How To Get Into Cars: Aero Mods For More Grip

August 19, 2020 by Lewin Day 32 Comments

In 1960, Enzo Ferrari said “Aerodynamics are for people who can’t build engines”. It’s a quote that’s been proven laughably wrong in decades since. Aerodynamics are a key consideration for anyone serious about performance in almost any branch of motorsport. Today, we’ll take a look at how aero influences the performance of your car, and what modifications you might undertake to improve things.

Gains To Be Had

Improving the aerodynamics of your vehicle can mean wildly different things, depending on what your end goal is. Aerodynamics affects everything from top speed, to fuel economy, to grip, and optimizing for these different attributes can take wildly different routes. Often, it’s necessary to find a balance between several competing factors, as improvements in one area can often be detrimental in another.

To understand aerodynamics with regards to cars, we need to know about the forces of lift (or downforce), and drag. Drag is the force that acts against the direction of motion, slowing a vehicle down. Lift is the force generated perpendicular to the direction of motion. In the context of flight, the lift force is generated upwards with respect to gravity, lofting planes into the air. In an automotive context, we very much prefer to stay on the ground. Wings and aerodynamic surfaces on cars are created to create lift in the opposite direction, pushing the vehicle downwards and creating more grip. We refer to this “downwards lift” as downforce.

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Linux-Fu: One At A Time, Please! Critical Sections In Bash Scripts

August 18, 2020 by Al Williams 12 Comments

You normally think of a critical section — that is, a piece of a program that excludes other programs from using a resource — as a pretty advanced technique. You certainly don’t often think of them as part of shell scripting but it turns out they are surprisingly useful for certain scripts. Most often, a critical section is protecting some system resource like a shared memory location, but there are cases where a shell script needs similar protection. Luckily, it is really easy to add critical sections to shell scripts, and I’ll show you how.

Sometimes Scripts Need to Be Selfish

One very common case is where you want a script to run exactly one time. If the same script runs again while the original is active, you want to exit after possibly printing a message. Another common case is when you are updating some file and you need undisturbed access while making the change.

That was actually the case that got me thinking about this. I have a script — may be the subject of a future Linux-Fu — that provides dynamic DNS by altering a configuration file for the DNS server. If two copies of the script run at the same time, it is important that only one of them does modifications. The second copy can run after the first is totally complete.

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Inputs Of Interest: The Infogrip BAT Chording Keyboard

August 18, 2020 by Kristina Panos 32 Comments

I guess it shouldn’t surprise me that by researching weird and interesting keyboards, I would uncover more weird and interesting keyboards. This is the BAT personal keyboard by Infogrip, and it’s something I came across while researching the DataHand keyboard and mentally filed away as something cool to look into.

When I came across a used BAT for a reasonable price, I snagged it, even though it didn’t come with any of the manuals or software, not even a cord. Like I said, reasonable price. I looked these keyboards up and found out that you can buy them new for a lot more than what I paid.

My gently used BAT in all its angular glory.

The lowercase letter chords use either the middle thumb key or no thumb key. Image via Infogrip

So what is this thing? It’s a chording keyboard that’s meant to be used a standard PC input device by anyone who either can’t use a regular keyboard or has a need for speed. Years of research went into the BAT’s chording scheme, which was developed in conjunction with NASA’s Stennis Space Center.

Instead of stretching your fingers all over a regular keyboard, poking keys one at a time to spell out words, you press combinations of keys simultaneously, like playing chords on a piano.

You’re meant to use your thumb for the red, grey, and blue keys, and lay the other four on the rest of the keys. All of the alphabet keys are chorded with or without the gray thumb key, and all the number, symbol, and modifier keys are accessed through the red and blue layers.

Why would you want one of these? Well, given enough time to learn the chords, you can do anything a standard 104+ keyboard can do with only seven keys. You would never need to look down, not even for those weird seldom-used keys, and the only finger that ever travels is your thumb. All of this reduced hand/finger/wrist travel is going to be easier on the body.

The BAT lets you CAD like a madlad. Via Bill Buxton

The BAT is also part programmable macro pad, and from what I can gather, the main selling point was that you could quickly input shortcuts in CAD programs and the like, because you could keep one hand on the mouse.

The BAT came in both left- and right-handed versions that can be used either alone or together. Imagine how fast you could type if you chorded everything and split the typing duties between both hands! The only trouble is learning all those different finger combinations, although they say it doesn’t take that long.

