First off, sometimes you just don’t need the speed. When you’re just blinking LEDs on a human timescale, the general-purpose Arduino functions are good enough. I’ve written loads of useful firmware that fits this description. When the timing requirements aren’t tight, slow as dirt can be fast enough.
But eventually you’ll want to build a project where the old slow-speed pin toggling just won’t cut it. Maybe it’s a large LED matrix, or maybe it’s a motor-control application where the loop time really matters. Or maybe it’s driving something like audio or video that just needs more bits per second. One way out is clever coding, maybe falling back to assembly language primitives, but I would claim that the right way is almost always to use the hardware peripherals that the chipmakers gave you.
For instance, in the end of the video linked above, the hacker wants to drive a large shift register string that’s lighting up an LED matrix. That’s exactly what SPI is for, and coming to this realization makes the project work with timing to spare, and in just a few lines of code. That is the way.
Which brings me to the double-edged sword that the Arduino’s abstraction creates. By abstracting away the chips’ hardware peripherals, it makes code more portable and certainly more accessible to beginners, who don’t want to learn about SPI and I2C and I2S and DMA just yet. But by hiding the inner workings of the chips in “user friendly” libraries, it blinds new users to the useful applications of these same hardware peripherals that clever chip-design engineers have poured their sweat and brains into making do just exactly what we need.
This isn’t really meant to be a rant against Arduino, though. Everyone has to start somewhere, and the abstractions are great for getting your feet wet. And because everything’s open source anyway, nothing stops you from digging deeper into the datasheet. You just have to know that you need to. And that’s why we write up videos like this every five years or so, to show the next crop of new hackers that there’s a lot to gain underneath the abstractions.
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The B&W Nautalis is, depending who you ask, either infamous or an icon of modern design. Want the look but don’t have a hundred grand to spare? [Every Project All at Once] has got aNautalis-inspired design on printablesyou can run off for pennies. He also provides a tutorial video (embedded below) so you can follow along with his design process and get build instructions.
The model was done in Blender, and is designed to contain a 3.5″ full-range driver by Dayton Audio — a considerable simplification from the array of woofers and tweeters in the original Nautalis. On the other hand, they cost considerably less than a car and have no production wait list. [Every Project All At Once] is apparently working on a matching woofer if that interests you, but unless he invests in a bigger printer it seems we can safely say that would require more assembly than this project.
Of course it would also be possible to copy B&W’s design directly, rather than print a loose inspiration of it as makers such as [Every Project All At Once] have done, but what’s the fun in that? It’s a much more interesting hack to take an idea and make it your own, as was done here, and then you can share the design without worrying about a luxury brand’s legal team.
The M.2 slot is usually used for solid-state storage devices. However, [bitluni] had another fun idea for how to use the interface. He built an M.2 compatible LED matrix that adds a little light to your motherboard.
[bitluni] built a web tool for sending images to the matrix.[bitluni] noted that the M.2 interface is remarkably flexible, able to offer everything from SATA connections to USB, PCI Express, and more. For this project, he elected to rely on PCI Express communication, using a WCH CH382 chip to translate from that interface to regular old serial communication.
He then hooked up the serial interface to a CH32V208 microcontroller, which was tasked with driving a 12×20 monochrome LED matrix. Even better, he was even able to set the microcontroller up to make it programmable upon first plugging it into a machine, thanks to its bootloader supporting serial programming out of the box. Some teething issues required rework and modification, but soon enough, [bitluni] had the LEDs blinking with the best of them. He then built a web-based drawing tool that could send artwork over serial direct to the matrix.
While most of us are using our M.2 slots for more traditional devices, it’s neat to see this build leverage them for another use. We could imagine displays like this becoming a neat little add-on to a blingy computer build for those with a slot or two to spare. Meanwhile, if you want to learn more about M.2, we’ve dived into the topic before.
When retro computing nostalgia meets modern wireless wizardry, you get a near-magical tap-to-load experience. It’ll turn your Commodore 64 into a console-like system, complete with physical game cards. Inspired by TapTo for MiSTer, this latest hack brings NFC magic to real hardware using the TeensyROM. It’s been out there for a while, but it might not have caught your attention as of yet. Developed by [Sensorium] and showcased by YouTuber [StatMat], this project is a tactile, techie love letter to the past.
