Monthly Archives: April 2022

Source: Hack a Day

It’s a fair bet that anyone regularly reading Hackaday has a voltmeter within arm’s reach, and there’s a good chance an oscilloscope isn’t far behind. But beyond that, things get a little murky. We’re sure some of you have access to a proper lab full of high-end test gear, even if only during business hours, but most of us have to make do with the essentials due to cost and space constraints.

The ideal solution is a magical little box that could be whatever piece of instrumentation you needed at the time: some days it’s an oscilloscope, while others it’s a spectrum analyzer, or perhaps even a generic data logger. To simplify things the device wouldn’t have a physical display or controls of its own, instead, you could plug it into your computer and control it through software. This would not only make the unit smaller and cheaper, but allow for custom user interfaces to be created that precisely match what the user is trying to accomplish.

Wishful thinking? Not quite. As guest host Ben Nizette explained during the Software Defined Instrumentation Hack Chat, the dream of replacing a rack of test equipment with a cheap pocket-sized unit is much closer to reality than you may realize. While software defined instruments might not be suitable for all applications, the argument could be made that any capability the average student or hobbyist is likely to need or desire could be met by hardware that’s already on the market.

Ben is the Product Manager at Liquid Instruments, the company that produces the Moku line of multi-instruments. Specifically, he’s responsible for the Moku:Go, an entry-level device that’s specifically geared for the education and maker markets. The slim device doesn’t cost much more than a basic digital oscilloscope, but thanks to the magic of software defined instrumentation (SDi), it can stand in for eleven instruments — all more than performant enough for their target users.

So what’s the catch? As you might expect, that’s the first thing folks in the Chat wanted to know. According to Ben, the biggest drawback is that all of your instrumentation has to share the same analog front-end. To remain affordable, that means everything the unit can do is bound by the same fundamental “Speed Limit” — which on the Moku:Go is 30 MHz. Even on the company’s higher-end professional models, the maximum bandwidth is measured in hundreds of megahertz.

Additionally, SDI has traditionally been limited to the speed of the computer it was attached to. But the Moku hardware manages to sidestep this particular gotcha by running the software side of things on an internal FPGA. The downside is that some of the device’s functions, such as the data logger, can’t actually live stream the data to the connected computer. Users will have to wait until the measurements are complete before they  pull the results off, though Ben says there’s enough internal memory to store months worth of high-resolution data.

Of course, as soon as this community hears there’s an FPGA on board, they want to know if they can get their hands on it. To that end, Ben says the Moku:Go will be supported by their “Cloud Compile” service in June. Already available for the Moku:Pro, the browser-based application allows you to upload your HDL to the Liquid Instruments servers so it can be built and optimized. This gives power users complete access to the Moku hardware so they can build and deploy their own custom features and tools that precisely match their needs without a separate development kit. Understanding that obsolescence is always a problem with a cloud solution, Ben says they’re also working with Xilinx to allow users to do builds on their own computers while still implementing the proprietary “secret sauce” that makes it a Moku.

It’s hard not to get excited about the promise of software defined instrumentation, especially with companies like Liquid Instruments and Red Pitaya bringing the cost of the hardware down to the point where students and hackers can afford it. We’d like to thank Ben Nizette for taking the time to talk with the community about what he’s been working on, especially given the considerable time difference between the Hackaday Command Center and Liquid’s Australian headquarters. Anyone who’s willing to jump online and chat about FPGAs and phasemeters before the sun comes up is AOK in our book.

The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Source: Ars Technica

Enlarge / Elon Musk at a press conference at SpaceX's Starbase facility in Texas on February 10, 2022. (credit: Getty Images | Jim Watson)

Twitter's board of directors has agreed to sell the company to Elon Musk for $44 billion, the company announced today.

"Free speech is the bedrock of a functioning democracy, and Twitter is the digital town square where matters vital to the future of humanity are debated," Musk said in the purchase announcement.

The deal, which is pending shareholder approval and expected to close later this year, comes just 10 days after the Twitter board approved a poison pill to prevent a hostile takeover in response to Musk's attempt to buy the company. Board members started taking Musk's offer more seriously after he lined up $46.5 billion in financing. The sale agreement was announced hours after reports that a deal between Twitter and Musk was close.

