Building And Flying A Helicopter With A Virtual Swashplate

June 25, 2020 by Dan Maloney 33 Comments

They say that drummers make the best helicopter pilots, because to master the controls of rotary-wing aircraft, you really need to be able to do something different with each limb and still have all the motions coordinate with each other. The control complexity is due to the mechanical complexity of the swashplate, which translates control inputs into both collective and cyclical changes in the angle of attack of the rotor blades.

As [Tom Stanton] points out in his latest video, a swashplate isn’t always needed. Multicopters dispense with the need for one by differentially controlling four or more motors to provide roll, pitch, and yaw control. But thanks to a doctoral thesis he found, it’s also possible to control a traditional single-rotor helicopter by substituting flexible rotor hinges and precise motor speed control for the swashplate.

You only need to watch the slow-motion videos to see what’s happening: as the motor speed is varied within a single revolution, the tips of the hinged rotor blades lead and lag the main shaft in controlled sections of the cycle. The hinge is angled, which means the angle of attack of each rotor blade changes during each rotation — exactly what the swashplate normally accomplishes. As you can imagine, modulating the speed of a motor within a single revolution when it’s spinning at 3,000 RPM is no mean feat, and [Tom] goes into some detail on that in a follow-up video on his second channel.

It may not replace quadcopters anytime soon, but we really enjoyed the lesson in rotor-wing flight. [Tom] always does a great job of explaining things, whether it’s the Coandă effect or anti-lock brakes for a bike.

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3D-Printed Tools Make Circuit Sculpture A Little Easier

June 24, 2020 by Dan Maloney 7 Comments

Having the tools needed to do a job is a powerful thing. Having the tools needed to make more tools for doing cool things is even better, though, and that’s where [Jiří Praus] took things with this 3D-printed jig for making his blooming tulip circuit sculpture.

If you haven’t seen [Jiří]’s tulip, check out our coverage from back when he first built it. The brass wire and tube mechanism and some clever linkages let a single servo open the Neopixel-adorned petals at a touch. But what started as a one-off romantic gesture for his wife on Valentine’s Day became something more, and what was a labor of love turned into just labor very quickly. [Jiří]’s solution, explained in the brief video below, is a 3D-printed jig that holds all the wires that form the tulip petals locked into position. The wire that defines the spine of the petal goes into a groove and gets held down with removable clips. The edge wires are held by rotating clips, and the veins of the petals just lay in place in grooves. The area around each joint is hollowed out so [Jiří] can solder easily without melting the plastic jig.

The best part comes at the end, when it’s time to release the completed petal. For that, a tool with pins that looks a little like a hedgehog is inserted from below, and pins that fit into each joint’s hole pop the finished petal off. We can see how this tool would greatly increase the production of his tulips, so if that’s his goal, he’s on track.

If you’re into circuit sculpture, you’re in the right place. Check out [Mohit Bhoite]’s Supercon talk on the subject, or some more of the tools [Jiří] has come up with to improve his art.

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Gigatron Hack Chat

June 22, 2020 by Dan Maloney 6 Comments

Join us on Wednesday, June 24 at noon Pacific for the Gigatron Hack Chat with Walter Belgers!

There was a time when if you wanted a computer, you had to build it. And not by ordering parts from Amazon and plugging everything together in a case — you had to buy chips, solder or wire-wrap everything, and tinker endlessly. The process was slow, painful, and expensive, but in the end, you had a completely unique machine that you knew inside out because you put every bit of it together.

In some ways, it’s good that those days are gone. Being able to throw a cheap, standardized commodity PC at a problem is incredibly powerful, but that machine will have all the charm of a rubber doorstop and no soul at all. Luckily for those looking to get back a little of the early days of the computer revolution or those that missed them entirely, there are alternatives like the Gigatron. Billed as a “minimalistic retro computer,” the Gigatron is a kit that takes the builder back even further in time than the early computer revolution since it lacks a microprocessor. All the logic of the 8-bit computer is built up from discrete 7400-series TTL chips.