At the heart of it is the TeensyROM cartridge, which – thanks to some clever firmware modding – now supports reading NFC tags. These are writable NTag215 cards storing the path to game files on the Teensy’s SD card. Tap a tag to the NFC reader, and the TeensyROM boots your game. No need to fumble with LOAD “*”,8,1. That’s not only cool, it’s convenient – especially for retro demo setups.
What truly sets this apart is the reintroduction of physical tokens. Each game lives on its own custom-designed card, styled after PC Engine HuCards or printed with holographic vinyl. It’s a tangible, collectible gimmick that echoes the golden days of floppies and cartridges – but with 2020s tech underneath. Watch it here.
Typically, when we think about forming metal parts, we think about beating them with hammers, or squeezing them with big hydraulic presses. But what if magnets could do the squeezing? As it turns out—Grumman Aerospace discovered they can, several decades ago! Even better, they summed up this technique in a great educational video which we’ve placed below the break.
The video concerns the development of the Grumman EMF Torque Tube. The parts are essentially tubes with gear-like fittings mounted in either end, which are fixed with electromagnetic forming techniques instead of riveting or crimping. Right away, we’re told the key benefits—torque tubes built this way are “stronger, lighter, and more fatigue resistant” than those built with conventional techniques. Grumman used these torque tubes in such famous aircraft as the F-14 Tomcat, highlighting their performance and reliability.
Before……and after. The part is formed and the coil is destroyed.
The video goes on to explain the basics of the EMF torque tube production process. A tube is placed inside a coil, with the end fitting then installed inside. A capacitor bank dumps current through the coil to generate a strong electromagnetic field. This field is opposed by a secondary field generated by eddy currents. The two forces result in an explosive force which drives the tube inwards, gripping into the grooves of the end fitting, and destroys the coil in the process. Grumman notes that it specifically optimized a grooving profile for bonding tubes with end fittings, which maximised the strength of these EMF-produced joints.
This tip was sent in by [irox]. The video itself was posted by [Greg Benoit], who notes his father Robert Benoit was intimately involved with the development of the technique. Indeed, it was useful enough that the technology was licensed to Boeing, generating many millions of dollars for Grumman.
We feature all kinds of machining and forming techniques here, but this sort of forming isn’t something we see a lot of around these parts. Still, we’re sure someone will be Kickstarting a home EMF forming machine before the end of next week.
This project submitted to the 2025 Pet Hacks Contest brings a bit of IoT to your finned friends. Aquassist is a fish feeder that is primarily 3D printed only requiring a servo and a microcontroller to give you remote control of feeding your fish.
The Aquassist consists of just six 3D-printed parts. At its core is an Archimedes screw, a mechanism that ensures consistent portions of fish food are dispensed into the fish tank. A small hopper on top holds the food, and to minimize the part count, all 3D-printed components are designed to be glued together.
The brains of the operation take place in a Wemos D1 mini, a compact ESP8266 board programed using the Arduino IDE. The feeding mechanism relies on an SG90 continuous rotation servo, which rotates the Archimedes screw to dispense food. Unlike standard servos, this model offers ample torque in a small package and can rotate continuously without hitting an angular limit.
The Aquassist is controlled via a web-based application accessible from any device. The D1 Mini connects to Firebase to check the feeding schedule or detect if the “Feed Now” button has been pressed. Users can set feeding times or trigger an immediate feeding through the app’s intuitive interface. Check out a video below to see the Aquassist in action, and check our our other entries into the 2025 Pet Hacks Contest.
[Dmytro] was able to lay his hands on a InfiRay T2S+ camera. It’s a capable thermal imaging unit that comes at a cheaper price than many of its rivals. [Dmytro] decided to pull it apart to see what makes it tick, and he discovered a few interesting things along the way.
Like so much modern hardware, pulling the case apart does require some spudging and levering. Once inside, though, it comes apart in a relatively straightforward manner. Once inside, [Dmytro] notes some similarities between this camera and the Flir Lepton, another affordable thermal camera on the market. He also finds a clone of the Cypress FX2LP chip, which is used for talking USB. There’s also an Gowin FPGA inside, with [Dmytro] suspecting the gateware onboard could be modified. If so, the camera may be a candidate for running open source firmware in future.
What bothered [Dmytro] about this camera, though, was the software. When used with an Android phone, the camera demands the use of a proprietary app with with questionable permissions. It can be used on a regular computer, where it appears as a standard webcam. However, in this mode, the camera fails to self-calibrate, and the images quickly become useless. [Dmytro] worked to hack around this, by figuring out a way to trigger calibrations and run the proper image corrections manually when using the camera without the smartphone app. He also explores techniques to improve the resolution of the thermal measurements made by the camera.
