both passengers. The solar panels charge two 12V 100ah LifePo4 batteries and run a pair of motors. That’s another benefit of using a sailing cat as an electric boat platform: the rudders can be removed and a pair of motors installed without any additional drilling in the hulls, and the boat can be steered with differential thrust, although this boat also makes allowances for pointing the motors in different directions as well. 

In addition to a highly polished electric drivetrain, the former sailboat adds some creature comforts as well, replacing the trampoline with a pair of seats and adding an electric hoist to raise and lower the canopy. As energy density goes up and costs come down for solar panels, more and more watercraft are taking advantage of this style of propulsion as well. In the past we’ve seen solar kayaks, solar houseboats, and custom-built catamarans (instead of conversions) as well.