Arduino Auto-Glockenspiel Looks Proper In Copper

December 16, 2023 by Kristina Panos 19 Comments

What is it about solenoids that makes people want to make music with them? Whatever it is, we hope that solenoids never stop inspiring people to make instruments like [CamsLab]’s copper pipe auto-glockenspiel.

At first, [CamsLab] thought of striking glasses of water, but didn’t like the temporary vibe of a setup like that. They also considered striking piano keys, but thought better of it when considering the extra clicking sound that the solenoids would make, plus it seemed needlessly complicated to execute. So [CamsLab] settled on copper pipes.

That in itself was a challenge as [CamsLab] had to figure out just the right lengths to cut each pipe in order to produce the desired pitch. Fortunately, they started with a modest 15-pipe glockenspiel as a proof of concept. However, the most challenging aspect of this project was figuring out how to mount the pipes so that they are close enough to the solenoids but not too close, and weren’t going to move over time. [CamsLab] settled on fishing line to suspend them with a 3D-printed frame mounted on extruded aluminium. The end result looks and sounds great, as you can hear in the video after the break.

Of course, there’s more than one way to auto-glockenspiel. You could always use servos.

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Conductive Cellulose-Based Fibers For Clothing: Coming Soon?

December 16, 2023 by Maya Posch 4 Comments

Summary of the process of producing side-by-side PANI and cotton cellulose fibers. (Credit: Wongcheng Liu et al., 2023)

With the rise of ‘smart’ devices, it seems like only a matter of time before smart fabrics become an every day thing. Yet a complication with these is that merely threading copper wires into clothing is neither practical nor very durable, which is why researchers have been trying to find a way to combine cellulose-based fibers like cotton with another, conductive material like carbon to create an affordable, resilient material which can provide the pathways for these smart fabrics. Recently a team at Washington State University created a version that integrates polyaniline (PANI, press release for paywalled paper), which is a well-known conductive polymer.

A recent review article by Duan-Chao Wang and colleagues in Polymers covers the research in conductive fibers, with conductive additives ranging from carbon nanotubes (CNT) and graphene to various metallic compounds and conductive polymers. As noted by Wang et al., a major aspect to successful commercialization is enabling scaling and cost-effectiveness of producing such fibers. This is the core of the achievement by the WSU team, who used a side-by-side structure of a cellulose substrate and the PANI conductive covering, which should be easier to produce and more durable than previous attempts to merge these two materials into conductive fibers suitable for fabrics.

Other research by Zhang-Chi Ling and colleagues, as reported earlier this year in NPG Asia Materials, details the creation of composite, conductive fibers made from bacterial cellulose with in-situ entanglement of CNTs. With even 100,000 bending cycles not showing much degradation, this could be another good candidate for conductive fabrics. Which of these approaches will first hit mass-production is still anyone’s guess, but we might see them sooner rather than later.

Roll Your Own SDR

December 16, 2023 by Al Williams 8 Comments

If you have software-defined radio hardware and you are only using someone elses’ software, you are missing out on half of the fun. [Tech Minds] shows you how easy it can be to roll your own software using GNU Radio Companion in a recent video.

GNU Radio usually uses Python, but with the companion software you rarely need to know any actual Python. Instead, you simply drag blocks around to represent filters, DSP processing, and other functions you need to create the processing for your application.

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Hubless E-Bike Is Nostalgic

December 16, 2023 by Al Williams 12 Comments

[Chris Makes Stuff] is an aptly named channel. His recent video shows how he took a kid’s electric motorcycle toy and built a “penny farthing” bicycle. You might not know the bike by that name, but when you see it in the video below, you’ll recognize it. These Victorian-era bikes used a single large wheel before chain drives on a bike became a thing.

Of course, the big part of this — literally and figuratively — is the giant front wheel. There’s a second video showing how it was built in layers using wood.

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The Logg Dogg: How A Mysterious Logging Robot Leads Down Twisting Forestry Paths

December 16, 2023 by Maya Posch 31 Comments

There are many places where you’d want to use remotely controlled robots, but perhaps forestry isn’t the first application to come to mind. Yet there are arguments to be made for replacing something like a big logging machine with grapple for a much smaller robot. The reduced ground pressure can be beneficial in fragile ecosystems, and removing the operator is much safer if felling a tree goes wrong.

This is where a US company called Forest Robots tried to come in, with their Logg Dogg, of which [Wes] over at Watch Wes Work found a very unique prototype abandoned in a barn, courtesy of Zuckerberg’s marketplace of wonders.