We’ve seen some other neat thermal camera hacks over the years. Video after the break.
Digital Rights Management (DRM) has been the bane of users since it was first introduced. Who remembers the battle it was getting Netflix running on Linux machines, or the literal legal fight over the DVD DRM decryption key? So the news from Signal, that DRM is finally being put to use to protect users is ironic.
The reason for this is Microsoft Recall — the AI powered feature that takes a snapshot of everything on the user’s desktop every few seconds. For whatever reason, you might want to exempt some windows from Recall’s memory window. It doesn’t speak well for Microsoft’s implementation that the easiest way for an application to opt out of the feature is to mark its window as containing DRM content. Signal, the private communications platform, is using this to hide from Recall and other screenshotting applications.
The Signal blogs warns that this may be just the start of agentic AI being rolled out with insufficient controls and permissions. The issue here isn’t the singularity or AI reaching sentience, it’s the same old security and privacy problems we’ve always had: Too much information being collected, data being shared without permission, and an untrusted actor having access to way more than it should.
Legacy Malware?
The last few stories we’ve covered about malicious code in open source repositories have featured how quickly the bad packages were caught. Then there’s this story about two-year-old malicious packages on NPM that are just now being found.
It may be that the reason these packages weren’t discovered until now, is that these packages aren’t looking to exfiltrate data, or steal bitcoin, or load other malware. Instead, these packages have a trigger date, and just sabotage the systems they’re installed on — sometimes in rather subtle ways. If a web application you were writing was experiencing intermittent failures, how long would it take you to suspect malware in one of your JavaScript libraries?
Where Are You Calling From?
Phone phreaking isn’t dead, it has just gone digital. One of the possibly apocryphal origins of phone phreaking was a toy bo’sun whistle in boxes of cereal, that just happened to play a 2600 Hz tone. More serious phreakers used more sophisticated, digital versions of the whistle, calling them blue boxes. In modern times, apparently, the equivalent of the blue box is a rooted Android phone. [Daniel Williams] has the story of playing with Voice over LTE (VoLTE) cell phone calls. A bug in the app he was using forced him to look at the raw network messages coming from O2 UK, his local carrier.
And those messages were weird. VoLTE is essentially using the Session Initiation Protocol (SIP) to handle cell phone calls as Voice over IP (VoIP) calls using the cellular data network. SIP is used in telephony all over the place, from desk phones to video conferencing solutions. SIP calls have headers that work to route the call, which can contain all sorts of metadata about the call. [Daniel] took a look at the SIP headers on a VoLTE call, and noticed some strange things. For one, the International Mobile Subscriber Identity (IMSI) and International Mobile Equipment Identity (IMEI) codes for both the sender and destination were available.
He also stumbled onto an interesting header, the Cellular-Network-Info header. This header encodes way too much data about the network the remote caller is connected to, including the exact tower being used. In an urban environment, that locates a cell phone to an area not much bigger than a city block. Together with leaking the IMSI and IMEI, this is a dangerous amount of information to leak to anyone on the network. [Daniel] attempted to report the issue to O2 in late March, and was met with complete silence. However, a mere two days after this write-up was published, on May 19th, O2 finally made contact, and confirmed that the issue had finally been resolved.
ARP Spoofing in Practice
TCP has an inherent security advantage, because it’s a stateful connection, it’s much harder to make a connection from a spoofed IP address. It’s harder, but it’s not impossible. One of the approaches that allows actual TCP connections from spoofed IPs is Address Resolution Protocol (ARP) poisoning. Ethernet switches don’t look at IP addresses, but instead route using MAC addresses. ARP is the protocol that distributes the MAC Address to IP mapping on the local network.
And like many protocols from early in the Internet’s history, ARP requests don’t include any cryptography and aren’t validated. Generally, whoever claims an IP address first wins, so the key is automating this process. And hence, enter NetImposter, a new tool specifically designed to automate this process, sending spoofed ARP packets, and establishing an “impossible” TCP connection.
