Kritik sah

Learning a new language is a great way to exercise the mind and learn about different cultures, and it’s great to have a native speaker around to improve the learning experience. Without one it’s still possible to learn via videos, books, and software though. The task does get much more complicated when trying to learn a language that isn’t spoken, though, like American Sign Language. This project allows users to learn the ASL alphabet with the help of computer vision and some machine learning algorithms . The build uses a computer vision model in MobileNetV2 which is trained for each sign in the ASL alphabet. A sign is shown to the user on a screen, and the user needs to demonstrate the sign to the computer in order to progress. To do this, OpenCV running on a Raspberry Pi with a PiCamera is used to analyze the frames of the user in real-time. The user is shown pictures of the correct sign, and is rewarded when the correct sign is made. While this only works for alphabet signs in A

Stereophotography cameras are difficult to find, so we’re indebted to [DragonSkyRunner] for sharing their build of an exceptionally high-quality example . A stereo camera has two separate lenses and sensors a fixed distance apart, such that when the two resulting images are viewed individually with each eye there is a 3D effect. This camera takes two individual Sony cameras and mounts them on a well-designed wooden chassis, but that simple description hides a much more interesting and complex reality. Sony once tested photography waters with the QX series — pair of unusual mirrorless camera models which took the form of just the sensor and lens.  A wireless connection to a smartphone allows for display and data transfer. This build uses two of these, with a pair of Android-running Odroid C2s standing in for the smartphones. Their HDMI video outputs are captured by a pair of HDMI capture devices hooked up to a Raspberry Pi 4, and there are a couple of Arduinos that simulate mouse inpu

Anyone who has played an online shooter game in the past two or three decades has almost certainly come across a person or machine that cheats at the game by auto-aiming. For newer games with anti-cheat, this is less of a problem, but older games like Team Fortress have been effectively ruined by these aimbots. These types of cheats are usually done in software, though, and [Kamal] wondered if he would be able to build an aim bot that works directly on the hardware instead . First, we’ll remind everyone frustrated with the state of games like TF2 that this is a proof-of-concept robot that is unlikely to make any aimbots worse or more common in any games. This is mostly because [Kamal] is training his machine to work in Aim Lab, a first-person shooter training simulation, and not in a real multiplayer videogame. The robot works by taking a screenshot of his computer in Python and passing the information through a computer vision algorithm which recognizes high-contrast targets. From t

[GreatScott!] was bummed to see his greenhouse be empty and lifeless in winter. So, he set out to take the greenhouse home with him . Well, at least, a small part of it. First, he decided to produce artificial sunlight, setting up a simple initial experiment for playing with different wavelength LEDs. How much can LEDs affect plant growth, really? This is the research direction that Würth Elektronik, supporting his project, has recently been expanding into. They’ve been working on extensive application notes , explaining the biological aspects of it for us — a treasure trove of resources available at no cost, that hackers can and should learn from. Initially, [GreatScott!] obtained LEDs in four different colors – red, ‘hyper red’, deep blue, and daylight spectrum. The first three are valued because their specific wavelengths are absorbed well by plants. The use of daylight LEDs though has been controversial.  Nevertheless, he points out that the plant might require different waveleng

When it comes to interpreting sensor data automatically, it helps to have a large data set to assist in validating it, as well as training when it concerns machine learning (ML). Creating this data set with carefully tagged and categorized information is a long and tedious process, which is where the idea of cross-domain translations come into play, as in the case of using millimeter wave (mmWave) radar sensors to recognize activity of e.g. building occupants with the IMU2Doppler project at Smash Lab of Carnegie Mellon University. The most commonly used sensor type when it comes to classifying especially human motion are inertial measurement units ( IMU ) such as accelerometers and gyroscopes, which are found in everything from smartphones to smart watches and fitness bands. For these devices it’s common to classify measurement patterns as matches a particular activity, such as walking, jogging, or brushing one’s teeth. This makes them both well-defined and very accessible. As for

[Jeshua Lacock] from 3DTOPO owns a large-format CNC (4’x8′, or 1.2×2.4 m), that he strongly feels is lacking laser-cutting capabilities. The frame is there, and a 150 W CO2 laser tube has been sitting in a box for ages – what else could you need? Sadly, at such a scale, aligning the mirrors is a tough and finicky job – and misalignment can be literally blinding. After reading tales about cutters of such size going out of alignment when someone as much as walked nearby, he dropped the idea – and equipped the CNC head with a high-power laser diode module instead . Having done mirror adjustment on a few CO2 tube-equipped lasers, we can see where he’s coming from. Typically, the laser modules you see bolted onto CNC heads are firmly under three watts, which is usually only enough for engraving. With a module that provides 5 watts of optical power, [Jeshua] can cut cardboard and thin plywood as well he tells us even 10 W optical power modules are available, just that he didn’t go for one

