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Hackaday Links: June 14, 2020

You say you want to go to Mars, but the vanishingly thin atmosphere, the toxic and corrosive soil, the bitter cold, the deadly radiation that sleets down constantly, and the long, perilous journey that you probably won’t return from has turned you off a little. Fear not, because there’s still a way for you to get at least part of you to Mars: your intelligence. Curiosity, the Mars rover that’s on the eighth year of its 90-day mission, is completely remote-controlled, and NASA would like to add some self-driving capabilities to it. Which is why they’re asking for human help in classifying thousands of images of the Martian surface. By annotating images and pointing out what looks like soil and what looks like rock, you’ll be training an algorithm that one day might be sent up to the rover. If you’ve got the time, give it a shot — it seems a better use of time than training our eventual AI overlords.

We got a tip this week that ASTM, the international standards organization, has made its collection of standards for testing PPE available to the public. With titles like “Standard Test Method for Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity)”, it seems like the standards body wants to make sure that that homebrew PPE gets tested properly before being put into service. The timing of this release is fortuitous since this week’s Hack Chat features Hiram Gay and Lex Kravitz, colleagues from the Washington University School of Medicine who will talk about what they did to test a respirator made from a full-face snorkel mask.

There’s little doubt that Lego played a huge part in the development of many engineers, and many of us never really put them away for good. We still pull them out occasionally, for fun or even for work, especially the Technic parts, which make a great prototyping system. But what if you need a Technic piece that you don’t have, or one that never existed in the first place? Easy — design and print your own custom Technic pieces. Lego Part Designer is a web app that breaks Technic parts down into five possible blocks, and lets you combine them as you see fit. We doubt that most FDM printers can deal with the fine tolerances needed for that satisfying Lego fit, but good enough might be all you need to get a design working.

Chances are pretty good that you’ve participated in more than a few video conferencing sessions lately, and if you’re anything like us you’ve found the experience somewhat lacking. The standard UI, with everyone in the conference organized in orderly rows and columns, reminds us of either a police line-up or the opening of The Brady Bunch, neither of which is particularly appealing. The paradigm could use a little rethinking, which is what Laptops in Space aims to do. By putting each participant’s video feed in a virtual laptop and letting them float in space, you’re supposed to have a more organic meeting experience. There’s a tweet with a short clip, or you can try it yourself. We’re not sure how we feel about it yet, but we’re glad someone is at least trying something new in this space.

And finally, if you’re in need of a primer on charlieplexing, or perhaps just need to brush up on the topic, [pileofstuff] has just released a video that might be just what you need. He explains the tri-state logic LED multiplexing method in detail, and even goes into some alternate uses, like using optocouplers to drive higher loads. We like his style — informal, but with a good level of detail that serves as a jumping-off point for further exploration.

Machine Builds Rise From The Ashes

I was enchanted by a failed project this week. [Andrew Consroe]’s CNC scroll saw doesn’t work yet, but the emphasis is on the word “yet”. Heck, even when it does work, it might not make sense, but that’s not the point anyway.

cncsaw_thumb.jpg?w=250

A scroll saw table has a vertical reciprocating blade perpendicular to a table, a lot like a band saw but with a shorter blade. You push the wood sheet to be cut into the blade, and because it’s thin, you can twist and turn all sorts of interesting jigsaw-puzzle shapes. [Andrew] automated this with an X-Y gantry and an innovative geared rotating ring, needed to keep the wood fed into the cutting edge of the blade.

It’s a crazy contraption, and a difficult and unique movement planning problem, and watching it move in the video is a joy. But it’s not working either: errors in the motion add up over a cut, and he’s ended up snapping a blade on every piece. And this is version three of the device!

But here comes the inspiration. First, the only reason he’s filming this is to keep a log of how the project looked at this phase — he’s already planning out the next one. Second, this is the soul of learning by doing. You don’t learn anything unless you’re trying something new.

And finally, [Andrew]’s project reminds me of why I love machine builds in the age of rapid prototyping. Blazing through three entirely different machines cost him essentially nothing. Tearing apart version one left him with the same stepper motors, aluminum extrusions, and electronics as when he started out. Except that he now knew so much more about his particular problem space. Now he’s ready to go again.

So if you’re at all robotically inclined, but you’re looking at the cost of motors, belts, bearings, and steel, don’t think of it as an expense for this project, but for years’ worth of iterations, and maybe even fully different machines.

