Kritik sah

Observing a colony, swarm or similar grouping of creatures like ants or zebrafish over longer periods of time can be tricky. Simply recording their behavior with a camera misses a lot of information about the position of their body parts, while taking precise measurements using a laser-based system or LiDAR suffers from a reduction in parameters such as the resolution or the update speed. The ideal monitoring system would be able to record at high data rates and resolutions, while presenting the recorded data all three dimensions. This is where the work by Kevin C. Zhou and colleagues seeks to tick all the boxes, with a recent paper ( preprint , open access ) in Nature Photonics  describing their 3D-RAPID system. This system features a 9×6 camera grid, making for a total of 54 cameras which image the underlying surface. With 66% overlap between cameras across the horizontal dimension, there enough duplicate data between image stream that is subsequently used in the processing step t

If you look up at the night sky in a dark enough place, with enough patience you’re almost sure to see a satellite cross the sky. It’s pretty cool to think you’re watching light reflect off a hunk of metal zipping around the Earth fast enough to never hit it. Unfortunately, it doesn’t work during the daylight hours, and you really only get to see satellites in low orbits. Thankfully, there’s a trick that allows you to see satellites any time of day, even the ones in geosynchronous orbits — you just need to look using microwaves . That’s what [Gabe] at [saveitforparts] did with a repurposed portable satellite dish, the kind that people who really don’t like being without their satellite TV programming when they’re away from home buy and quickly sell when they realize that toting a satellite dish around is both expensive and embarrassing. They can be had for a song, and contain pretty much everything needed for satellite comms in one package: a small dish on a motorized altazimuth moun

When you want a backpack that turns heads and gets people talking, you can get ahead of the conversation with a talking backpack. [Nina] created a rucksack with the legendary babbler itself, the infamous Furby . Believe it or not, no actual Furbies were sacrificed in the making of this backpack. The build uses an Arduino Nano, two servos, and a DFPlayer Mini for audio. A 3D printed faceplate is used for the iconic eyes and face. The code is fairly simple, waiting for a random delay and then triggering one of four effects. It can play a sound or blink and does its best to move the mouth while the sound is playing thanks to the handy busy line coming off the sound module. A unicorn children’s backpack offered a furry shell to stuff the electronics inside. A custom PCB makes the whole thing just a little neater internally. Perhaps next [Nina] can integrate voice recognition so that the backpack can answer simple questions like an Alexa-powered Furby we’ve seen before . from Blog

Every so often, a new technology comes along that offers a broad range of benefits over what we already have. Just as lithium-ion batteries have made nickel-cadmium cells boring and old hat, gallium nitride semiconductors are making silicon parts look unimpressive by comparison. [Brian Dipert] looked at what this means in a practical sense by tearing down a GaN phone charger. The charger in question is a 30 watt USB-C charger produced by Voltme. It cost [Brian] just $10, as prices of GaN hardware have come down significantly as economies of scale have kicked in. The charger measures just 1.2×1.3×1.2 inches, and weighs only 1.5 ounces. That compact size is thanks to GaN semiconductors, which are able to run cooler at higher power levels than their silicon forebearers. Cracking into the charger required levering open the case. The back panel came off with some work, revealing the mains terminals, which deliver AC power to the PCB inside via the case holding them in contact. Interestin

There’s a naming overload here, as two bits of security news this week are using the “MacStealer” moniker. We’re first going to talk about the WiFi vulnerability , also known as Framing Frames (pdf). The WPA encryption schemes introduced pairwise encryption, ensuring that not even other authenticated users can sniff each others’ traffic. At least that’s the idea, but this attack finds a couple techniques to bypass that protection. A bit more background, there are a couple ways that packets can be delayed at the sender side. One of those is the power-save message, that signals the access point that the given client is going into a low power state. “Hold my calls, I’m going to sleep.” That message is a single bit in a frame header. And notably, that bit isn’t covered by WPA encryption or verification. An attacker can send a message, spoof a victim’s MAC address, and the access point marks that client as being in power-save mode. This observation leads to a question: What happens when

Despite the popular adage about everything on the internet being there forever, every day pages of information and sometimes entire websites are lost to the sands of time. With the imminent shutdown of the DPReview website, nearly 25 years of reviews and specifications of cameras and related content are at risk of vanishing. Also lost will be the content of forum posts, which can still be requested from DPReview staff until April 6th. All because the owner of the site, Amazon, is looking to cut costs. As announced on r/photography , the Archive.org team is busy trying to download as much of the site as possible, but due to bottlenecks may not finish in time . One way around these bottlenecks is what is called the Archive Team Warrior , which involves either a virtual machine or Docker image that runs on distributed systems. In early April an archiving run using these distributed systems is planned, in a last-ditch attempt to retain as much of the  decades of content. The thus arch

