Magnetic Couplings Make This Lego Submarine Watertight

Although you’d be hard-pressed to tell in some areas, it’s summer in the northern hemisphere, which always seems to bring out the projects that require a swimming pool for adequate testing. The [Brick Experiment Channel]’s latest build, a submersible made almost entirely from Lego, is one such project and has us pining for weather that makes a dip sensible rather than suicidal.

The sub featured in the video below is a significant improvement over the “Sub in a Jug” approach the [Brick Experiment Channel] favored for version 1. Rather than starting with a vessel specifically designed not to hold water, the hull for this vessel is an IKEA food container, with a stout glass body and a flexible lid with silicone seals. And instead of penetrating the hull for driveshafts and attempting to seal them, this time around he built clever magnetic couplings.

The couplings transmit torque from the motors on the inside to gears and props on the outside. And where the first version used a syringe-pump ballast tank to control the depth, this one uses vertical thrusters. The flexible lid proved to be a problem with that scheme, since it tended to collapse as the depth increased, preventing the sub from surfacing. That was solved with some Lego bracing and adjustment of the lead shot ballast used to keep the sub neutrally buoyant.

This looks like a ton of summer fun, and even if you don’t have Legos galore to work with, it could easily be adapted to other materials. There are a ton of other fun [BEC] Lego builds to check out, some of which we’ve covered, including a Lego drone and a playing card shooter.

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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.

Custom Lego Server Case Looks As Though It Came Straight From A Data Center

The picture above appears to show two unremarkable 2U rack servers, of the kind that are probably hosting the page you’re reading right now. Nothing special there – until you look carefully and realize that the rack server case on the left is made entirely from Lego. And what’s more, the server even works.

When it comes to building Lego computers, [Mike Schropp] is the guy to call. We’ve previously featured his Lego gaming computer, a striking case wrapped around what was a quite capable machine by 2016 standards, as well as an earlier case that reminds us a little of a NeXT. His reputation for Lego-clad computers led server maker Silicon Mechanics to commission a case for a trade show, and [Mike] jumped at the challenge.

Making a home-grade machine is one thing, but supporting all the heavy drives, power supplies, and fans needed to make the machine work is something else. He used a combination of traditional Lego pieces along with a fair sampling of parts from the Lego Technics line to pull off the build, which looks nearly perfect. Sadly, the Lego unit sizes make the case slightly taller than 2U, but that’s a small quibble when everything else matches so well, even the colors. And the fact that the server works, obviously important for a trade show demo, is pretty amazing too. The power supplies are even hot-swappable!

Congratulations to [Mike] on yet another outstanding Lego creation.

FOSSCON 2018: Where Open Source And LEGO Collide

It probably won’t come as a surprise to anyone reading this, but hackers and makers absolutely love LEGO. We think you’d be hard pressed to find a Hackaday reader, young or old, that hasn’t spent some quality time with the little plastic bricks from Billund, Denmark. So it follows that there’s a considerable community of individuals who leverage their better than average technical prowess to utilize LEGO in new and unique ways. But the activities and history of these LEGO hackers is not exactly common knowledge to those who aren’t heavily vested in the hobby.

During the recent FOSSCON 2018 in Philadelphia, Daniel Pikora gave attendees a comprehensive look at the intersection of open source development and the world’s most popular brand of construction toys. A software developer with a penchant for open source code by trade, he’s also an avid member of what’s known as the Adult Fan of LEGO (AFOL) community who’s exhibited his creations at shows across the United States and Canada. Such a unique perspective, with a foot in both the FOSS and LEGO camps, makes Daniel an ideal tour guide for this particular microcosm of toys and tech.