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Source: Hack a Day

At the intersection of saving a few bucks and expensive home insurance claims due to a house fire, we find clones of certified and tested electrical connectors, even when many would argue that so-called wire nuts are fire hazards no matter how many certification labels are on them. When it comes to no-fuss wire connectors, Wago clamp connectors are an attractive target to save some money on due to their perceived high cost. But how expensive are they really?

This was the thought behind a recent video by [GreatScott!] (also embedded after the break) when he hopped onto everyone’s favorite e-commerce website and searched for ‘clamp lever terminal’. The resulting selection of seven connectors come in a wide variety of shapes, colors and configurations, though all are supposedly rated for mains (250 VAC) voltage and safe enough to put into a permanent installation.

While running the connectors through their paces with high-current, fire and mechanical strength tests, the conclusion was that all are good enough for hobbyists use and some brief connections while testing, but that only the ones with independent certification marks (like VDE) filled him with enough confidence to consider using in house wiring. One of these being the connectors by the German brand ViD, which would seem to be a slightly cheaper alternative to the Wago connectors, with similar guarantees of safety.

At the end of the day it is the certification that matters, after all, since long-term reliability is of primary concern with house wiring, not whether a few Euros were saved on material costs.

Source: The Week: Most Recent Home Page Posts

After extensive studies of how COVID spreads, scientists and policy makers are focusing on indoor air quality. Here's everything you need to know:

What do we know?

One of the most powerful tools for limiting the spread of COVID-19 has been right in front of our noses: purifying the air we breathe. After extensive studies of outbreaks, superspreader events, and aerosol dynamics, epidemiologists who specialize in respiratory disease have warned that maintaining 6 feet of distance from others isn't sufficient to avoid indoor infection. It took the World Health Organization more than a year to acknowledge that COVID doesn't just travel via large respiratory droplets that fall to the ground quickly, but also spreads in tiny, aerosolized particles that can linger in the air like a fine mist for hours. As mask mandates are lifted, this underscores how crucial it is to keep air flowing in crowded indoor places, by equipping buildings with ventilation systems that pump virus-laden air outside, and with filtration devices that trap viral particles. Think of aerosolized virus as cigarette smoke, said Joseph Allen, director of Harvard's Healthy Buildings Program. "If I'm smoking in the corner of a classroom and you have low ventilation/filtration, that room is going to fill up with smoke," Allen said. But outdoors, he said, "you could be a couple of feet from me, depending which way the wind was blowing, you may not even know I'm smoking."

How does the coronavirus travel?

Every time we exhale, air rushes out of our lungs and through our nose and mouth in a warm cloud of respiratory fluid. Droplets that emerge when we yell or cough can be as wide as a strand of human hair, but the coronavirus travels mainly through the millions of aerosols — droplets just a few thousandths of a millimeter wide — released with each breath. In a crowded, poorly ventilated room, up to 4 percent of each inhalation is someone else's breath; University of Oregon researchers found there was not much difference between the number of aerosol particles shared between people standing 4 feet versus 11 feet apart. Humidity helps, however. Studies indicate that in dry places, like many offices and restaurants, respiratory droplets travel farther and longer. 

Where do infections occur?

Mostly indoors. There have been very few reports of outdoor transmission, even when tens of thousands of people converge for concerts or sporting events, because there's unlimited ventilation outside. One of the first COVID superspreader events — at a March 2020 choir rehearsal in Washington state — highlighted the limitations of indoor social distancing. Despite taking steps to spread out singers in the church, 52 out of 61 participants tested positive for COVID within a few weeks, and two choir members died. Scientists point out that the more people there are in an indoor space, the greater the risk one of them is infectious and emitting invisible clouds of virus. That explains why crowded restaurants, gyms, and conference rooms with poor circulation have produced many outbreaks. 

How can ventilation help?