[Christiaan Huygens] was a pretty decent mathematician and scientist by the standards of the 17th century. However, the telescopes he built were considered to be relatively poor in quality for the period. Now, as reported by Science News , we may know why. The well-known Huygens may have needed corrective glasses all along. Much of Huygens’ astronomical work concerned Saturn. Huygens is known for, among other things, his contribution to astronomy. He discovered Titan, the largest moon of Saturn, and also studied the planet’s rings. He achieved this despite telescopes that were described at the time as fuzzy or blurrier than they otherwise should have been. Huygens built two-lens telescopes, and would keep a table of which lenses to combine for different magnification levels. However, his calculations don’t align well with today’s understanding of optics. As it turns out, Huygens may have been nearsighted, which would account for why his telescopes were blurry. To his vision, they

Typically, when you’re putting electronics in a robot, you install the various controller PCBs into the robot’s chassis. But what if the PCB itself was the chassis? [Carl Bugeja’s] latest design explores just that idea. Yes, [Carl] decided to build a tiny robotic rover out of a foldable PCB. This choice was made as using a flexible foldable PCB would allow for the creation of a 3D chassis without the need for bulky connectors joining several boards together. A key part of the design was allowing the structure to unfold easily for serviceability’s sake. To that end, the structure is held together by the bolts that also act as the axles for the rover’s wheels. Even more brilliantly, the wheels are turned by motors built into the very PCB itself. Control is via a PlayStation controller, connected wirelessly to command the robot. The little bot is surprisingly capable, especially when juiced up with a twin-cell lithium battery. It’s tiny, with minimal ground clearance, so it’s not the b

When [Jay Bowles] demoed his first-generation ion thruster on Plasma Channel , the resulting video picked up millions of views and got hobbyists and professionals alike talking. While ionic lifters are nothing new, this robust multi-stage thruster looked (and sounded) more like a miniature jet engine than anything that had come before it. Optimizations would need to be made if there was even a chance to put the high-voltage powerplant to use, but [Jay] was clearly onto something. Fast forward six months, and he’s back with his Mark II thruster . It operates under the same core principles as the earlier build, but swaps out the open-frame design and acrylic construction for a rigid 3D printed structure designed to more effectively channel incoming air. The end result is a thruster that’s smaller and has a lower mass, while at the same time boasting nearly double the exhaust velocity of its predecessor. Testing airflow through a single stage of the thruster. Even though many lesson

The TA-1042 is the most badass looking telephone you’ll ever see. It’s a digital military telephone from the 1980s, but sadly non-functional unless it’s hooked up to the military phone switches it was designed to work with. These days, they’re really only useful as a heavy object to throw at somebody… that is, unless you had the suitable supporting hardware. As it turns out, [Nick] and [Rob] were able to whip up exactly that. Their project involved implementing the TA-1042’s proprietary switching protocol on a Raspberry Pi Pico. The microcontroller’s unique Programmable I/O subsystem proved perfect for the task. With a little programming and a hat for the Pico to interface with the hardware, they were able to get the TA-1042 working as intended. It involved learning how to encode and decode the Manchester encoded data used by the Digital Non-secure Voice Terminal equipment. Notably, the TA-1042 isn’t the only phone you can use with this setup. You can also hook up other US military

While building a skate park might not appear to have much in common with software development, at they very least, they both suffer from a familiar problem: scalability. Bigger skate parks need more ramps and features, and there’s no real way to scale up a construction project like this efficiently like you could with certain kinds of software other than simply building more features. This was something [Kirk] noticed, but was able to scale up a skate park in a way we’ve never thought of before. He built a mobile skateboard ramp that can turn any place into a skate park . The mobile and approximately sidewalk-width platform is able to move around thanks to an electric skateboard as its foundation. It adds a NVIDIA Jetson Nano for control with a PS4 controller for input, although steering a skateboard with an actuator took a few prototypes to figure out since skateboards are designed to be steered by shifting the rider’s weight. Since they are already designed to carry a human-amount