The Gigatron is the brainchild of Marcel van Kervinck and Walter Belgers. Tragically, Marcel recently passed away, but Walter is carrying the Gigatron torch forward and leading a thriving community of TTL-computer aficionados as they extend and enhance what their little home-built machines can do. Walter will stop by the Hack Chat to talk all things Gigatron, and answer your questions about how this improbably popular machine came to be.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, June 24 at 12:00 PM Pacific time. If time zones have you down, 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: June 21, 2020

June 21, 2020 by Dan Maloney 19 Comments

When Lego introduced its Mindstorms line in 1998, in a lot of ways it was like a gateway drug into the world of STEM, even though that term wouldn’t be invented for another couple of years. Children and the obsolete children who begat them drooled over the possibility of combining the Lego building system with motors, sensors, and a real computer that was far and away beyond anything that was available at the time. Mindstorms became hugely influential in the early maker scene and was slowly but steadily updated over the decades, culminating with the recently released Mindstorms Robot Inventor kit. In the thirteen years since the last release, a lot has changed in the market, and we Hackaday scribes had a discussion this week about the continued relevancy of Mindstorms in a time when cheap servos, microcontrollers, and a bewildering array of sensors can be had for pennies. We wonder what the readers think: is a kit that burns a $360 hole in your pocket still worth it? Sound off below.

Are you looking for a way to productively fill some spare time? Plenty of people are these days, and Hackaday has quite a deal for them: Hackaday U! This series of online courses will get you up to speed on a wide range of topics, starting tomorrow with Matthew Alt’s course on reverse engineering with Ghidra. Classes meet online once a week for four weeks, with virtual office hours to help you master the topic. Beside reverse engineering, you can learn about KiCad and FreeCad, quantum computing, real-time processing of audio and sensor data, and later in the year, basic circuit theory. We’ve got other courses lined up to fill out the year, but don’t wait — sign up now! Oh, and the best part? It’s on a pay-as-you-wish basis, with all proceeds going to charity. Get smarter, help others while doing it — what’s not to love about that?

Speaking of virtual learning, the GNU Radio Conference will be moving online for its 10th anniversary year. And while it’s good news that this and other cons have been able to retool and continue their mission of educating and growing this community, it’s still a bummer that there won’t be a chance to network and participate in all the fun events such cons offer. Or perhaps there will — it seems like the Wireless Capture the Flag (CTF) event is still going to happen. Billed as “an immersive plot-driven … competition featuring the GNU Radio framework and many other open-source tools, satellite communications, cryptography, and surreal global landscapes,” it certainly sounds like fun. We’d love to find out exactly how this CTF competition will work.

Everyone needs a way to unwind, and sometimes the best way to do that is to throw yourself into a project of such intricacy and delicate work that you’re forced into an almost meditative state by it. We’ve seen beautiful examples of that with the wonderful circuit sculptures of Mohit Bhoite and Jiří Praus, but here’s something that almost defies belief: a painstakingly detailed diorama of a vintage IBM data center. Created by the aptly named [minatua], each piece of this sculpture is a work of art in its own right and represents the “big iron” of the 1400 series of computers from the early 1960s. The level of detail is phenomenal — the green and white striped fanfold paper coming out of the 1403 line printer has tiny characters printed on it, and on the 729 tape drives, the reels spin and the lights flash. It’s incredible, all the more so because there don’t appear to be any 3D-printed parts — everything is scratch built from raw materials. Check it out.

As you can imagine, the Hackaday tip line attracts a fair number of ideas of the scientifically marginal variety. Although we’re not too fond of spammers, we try to be kind to everyone who bothers to send us a tip, but with a skeptical eye when terms like “free energy” come across. Still, we found this video touting to Nikola Tesla’s free energy secrets worth passing on. It’s just how we roll.