Impossible RCE in SSH
Over two years ago, researchers at Qualsys discovered a pre-authentication double-free in OpenSSH server version 9.1. 9.2 was quickly released, and because none of the very major distributions had shipped 9.1 yet, what could have been a very nasty problem was patched pretty quietly. Because of the now-standard hardening features in modern Linux and BSD distributions, this vulnerability was thought to be impossible to actually leverage into Remote Code Execution (RCE).
If someone get a working OpenSSH exploit from this bug, I'm switching my main desktop to Windows 98 (this bug was discovered by a Windows 98 user who noticed sshd was crashing when trying to login to a Linux server!)
The bug was famously discovered by attempting to SSH into a modern Linux machine from a Windows 98 machine, and Tavis Ormandy claimed he would switch to Windows 98 on his main machine if someone did actually manage to exploit it for RCE. [Perri Adams] thought this was a hilarious challenge, and started working an exploit. Now we have good and bad news about this effort. [Perri] is pretty sure it is actually possible, to groom the heap and with enough attempts, overwrite an interesting pointer, and leak enough information in the process to overcome address randomization, and get RCE. The bad news is that the reward of dooming [Tavis] to a Windows 98 machine for a while wasn’t quite enough to be worth the pain of turning the work into a fully functional exploit.
But that’s where [Perri’s] OffensiveCon keynote took an AI turn. How well would any of the cutting-edge AIs do at finding, understanding, fixing, and exploiting this vulnerability? As you probably already guessed, the results were mixed. Two of the three AIs thought the function just didn’t have any memory management problems at all. Once informed of the problem, the models had more useful analysis of the code, but they still couldn’t produce any remotely useful code for exploitation. [Perri’s] takeaway is that AI systems are approaching the threshold of being useful for defensive programming work. Distilling what code is doing, helping in reverse engineering, and working as a smarter sort of spell checker are all wins for programmers and security researchers. But fortunately, we’re not anywhere close to a world where AI is developing and deploying exploitations.
The Foscam X5 security camera has a pair of buffer overflows, each of which can be leveraged to acieve arbitrary RCE. One of the proof-of-concepts has a very impressive use of a write-null-anywhere primitive to corrupt a return pointer, and jump into a ROP gadget. The concerning element of this disclosure is that the vendor has been completely unresponsive, and the vulnerabilities are still unaddressed.
Dutch research institute [AMOLF] shows off a small robot capable of walking, hopping, and swimming without any separate control system. The limbs synchronize thanks to the physical interplay between the robot’s design and its environment. There are some great videos on that project page, so be sure to check it out.
A kinked soft tube oscillates when supplied with continuous air.
Powered by a continuous stream of air blown into soft, kinked tubular limbs, the legs oscillate much like the eye-catching “tube man” many of us have seen by roadsides. At first it’s chaotic, but the movements rapidly synchronize into a meaningful rhythm that self-synchronizes and adapts. On land, the robot does a sort of hopping gait. In water, it becomes a paddling motion. The result in both cases is a fast little robot that does it all without any actual control system, relying on physics.
You can watch it in action in the video, embedded below. The full article“Physical synchronization of soft self-oscillating limbs for fast and autonomous locomotion” is also available.
Gait control is typically a nontrivial problem in robotics, but it doesn’t necessarily require a separate control system. Things like BEAM robotics and even the humble bristlebot demonstrate the ability for relatively complex behavior and locomotion to result from nothing more than the careful arrangement of otherwise simple elements.
It might be too soon to consider the innards of the old CRT monitor at the back of your closet to be something worth putting on display in your home or workshop. For that curio cabinet-worthy appeal, you need to look a bit further back. Say, about 150 years. Yes, that’ll do. A Crookes tube, the original electron beam-forming vacuum tube of glass, invented by Sir William Crookes et al. in the late 19th century, is what you need.
And a Crookes tube is what [Markus Bindhammer] found on AliExpress one day. He felt that piece of historic lab equipment was asking to be put on display in proper fashion. So he set to work crafting a wooden stand for it out of a repurposed candlestick, a nice piece of scrap oak, and some brass feet giving it that antique mad-scientist feel.
After connecting a high voltage generator and switch, the Crookes tube should have been all set, but nothing happened when it was powered up. It turned out that a capacitance issue was preventing the tube from springing to life. Wrapping the cathode end of the tube in aluminum foil, [Markus] formed what is effectively a Leyden jar, and that was the trick that kicked things into action.
