Kritik sah

As cool as it would have been to wield lasers that produce a beam of neutrinos, recently two papers were published by MIT researchers that seem to dampen the likelihood of such lasers being at all possible. In a review paper by [Ana Maria Rey] et al. these two papers are investigated in more detail. Although the concept behind a neutrino laser is rather simple, using the same superradiance effect involving a Bose-Einstein condensate (BEC) that allows for stimulation by photons to result in a synchronized direction of emitted photons, the idea of using a BEC of radioisotopes that naturally emit neutrinos in this fashion has now been effectively shot down. The problem lies in taking the leap from photons with a BEC and applying this to a BEC of radioisotopes. Whereas photons are relatively slow and low-energy at a mere 1 eV, a neutrino is extremely fast and at 1+ MeV correspondingly has a much greater kinetic effect on the particle that emitted it. Unlike a photon emitted by an atom...

Once you arrive at your destination via plane, it can be a drag waiting for a rental car. Why not bring your own with a replica of the Mazda suitcase car ? The heady days of the 90s brought us many wild vehicles from Japan, and in 1991, Mazda built three prototype go carts built inside Samsonite suitcases as a potential rival to the Honda Motocompo. After some appearances on the talk show circuit, two of the prototypes were destroyed, and the world moved on. [Bucket] felt wistful about the vehicle and decided it was time to build his own since the only remaining example is in collector hands, although they were able to reach out to the owner for more information on how the original prototypes functioned. Using a very small gas motor from a pocket rocket and a welded aluminum frame inside the suitcase, the builders managed to beat the stated top speed of the original, hitting 33 kph (20 mph) before the driver decided things were getting too frightening. The final build tips the scales...

Even if the world has already settled on plain old propellers as the way to make quadcopter drones fly, this doesn’t mean that you cannot give other designs a shake to see what kind of flying performance they result in. For example impeller designs that depart radically from standard propellers – themselves a sub-category of axial impellers – and go radically radial instead as in this design by [quadmovr] with accompanying demonstration video . This is itself a remix of a design by [Baba] to make it fit the target 1750KV T-mount motor. As for whether this is a design that you want to slap on your own quadcopter, the obvious disadvantage is that it’s much heavier than regular propellers. Weighing [quadmovr]’s drone without battery pack and with these 3D-printed PETG impellers shows them to weigh 189 grams. This compares to 141 grams with the standard three-bladed propellers, or a hefty 12.8 gram weight penalty per impeller. Naturally this translates into...

In the US, among other places, housing costs are skyrocketing. It can sometimes be difficult to get a feel for the scale of the issue and how it hits neighborhoods differently. [Justin Blinder] has designed a device to help people get a more visceral understanding of the problem . In New York City, Citi Bikes are everywhere in the city’s transportation landscape. [Blinder] used a GPS module plugged into an ESP32S3 to vary the amount of resistance on one of these bikes by actuating the front brake with a servo. As a rider takes the bike through different neighborhoods, the resistance varies in proportion to the rent burden experienced there. [Blinder] explains, “One of the main technical challenges was calibrating this relationship so that the changes were physically noticeable without feeling abrupt or unsafe.” As rent burden is merely the percentage of income taken up by rent in an area (by the block in this dataset), it is only one indicator of the additional frict...

Photodetectors come in a wide variety of constructions and materials, with the Cu 2 O-based photodetector that [Mad Scientist Creations] demonstrates in a recent video being a good example of a photodetector that can be created at home using nothing but some copper and a heat source. Of the two copper elements in a salt water cell, one element is heated to the point where a copper oxide layer forms, specifically Cu 2 O, which acts as a semiconductor and provides the photosensitive layer. Even a fairly crude sensor created with a regular gas stove produces enough of a current that it can be used in a simple light detection circuit. Although copper-oxide photodetectors may seem quaint, they are getting a lot of interest as they feature a very narrow bandgap at 1.2 eV. In a 2019 study by [Hyeon-Joo Song] et al. as published in  Scientific Reports such a sensor is enhanced with an optimized grain structure that improves its performance, with much higher sensitivity and faster response...