Those of us beyond a certain age will very likely have some fond memories of many an hour spent and pocket money devoured feeding the local arcade pinball machine. At one time they seemed to be pretty much everywhere, but sadly, these days they seem to have largely fallen out of favour and are becoming more of speciality to be specifically sought out. Apart from a few random ones turning up — there’s a fun Frankenstein-themed machine in the Mary Shelley Museum in Bath, England — a trip to a local amusement arcade is often pretty disappointing, with modern arcade machines just not quite scratching that itch anymore, if you ask us. So what’s an old-school hacker to do, but learn how to build a machine from scratch, just the way we want it? A great resource for this is the excellent Pinball Makers site , which shows quite a few different platforms to build upon and a whole ton of resources and guides to help you along the way. P3-ROC pinball machine controller mainboard – note the Xil

You can’t do much development without running into Git, the version control management system. Part of that is because so much code lives on GitHub which uses Git, although you don’t need to know anything about that if all you want to do is download code. [Dr. Torq] has a good primer on using Git with the Arduino IDE , if you need to get your toes wet. You might think if you develop by yourself you don’t need something like Git. However, using a version control system is a great convenience, especially if you use it correctly. There’s a bug out in the field? What version of the firmware? You can immediately get a copy of the source code at that point in time using Git. A feature is broken? It is very easy to see exactly what changed. So even if you don’t work in a team, there are advantages to having source code under control. If you are already using a more advanced IDE, Git is probably integrated into your environment, or, at least, it could be. If you are allergic to the command

For how common motorcycles are, the designs and parts used in them tend to vary much more wildly than in cars and trucks. Sometimes this is to the rider’s advantage, like Honda experimenting with airbags or automatic transmissions. Sometimes it’s a little more questionable, like certain American brands holding on to pushrod engine designs from the ’40s. And sometimes it’s just annoying, like the use of cheap voltage regulators that fail often and perform poorly. [fvfilippetti] was tired of dealing with this on his motorcycle, so he built a custom voltage regulator using MOSFETs instead . Unlike a modern car alternator, which can generate usable voltage even at idle, smaller or older motorcycle alternators often can’t. Instead they rely on a simpler but less reliable regulator that is typically no more than a series of diodes, but which can only deliver energy to the electrical system while the motor is running at higher speeds. Hoping to improve on this design, [fvfilippetti] designe

You probably know what a cyberdeck is by now, but you’ll find that people’s definitions differ. Some use the term rather loosely, applying it to things that are luggable at best. But we think you’ll agree that [Daniel Norris]’ chonky palmtop is without a doubt, quite cyberdeckian. One of the hallmarks of a cyberdeck is that it folds up, often like a laptop in the screen-over-keyboard sense. Not only does chonky palmtop do that, but the split keyboard (more on that later) has this impressive pivot geometry and really satisfying slider mechanism thing going on. The whole thing folds up into a little brick, which [Daniel] says is about the size of an old Asus EEE laptop. (Remember those bad boys? Those were the days.) Inside the brick is some stuff you might expect, like a Raspberry Pi 4 and a 7″ touchscreen. [Daniel] also packed in an AmpRipper 3000 LiPo charger, which is especially good for high voltage projects. Speaking of, there is a voltage button to check the battery level, whi

What is it that’s not quite either a plane or a boat, but has characteristics of both? There are probably a lot of things that fit that description, but the one that [Nick Rehm] is working on is known as an ekranoplan. Specifically, he’s looking to make the surface-skimming ground-effect vehicle operate autonomously . If you think you’ve heard about ekranoplans around here before, you’d be right — we’ve covered a cool LIDAR-controlled model ekranoplan that [rctestflight] worked on about a year ago, and more recently, [ThinkFlight]’s attempts to make an autonomous ekranoplan that can follow behind a boat. The latter is where [Nick] enters the collaboration, and the featherweight foam ground-effect vehicle shown in the video below is his test platform. After sorting out the basic airframe design and getting the LIDAR integrated, he turned his attention to the autonomous bit, which relies on a Raspberry Pi 4 running ROS and a camera with a wide-angle lens. The Pi uses machine vision

