3D Printing Stacks

There is a big difference between building one of something and building, say, 100 of the same item. It isn’t surprising, then, that 3D printing in bulk differs from printing one object at a time. Of course, filling up your build plate is not a new idea. But [Keep Making] wants to encourage you to think in three dimensions and fill up your build volume in the Z axis, as well.

When you fill your X and Y axes, it is easy to see how the parts separate. But with stack printing, you must separate the parts from different layers. Each part has a single-layer gap, and the top surfaces are ironed for a better finish. Sometimes the prints may stick, and the video shows how to use a screw to pop off recalcitrant prints. The technique produces one side that isn’t as nice a finish as the other side, but it isn’t bad, and for many applications, you don’t care, anyway.

Before you get too excited about your own designs, you might try a simple test file and get your print settings dialed in. Obviously, if you need just two or three copies of something small, it is easier to step and repeat them across the build surface. But if you need to maximize your throughput or make multiple copies of large objects, this might be the technique for you.

Looks like an interesting technique that doesn’t require you to do anything strange like, say, waterproof your printer. No strings attached.

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Hidden Wall-Mount Table Looks Like Hanging Art

If you live in a compact space, sometimes you have to get creative with your furniture to make the most of it. This wall-hanging table design from [diyhuntress] is perfect for those situations where you need a table, but you don’t want it taking up the whole room when it’s not in use. Plus, it’s kinda stealthy, which makes it even more fun!

The table is a folding design, with a flat wooden top, and an equally-sized supporting leg that goes down to the ground. The other end of the table is supported by a frame on the wall, which also contains several shelves for small objects. The trick is that the table top and support are hinged together, so that they can fold up and sit in front of the shelves, essentially hanging the whole assembly from the wall. Even better, by painting a simple artwork on the support, the whole thing just looks like a decor piece with no clue as to its hidden functionality.

It’s a fun build, and one that you could easily knock out in a weekend with some basic woodworking skills. We’ve featured some other nifty shelf designs before, too. Just remember, too – a neat and tidy space is a boost to your hacker productivity, so don’t rule this out for your own use!

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Hackaday Links: December 24, 2023

Back near the beginning of the current Solar Cycle 25, we penned an article on what the whole deal is with solar cycles, and what could potentially lie in store for us as the eleven-year cycle of sunspot population developed. Although it doesn’t really come across in the article, we remember being somewhat pessimistic about things, thinking that Solar Cycle 25 would be somewhat of a bust in terms of increased solar activity, given that the new cycle was occurring along with other, longer-period cycles that tend to decrease solar output. Well, looks like we couldn’t have gotten that more wrong if we tried, since the Sun lashed out with a class X solar flare last week that really lit things up. The outburst came from a specific sunspot, number 3514, and clocked in at X2.8, the most powerful flare since just before the end of the previous solar cycle. To put that into perspective, X-class flares have a peak X-ray flux of 10-4 watts/m², which when you think about it is a lot of energy. The flare resulted in a strong radio blackout; pretty much everything below 30 MHz was unusable for a while.

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Absorbing Traffic Noise With Bricks Using Helmholtz Resonators

One inevitable aspect of cities and urban life in general is that it is noisy, with traffic being one of the main sources of noise pollution. Finding a way to attenuate especially the low-frequency noise of road traffic was the subject of [Joe Krcma]’s Masters Thesis, the results of which he gave a talk on at the Portland Maker Meetup Club after graduating from University College London. The chosen solution in his thesis are Helmholtz resonators, which are a kind of acoustic spring. Using a carefully selected opening into the cavity, frequencies can be filtered out, and extinguished inside the cavity.

Basic functionality and formula used to determine the dimensions of a Helmholtz Resonator.
Basic functionality and formula used to determine the dimensions of a Helmholtz Resonator.

As examples of existing uses of Helmholtz resonators in London, he points at the Queen Elizabeth Hall music venue, as well as the newly opened Queen Elizabeth Line and Paddington Station. For indoor applications there are a number of commercial offerings, but could this be applied to outdoor ceramics as well, to render urban environments into something approaching an oasis of peace and quiet?

For the research, [Joe]’s group developed a number of Helmholtz resonator designs and manufacturing methods, with [Joe] focusing on clay fired versions. For manufacturing, 3D printing of the clay was attempted, which didn’t work out too well. This was followed by slip casting, which allowed for the casting of regular rectangular bricks.

