When firefighters are battling a blaze, it’s difficult for them to find each other in the smoky darkness. To help stand out they wear glow-in-the-dark decals on their helmets, but since they spend so much of their down time stowed away in a dark locker, they don’t always have a chance to charge up.
[Bin Sun]’s firefighter friend inspired them to build a portable charging system that can stuff those helmet decals full of photons in a matter of minutes. Although phosphorescent materials will charge in any light, they charge the fastest with ultraviolet light. This uses a pair of UV LED strips controlled by an off-the-shelf programmable timer, and powered with an 18-volt drill battery stepped down to 12 V. The timer makes it easy for [Bin Sun]’s friend to schedule charge times around their shifts, so the battery lasts as long as possible while keeping the decals ready to glow.
We love that [Bin Sun] seems to have thought of everything. The light strips are nestled into 3D-printed holders that also house small magnets. This makes it easy to position the lights on either side of the locker so both the front and back decals soak up the light.
Just like everything else in 2020, the four-day, multi-stage festival of music and art known as Bonnaroo has been cancelled. This would have been [Guy Dupont]’s fifth year making the journey to Tennessee with his friend. Since they couldn’t go, [Guy] decided to build an interactive Bonnaroo mix tape into an 80s clock radio as a birthday present.
[Guy] was able to re-purpose all the original buttons and dials to navigate through the schedule of acts that would have performed across four days and five stages. The conveniently four-way function slider is used to choose the day, and the radio tuning dial selects the stage, complete with delightful static between the positions. The rest of the buttons move back and forth through the scheduled set times, and one will scroll the track and artist name across the 16-segment displays. The snooze button has the honor of being the play/pause button.
All the inputs are controlled with a Feather M4 express, and the music comes through a DFPlayer Mini. We love that [Guy] was able to repurpose the analog tuning dial by coupling it to a slide potentiometer that fit perfectly in a slot on the underside of the plastic. Stay tuned for a great video that starts with an explanation and demo and then goes into the build.
Though the utility of the clock radio may have been supplanted by cell phone alarms and doomscrolling, that just means that there are theoretically more of them to gut and turn into other things, like this Fallout-inspired luggable Pip-Boy.
No matter how much geek cred your old vintage keyboard pulls, it’s not worth suffering through wrist pain or any other discomfort while using it. Especially now, when there are so many points of entry into the rabbit hole world of DIY mechanical keebs.
Once the wrist pain started, [Ben Congdon] switched from a big old Apple keeb to a Kinesis Freestyle — it’s basically a regular keyboard, but in two halves that can be placed far enough apart that [Ben]’s wrists are straight while typing. Comfortable as that split rectangle may be, it’s just not that cool looking, and he was ready to build something new, as long as it had enough keys.
[Ben] settled on building a Keebio Sinc, a new board which comes mostly soldered already and supports a handful of layouts. In the spirit of leaving doors open, [Ben] soldered in hot-swap sockets instead of permanently attaching the key switches to the PCB. This way, those Gateron reds can be easily switched out for something else, for instance should [Ben] want to try a little tactility down the road.
We think the Sinc is a cool offering precisely because it is such a full keyboard. Not everyone is ready to jump into 60% layouts or thumb clusters, and it’s nice to have options. This is entry-level ergo and DIY all at once. What’s not to like? Even if you want to go for something small and ortholinear, there are options. Here’s a build we saw recently that starts with a breakaway PCB that lets you choose between small and smaller.
How cool would it be if there was a material that couldn’t be cut or drilled into? You could make the baddest bike lock, the toughest-toed work boots, or the most secure door. Really, the list of possibilities just goes on and on.
Proteus chews through an angle grinder disc in seconds.
The material is made of aluminium foam that’s embedded with a bunch of small ceramic spheres. It works by inducing retaliatory vibrations into the cutting tools, which turns the tools’ force back on themselves and quickly dulls their edges.
The creators have named the material Proteus after the elusive and shape-shifting prophet of Greek mythology who would only share his visions of the future with those who could get their arms around him and keep him still. It sounds like this material could give Proteus a run for his money.
The ceramic spheres themselves aren’t indestructible, but they’re not supposed to be. Abrading the spheres only makes Proteus stronger. As the cutting tool contacts them, they’re crushed into dust that fills the voids in the aluminium foam, strengthening the material’s destructive vibratory effect. The physical inspiration for Proteus comes from protective hierarchical structures in nature, like the impact-resistant rind of grapefruit and the tendency of abalone shells to resist fracture under the impact of shark teeth.
How It’s Made
Proteus recipe in pictures.