So, you now know the basics of approaching PCIe, and perhaps you have a PCIe-related goal in mind. Maybe you want to equip a single-board computer of yours with a bunch of cheap yet powerful PCIe WiFi cards for wardriving, perhaps add a second NVMe SSD to your laptop instead of that Ethernet controller you never use, or maybe, add a full-size GPU to your Raspberry Pi 4 through a nifty adapter. Whatever you want to do – let’s make sure there isn’t an area of PCIe that you aren’t familiar of. Splitting A PCIe Port You might have heard the term “bifurcation” if you’ve been around PCIe, especially in mining or PC tinkering communities. This is splitting a PCIe slot into multiple PCIe links, and as you can imagine, it’s quite tasty of a feature for hackers; you don’t need any extra hardware, really, all you need is to add a buffer for REFCLK. See, it’s still needed by every single extra port you get – but you can’t physically just pull the same clock diffpair to all the slots at once,

Clockwork devices were popular right up until motors and electronics proved far more capable in just about every way. However, there’s something charming about a device you can wind up to make it do its thing. To recreate this feeling on modern technology, [Kousuke Saito] created a clockwork winder that you can fit to a wide variety of modern appliances.  Somehow it just feels right. The design is simple. It consists of a motor which is run from a battery. The two components are installed in a 3D printed housing with a magnet on the bottom. When the device is attached to a metal surface, a switch is activated which turns the motor on. The motor is attached to a large printed “winding key” that would be familiar to anyone who has used a clockwork toy or timepiece before. If the magnetic manner of activation is familiar, you might recall it from [Kousuke Saito’s] chirping cicada project . It’s a silly build, to be sure. Regardless, when placed on certain appliances, like a simple f

If there’s one thing we’ve learned from [Chris] at Clickspring, it’s that a clockmaker will stop at nothing to make a clock not only work perfectly, but look good doing it. That includes measures as extreme as this complete re-toothing of a wheel from a clock . Is re-toothing even a word? The obsessive horologist in this case is [Tommy Jobson], who came across a clock that suffered a catastrophic injury: a sudden release of energy from the fusee, the cone-shaped pulley that adjusts for the uneven torque created by the clock’s mainspring. The mishap briefly turned the movement into a lathe that cut the tops off all the teeth on the main wheel. Rather than fabricate a completely new wheel, [Tommy] chose to rework the damaged one. After building a special arbor to hold the wheel, he turned it down on the lathe, leaving just the crossings and a narrow rim. A replacement blank was fabricated from brass and soldered to the toothless wheel, turned to size, and given a new set of teeth usin

While we might all be quick to grab a microcontroller and an appropriate sensor to solve some problem, gather data about a system, or control another piece of technology, there are some downsides with this method. Software has a lot of failure modes, and relying on it without any backups or redundancy can lead to problems. Often, a much more reliable way to solve a simple problem is with hardware. This heating circuit, for example, uses a MOSFET as a heating element and as its own temperature control . The function of the circuit relies on a parasitic diode formed within the transistor itself, inherent in its construction. This diode is found in most power MOSFETs and conducts from the source to the drain. The key is that it conducts at a rate proportional to its temperature, so if the circuit is fed with AC, during the negative half of the voltage cycle this diode can be probed and used as a thermostat. In this build, it is controlled by a set of resistors attached to a voltage regu

It’s been a long time since vacuum tubes were cutting-edge technology, but that doesn’t mean they don’t show up around here once in a while. And when they do, we like to feature them, because there’s still something charming, nay, romantic about a circuit built around hot glass and metal. To wit, we present this compact two-tube “spy radio” transmitter . From the look around his shack — which we love, by the way — [Helge Fykse (LA6NCA)] really has a thing for old technology. The typewriter, the rotary phones, the boat-anchor receiver — they all contribute to the retro feel of the space, as well as the circuit he’s working on. The transmitter’s design is about as simple as can be: one tube serves as a crystal-controlled oscillator, while the other tube acts as a power amplifier to boost the output. The tiny transmitter is built into a small metal box, which is stuffed with the resistors, capacitors, and homebrew inductors needed to complete the circuit. Almost every component used has

When it comes to reducing emissions from human sources, we’re at the point now where we need to take a broad-based approach. It’s not enough to simply make our cars more efficient, or start using cleaner power plants. We need to hit carbon zero, and thus everything has to change. To that end, even recreational watercraft are going electric in this day and age. Several companies are developing motor-powered models that deliver all the fun without the emissions. But to do that, they’re taking to the air. Wave Racers (Batteries Included) The jet ski is a simple enough craft to understand. You put a powerful combustion engine into a small hull big enough to stand or sit on. You pair it with a jet drive that squirts water out the back to propel it at great speed. The result is a lightweight, fun watercraft that pairs great agility and acceleration with noise loud enough to annoy wealthy lakeside residents. However, that formula doesn’t work as well when you try to shift to electric d