[Jeff Geerling] saw the Raspberry Pi Compute Module 4 and its exposed PCI-Express 1x connection, and just naturally wondered whether he could plug a GPU into that slot and get it to work. It didn’t. There were a few reasons why, such as the limited Base Address Register space, and drivers that just weren’t written for ARM hardware. A bit of help from the Raspberry Pi software engineers and other Linux kernel hackers and those issues were fixed, albeit with a big hurdle in the CPU. The Broadcom chip in the Pi 4, the BCM2711, has a broken PCIe implementation. There has finally been a breakthrough — Thanks to the dedicated community that has sprung up around this topic, a set of kernel patches manage to work around the hardware issues. It’s now possible to run a Radeon HD 5000/6000/7000 card on the Raspberry Pi 4 Compute Module . There are still glitches, and the Kernel patches to make this work will likely never land upstream. That said, It’s possible to run a desktop environment on th

Plastic is a remarkable material in many ways. Cheap, durable, and versatile, it is responsible for a large percentage of the modern world we live in. As we all know, though, it’s not without its downsides. Its persistence in the environment is quite troubling, so any opportunity we can take to reduce its use is welcome. This 3D printed machine , although made out of plastic, is made out of repurposed water bottles that have been turned into the filament for the 3D printer. While there’s not too much information available on the site, what we gather is that the machine cuts a specific type of plastic water bottle made out of PET plastic into strips, and then feeds the strips into a heated forming tool. The tool transforms the strips into the filament shape and spools them so they are ready to feed back into a 3D printer. As a proof of concept, it seems as though this machine was made from repurposed plastic, but it could also be made using whatever filament you happen to have on han

Most crystal radio receivers have a decidedly “field expedient” look to them. Fashioned as they often are from a few turns of wire around an oatmeal container and a safety pin scratching the surface of a razor blade, the whole assembly often does a great impersonation of a pile of trash whose appearance gives little hope of actually working. And yet work they do, usually, pulling radio signals out of thin air as if by magic. Not all crystal sets take this slapdash approach, of course, and some, like this homebrew multiband crystal receiver , aim for a feature set and fit and finish that goes way beyond the norm. The “Husky” crystal set, as it’s called by its creator [alvenh], looks like it fell through a time warp right from the 1920s. The electronics are based on the Australian “Mystery Set” circuit, with modifications to make the receiver tunable over multiple bands. Rather than the traditional galena crystal and cat’s whisker detector, a pair of1N34A germanium diodes are used as r

Imagine if you had some magic glowing beads, that would emit beautiful colors without any wires tangling them up. They exist, in the form of wireless induction-powered LEDs, and [Debra] of Geek Mom Projects has been experimenting with them in a new way. The build takes the wireless LEDs and wraps each one up in a 1/4″-thick clear ring of acrylic. This toughens up the LEDs and helps diffuse their light. They’re then installed in a hexagonal plastic container, featuring a grid of screws not unlike the metal pins of the game Plinko. Thanks to the induction coil mounted behind, the LEDs glow as they ricochet around the metal pins in various ways. We’d love to see the container full of LEDs mounted on a slowly-turning motor, such that they would tumble around endlessly, glowing all the while. It would be quite mesmerizing, in much the same way as the kaleidoscope project [Debra] built using these parts previously . Video after the break. New wireless (induction powered) LED experime

Most of us are familiar with virtual machines (VMs) as a way to test out various operating systems, reliably deploy servers and other software, or protect against potentially malicious software. But virtual machines aren’t limited to running full server or desktop operating systems. This tiny VM is capable of deploying software on less powerful systems like the Raspberry Pi or AVR microcontrollers, and it is exceptionally fast as well. The virtual machine is built from scratch, including the RISC processor with only 61 opcodes, a 64 bit core, and runs code written in his own programming language called “Brackets” or in assembly. It’s designed to be modular, so only those things needed for a given application are loaded into the VM. With these design criteria it turns out to be up to seven times as fast as comparably small VMs like NanoVM. The project’s creator, [koder77], has even used its direct mouse readout and joystick functionality to control a Raspberry Pi 3D camera robot. Fo

Electric vehicles (EVs) are something of a hot topic, and most of the hacks we’ve featured regarding them center on conversions from Internal Combustion to Electric. These are all fine, and we hope to see plenty more of them in the future. There’s another aspect that doesn’t get covered as often: How to charge electric vehicles- especially commercially produced EV’s rather than the DIY kind. This is the kind of project that [fotherby] has taken on: A 7.2 kW EV charger for his Kia . Faced with spending £900 (about $1100 USD) for a commercial unit installed by a qualified electrician, [fotherby] decided to do some research. The project wasn’t outside his scope, and he gave himself a head start by finding a commercial enclosure and cable that was originally just a showroom unit with no innards. An Arduino Pro Mini provides the brains for the charger, and the source code and all the needed information to build your own like charger is on GitHub . What’s outstanding about the guide thou