One of the two receivers on the Forest Robots' Logg Dogg logging robot prototype. (Credit: Watch Wes Work) — One of the two receivers on the Forest Robots’ Logg Dogg logging robot prototype. (Credit: Watch Wes Work)

After lugging the poor abandoned robot back into a warm repair shop, he set to work on figuring out what it was that he had bought. At the time he knew only that it was some kind of logging robot, but with no model number or name on the robot, it was tough to find information. Eventually he got tipped off about it being the Logg Dogg, with even a video of the robot in action, helpfully uploaded to YouTube by [Hankey Mountain Garage] and embedded below for your viewing pleasure.

As [Wes] noticed during teardown and inspection was that it has that distinct mix-and-match feel to it of a prototype, ranging from metric and US customary bolts to both European and US/Canadian supplied components. Although it has two RF receivers on the device, no remote(s) came with the device, and the seller only knew that it was already in the barn when they purchased the place. After getting the engine working again on the robot, [Wes] contacted one of the people behind the robot: [Dean Edwards], a professor at the University of Idaho, hoping to learn more about this robot and how it ended up abandoned in a barn.

Hopefully we’ll find out in a Part 2 whether [Wes] got a response, and whether this robot will get a second chance at life. Meanwhile, in countries such as Portugal such robots are already finding significant use, including for fire protection in its forests, tackling difficult terrain more easily than humans. With forest fires an increasing risk, perhaps the Logg Dogg and kin could find a use there.

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You Can’t Make What You Can’t Measure

December 16, 2023 by Elliot Williams 30 Comments

What’s the most-used tool on your bench? For me, it’s probably a multimeter, although that’s maybe a tie with my oscilloscope. Maybe after that, the soldering iron and wire strippers, or my favorite forceps. Calipers must rate in there somewhere too, but maybe a little further down. Still, the top place, and half of my desert-island top-10, go to measuring gear.

That’s because any debugging, investigation, or experimentation always starts with getting some visibility on the problem. And the less visible the physical quantity, the more necessary to tool. For circuits, that means figuring out where all the voltages lie, and you obviously can’t just guess there. A couple months ago, I was doing some epoxy and fiberglass work, and needed to draw a 1/2 atmosphere vacuum. That’s not the kind of quantity you can just eyeball. You need the right measurement tool.

A few weeks ago, I wrote about my disappointment in receiving a fan that wouldn’t push my coffee beans around in the homemade roaster. How could I have avoided this debacle? By figuring out the pressure differential needed and buying a fan that’s appropriately rated. But I lacked pressure and flow meters.

Now that I think about it, I could have scavenged the pressure meter from the fiberglassing rig, and given that a go, but with the cheap cost of sensors and amplifiers, I’ll probably just purpose-build something. I’m still not sure how I’ll measure the flow; maybe I’ll just cheese out and buy a cheap wind-speed meter.

When people think of tools, they mostly think of the “doers”: the wrenches and the hammers of this world. But today, let’s all raise a calibrated 350 ml glass to the “measurers”. Without you, we’d be wandering around in the dark.

The Small And Silly Synth Now Even Smaller (But Just As Silly)

December 16, 2023 by Dan Maloney 9 Comments

What do you do when you’ve carved out a niche for yourself as a builder of small and useless synthesizers? Why, build an even smaller and less useful synthesizer, of course!

If you’ve been paying even a minimal amount of attention you’ll know right away that this comes to use from [mitxela], who while not playing with volumetric POV displays is often found building smaller and smaller synthesizers, including putting them in DIN plug shells. The current synth is based on his “Silly Synth,” which puts all the guts for the synth inside a USB connector. This time around, though, it’s USB-C, and rather than fitting everything inside the connector shell, the entire synth sits on a PCB that’s smaller than a tiny piezo speaker. The whole thing runs on a CH32V003 microcontroller, and aside from a few support components and the right-angle USB-C plug, not much else.

The PCB is what really shines in [mitxela]’s design, especially the routing. He’s got a 20-pin QFN chip on one side of the board and the USB plug right behind it on the other side to deal with, plus the big through-holes for the speaker and the physical connections on the plug. It’s quite a crowded design, but it gets the job done. What’s more, he panelized the design so that mass production is possible; the reason for this is revealed at the end of the video below.

Pretty much every time we see one of these “smallest synth” videos we’re convinced that we’re seeing the lower limit of what’s possible, but every time, [mitxela] goes ahead and proves us wrong. That’s fine, of course — we don’t mind being wrong about something like this.

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