Author: Dan Maloney

3368 Articles

3D Printed Strain-Wave Gearbox Turns Up The Torque

September 17, 2022 by 6 Comments

3D printers are good for a lot of things, but making parts for power transmission doesn’t seem to be one of them. Oh sure, some light-duty gears and timing belt sprockets will work just fine when printed, but oftentimes squooshed plastic parts are just too compliant for serious power transmission use.

But that’s not a hard and fast rule. In fact, this 3D-printed strain-wave transmission relies on the flexibility of printed parts to work its torque amplification magic. In case you haven’t been briefed, strain-wave gearing uses a flexible externally toothed spline nested inside an internally toothed stationary gear. Inside the flexible spline is a wave generator, which is just a symmetrical cam that deforms the spline so that it engages with the outside gear. The result is a high ratio gear train that really beefs up the torque applied to the wave generator.

It took a couple of prototypes for [Brian Bocken] to dial in his version of the strain-wave drive. The PLA he used for the flexible spline worked, but wasn’t going to be good for the long haul. A second version using TPU proved better, but improvements to the motor mount were needed. The final version proved to pack a punch in the torque department, enough to move a car. Check it out in the video below.

Strain-wave gears have a lot of applications, especially in robotic arms and legs — very compact versions with the motor built right in would be great here. If you’re having trouble visualizing how they work, maybe a Lego version will clear things up.

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Scratch-Built RC Excavator Is A Model Making Tour De Force

September 16, 2022 by 20 Comments

Some projects just take your breath away with their level of attention to detail. This scratch-built RC-controlled model excavator is not only breathtaking in its detail, but also amazing for the materials and tools used to create it.

We’ve got to be honest, we’ve been keeping an eye on the progress [Vang Hà] has been making on this build for a few weeks now. The first video below is a full tour of the finished project, which is painstakingly faithful to the original, a Caterpiller 390F tracked excavator. As impressive as that is, though, you’ve got to check out the build process that starts with fabricating the tracks in the second video below. The raw material for most of the model is plain gray PVC pipe, which is sliced and diced into flat sheets, cut into tiny pieces using a jury-rigged table saw, and heat formed to create curved pieces. Check out the full playlist for a bounty of fabrication delights, like tiny hinges and working latches.

We can’t possibly heap enough praise onto [Vang Hà] for his craftsmanship, but that’s not all we love about this one. There are tons of helpful tips here, and plenty of food for thought for more practical builds. We’re thinking about that full set of working hydraulic cylinders that operates the boom, the dipper, and the bucket, as well as the servo-operated hydraulic control valves. All of it is made from scratch, of course, and mostly from PVC. Keep that in mind for a project where electric motors or linear actuators just won’t fill the bill.

If this construction technique seems familiar to you, it could because we featured a toolbox made out of similarly processed PVC pipes back in June.

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This Simple Light-Controlled Synth Has A Surprisingly Rich Sound

September 15, 2022 by 5 Comments

Audio synthesizers can range from vast racks of equipment with modules stitched together by a web of patch cords to a couple of 555s wired together in an Atari punk arrangement. This light-controlled synth comes in closer to the lower extreme of that range, but packs a sonic punch that belies its simplicity.

The project is the latest version of [lonesoulsurfer]’s “Moog Light Synthesizer,” which shares a lot of the circuitry found in his first version a couple of years ago. This one has a lot of bells and whistles, but it all starts with a PWM oscillator that contributes to the mean, growling quality of its sound. There’s also a low-pass filter that’s controlled by a couple of light-dependent resistors, which can be played by blocking them off with a fingertip. A couple of inverters form a drone oscillator that can be switched into the circuit, as well as a 555-based arpeggiator to chop things up a bit.

All those circuits, as well as support for a thirteen-key keyboard, live on one custom PCB. There’s also an off-the-shelf echo/reverb module that’s been significantly hacked to add to the richness of the sound. The custom wood and acrylic case make the whole thing look as good as it sounds.

We noted that [lonesoulsurfer]’s previous “Box of Beezz” drone synth seemed to evoke parts of the “THX Deep Note” at times; similarly, some of the sounds of this synth sound like they’d come from the soundtrack of a [Christopher Nolan] film  — check it out in the video below.

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Neon Lamps — Not Just For Pilot Lights

September 13, 2022 by 30 Comments

It’s easy to see why LEDs largely won out over neon bulbs for pilot light applications. But for all the practical utility of LEDs, they’re found largely lacking in at least one regard over their older indicator cousins: charm. Where LEDs are cold and flat, the gentle orange glow of a neon lamp brings a lot to the aesthetics party, especially in retro builds.

