Kritik sah

Anyone who’s ever built their own motors knows how tedious winding the coils soon becomes; in [Larry]’s case, the issue was even worse. He’s building his own flip-dot matrix display, and each dot uses two electromagnetic coils to flip a magnet in the dot. Rather than wind each of these by hand, therefore, he built his own coil-winding machine . The coil winder uses two stepper motors: one to wind wire onto the bobbin, and one to move the wire guide carriage back and forth, distributing the wire evenly across the bobbin. The bobbin is held in place by a retainer, which doubles as a tie point for the end of the wire. The spool of wire rotates on a pair of bearings, and the wire is fed between two pieces of foam to provide adjustable tension. The housing is mostly 3D-printed, with some metal rods, bearings, and belt drives fleshing out the structure. On the electronics side, a Teensy controls the winder, with an OLED display and a rotary encoder for control. Before beginning on a coil, ...

The Chinese had been using large crossbows – akin to Greek and Roman ballistae – for warfare for many of the same reasons that European armies loved them. Their single, large arrow was effectively unstoppable, though this also was rather useless against large groups of infantry unless they were so kind to neatly line up. Old Chinese records mention a special kind of ammunition, called a cup arrow, or ‘storm of crows’, which involves launching many smaller arrows instead of a single large one, a feat that [Tod] really wanted to try and recreate . In itself this doesn’t sound too complex: just grab some arrows, loosely tie them together in a bundle and slap them on the crossbow. Yet with the immense forces applied on this bundle it clearly turns out that the engineering challenge isn’t quite that straightforward, as the arrows love to scatter wildly in all directions or otherwise be rather unpredictable. Although we can find historical references to ...

The Philips CD-i is a console with many shortcomings, and those include the power supply. For whatever reason, the engineering team decided it should use an 8P8C connector just like Ethernet. Thus, just like your Ethernet cables, it has that annoying problem of the tab snapping off all the time. [MattKC] wondered if the CD-i could benefit from a USB power upgrade instead, and set about making it a reality. The plan was simple enough—get the CD-i running off of USB-C instead of the ungainly original power supply that shipped with the unit. Given the console runs almost exclusively off of 5 V power, it should have been pretty easy. Only, the original spec adds one little detail that makes things a bit harder. The console is designed to draw up to 3 A from the 5 V line, while also having a -5 V line at 0.2 A. If not for that negative supply, it would have been easy to run the unit off any old 15 W USB-C charger spitting out 5 V. That extra negative line complicates things, because while ...

One of the major limits of mass-produced batteries is the electrolyte. From lead-acid to lithium ion, there’s some temperature where the electrolyte will freeze and cause all sorts of problems, from cracked casings to various non-favorable chemical changes in the battery itself. But if there’ a solid electrolyte available, many of the downsides of charging and discharging batteries in extreme cold disappear. These batteries developed by NASA, for example, can survive some wild temperature swings . The electrolytes used for these batteries are either a ceramic or polymer electrolyte, both of which are solid. In testing, the batteries could meaningfully operate at temperatures of -60° C and up to 80 ° C on the high end. Further, the solid electrolyte helps protect them even outside of these temperature ranges. Bringing the battery temperature down to -170 ° C was not enough to damage the battery at all, and using a small heater to bring the temperature back up to its operat...

For as many sensors, cameras, and computers as there are on modern cars, they ought to be a dream to poke around in and customize to one’s liking. Unfortunately they’re generally plagued by the same locked-down, proprietary software that most consumer electronics ship with, making it very difficult to interact with these systems in ways the manufacturer doesn’t approve of. There are a few exceptions to this rule, though, and [Sasha] built this system which backs up the footage from their electric car’s on-board cameras automatically to a NAS . The system is built around a Raspberry Pi Zero 2 W which plugs directly into a USB port in the car’s glovebox. To set it up, the software only needs to be flashed onto the Pi and then it can be controlled from a smartphone. It can connect to any NAS over a variety of protocols and keeps track of what footage has been backed up, and can even automatically restart a backup if the car drives away before it has completed...

If you’ve ever pulled apart a set of digital calipers, you’ve probably marvelled at the capacitive encoder that does all the measuring work. There’s nothing stopping you from using the same techniques yourself, as [Nick] demonstrates with an open-source capacitive encoder of his own design. The sensor PCB works by by having a grid of eight transmitting antennas, etched into a PCB, beneath a larger receiving antenna. The transmitting antennas pulse out a pattern as the sensor PCB moves, with the signals bouncing back from the reflector PCB which is fixed in place. The varying capacitance caused by the position of the reflector elements relative to the sensor PCB varies the strength of the pulses hitting the receiving antenna. A microcontroller—in this case an STM32—can read those pulses to determine the displacement of the sensor PCB relative to the reflector down to a very fine degree. In this case, to an accuracy of 40 micrometers. Not bad! If you need ultra-fine li...