So why is it called the BAT? Legend has it that it’s because company started out in Baton Rouge, Louisiana, but also because a pair of BATs sitting next to each other resembles a bat (PDF).

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E3D Teaches Additive 3D-Printers How To Subtract

August 18, 2020 by Sonya Vasquez 29 Comments

We might’ve thought that extrusion based 3D printers have hit their peak in performance capabilities. With the remaining process variables being tricky to model and control, there’s only so much we can expect on dimensional accuracy from extruded plastic processes. But what if we mixed machines, adding a second machining process to give the resulting part a machined quality finish? That’s exactly what the folks at E3D have been cooking up over the last few years: a toolchanging workflow that mixes milling and 3D printing into the same process to produce buttery smooth part finishes with tighter dimensional accuracy over merely 3D printing alone.

Dubbed ASMBL (Additive/Subtractive Machining By Layer), the process is actually the merging of two complimentary processes combined into one workflow to produce a single part. Here, vanilla 3D printing does the work of producing the part’s overall shape. But at the end of every layer, an endmill enters the workspace and trims down the imperfections of the perimeter with a light finishing pass while local suction pulls away the debris. This concept of mixing og coarse and fine manufacturing processes to produce parts quickly is a re-imagining of a tried-and-true industrial process called near-net-shape manufacturing. However, unlike the industrial process, which happens across separate machines on a large manufacturing facility, E3D’s ASMBL takes place in a single machine that can change tools automatically. The result is that you can kick off a process and then wander back a few hours (and a few hundred tool changes) later to a finished part with machined tolerances.

What are the benefits of such an odd complimentary concoction, you might ask? Well, for one, truly sharp outer corners, something that’s been evading 3D printer enthusiasts for years, are now possible. Layer lines on vertical surfaces all but disappear, and the dimensional tolerances of holes increases as the accuracy of the process is more tightly controlled (or cleaned up!) yielding parts that are more dimensionally accurate… in theory.

But there are certainly more avenues to explore with this mixed process setup, and that’s where you come in. ASMBL is still early in development, but E3D has taken generous steps to let you build on top of their work by posting their Fusion 360 CAM plugin, the bill-of-materials and model files for their milling tool, and even the STEP files for their toolchanging motion system online. Pushing for a future where 3d printers produce the finer details might just be a matter of participating.

It’s exciting to see the community of 3D printer designers continue to rethink the capabilities of its own infrastructure when folks start pushing the bounds beyond pushing plastic. From homebrew headchanging solutions that open opportunity by lowering the price point, to optical calibration software that makes machines smarter, to breakaway Sharpie-assisted support material, there’s no shortage of new ideas to play with in an ecosystem of mixed tools and processes.

Have a look at ASMBL at 2:29 in their preview after the break.

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The Mostly Forgotten Story Of Atmospheric Railway

August 17, 2020 by Jenny List 58 Comments

It doesn’t matter whether you know it as a railway, a railroad, a chemin de fer, or a 铁路, it’s a fair certainty that the trains near where you live are most likely to be powered either by diesel or electric locomotives. Over the years from the first horse-drawn tramways to the present day there haven’t been many other ways to power a train, and since steam locomotives are largely the preserve of museums in the 21st century, those two remain as the only two games in town.

But step back to the dawn of the railway age, and it was an entirely different matter. Think of those early-19th-century railway engineer-barons as the Elon Musks and Jeff Bezos’ of their day, and instead of space and hyperloop startups their playground was rail transport. Just as some wild and crazy ideas are spoken about in the world of tech startups today, so it was with the early railways. One of the best-known of these even made it to some real railways, I’m speaking of course about the atmospheric railway.

These trains were propelled not by a locomotive, but by air pressure pushing against a piston in a partially evacuated tube between the tracks.

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Open And Sustainable Engineering Hack Chat

August 17, 2020 by Dan Maloney No comments

Join us on Wednesday, August 19 at noon Pacific for the Open and Sustainable Engineering Hack Chat with Joshua Pearce!

Since the first of our hominid ancestors learned to pick up a rock and make it into a tool, we humans have been using our engineering skills to change the world. For most of the 2 million or so years since that first technological leap, natural materials like stone and wood were the focus of our engineering projects, and except for a few tantalizing remnants, most of what was built has returned to the Earth whence it came.