Just be sure to take [Andrew]’s lead and get it down and documented before you take it apart! Heck, send it in to Hackaday and it’ll live forever.

This Week In Security: Crosstalk, TLS Resumption, And Brave Shenanigans

Intel announced CrossTalk, a new side-channel attack that can leak data from CPU buffers. It’s the same story we’ve heard before. Bits of internal CPU state can be inferred by other processes. This attack is a bit different, in that it can leak data across CPU cores. Only a few CPU instructions are vulnerable, like RDRAND, RDSEEED, and EGETKEY. Those particular instructions matter, because they’re used in Intel’s Secure Enclave and OpenSSL, to name a couple of important examples.
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Hackaday Podcast 071: Measuring Micrometers, The Goldilocks Fit, Little Linear Motors, And 8-bit Games On ESP32

Hackaday editors Mike Szczys and Elliot Williams fan through a fantastic week of hacking. Most laser cutters try to go bigger, but there’s a minuscule one that shows off a raft of exotic components you’ll want in your bag of tricks. Speaking of tricks, this CNC scroll saw has kinematics the likes of which we’ve never seen before — worth a look just for the dance of polar v. Cartesian elements. We’ve been abusing printf() for decades, but it’s possible to run arbitrary operations just by calling this Turing-complete function. We wrap the week up with odes to low-cost laptops and precision measuring.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

Continue reading “Hackaday Podcast 071: Measuring Micrometers, The Goldilocks Fit, Little Linear Motors, And 8-bit Games On ESP32”

Retrotechtacular: Wire Splicing The Army Way

For those of us who started experimenting with electricity when we were very young, one of the essential first skills was learning how to twist wires together. It seems like there’s not much to learn, but after a few failed attempts with nothing but your fingers, you learned a few tricks that are probably still with you to this day. It’s not surprising, then, that there’s an official US Army way to twist wires together, as this Signal Corps training film from 1941 shows.

Considering that the Signal Corps had nearly 80 years of experience with wiring battlefield communications at the outbreak of World War II, their methods were pretty solid, as were their materials. The film mainly concerns the splicing together of rolls of type W110-B field wire, used by the Signal Corps to connect command posts to forward positions, observation posts, and the rear echelons. More often than not laid directly upon the ground, the wire had to be tough, waterproof, and conductive enough that field telephone gear would still work over long loop lengths. As such, the steel-reinforced, rubber-and-fabric clad cable was not the easiest stuff to splice. Where we might cringe at the stresses introduced by literally tying a conductor in knots, it was all part of the job for the wire-laying teams that did the job as quickly as possible, often while taking enemy fire.

The film also has a section on splicing a new line into an existing, in-service circuit, using a T-splice and paying careful attention to the topology of the knots used, lest they come undone under stress. It’s fascinating how much thought was put into something as mundane as twisting wires, but given the stakes, we can appreciate the attention to detail.

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A Beginner’s Guide To Lithium Rechargeable Batteries

Batteries were once heavy, awkward things, delivering only a limp amount of current for their size and weight. Thankfully, over time, technology has improved, and in 2020, we’re blessed with capable, high-power lithium polymer batteries that can provide all the power your mobile project could possibly need. There are some considerations one must make in their use however, so read on for a primer on how to properly use LiPos in your project!

So Many Types!

With the first commercial lithium-ion battery entering the market in 1991, the (nearly) 30 years since have seen rapid development. This has led to a proliferation of different technologies and types of battery, depending on construction and materials used. In order to treat your batteries properly, it’s important to know what you’ve got, so paying attention to this is critical. Continue reading “A Beginner’s Guide To Lithium Rechargeable Batteries”

Surviving The Pandemic As A Hacker: Making A Mask Of Your Very Own

As the COVID-19 pandemic has continued along its way through the world, our community has responded as it always does, by designing and making things intended to solve the problems thrown up by the situation we find ourselves in. Much of this effort has gone into the production of PPE to plug the gap and many essential staff have been protected by maker-provided equipment, while the remainder of the effort has produced a wide array of clever designs for COVID-related items.

With curves flattened in many areas, Governments around the world are now encouraging the wearing of face masks in everyday social interactions. The purpose of mask for the general public is for droplet catching rather than virus filtering, and home made masks easily accomplish this. So let’s take a look at what you need to know about making a mast of your very own.

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