There are plenty of Wi-Fi radios out there that were built over the last two decades or so. However, many older models are now becoming less useful because many internet radio stations are switching to newer streaming formats that they don’t support. [Clifford Farrugia] has been working on a little project to save these appliances from the e-waste bin. The HLS Radio Converter is the result of that work. It’s a small open-source tool that converts modern HTTP Live Streaming (HLS) protocol streams into regular old HTTP MP3 streams that older internet radio appliances are built to decode. You can run the tool on something as simple as an old Raspberry Pi. To make it work, you just give the tool the URL of the stream you’re looking to convert, and it then spits out a new URL to point your radio to which has the stream in the old-school format instead. It’s a simple tool, but one that should prove very useful if you have a beloved old internet radio that can’t...

Before the advent of effective semiconductor LEDs many display types existed to display things like numbers and other characters. The Nixie tube is a well-known one, along with VFDs and there are also lesser known ones such as Burrough’s Panaplex, which all saw plentiful use in everything from calculators to audio equipment. The design that [Witchcraft and Alchemy] made appears to lean heavily on this Panaplex design. Rather than neon, this uses argon as the gas. The anode is formed by the indium-tin oxide layer on a piece of glass, with the cathode sputtered onto the other side in the form of first a titanium layer followed by platinum. This combination helps to prevent the latter from flaking off due to incompatibilities between the molecular matrices of the glass and platinum. Since this is an early prototype, only five segments were sputtered onto the glass and driven with a 74141 Nixie driver IC, creating the expected purple glow in a vacuum chamber. Following this a self-...

Measuring electric currents is an essential element of many electrical systems, but doing so in a way that is as nonintrusive as possible is not an easy problem to solve. Due to this we got a wide variety of current sensors to choose from for any given application, with [ElectrArc240] running us through these variants in a recent video. The fairly low-tech, cheap and quite reliable method of using a shunt resistor is first demonstrated. This sees a lot of use in fairly low-voltage and low-current applications, with for example videocards using it to limit the amount of power the GPU can use, a feature that modders will happily bypass. Here simply the voltage drop across a known resistance value is measured, from which the current can be derived. Of course, you got higher voltage and higher current applications too, as well as direct- and alternating current, with the latter especially allowing for easy current measurements simply from the electromagnetic field, or flux. Anyone who h...

The Philips CD-i was not popular upon its launch in 1991, and is barely acknowledged today. In the opinion of [MattKC], it had a particularly poor selection of controllers, too, and it’s often hard to find used examples anyway. To rectify this situation, he whipped up an adapter to let him use Sega Genesis controllers instead. The benefit of the Genesis controller is that it uses DB-9 connectors that are readily available, and it’s got a simple pinout that is compatible with the Atari joystick port, too. It makes interfacing the controllers supremely easy. Converting the controllers required using a Arduino Pro Micro to read the Genesis pad and translate it into something suitable for the CD-i. On the Sega controller side, the microcontroller just has to strobe one pin while reading the state of others to determine what all the buttons are doing. The CD-i, however, expects a serial data stream from the original Philips controllers. Thus, the microcontroller is set up to po...

We don’t generally think of 3D printing and knitting in the same sentence. One uses threads and fine motor control, while the other requires great knowledge of pressing buttons and plastics. That said, they both entail stacking material over and over until a finished product emerges. So why not blend the two crafts together? [Joram de Haas] decided to work on just that in the form of FilaLoom . 2D, 3D, and even embedded mechanisms! This isn’t the first time we have seen additional elements embedded into 3D printed parts here on Hackaday. However, this particular implementation has some extra features which allow the embedded structures to grow larger than most examples prior. Instead of placing any implements directly into a structure by hand, all thread is placed by a tool head not so different from tool-changer printers. Using both the 3D printing tool head and the thread tool, some truly interesting properties can emerge from the finished product. If you aren’t interested in...