As of this writing, there are no longer any Crookes tubes that we could find on AliExpress, so you’ll have to look elsewhere if you’re interested in showing off your own 19th century electron-streaming experiment. Check out the Crookes Radiometer for some more of Sir Williams Crookes’s science inside blown glass.
If you grew up with a beige Atari ST on your desk and a faint feeling of being left out once Doom dropped in 1993, brace yourself — the ST strikes back. Thanks to [indyjonas]’s incredible hack, the world now has a working port of DOOM for the Atari STe, and yes — it runs. It’s called STDOOM, and even though it needs a bit of acceleration or emulation to perform, it’s still an astonishing feat of retro-software necromancy.
[indyjonas] did more than just recompile and run: he stripped out chunks of PC-centric code, bent GCC to his will (cheers to Thorsten Otto’s port), and shoehorned Doom into a machine never meant to handle it. That brings us a version that runs on a stock machine with 4MB RAM, in native ST graphics modes, including a dithered 16-colour mode that looks way cooler than it should. The emotional punch? This is a love letter to the 13-year-old Jonas who watched Doom from the sidelines while his ST chugged along faithfully. A lot of us were that kid.
Sound is still missing, and original 8MHz hardware won’t give you fluid gameplay just yet — but hey, it’s a start. Want to dive in deeper? Read [indyjonas]’ thread on X.
Electrostatic droplet capture system installed on an HVAC condenser. (Credit: Infinite Cooling)
As a common feature with thermal power plants, cooling towers enable major water savings compared to straight through cooling methods. Even so, the big clouds of water vapor above them are a clear indication of how much cooling water is still effectively lost, with water vapor also having a negative impact on the environment. Using so-called plume abatement the amount of water vapor making it into the environment can be reduced, with recently a trial taking place at a French nuclear power plant.
This trial featured electrostatic droplet capture by US-based Infinite Cooling, which markets it as able to be retrofitted to existing cooling towers and similar systems, including the condensers of office HVAC systems. The basic principle as the name suggests involves capturing the droplets that form as the heated, saturated air leaves the cooling tower, in this case with an electrostatic charge. The captured droplets are then led to a reservoir from which it can be reused in the cooling system. This reduces both the visible plume and the amount of cooling water used.
In a 2021 review article by [Shuo Li] and [M.R. Flynn] in Environmental Fluid Mechanics the different approaches to plume abatement are looked at. Traditional plume abatement designs use parallel streams of air, with the goal being to have condensation commence as early as possible rather than after having been exhausted into the surrounding air. Some methods used a mesh cover to provide a surface to condense on, while a commercially available technology are condensing modules which use counterflow in an air-to-air heat exchanger.
Other commercial solutions include low-profile, forced-draft hybrid cooling towers, yet it seems that electrostatic droplet capture is a rather new addition here. With even purely passive systems already seeing ~10% recapturing of lost cooling water, these active methods may just be the ticket to significantly reduce cooling water needs without being forced to look at (expensive) dry cooling methods.
Top image: The French Chinon nuclear power plant with its low-profile, forced-draft cooling towers. (Credit: EDF/Marc Mourceau)
Typing can be difficult to learn at the best of times. Until you get the muscle memory down, it can be quite challenging. However, if you’ve had one or more fingers amputated, it can be even more difficult. Just reaching the keys properly can be a challenge. To help in this regard, [Roei Weiman] built some assistive typing tools for those looking for a little aid at the keyboard.
The devices were built for [Yoni], who works in tech and has two amputated fingers. [Roei] worked on many revisions to create a viable brace and extension device that would help [Yoni] type with greater accuracy and speed.
While [Roei] designed the parts for SLS 3D printing, it’s not mandatory—these can easily be produced on an FDM printer, too. For SLS users, nylon is recommended, while FDM printers will probably find best results with PETG. It may also be desirable to perform a silicone casting to add a grippier surface to some of the parts, a process we’ve explored previously.
The great thing about 3D printing is that it enables just about anyone to have a go at producing their own simple assistive aids like these. Files are on Instructables for the curious. Video after the break.
If you want a regular table saw, you’re probably best off just buying one—it’s hard to beat the economies of scale that benefit the major manufacturers. If you want a teeny one, though, you might like to build it yourself. [Maciej Nowak] has done just that.