It brings in fresh air and pumps out air that people have exhaled, thus diluting the concentration of possible coronavirus particles. (It also reduces the risk of catching the flu and cold viruses, which also spread through the air.) A study of more than 10,000 classrooms in Italy found that good ventilation systems reduced COVID transmission by 82.5 percent. Airplanes are another good example of ventilation in action. Sitting in an aircraft cabin is one of the safest ways to travel, since half of the air passengers breathe comes from outside the plane, and the other half is recirculated through high-efficiency particulate air (HEPA) filters that provide a minimum capture efficiency of 99.97 percent — better than in most buildings. You can, however, be infected on a plane if you're sitting next to an infected person.

What steps should be taken?

Just opening windows improves ventilation, especially when they're at opposite ends of a room. Portable HEPA filters are effective, and UV light has also proven to be effective when used to treat air passing through a building's heating, ventilation, and air-conditioning system (HVAC). Experts are also publicizing the folly of using plexiglass dividers to shield people from one another's breath. Studies show that while these barriers might block a spray of droplets, like sneeze guards at salad bars, they also impede air circulation and may serve to raise the risk of infection. 

Is good ventilation commonplace?

No, which is why the White House recently released an action plan for improving indoor air quality to fight the spread of COVID. For decades, engineers have prioritized making buildings more energy efficient, favoring recirculation over ventilation. Pumped-in outdoor air needs to be cooled or heated, and in a typical commercial building, HVAC accounts for up to 40 percent of total energy expended; that percentage rises when thick MERV 13 filters are installed to capture aerosols. Overhauling HVAC systems is expensive, so there will be resistance, said Linsey Marr, an engineering professor at Virginia Tech. "To put some teeth into this,'' she said, "there will need to be standards and regulations. And those will take years."

Air-quality problems in schools

The average U.S. public school building is more than 45 years old, and many have outdated or poorly functioning HVAC systems, according to the Government Accountability Office. During the pandemic, some desperate schools left windows open during frigid winter months to improve ventilation. Facing enormous pressure to improve air quality and reduce the risk of COVID outbreaks, public schools earmarked an estimated $4.4 billion for HVAC projects. A study of Georgia schools found that improved ventilation and HEPA filtration led to a 48 percent lower COVID rate. As a stopgap, school districts across the country also spent tens of millions of dollars on portable air purifiers, which often overstate their effectiveness and are known to release ozone particles, which can cause asthma in developing lungs. The best solution is to upgrade HVAC systems to provide frequent air turnover, said Tracy Washington Enger, an indoor-air specialist with the Environmental Protection Agency. To enable the transition to living with COVID as "an endemic disease," she said, schools need "long-term, effective management strategies that address indoor air quality." 

This article was first published in the latest issue of The Week magazine. If you want to read more like it, you can try six risk-free issues of the magazine here.

Source: Hacker News

Source: adafruit industries blog

Sabukaru Online looks at the utility of the keyboard equipped mobile phones from turn of the century.

Urban infrastructure has a lot to do with the standardization of smartphone designs. The way our phones are designed has a lot to do with how they’ll interact with the “smart cities” of the future. Standardizing the design of common communication devices makes the experience many people have with their devices, apps, and consumers more uniform.

Don’t get me wrong, there are many amazing things you can do with an iPhone but using it as the tool for essayists isn’t one of them. Part of the fun of being a writer is the experience of actually writing.

Have you ever typed on a typewriter? The feeling you get from that is pretty fun, so much so that more modern companies have tried to emulate that technology of old, giving today’s writers the classic feel of a typewriter. The sounds, the confirmation, you get seeing each letter pressed onto the page. It’s all very eventful. Input devices can indeed affect our processes and ideas about the world.

The author looks at two modern devices which provide similar experiences: the F[x] Tec Pro1 and the Unihertz Titan (below). See the article for more detail.

Source: Published articles

Hell yeah Dan, hell yeah.

Source: Ars Technica

Enlarge (credit: Getty Images | Aurich Lawson)

Google has announced a bizarre policy that effectively bans call-recording apps from the Play Store. As part of Google's crackdown on apps that use Android's accessibility APIs for non-accessibility reasons, Google says call recording is no longer allowed via the accessibility APIs. Since the accessibility APIs are the only way for third-party apps to record calls on Android, call-recording apps are dead on Google Play.