Some sad news to start this week off — after 52 years in business, Sherline has announced they are winding down their manufacturing operations . By the end of October they estimate they’ll have produced their last tool, and although they will no longer be making new products, they plan on supporting their existing customers for as long as possible. Although from the sound of the press release, that may mean simply keeping the website up and selling through their inventory of spare parts. The company offered a range of American-made miniature lathes and mills, and while their manual machines may have been better known in our community, they did eventually branch out into CNC. The press release doesn’t go into a lot of details the chain of events that lead up to this decision, but they do mention the challenges of modern manufacturing and the lingering after effects of the COVID pandemic. At first blush it might seem strange that the company would falter just as deskto...

TEMPEST attacks are often the most effective way to break air-gapped security: rather than directly accessing a computer, the attacker records the system’s unintended radio emissions and uses them to reconstruct its internal operations. This kind of attack was much more effective in the days of noisy, high-voltage CRT displays, and has gradually become less effective as electronics migrate to quieter, less powerful components. A group of researchers, however, has found that even modern electronics can become effective TEMPEST transmitters when irradiated with an RF signal. The RF a device emits depends on the unintentional antennas in its internal structure. These are difficult to eliminate, and it’s usually not worth the effort; they’re usually small enough that they only effectively radiate at much higher frequencies than the electronics carry. The researchers’ technique, called InjectEave, radiated these electronics with a radio frequency tuned to their internal antennas, in...

Getting rid of rodents like squirrels, mice, or groundhogs is a lot like digging a hole on the beach. No matter how much you remove, it’ll always fill back in. So, while [Super Valid Designs] could keep trapping and “removing” the mice in his chicken coop, more will always work their way back in. His theory is that removing them live from the chicken coop and placing them some distance away will be more effective, and with this semi-automated ski lift that traps them and carts them off, it might end up being less work too . The build comes to us in roughly two parts. The first is the gondolas, which not only cart the mice down the hill to freedom but also double as the mousetrap themselves. They are placed in the chicken coop, and a trap door on the ceiling with bait causes the mice to fall inside. 3D printed with acrylic windows, they are a luxurious way for a mouse to travel. At the bottom, another trap door opens onto a pile of brush, releasing the mice. The second...

Water timers are nifty devices that can water the lawn at set times or keep that vegetable garden from turning into a dustbowl. When [electronupdate] timer refused to output water on any of its three outlets, he did the right thing. Instead of angrily checking the warranty on the sodding thing, he tore it apart to attempt a repair . As expected, the design of these devices is quite straightforward. Three solenoids control whether an outlet is open or closed. A control board also handles the user controls and display. There was no obvious sign of damage, and the PCB was potted in a white substance that should have kept out any moisture. A quick check with a battery revealed that the three solenoids also worked just fine, so the cause likely was somewhere on the — potted — PCB. These solenoids are rated for 6VDC and take about 20 ms to act, but on an oscilloscope capture it was plain to see that the board was only putting out around 2V. This wasn’t enough to drive the...

The RP2350 is actually a pretty secure chip, all things considered. It has secure boot, ARMv8’s TrustZone to split secure and non-secure execution, and you can permanently disable debug — the Pi Foundation even included glitch detection, meaning the traditional ‘zap the chip until it obeys’ technique is blocked. That’s why the [Ledger Donjon] security team went full Bond Villain and strapped everyone’s favourite fruit-flavoured microcontroller to a table with a slowly-approaching laser beam. The bench setup to do all this is pretty impressive– and came with an impressive 250,000 USD price tag. Okay — movie clichés aside, the laser was in fact very carefully focused on target before they turned it on. That target was the register that enables the 2350’s debug features. Said register was located by decapsulating the chip and examining the die with photon-emission electron microscopy; the actual attack was carried out on a chip that had be...

A Linux handheld computer is, in theory, easy and inexpensive given the availability of single-board computers, but in practice the budget invariably edges well into three figures. There’s an interesting alternative from [bkovac] that won’t break the bank as much, using a cheap 4G wireless hotspot, an iPhone USB keyboard case accessory, and, though a cheaper display could suffice, a fancy Adafruit Sharp memory display. The hotspot is available from AliExpress for around 20 dollars/Euros/pounds, and it’s referred to by its model number, MF800. It’s powered by a Qualcomm MSM8916, also known as the Snapdragon 410, which you might have found in a budget cellphone early in the last decade. Importantly, though, it’s supported by mainstream Linux, and while it’s by no means the fastest on the block, it can be a poor man’s alternative to a Raspberry Pi. It comes with a small SPI display, but this project replaces it with a much bigger Sharp SPI memory...