In a whirlwind presentation that took attendees through 49 slides in about as many minutes, Daniel covered LEGO’s beginnings in the 1930s to the rise of 3D printed custom bricks, and everything in between. Some of the engineering-centric product lines, such as Technic and Mindstorms, were already fairly well known to the types of folk who spent a beautiful Saturday in Philadelphia at an open source conference. But Daniel’s deep-dive into the long history of open source LEGO projects brought to light the work of so many dedicated developers that everyone walked away with a newfound respect for the amount of work the AFOL community has put into elevating LEGO from a child’s toy to a legitimate tool. Join me below for a look at the particulars of that deep dive.

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Freakishly Agile Crawler Rocks All-LEGO Mechanum Wheels

Mechanum wheels are great, but you have to have them perfectly alined or they come across a little clunky, giving your robot a herky-jerky movement. Robotics educator and supreme LEGO builder [Yoshihito Isogawa] built a mechanum-wheeled rover that has the angles right: each wheel consists of 12 smaller rubber tires angled at 45 degrees. The key to the project is Part Number 85940, accurately if unsexily named “double Ø4.85 hole w/ Ø3.2 shaft”. It consists of a double technic hole with a shaft projecting in a 45-degree angle.

Unlike his omni-roller project with 3 large wheels and the mechanum tank treads he built for another project, this one features the gold standard of mechanum movement: creepy agility. He also did a version with 9 side rollers per wheel, and it was nearly as stable.

Hackaday loves [Yoshihito]’s great creations, which are as beautiful and elegant as they are functional. His all-LEGO centrifugal pump and his spirograph machine make expert use of parts to make the builds as simple as possible.

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LEGO Technics Machine Produces True Braided Rope

We love a good LEGO build as much as anyone, but Technics takes it to the next level in terms of creating working mechanisms. And nobody takes Technics as far as [Nico71], as evidenced by his super-fast Technics rope braiding machine.

The last time we saw one of [Nico71]’s builds, it was also a LEGO Technics rope-making machine. At the time, we called it a “rope-braiding machine” and were taken to task in the comments since the strands were merely twisted to make the final product. [Nico71] must have taken that to heart, because the current build results in true braided cordage. That trick is accomplished by flying shuttles that are not attached to either of the two counter-rotating three-spoked wheels. The shuttles are transferred between the two wheels by a sweeper arm, each making a full revolution with one wheel before being transferred to the other. Each shuttle’s thread makes an intertwining figure-eight around the threads from the two fixed bobbins, and the result is a five-strand braided cord. The whole machine is mesmerizing to watch, and the mechanism is silky smooth even at high speeds. It seems like a much simpler design than the previous effort, too.

You’ve got to hand it to builders like [Nico71] that come up with fascinating machines while working within the constraints of the Technics world. And those that leverage the Technics platform in their builds can come up with pretty neat stuff, like this paper tape reader for a music machine.

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Lego Technic Of The Past Eliminates Apple ][ With Arduino And Touchscreen

[JAC_101], the Director of Legal Evil Emeritus for LVL1 Hackerspace (don’t ask me, it’s their title system), was challenged to a hacking duel. It all started years ago. The person who is now president of LVL1, visited the space for the first time and brought with her a discarded Apple II controller for Lego bricks which had previously belonged to her father. Excited to test it, the space found that, unfortunately, LVL1’s Apple II wouldn’t boot. An argument ensued, probably some trash talking, and [JAC_101] left with the challenge: Could he build an Arduino interface for the Apple II Lego controller quicker than the hackerspace could fix its Apple II?”

Other things that belonged to people's fathers.
Other things that belonged to people’s fathers.

In the end, a concentrated force by one hacker over two years overcame the collective ADHD of many. He began by opening the interface to look inside, a completely unnecessary step since he found it was already thoroughly documented. Next he forgot about the project for a year. Then he remembered it, and built an interface for an Arduino Uno to hook to the controller and wrote a library for the interface. Realizing that sending serial commands was not in line with the original friendly intention of the device, he added a graphical display to the project; which allowed the user to control the panel with touch. In the end he won the challenge and LVL1 still doesn’t have a working Apple II. We assume some gloating occurred. Some videos of it in action after the break.

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