But after issues with making casting hollow bricks work, as well as the cracking of the bricks during firing in the kiln, the work of another student in the group inspired [Joe] to try a different approach. The result was a very uniquely shaped ‘brick’ that, when assembled into a wall, forms three Helmholtz resonators: inside it, as well as two within the space with other bricks. During trials, the bricks showed similar sound-deadening performance as  foam and wood. He also made the shape available on Thingiverse, if you want to try printing or casting it yourself.

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DIY Cleats Give You Traction In Ice And Snow

It’s getting into the cold and snowy season for much of the world, and that means it can be slippy when you go walking outside. If you need more traction, but your shoes don’t have spikes, fear not. You can build yourself a set of these nifty strap-on cleats designed by [Zero To Infinity].

The cleats are a 3D printed design, which [Zero To Infinity] modeled in Fusion 360 to match their own shoes. Obviously, everybody’s shoes differ, so they’ve provided simple instructions on how to design your own similar cleats to suit your personal footwear. They’re then printed in a stiff TPU to give them the right amount of flex for bending to conform to the shoe. The cleats themselves are simply M4 bolts, nuts, and washers screwed through the cleats, pointy-side down. They can then be strapped to a shoe, and you’re done!

We’d love to see a set of snow shoes that are fully printed and ready to accept cleats. Indeed, we’ve seen some neat printed sneaker designs before. They haven’t really caught on yet, but there’s nothing to stop you printing the hottest kicks of 2024 right in your own home. When you do, don’t hesitate to hit up the tipsline!

How Does A Sewing Machine Sew?

Like all Hackaday readers, we pride ourselves on having at least a passing acquaintance with how most things work. But we suspect to a lot of people, things we take for granted — computers, air conditioning, motors, and cell phones — are just black magic. That’s how we feel about sewing machines. Sure, there’s a motor. There’s a needle and some thread. But how does the machine make a stitch? We always wondered, but after watching a recent video from [Veritasium] we can at least claim we have an idea.

First, he shows the intrinsic problem: sewing by hand requires you to reverse the direction of the needle, and it isn’t clear how to make a simple machine to do that. Sure, today you could probably make a robot that sews like a human does, but sewing machines have been around for a very long time.

In addition to showing how a chain stitch and lock stitch work, the video shows the history of the machines, including 50,000-year-old needles and the progression of innovations required to get to the modern sewing machine. In addition, he shows a large model sewing machine to clearly explain the concepts.

You might think you don’t care about sewing, but machine sewing has touched nearly everyone. The video says that in 1900, a family might spend 15% of their income on clothes. In 2003, that number drops to under 4%, yet the family will have many more clothes than they did in 1900. This is possible because of machine sewing and other innovations.

You can, of course, make your own sewing machine. If you want to get an industrial one, we have some advice.

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Talking Ohmmeter Also Spits Out Color Bands For You

If you’ve got a resistor and you can’t read the color bands (or they’re not present), you can always just grab a multimeter and figure out its value that way. [Giacomo Yong Cuomo] and [Sophia Lin] have built an altogether different kind of ohmmeter, that can actually spit out color values for you, and even read the resistance aloud. It’s all a part of their final project for their ECE 4760 class.

The build is based around a Raspberry Pi Pico. It determines the value of a resistor by placing it in a resistor divider, with the other reference resistor having a value of 10 kΩ. The resistor under test is connected between the reference resistor and ground, while the other leg of the reference resistor is connected to 3.3 V. The node between the two resistors is connected to the Pi Pico’s analog-to-digital converter pin. This allows the Pico to determine the voltage at this point, and thus calculate the test resistor’s value based on the reference resistor’s value and the voltages involved.

A large fake resistor provides user feedback. It’s filled with addressable LEDs, which light up the appropriate color bands depending on the test resistor’s value. It’s capable of displaying both 3-band, 4-band, and 5-band color configurations. While six-band resistors do exist, the extra band is typically used for denoting temperature coefficients which can’t readily be determined by this simple test. It can also play audio files to announce the resistance value over a speaker.

It’s a neat project that surely taught the duo many useful skills for working with microcontrollers. Plus, it’s kinda fun — we love the big glowing resistor. We’ve featured some other fancy resistors before, too!

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