Back in the 90s, the console wars were in full swing. Nintendo vs Sega was an epic showdown at first, but when Nintendo seemed sure to clench the victory Sony came out of nowhere with the PlayStation. While these were the most popular consoles at the time, there were a few others around that are largely forgotten by history even if they were revolutionary in some ways. An example is the Pippin, a console made by Apple, which until now has been unable to run any software not signed by Apple . The Pippin was Apple’s only foray into gaming consoles, but it did much more than that and included a primitive social networking system as well as the ability to run Apple’s Macintosh operating system. The idea was to be a full media center of sorts, and the software that it would run would be loaded from the CD-ROM at each boot. [Blitter] has finally cracked this computer, allowing it to run custom software, by creating an authentication file which is placed on the CD to tell the Pippin that it

Drones have revolutionized the world of videography in perhaps the biggest way since the advent of digital hardware. They’re used to get shots that are impractical or entirely impossible to get by any other means. The [Dutch Drone Gods] specialize in such work. When it came to filming an urban mountain bike race in a dense Chilean city, they had to bust out some serious tricks. The FPV video feed was grainy, but good enough to keep the pilot on track. The drone carried a separate second camera for capturing high-quality footage of the run. Typically, running a drone chase cam behind a biker would require some good first-person flying skills and a quick drone. However, for the Red Bull Valparaiso Cerro Abajo urban downhill event, this alone would not be enough. The tight course winds down staircases between thick concrete walls and even through houses, presenting huge challenges to maintaining signal integrity. Without a clear video signal, the pilot can’t fly the drone without cra

It’s very early days for CAD Sketcher , a new parametric CAD add-on for Blender by [hlorus], but it looks very promising. We do a lot of 3D work and like Blender as an environment. It’s always annoying that Blender doesn’t do parametric modeling, so we’re forced into a dedicated CAD package. Blending the two for that robot ocelot is always particularly annoying. CAD Sketcher lets the user make a ‘sketch’, a 2D drawing. They then  constrain it, saying “this line is vertical, that line is parallel to this one”, until the sketch is fully defined. It’s a normal part of parametric modelling. This is powerful when your model needs refined over and over. There’s an old adage, “Better a tool that does 90% of the job well than one that does 100% poorly”. For CAD systems, (and much other software), we’d suggest “Better a tool that does 90% of the job well and works with whatever does the other 10%”. Guard Drawn In CAD Sketcher And Blender We tried a test part, and being in Blender’s univ

As the world becomes more and more digital, there are still a few holdouts from the analog world we’ve left behind. Vinyl records are making quite the comeback, and film photography is still hanging on as well. While records and a turntable have a low barrier for entry, photography is a little more involved, especially when developing the film. But with the right kind of equipment you can bridge the gap from digital to analog with a darkroom setup that takes digital photographs and converts them to analog prints . The project’s creator, [Muth], has been working on this project since he found a 4K monochrome display. These displays are often used in resin 3D printers, but he thought he could put them to use developing photographs. This is much different from traditional darkroom methods, though. The monochrome display is put into contact with photo-sensitive paper, and then exposed to light. Black pixels will block the light while white pixels allow it through, creating a digital-to-a

As one becomes more and more involved in hobbies that involve electronics of almost any kind, it becomes necessary to graduate from wall warts and USB power breakout boards and move up to something more substantial. One great way to do this is to repurpose an old computer PSU, and that’s exactly what the excellent writeup by [Mukesh Sankhla] shows us how to do. Starting with an ATX power supply from a derelict computer that was otherwise heading to to the bin, [Mukesh] walks us through the teardown of the power supply as well as how we can rebuild it in a snazzy 3d printed case complete with a voltage readout. Now it’s easy to say “Sure, this is just another ATX PSU project” but the care that went into making a nice case adds a lot to build. There’s another element that is extremely important: The power resistor across the 5 Volt power bus. There are cheap kits online that will break out an ATX PSU into banana plugs, but they omit this vital piece. Depending on the ATX power supply

Typically, if you want to convert solar energy into electrical energy, you use either photovoltaic (PV) cells, or you use the sunlight to create steam to turn a turbine. Both of these methods are well-established and used regularly in both small- and grid-scale applications. However, [Nick Poole] wanted to investigate an alternative method, using thermionic converters for solar power generation. [Nick] has been gearing up to produce various styles of vacuum tubes, and noted that the thermionic effect that makes them work could also be used to generate electricity. They are highly inefficient and produce far less power than a photovoltaic solar cell, meaning they’re not in common use. However, as [Nick] notes, unlike PV cells etched in silicon, a thermionic converter can be built with basic glassworking tools, requiring little more than a torch, a vacuum pump, and a spot welder. Experiments with a large lens to focus sunlight onto a 6V3A diode tube showed promise. [Nick] was able to