At this point, Proteus is a proof of concept. Adjustments would likely have to be made before it can be produced at any type of scale. Even so, the recipe seems pretty straightforward. First, an aluminium alloy powder is mixed with a foaming agent. Then the mixture is cold compacted in a compressor and extruded in dense rods. The rods are cut down to size and then arranged along with the ceramic spheres in a layered grid, like a metallurgical lasagna.
The grid is spot-welded into a steel box and then put into a furnace for 15-20 minutes. Inside the furnace, the foaming agent releases hydrogen gas, which introduces voids into the aluminium foam and gives it a cellular structure.
Effects of cutting into a cylinder of Proteus with an angle grinder.
According to their paper, the researchers tried to penetrate the material with an angle grinder, a water jet cutter, and a drill. Of these, the drill has the best chance of getting through because the small point of contact can find gaps more easily, so it’s less likely to hit a ceramic sphere. The researchers also made cylindrical samples without steel cladding which they used to test the compressive strength and prove Proteus’ utility as a structural material for beams and columns. It didn’t fare well initially, but became less compressible as the foam matrix collapsed.
The creation process lends some leeway for customization, because the porosity of the aluminium foam can be varied by changing the bake time. As for the drill bit problem, tightening up security is as easy as adjusting the size and/or density of the ceramic spheres.
In the video after the break, you can watch a chunk of Proteus eat up an angle grinder disc in under a minute. Some may argue about the tool wielder’s technique, but we think there’s something to be said for any material that can destroy a cutting disc that fast. They don’t claim that Proteus is completely impenetrable, but it does look impressive. We wish they would have tried more cutting tools like a gas torch, or experimented with other destructive techniques, like plastic explosives, but we suppose that research budgets only go so far.
Even if you already know how to do this, there’s probably a good tip in here somewhere. One of them being that you should always pour your silicone from one place and let it coat the piece being copied. Otherwise, there might be lines on the mold. Another tip is for DIY mold release made from petroleum jelly thinned with naphtha.
Our favorite tip has to do with the way [Eric] makes this a reusable two-part mold, which is more akin to injection molding. To pour silicone for the second part and get it to separately nicely, [Eric] uses sprues made out of resin rods that were cast inside of drinking straw molds. These he chamfers against a belt sander to minimize the contact with the cast part, which makes them a snap to break off. [Eric] says this is just the beginning, and there are more videos to come that will break down the steps.
There’s more than one way to make a mold, especially for casting in metal. We’ve seen everything from 3D-printed molds to kinetic sand.
Blast fishing — the act of using explosives underwater to kill entire schools of fish with shock waves — has been a widespread problem in the Philippines for decades. Although a few fishermen get rich from the first blast at a fresh site, it isn’t good for anyone in the long term, especially the coral and other sea life. Many blast fisherman use homemade explosives, often at the risk of losing fingers and limbs.
The CBobby system works by analyzing the audio spectrum. It looks for transient changes from the ambient background noise levels, and analyzes duration and the frequencies it heard to decide whether there was an explosion or not. Plans to field test this in the Philippines have been dashed by the pandemic, but [ifthekar] has been hard at work testing in Germany with underwater speakers blasting out explosion noises. Already, the system can differentiate the blasts from various environmental sounds like ships, the bellows of large sea creatures, earthquakes, rain, and thunder.
Although the test rig is encased in neon orange acrylic, the actual blast fishing tattler will be disguised as a venomous stonefish, making it as appealing to mess with as fire ants or wasps.
Menopause, that fireworks finale of fertility, is like a second puberty that works in reverse. At least, that’s what we hear. Along with mood swings and acne, there are new joys like hot flashes that make you want to jump naked into the nearest snowdrift, or at least put your head in the freezer for a while. Sounds great; can’t wait.
The biggest problem with menopause is that it gives suffers pause when it comes to getting help. This is natural, they think. There’s nothing I can do but ride it out. Those who do seek relief are likely to find expensive products that only treat single symptoms. This dearth of solutions inspired [Moinak Ghosh] to create one system to rule them all, a wearable with a suite of sensors that’s designed to take the pause out of menopause.
MenoPlay will take temperature readings at the neck and pelvis and switch on a Peltier module worn on the back of the neck when it senses a hot flash in progress. Exercise is a natural defense against hormonal imbalance, but step counters are too easy to cheat or ignore. The MenoPlay system will model the user’s movements using 9DoF accelerometers and suggest exercises that fill in the gaps.
We particularly like the automation aspect of this wearable. After decades of manually tracking menstrual cycles and everything that implies, the idea of so much useful biological data being collected automatically and fed over BLE to a NodeRed application sounds wonderful.