This article is written on an open-source operating system, but not an open-source machine — the BIOS isn’t open-source, and even if it were supported by the coreboot project (formerly LinuxBIOS), there would still be a whole host of binary blobs required to get it to boot. On one vintage architecture, there’s one less blob, as coreboot can now initialize DRAM on Intel Bay Trail SOCs, as [Mate Kukri] presented in a talk at the recent Open Source Firmware Conference. Bay Trail isn’t exactly cutting-edge hardware, to be sure — the SoCs are over a decade old at this point, and were only used in low-performance mobile applications like Chromebooks. On the other hand, coreboot has been on Chromebooks for at least as long. Getting DRAM set up is difficult because, well, you don’t have any memory to work with until you do. Traditionally, the way you did that was to call on one of the many proprietary ‘binary blobs’ provided with next to no docum...

If you’ve used MicroPython much, you know that debugging usually amounts to printing a few things out, trying your code out, and then repeating. But [ghi-electronics] wants you to have full on-chip source-code debugging in Visual Studio . You don’t need anything special to use it — just a supported MicroPython host and the same USB cable you program with now. The downside is that you either have to build a custom MicroPython image and flash it or use one that they include. They support several Raspberry Pi Pico versions and ESP32 chips, as well. However, at least one “odd” Pico we had lying around wouldn’t take the firmware. A stock one did, and it worked as you would expect. A little more investigation showed the odd Pico (an RP2040 GEEK) probably did take the firmware; it just produced an error during setup. There is a known problem with Linux and the ESP32-S3 having similar behavior. Of course, you can build your own image, but now you are talki...

In 1982, desktop computers were coming into their own, and no clear leaders had emerged. But everyone knew they wanted a piece of the action. This led to, among other things, Sony’s SMC-70 , which, frankly, for 1982, was a good-looking, if not oddball, machine. [Tech Tangents] shows the machine off in a recent video. From the front, the computer looks more-or-less like everything else. But as you move backward, you can see this computer wasn’t another typical entry into the market. One of the things that was the hallmark of successful business computers of the day was expandability. The earlier Altair had the later-titled S100 bus. The IBM PC had the ISA bus. But in both cases, you had to open the box to plug and unplug cards. The SMC-70, though, had a very unique system. Instead of boards, users would line up modules and stab them with what amounted to skewers to mechanically secure the stack of modules. You could stack some modules vertically or horizontally using ribbo...

In the cross-over between the era of tapes into that of MP3s, you’d see quite a few of those special cassette tapes that were actually digital music players inside. Some simply provided a 3.5 mm input, while others were complete MP3 players or Bluetooth receivers that just happened to also output to the magnetic read head of a cassette player. Recently [Jonathan Rowny] decided to make his own version of the latter . Although getting the actual audio signal into the read head is easy enough – requiring little more than its equivalent being used as a write head on the cassette side – actually interfacing with the player’s mechanisms like auto-stop, reverse and so on requires the use of some gearing that detect motion on what would be the tape spools, as well as transfer the motion from the take-up spool to the other spool so that features like the auto-stop mechanism don’t get triggered. A lot of inspiration here can be found in e.g. the videos made by [Cli...

Before moving to land grid array (LGA) packaging whereby each pin on the substrate is just a copper pad, processors commonly used pin grid array (PGA) packaging, including the still highly relevant AMD AM4 socket. With PGA you get a pin soldered onto the copper pad which inserts into the ZIF socket, rather than a fragile pin on the mainboard side. Repairing a damaged PGA pin can be easy if just the pin broke off at the solder joint, or rough if the pad was destroyed, as in the case of this Pentium III CPU that [Bits und Bolts] recently tried to fix . In the case of something like a ground pin or similarly unimportant pin you can ignore the damage, but in this case it concerned an important pin for this 1.2 GHz Tualatin PIII core, with the damage consisting of a well and truly destroyed pad. The first step to repair the damage is thus to try and rebuild the pad, which was done using solder mask and solder. Although a PIII-era Celeron CPU is definitely not a high-value CPU, since they ...