But looks aren’t the only thing these tiny glow lamps have going for them, and [David Lovett] shows off some of the surprising alternate uses for neon lamps in his new video. He starts with an exploration of the venerable NE-2 bulb, which has been around forever, detailing some of its interesting electrical properties, like the difference between the voltage needed to start the neon discharge and the voltage needed to maintain it. He also shows off some cool neon lamp tricks, like using them for all sorts of multi-vibrator circuits without anything but a few resistors and capacitors added in. The real fun begins when he breaks out the MTX90 tube, which is essentially a cold cathode thyratron. The addition of a simple control grid makes for some interesting circuits, like single-tube multi-vibrators.

The upshot of all these experiments is pretty clear to anyone who’s been following [David]’s channel, which is chock full of non-conventional uses for vacuum tubes. His efforts to build a “hollow state” computer would be greatly aided by neon lamp circuits such as these — not to mention how cool they’d make everything look.

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Heavy Engineering Hack Chat

September 13, 2022 by 1 Comment

Join us on Wednesday, September 14 at noon Pacific for the Heavy Engineering Hack Chat with Andy Oliver!

Here at Hackaday, we focus mainly on engineering at the small end of the spectrum. Millimeter waves, nearly microscopic SMD components, nanoscale machines like MEMS accelerometers, and silicon chips with features that measure in the nanometer range. We’ve all become pretty good at wrapping our heads around problems at the wee end of the spectrum.

And while all that tiny stuff is great, there’s a whole, big world out there to explore, with big engineering to solve big problems. Think of things like dam spillways, lift bridges, and canal locks — big stuff that still has to move, and has to do it safely and efficiently. Those are problems that demand an entirely different way of thinking, and skills that not a lot of us have.

join-hack-chatAndy Oliver works in the world of big, movable structures, designing control systems for them. He’ll drop by the Hack Chat to discuss the engineering that not only makes these structures work but also keeps them safe and reliable. If you’ve ever wondered how big things work, you won’t want to miss this one.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 14 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Hackaday Links: September 4, 2022

September 4, 2022 by 19 Comments

Say what you will about Tesla, but there’s little doubt that the electric vehicle maker inspires a certain degree of fanaticism in owners. We’re used to the ones who can’t stop going on about neck-snapping acceleration and a sci-fi interior. But the ones we didn’t see coming are those who feel their cars are so bad that they need to stage a hunger strike to get the attention of Tesla. The strike is being organized by a group of Tesla owners in Norway, who on their website enumerate a long list of grievances, including design defects, manufacturing issues, quality control problems, and customer service complaints. It’s not clear how many people are in the group, although we assume at least 18, as that’s the number of Tesla cars they used to spell out “HELP” in a parking lot. It’s also not clear how or even if the group is really off their feed, or if this is just a stunt to get the attention of Tesla honcho and notorious social media gadfly Elon Musk.

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Machine Learning App Remembers Names So You Don’t Have To

September 3, 2022 by 9 Comments

Depending on your point of view, real-life conversations with strangers can either be refreshing or terrifying. Some of us are glib and at ease in new social situations, while others are sure that the slightest flub will haunt them forever. And perhaps chief among these conversational faux pas is forgetting the name of the person who just introduced themselves a few seconds before.

Rather than commit himself to a jail of shame on such occasions, [Caleb] fought back with this only slightly creepy name-recalling smartphone app. The non-zero creep factor comes from the fact that, as [Caleb] points out, the app crosses lines that most of us would find unacceptable if Google or Amazon did it — like listening to your every conversation. It does this not to direct ads to you based on your conversations, but to fish out the name of your interlocutor from the natural flow of the conversation.

It turns out to be a tricky problem, even with the help of named-entity recognition (NER), which basically looks for the names of things in natural text. Apache OpenNLP, the NER library used here, works well at pulling out names, but figuring out whether they’re part of an introduction or just a bit of gossip about a third party is where [Caleb] put the bulk of his coding effort. That, and trying to make the whole thing at least a little privacy-respecting. See the video below for a demo.

To be sure, this doesn’t do much more than a simple, ‘remind me of your name again?’ would, but without the embarrassment. It’s still pretty cool though, and we’re especially jazzed to learn about NER and the tons of applications for it. Those are projects for a future day, though. We’re just glad to see that [Caleb] has moved on from monitoring the bodily functions of his dog and his kid. At least for now.

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