The concept is simple enough; a small motor and a small blade make a small table saw. [Maciej] sourced a remarkably powerful 800-watt brushless motor for the build. From there, the project involved fabricating a suitable blade mount, belt drive, and frame for the tool. Some time was well-spent on the lathe producing the requisite components out of steel and aluminum, as well as a stout housing out of plywood. The motor was then fitted with a speed controller, with the slight inconvenience that it’s a hobby unit designed to run off DC batteries rather than a wall supply. Ultimately, though, this makes the saw nicely portable. All that was left to do was to fit the metal top plate, guides, and a suitably small 3″ saw blade to complete the build.
If we asked you to think of a device that converts a chemical reaction into electricity, you’d probably say we were thinking of a battery. That’s true, but there is another device that does this that is both very similar and very different from a battery: the fuel cell.
In a very simple way, you can think of a fuel cell as a battery that consumes the chemicals it uses and allows you to replace those chemicals so that, as long as you have fuel, you can have electricity. However, the truth is a little more complicated than that. Batteries are energy storage devices. They run out when the energy stored in the chemicals runs out. In fact, many batteries can take electricity and reverse the chemical reaction, in effect recharging them. Fuel cells react chemicals to produce electricity. No fuel, no electricity.
Superficially, the two devices seem very similar. Like batteries, fuel cells have an anode and a cathode. They also have an electrolyte, but its purpose isn’t the same as in a conventional battery. Typically, a catalyst causes fuel to oxidize, creating positively charged ions and electrons. These ions move from the anode to the cathode, and the electrons move from the anode, through an external circuit, and then to the cathode, so electric current occurs. As a byproduct, many fuel cells produce potentially useful byproducts like water. NASA has the animation below that shows how one type of cell works.
History
Sir William Grove seems to have made the first fuel cell in 1838, publishing in The London and Edinburgh Philosophical Magazine and Journal of Science. His fuel cell used dilute acid, copper sulphate, along with sheet metal and porcelain. Today, the phosphoric acid fuel cell is similar to Grove’s design.
The Bacon fuel cell is due to Francis Thomas Bacon and uses alkaline fuel. Modern versions of this are in use today by NASA and others. Although Bacon’s fuel cell could produce 5 kW, it was General Electric in 1955 that started creating larger units. GE chemists developed an ion exchange membrane that included a platinum catalyst. Named after the developers, the “Grubb-Niedrach” fuel cell flew in Gemini space capsules. By 1959, a fuel cell tractor prototype was running, as well as a welding machine powered by a Bacon cell.
One of the reasons spacecraft often use fuel cells is that many cells take hydrogen and oxygen as fuel and put out electricity and water. There are already gas tanks available, and you can always use water.
Types of Fuel Cells
Not all fuel cells use the same fuel or produce the same byproducts. At the anode, a catalyst ionizes the fuel, which produces a positive ion and a free electron. The electrolyte, often a membrane, can pass ions, but not the electrons. That way, the ions move towards the cathode, but the electrons have to find another way — through the load — to get to the cathode. When they meet again, a reaction with more fuel and a catalyst produces the byproduct: hydrogen and oxygen form water.
Most common cells use hydrogen and oxygen with an anode catalyst of platinum and a cathode catalyst of nickel. The voltage output per cell is often less than a volt. However, some fuel cells use hydrocarbons. Diesel, methanol, and other hydrocarbons can produce electricity and carbon dioxide as a byproduct, along with water. You can even use some unusual organic inputs, although to be fair, those are microbial fuel cells.
Common types include:
Alkaline – The Bacon cell was a fixture in space capsules, using carbon electrodes, a catalyst, and a hydroxide electrolyte.
Solid acid – These use a solid acid material as electrolyte. The material is heated to increase conductivity.
Phosphoric acid – Another acid-based technology that operates at hotter temperatures.
Molten carbonate – These work at high temperatures using lithium potassium carbonate as an electrolyte.
Solid oxide – Another high temperature that uses zirconia ceramic as the electrolyte.
In addition to technology, you can consider some fuel cells as stationary — typically producing a lot of power for consumption by some power grid — or mobile.
Using fuel cells in stationary applications is attractive partly because they have no moving parts. However, you need a way to fuel it and — if you want efficiency — you need a way to harness the waste heat produced. It is possible, for example, to use solar power to turn water into gas and then use that gas to feed a fuel cell. It is possible to use the heat directly or to convert it to electricity in a more conventional way.
Space
Fuel cells have a long history in space. You can see how alkaline Bacon cells were used in early fuel cells in the video below.
