Promethean Matches: The Ancestor To Modern Matches

December 25, 2023 by Maya Posch 7 Comments

The history of making fire at will is a long and storied one, stretching back to the days when we’d rub wooden sticks together, or use flint and steel to ignite tinder. An easier, albeit vastly more expensive and dangerous alternative came in the 19th century when chemists discovered auto-ignition using a potassium chlorate mixture and sulfuric acid. This method was refined and later patented by Samuel Jones in 1828 as the ‘promethean match’ after the God of Fire, Prometheus, which is the topic of a recent [NurdRage] chemistry video.

Using practically the same recipe of potassium chlorate and sugar as in the 19th century, [NurdRage] uses paper straws to contain this powder. Glue is used to section the paper straw into two compartments and seal in the components, with the smaller compartment used for a glass capsule containing sulfuric acid. This vial was produced from the tip of a glass pipette, using a hot flame to first seal the tip, then detach and seal the other end of the tip, resulting in the sulfuric acid capsule, ready to be added to the second compartment.

The moment this glass capsule is crushed, the sulfuric acid will soak into the paper, reaching the large compartment with the potassium chlorate and sugar mixture, causing a strongly exothermic reaction that ignites the paper. Yet as simple as this sounds, [NurdRage] found the three matches he made to be rather fickle, with one igniting beautifully after crushing the capsule with pliers, while one did nothing and the remaining match decided to violently explode rather than burn.

Considering the immense manual labor involved in making these matches, they never were very popular, and were quickly replaced by strike-anywhere matches, followed by safety matches, none of which require you to carry fragile glass capsules containing sulfuric acid with you. As a chemistry experiment, it is however a total blast that will set any boring chemistry class on fire.

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Radiochat Is A Simple LoRa Interface Over WiFi

December 25, 2023 by Lewin Day 20 Comments

LoRa is often talked about as a potentially useful solution for emergency communication. The problem is, few of us are running around with LoRa hardware on a day-to-day basis. Student [William Barkoff] designed the Radiochat device as a simple tool that could pair with virtually anything over WiFi, and allow it to send and receive LoRa messages.

Radiochat is based on the Raspberry Pi Pico W, and uses the microcontroller’s wireless hardware to communicate with other devices. It provides a WiFi network that devices like laptops or smartphones can connect to. The Pico serves up a simple web page which accepts text input. Type in a message and hitting enter and the Pico will command a LoRa radio module over SPI to send that message out over the airwaves. It can then be picked up by another Radiochat module which displays the message on its own webpage.

It’s in an early state of development, and the demo video shows there are still some bugs to work out. Ultimately, though, it could be a cheap battery-powered device that lets smartphones and laptops chat over LoRa in remote areas. Indeed, [William’s] trips to New Mexico on model rocketry expeditions were a big inspiration for the project.

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3D Printing Stacks

December 24, 2023 by Al Williams 3 Comments

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

December 24, 2023 by Lewin Day 13 Comments

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

December 24, 2023 by Dan Maloney 10 Comments

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

December 24, 2023 by Maya Posch 24 Comments

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.

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

December 24, 2023 by Lewin Day 16 Comments

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!