Although we generally do not look at bubbles in fluids as more than a curiosity – if not an outright annoyance – in certain contexts they can be very useful. If you can namely control their formation and position, you can use them in small systems to control actuators and dynamically affect acoustic systems. The main issues here are that controlling their formation, lifetime and controllability remain hard to solve. This is what [Zhiyuan Zhang] et al. sought to address, with a recent study published in  Science Advances covering their approach using ultrasound-driven, electronically programmable microbubbles. There’s also a Cornell press release article about their findings, which uses a new device that produces hydrogen bubbles along a grid of electrodes, before using ultrasound to steer them around. Using this chip-like device they claim to be able to control the 10-100 micron sized bubbles, with the ultrasound matching the resonant frequency of the target bubble...

If you have developed in Pascal or Delphi in the past decades, you’re probably familiar with the Lazarus IDE that provides an interface to the Free Pascal Compiler (FPC), much like Delphi’s IDE. For users of Lazarus IDE there’s now an exciting new development, with the announcement that FPC and Lazarus now support dynamic packages . The upshot of this is that you no longer need to rebuild the IDE if you want to add components, controls and Lazarus extensions. In addition you can use this same dynamic package feature in your own Pascal applications this way. Naturally this is a great improvement, and it’s good to see more improvements to such a venerable programming language. Not only is it still being used today for just about anything, including web development , but there is a good case to be made for using Pascal today as it’s no longer the language it was half a decade ago. We’d also be remiss to not mention the legacy of [Niklaus Wirth] , who...

When most radio enthusiasts start trying to pick up signals from satellites, they might put together a quick-and-dirty Yagi antenna and try to catch a repeater as is passes overhead, or they might grab a small unused dish from a satellite TV service and point it up at a weather satellite by hand to try to decode some of the data coming down. But [Cranktown City] had a different approach. He found an eight-foot dish online and built a massive articulating base station out of it as his first exploration into the world of satellites. The first problem that needs to be solved with a dish of this size is its mounting location. This installation uses a large post and concrete foundation with a custom-fabricated metal base at the bottom. The metal base houses all of the electronics not just for receiving signals from the dish, but also for orienting it properly. That includes a large metal gear driven by a wheelchair motor to control its azimuth and a linear actuator to take care of its ele...

One could make a joke about how an astronaut walking on the lunar surface is rather akin to a cat walking on the carpet in the living room, but out in space the resulting triboelectric discharge can do a lot more damage than just some stinging fingers and a bemused looking cat. The problem that NASA and other space agencies are dealing with is that the charge that builds up on a lunar-walking astronaut is very hard to equalize with something like a lunar lander. For this reason they have now set up the Lunar Grounding Challenge to consult the public whilst dangling $150,000 of rewards in front of anyone ready to pounce with a good idea. Here on Earth we got many ways in which we can get rid of such an unwanted charge, with dry winter weather demonstrating quite effectively why humidity is a crucial factor here. With no real atmosphere on the Moon, each astronaut thus becomes a walking capacitor, which is worsened when said astronaut ventures outside of the sunlit areas and then ret...

Although solar panels may seem like a kind of magic, they’re really quite simple devices, in their silicon form featuring nothing but the p-type silicon wafer and an n-type layer doped with e.g. phosphorus. Because of this simplicity it’s quite possible to make your own solar cells at home using only a few basic, off-the-shelf ingredients and a kiln, which in this recent video by [Dr. Semiconductor] uses a microwave kiln and thus justifies the video’s title. Even the silicon wafer that you start with can be easily purchased online, though you have to be careful that it’s a bare wafer, without existing etchings on it. On this you need to get a phosphorus-rich layer, which is done by creating a delicious mixture of 1 mL of tetraethyl orthosilicate (TEOS), 0.3 mL of 85 wt% phosphoric acid, 5 mL of ethanol and 0.25 mL of distilled water. After low heat boiling this for 30 minutes, it is spincoated onto the cut square of silicon wafer using a spinning platform, like...

Bicycles are the ultimate form of transportation freedom. They’re easy to repair, parts are cheap, and they will travel almost anywhere for free, as long as the rider has enough calories. Their only real downside is dealing with car-dependent societies, but once a year there’s a place in the American desert that eschews all of this and [Attoparsec] decided to take this custom cargo bike modified into an RV out to Burning Man , a place and time that would be perfect for a build like this. The build started out as a cargo bike, but not many of them have cargo areas long enough to support a sleeping human. To increase this storage capacity, the bed was extended towards the rear. Without moving the axle further back, though, this created a problem with tail-heaviness so two trailer jacks with wheels were added to the back to keep it from occasionally tipping up too far. The sleeping enclosure was built with rigid foam insulation and taped together, in a modified style common to...