Very early fuel cells — starting with Gemini in 1962 — used a proton exchange membrane. However, in 1967, NASA started using Nafion from DuPont, which was improved over the old membranes.
However, alkaline cells had vastly improved power density, and from Apollo on, these cells, using a potassium hydroxide electrolyte, were standard issue.
Even the Shuttle had fuel cells. Russian spacecraft also had fuel cells, starting with a liquid oxygen-hydrogen cell used on the Soviet Lunar Orbital Spacecraft (LOK).
The shuttle’s power plant measured 14 x 15 x 45 inches and weighed 260 pounds. They were installed under the payload bay, just aft of the crew compartment. They drew cryogenic gases from nearby tanks and could provide 12 kW continuously, and up to 16 kW. However, they typically were taxed at about 50% capacity. Each orbiter’s power plant contained 96 individual cells connected to achieve a 28-volt output.
Going Mobile
There have been attempts to make fuel cell cars, but with the difficulty of delivering, storing, and transporting hydrogen, there has been resistance. The Toyota Mirai, for example, costs $57,000, yet owners sued because they couldn’t obtain hydrogen. Some buses use fuel cells, and a small number of trains (including the one mentioned in the video below).
Surprisingly, there is a market for forklifts using fuel cells. The clean output makes them ideal for indoor operation. Batteries? They take longer to charge and don’t work well in the cold. Fuel cells don’t mind the cold, and you can top them off in three minutes.
There have been attempts to put fuel cells into any vehicle you can imagine. Airplanes, motorcycles, and boats sporting fuel cells have all made the rounds.
Can You DIY?
We have seen a few fuel cell projects, but they all seem to vanish over time. In theory, it shouldn’t be that hard, unless you demand commercial efficiency. However, it can be done, as you can see in the video below. If you make a fuel cell, be sure to send us a tip so we can spread the word.
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.
Inside the DIY control unit.
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.
DIY mechatronics always has some unique challenges when relying on simple tools. 3D printing enables some great abilities but high precision gearboxes are still a difficult problem for many. Answering this problem, [Sergei Mishin] has developed a very interesting gearbox solution based on a research paper looking into simple rollers instead of traditional gears. The unique attributes of the design come from the ability to have a compact angled gearbox similar to a bevel gearbox.
Multiple rollers rest on a simple shaft allowing each roller to have independent rotation. This is important because having a circular crown gear for angled transmission creates different rotation speeds. In [Sergei]’s testing, he found that his example gearbox could withstand 9 Nm with the actual adapter breaking before the gearbox showing decent strength.
Of course, how does this differ from a normal bevel gear setup or other 3D printed gearboxes? While 3D printed gears have great flexibility in their simplicity to make, having plastic on plastic is generally very difficult to get precise and long lasting. [Sergei]’s design allows for a highly complex crown gear to take advantage of 3D printing while allowing for simple rollers for improved strength and precision.
While claims of “zero backlash” may be a bit far-fetched, this design still shows great potential in helping make some cool projects. Unique gearboxes are somewhat common here at Hackaday such as this wobbly pericyclic gearbox, but they almost always have a fun spin!
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.
Regular vs gene-edited spider silk with a fluorescent gene added. (Credit: Santiago-Rivera et al. 2025, Angewandte Chemie)
Continuing the scientific theme of adding fluorescent proteins to everything that moves, this time spiders found themselves at the pointy end of the CRISPR-Cas9 injection needle. In a study by researchers at the University of Bayreuth, common house spiders (Parasteatoda tepidariorum) had a gene inserted for a red fluorescent protein in addition to having an existing gene for eye development disabled. This was the first time that spiders have been subjected to this kind of gene-editing study, mostly due to how fiddly they are to handle as well as their genome duplication characteristics.
In the research paper in Angewandte Chemie the methods and results are detailed, with the knock-out approach of the sine oculis (C1) gene being tried first as a proof of concept. The CRISPR solution was injected into the ovaries of female spiders, whose offspring then carried the mutation. With clear deficiencies in eye development observable in this offspring, the researchers moved on to adding the red fluorescent protein gene with another CRISPR solution, which targets the major ampullate gland where the silk is produced.
Ultimately, this research serves to demonstrate that it is possible to not only study spiders in more depth these days using tools like CRISPR-Cas9, but also that it is possible to customize and study spider silk production.
Conectar
(this bug was discovered by a Windows 98 user who noticed sshd was crashing when trying to login to a Linux server!)