NLL Apps—the developer of a call-recording phone app with a million downloads on the Play Store—has been tracking the policy change. The Google Play support page lays down the new law, saying: "The Accessibility API is not designed and cannot be requested for remote call audio recording." Google's ban kicks in on May 11, the first day of Google I/O, oddly.

There's no clear reason why Google is banning call recording from the Play Store. Many jurisdictions require the consent of one or more members of a call in order to start recording, but once you meet that requirement, recording is entirely legal and useful. The Google Recorder app is a product built entirely around the usefulness of recording conversations. Google doesn't seem to have a problem with call recording when it comes to its own apps, either—the Google Phone app on Pixel phones supports call recording in some countries. Google just doesn't provide the proper APIs to let third-party app developers compete with it in this market, and now it's shutting down their attempted workarounds.

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Source: The Week: Most Recent Home Page Posts

My personal superpower is that I always somehow pick the slowest line to stand in. I had occasion to muse on this fact on Sunday night ahead of a concert at New York's United Palace Theatre, when I hopped over to what appeared to be the shorter bag-check queue — only, inevitably, to end up behind someone who wanted to argue with the security guard over the venue's bag policy. Just my luck.

But my irritation at the hold-up turned into astonishment as I eavesdropped on the conversation: The guard was telling the ticketholder she couldn't enter unless she threw away her Ricola cough drops.

Now, I'm not a security expert, but it's hard to imagine how cough drops endanger to anyone's safety at a concert. (Examining the venue's lengthy list of prohibited items later, my only guess is that they qualified as "drugs.") But it's also not the first time I've been astonished at the strict — and arbitrary and out-of-control — bag policies at stadiums.

Anecdotally, if anything, they seem to be getting more egregious. Last year, I was almost denied entry to an Arizona Diamondbacks game when the guard insisted on measuring my iPhone-sized clutch (I passed, but just barely). I'm already in the process of shopping for a semi-stylish see-through bag just so I can be allowed into Mets games this season with my phone, keys, pencil, and scorebook.  

Yes, stadiums are a place where security ought to be high. But culturally, we're perhaps unduly haunted by fears of bags, from the backpack that smuggled the weapon into Columbine High School to the pressure cooker bombs hidden near the Boston Marathon finish line. But today's increasingly elaborate bag policies are largely a case of security theater. It also unfairly targets women (who tend to be the primary carriers of bags even in mixed-gender groups and whose clothes have smaller pockets for accommodating things like keys or large smartphones); new parents (diaper bags); and people with special needs or disabilities who need to bring along extra gear.

It's not even evident that bag policies work. "Let's be honest: There's one hundred ways to bring a gun or a knife into an NFL stadium, and no clear bag is going to stop that," one commenter told Sports Illustrated in 2019. "If two boys can sneak into the Super Bowl and make a YouTube video documenting it, I'm pretty sure someone can sneak a weapon in." Another grumbled, "You can carry a purse on an airplane, but you can't bring it into a football game." Both are fair points.

And while a small or clear bag might ostensibly speed up the screening process to get into the venue, clear bags still need to be "searched" like an opaque bag would be: "You have to look inside to see if anything contains a firearm," Michael Dorn, the executive director of the school safety nonprofit Safe Havens International, explained to Bloomberg in relation to schools adopting clear bag policies. Besides — as Bloomberg goes on to elucidate — "pistols and knives can be hidden in transparent bags just as easily as tampons can … [i]nside tennis shoes, or wrapped up in T-shirts."

The bizarrely restrictive rules about what otherwise normal items you can put inside those bags are no better, and those unintuitive distinctions further complicate the search process. Is that unmarked blister pack holding forbidden Benadryl or acceptable chewing gum? We'll have to check.

There have been too many tragedies at mass gatherings to skip stadium security altogether. But that doesn't mean anything and everything is reasonable, and bag policies in America have crossed the line. I should be able to attend a concert or baseball game with more than a glorified ziplock. Because where else would I keep my Ricola?