Meshtastic has gained a lot of popularity over the last few years thanks to its low barrier of entry. No licenses are needed and the hardware is dirt cheap, at least when compared to a lot of ham radio gear. But while that physical barrier is low, there is a bit of a learning curve. Part of that comes from the fact that there are a lot of channels and modes that people could be communicating on, and unless the user knows that information up front it can be hard to find where the conversations are happening. [cemaxecuter] noticed this problem and built a Meshtastic sniffer into his radio-forward Linux distribution, DragonOS . The sniffing software is built in C and comes as a complete standalone binary and does not rely on GNU Radio. With DragonOS up and running and the software loaded, it can look at the entire bandwidth that Meshtastic operates on and detect any traffic and decode it (as long as the key is known). [cemaxecuter] is using a HackRF as a software-defined radio for this p...

If you need a micro-manipulator, you probably already have a good idea of what it does. For example, you might be moving a probe over an IC die or wafer. You might be looking at something through a microscope. The key is moving something in very small, precise increments along three axes. An open-source design for a micro-manipulator has seen significant improvements lately. You can see several videos about the device below. The device uses stepper motors, parallel kinematics, and miniature ball joints to achieve precise motion. The recent version 4.0 update fixes a few problems. According to the GitHub page: Self-collision during homing fixed. Connection of the ball joint block with screws only was not well constrained and could be rotated a bit. No reliable way to ensure consistent linkage rod length Unnecessary ball joint friction Accurate ball position heavily dependent on print quality and corner rounding Rubber bands could not be changed or removed once glued in. We...

If there’s one thing everyone hated about Windows 98, was the lack of USB4.0 support. We remember vividly the cries of anguish at the launch party when we found out that 21 years in the future, the operating system wouldn’t support the then-undreamt of speeds of the thunderbolt-based fastest USB protocol. After two decades of living with this crushing disappointment, [Yeo Kheng Meng] has delivered the goods: the most modern of USB interfaces on some very much not modern versions of windows . This builds on [Yeo Kheng Meng]’s work on xHCI drivers for USB2.0 support, which we covered at the time . Like that hack, this one applies to Windows 98 through 7, and has a similar level of LLM-wrangling involved. There are actually a few parts to it– one is a USB3.0 driver, which replaces the old xHCI98 driver and is available on GitHub. On Windows98, USB3.0 speed caps out around 200 MB/s, likely restricted by Windows98’s maximum request limit of 64kB on USB transf...

While Hackaday doesn’t maintain a crime blotter, we couldn’t help but start this week’s post off with a bit of civil disobedience — a retired professor from the University of Pennsylvania was arrested earlier this week for standing in front of a delivery robot . Granted, she was standing there for long enough that the police were eventually called, but still. Previous reporting indicates that Carolyn Marvin has a history of blocking delivery robots as a form of protest, but this is the first time law enforcement got involved. We’re not lawyers here at Hackaday, so we can’t say for sure whether or not blocking the progress of a robot engaged in commercial operation actually violates any laws. But we do know that refusing a lawful request from a police officer will get you in trouble, and that seems to be what Marvin was actually charged with when she refused to move. From a robot stopped in its tracks to one that keeps on trucking, NASA is reporting...

Refrigeration has been a challenge for humanity since the start. Ancient civilizations in dry climates like Persia and Egypt could use evaporative cooling on a large scale with specialized architecture, and with easy access to electricity modern civilization can cool down almost anything it wants. But whether in a refrigerator or heat pump, the electricity demands can get out of hand quickly, and heat-driven systems often require dangerous or hard-to-get chemicals. But [Greenhill Forge] has crafted a system that creates effective refrigeration with only fire and salt … and a bit of electricity. Heat-driven systems are called absorption coolers. In this design, water is used as a refrigerant and forced to a very low pressure so that it can boil at a low temperature. When it boils it absorbs heat from the surrounding environment, and then that water vapor can be moved and condensed where it gives off that heat. The build has a few distinct loops to make all of this happen. The gene...

Although for many decades the planet Mars has been prodded, poked, driven upon, flown over and especially orbited by various spacecraft, landers and rovers sent over by a certain humanoid species on Earth, the two moons that orbit Mars have featured significantly more in science-fiction and video games than in scientific literature. This is now about to change when the Martian Moons eXploration (MMX) mission launches on October 19th, which will include a sample return from Phobos. So far these two moons of Mars – Phobos and Deimos – have only received a few cursory glances by passing spacecraft, leaving many fundamental questions surrounding their formation and composition very much open. With the MMX mission this should change dramatically, with this spacecraft intended to perform detailed measurements of both moons. In addition a rover – called Idefix – will perform a landing on Phobos for observations of its surface. This will be quite a feat as despite th...