And finally, aside from being the first full day of summer, today is Father’s Day. We just want to say Happy Father’s Day to all the dads out there, both those that inspired and guided us as we were growing up, and those who are currently passing the torch to the next generation. It’s not easy to do sometimes, but tackling a project with a kid is immensely important work, and hats off to all the dads who make the time for it.

Hackaday Podcast 072: Robo Golf Clubs, Plastic Speedboats, No-Juice Flipdots, And Super Soakers

June 19, 2020 by Dan Maloney No comments

With Editor-in-Chief Mike Szczys on a well-earned vacation, Staff Writer Dan Maloney sits in with Managing Editor Elliot Williams to run us through the week’s most amazing hacks and answer your burning questions. What do you do when you can’t hit a golf ball to save your life? Build a better club, of course, preferably one that does the thinking for you. Why would you overclock a graphing calculator? Why wouldn’t you! Will an origami boat actually float? If you use the right material, it just might. And what’s the fastest way to the hearts of millions of kids? With a Super Soaker and a side-trip through NASA.

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.)

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Fail Of The Week: How Not To Watercool A PC

June 17, 2020 by Dan Maloney 50 Comments

To those who choose to overclock their PCs, it’s often a “no expense spared” deal. Fancy heat sinks, complicated liquid cooling setups, and cool clear cases to show off all the expensive guts are all part of the charm. But not everyone’s pockets are deep enough for off-the-shelf parts, so experimentation with cheaper, alternatives, like using an automotive fuel pump to move the cooling liquid, seems like a good idea. In practice — not so much.

The first thing we thought of when we saw the title of [BoltzBrain]’s video was a long-ago warning from a mechanic to never run out of gas in a fuel-injected car. It turns out that the gasoline acts as a coolant and lubricant for the electric pump, and running the tank dry with the power still applied to the pump quickly burns it out. So while [BoltzBrain] expected to see corrosion on the brushes from his use of water as a working fluid, we expected to see seized bearings as the root cause failure. Looks like we were wrong: at about the 6:30 mark, you can see clear signs of corrosion on the copper wires connecting to the brushes. It almost looks like the Dremel tool cut the wire, but that green copper oxide is the giveaway. We suspect the bearings aren’t in great shape, either, but that’s probably secondary to the wires corroding.

Whatever the root cause, it’s an interesting tour inside a common part, and the level of engineering needed to build a brushed motor that runs bathed in a highly flammable fluid is pretty impressive. We liked the axial arrangement of the brushes and commutator especially. We wonder if fuel pumps could still serve as a PC cooler — perhaps changing to a dielectric fluid would do the trick.

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A Properly Engineered UV Chamber For PPE Sanitization

June 16, 2020 by Dan Maloney 49 Comments

Designed to be used once and then disposed of, personal protective equipment (PPE) such as N95 face masks proved to be in such short supply during the early days of the COVID-19 pandemic that getting a few extra uses out of them by sanitizing them after a shift seemed smart. And so we saw a bunch of designs for sanitizing chambers, mostly based on UV-C light and mostly, sad to say, somewhat dodgy looking. This UV-C disinfection chamber, though, looks like a much better bet.

The link above is to the final installment of a nine-part series by [Jim] from Grass Roots Engineering. The final article has links to all the earlier posts, which go back [Jim]’s early research on UV-C sanitization methods back in March. This led him to settle on an aquarium sanitizer as his UV-C source. A second-hand ultraviolet meter allowed him to quantify the lamp’s output and plan how best to use it, which he did using virtual models of various styles of masks. Knowing that getting light on every surface of the mask is important, he designed a mechanism to move the mask around inside a reflective chamber. The finished chamber, which can be seen in the video below, is 3D-printed and looks like it means business, with an interlock for safety and a Trinket for control.

We love the level of detail [Jim] put into these posts and the thoughtful engineering approach he took toward this project. And we appreciate his careful testing, too — after all, it wouldn’t do to use a germicidal lamp that actually doesn’t emit UV-C.

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