Then we discovered other materials; we learned to free metals from rocks and how to harvest the fossilized hydrocarbon remains of ancient plants. Iron, aluminum, plastic, and silicon became our stock in trade, and the planet is now layered so thick with these materials and the byproducts of harvesting them that a new geological epoch, the Anthropocene Epoch, has been proposed to cover this time of human activity and its impact on the geological record.

But if we humans are clever enough to make such an impact, we should be clever enough to think our way out of the mess, and wise enough to see the need. That’s where the efforts of Dr. Pearce’s research at the Michigan Tech Open Sustainability Technology (MOST) lab are focused. Dr. Pearce envisions a sustainable future powered by pervasive solar photovoltaic systems and using open-source technologies like 3D printing to drive new models for manufacturing. We’ve recently seen interesting work from his lab, like this grinder that makes custom compression screws for plastic recycling. The MOST page on Hackaday.io is filled with other great examples of the technology that supports their mission, from low-cost environmental testing instruments to 3D-printable microfluidics.

Dr. Pearce will join us on the Hack Chat to talk about open and sustainable engineering. Be sure to stop by with your questions and to find out what you can do to engineer a brighter future, starting right in your own shop.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 19 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Hackaday Links: August 16, 2020

August 16, 2020 by Dan Maloney 16 Comments

Potentially bad news for those of us who prefer not to be assimilated into the Google hive mind: Mozilla seems to be on the rocks. Citing revenue problems, the maker of Firefox and other popular tools will be trimming 250 employees, about a quarter of its workforce, and shuttering its office in Taipei. CEO Mitchell Baker specifically mentioned that “development tools, internal tooling, and platform feature development” in the Firefox team would see reduced investment. Like a lot of companies do these days, she managed to blame COVID-19 for the company’s woes. That seems a little specious to us, but whatever the reason for the downturn in revenue, here’s hoping that Mozilla can keep Firefox alive.

Speaking of our evil overlords, looks like it another one of those “oopsies” moment for Google when it “accidentally” activated some of its smart speakers to listen into household events without the wake word. In this case, a user reported getting a text about a smoke alarm going off in their home. The alarm was not a surprise, since the user was cooking at the time, but the notification was, since they didn’t opt into that particular service. Google’s response was that an update pushed to the speaker accidentally activated that feature, a situation that they say has since been rectified. To be clear, this is an interesting feature and one of the more compelling use cases we’ve seen for a smart speaker, but it’s something we’d certainly want to sign off on before it’s activated. Yes, accidents happen, but these kinds of accidents seem to happen to Google an awful lot lately.

We’ve probably all had the experience over the last few months of being in public when the urge to cough hits. Masked or not, you struggle to fight back the tickle, lest someone hear you and think you’re infected. But now it’s possible for a computer to cough-shame you, thanks to a deep learning cough locater. The model was trained against recordings of people coughing and is coupled to an acoustic camera, which identifies the cougher with a bounding box and a contour image of the cough which looks for all the world like a virtual cloud of microbes. It’s genuinely interesting technology, sort of the public health version of ShotSpotter, but we doubt it’ll be of much practical use in public; if you want to find someone who has just coughed, someone acting like this will likely already be on the case.

Modern jet fighter technology is advancing rapidly, so much so that the forces they can apply during extreme maneuvers can quickly be lethal to pilots. Given that humans aren’t likely to evolve the ability to resist turning into a puddle of goo under high g-forces anytime soon, fighters of the future will likely incorporate AI of some sort. To prepare for that eventuality, the Defense Advanced Research Projects Agency (DARPA) is running some AI fighter competitions this week that really look interesting. Dubbed Alpha Dogfight Trials, the challenge starts with simulated dogfights between AI systems. The winner of those rounds will go up against a human pilot in the final match, which will be streamed live with commentary and multi-screen coverage. You need to register to get in on the action, and time is limited.

And finally, let these three words roll around in your head for a minute: robotic chameleon tongue. It’s actually nowhere near as disturbing as it sounds, since at its heart the “Snatcher” is actually just a beefed-up tape measure. Designed for remote retrieval tasks, the Snatcher can shoots it steel proboscis out almost a meter in just 600 milliseconds. Its designers envision uses for it on drones, but we can see it potentially being deployed on satellites too. It shouldn’t be too hard to build something like this at home, either.