Surveillance cameras from Flock Safety have become a controversial privacy battleground, as the communities in which they are installed wake up to their sinister potential, and stories roll in of law enforcement professionals abusing their access. One has had its disk contents dumped, and we’ve been treated to some insights courtesy of [Micah Lee] . In short: their approach to security is deeply flawed. It’s interesting to find that instead of a custom hardened OS, these devices run Android. Not just Android, but Android 8.1, a long out of support version originally released in 2017. This is is the year Flock Safety was founded, which may or may not be coincidental. Like any old version of a widely used operating system it has a host of known vulnerabilities, none of which are patched on this version. The Android version is small beer compared to the revelation that they contain a hard-coded and very open-access API key that can be used by any mildly curious miscreant to r...

The Cheap Yellow Display is an all-in-one ESP32 board with a touchscreen, that’s as the name suggests, cheap. It’s appeared in a great many projects since it emerged from the depths of AliExpress, and today thanks to [Nickm324] it takes the turn of becoming a mini TV . The tiny TV project world is one of successive developers building on previous works to deliver their own refinements on the idea, so this one borrows heavily from an earlier ESP32 project . Its twist on the idea is a single button interface using the CYD’s BOOT button. It supports a range of “channels” of which each one is a different piece of media played from the SD card. As far as we can see it’s only able to play synchronised .mjpeg and audio files, probably a shortcoming of the older ESP32 found on the CYD. The photo features a rather cutesy retro 3D printed TV case which annoyingly isn’t linked from the repository at the time of writing. It’s a nice idea, and the CY...

With an El Niño event in full swing those of us in the northern hemisphere have just had a roasting hot summer, and those in the southern are about to have one. We know what that means, even with the best laid plans the slightest bit of exercise is going to raise a lot of sweat. And if you’re carrying a backpack that means a soaking down your back. Never fear though, because for that one, [Crafterboi] is here with a fan-assisted back protector . The idea is simple enough, an open framework that sits between you and the backpack, allowing air to flow. If that weren’t enough, there are a couple of 5 volt fans at the top to blow air through the space. It’s printed using PETG, because as he explains, on a really hot day some surfaces can exceed the temperature at which PLA starts to soften. We like the idea of this project, but what we especially like is that his prototype was made of a pizza box. ten out of ten for resourcefulness! Meanwhile this isn’t the first t...

With the Earth’s atmosphere being effectively just a less dense fluid than the oceans around us, it’s reasonable to ask why we got wind turbines and wind mills quite literally everywhere across the globe to harvest the power in the wind, whereas ocean waves and currents aren’t being exploited quite as much. In a recent video by [Giordano Scarciotti] this issue with wave power is addressed, in particular the massive engineering challenges involved. Internal view of the CorPower Ocean wave turbine buoy. (Credit: CorPower Ocean) One of the main problems is simply one of cost, with wind energy having converged on a single design involving effectively the same three-bladed rotor, gondola and tower design that has been optimized for decades now. For wave energy there’s no such one-design-fits-all solution, with each attempted design having its own advantages and disadvantages that may prevent it from working in various sites, or incur high maintenance costs in the h...

Although things may seem simple on the North American grid as an end-user if you limit yourself to just 120 VAC and NEMA 1-15 and 5-15 connectors, there is a veritable zoo of different voltages and receptacles out there in the NEMA connector catalogue. Recently [Practical Engineering] decided to not only take a look at how many of these defined standards are actually used , but also put them in a nice periodic table style graphic. Responsible for these standards is the National Electrical Manufacturers Association (NEMA), which as the name says is a collection of manufacturers. Founded in 1926, this US trade association also affects outlet standards in countries like Canada, Mexico, Japan and so on. The caveat here is that compatibility between e.g. a similar looking Japanese 1-15-style plug and a US 1-15 outlet is not guaranteed, even if you ignore voltage and grid frequency differences. In an ideal world everyone would agree on a set of reasonable connector designs and we could mo...