During World War II, as the Allies planned the invasion of Normandy, there was one major hurdle to overcome—logistics. In particular, planners needed to guarantee a solid supply of fuel to keep the mechanized army functional. Tanks, trucks, jeeps, and aircraft all drink petroleum at a prodigious rate. The challenge, then, was to figure out how to get fuel over to France in as great a quantity as possible.
War planners took a diverse approach. A bulk supply of fuel in jerry cans was produced to supply the initial invasion effort, while plans were made to capture port facilities that could handle deliveries from ocean-going tankers. Both had their limitations, so a third method was sought to back them up. Thus was born Operation Pluto—an innovative plan to simply lay fuel pipelines right across the English channel.
Assuming you’re not stuck in a prison cell without windows, you could feasibly keep track of the moon and tides by walking outside and jotting things down in your notebook. Alternatively, you could save a lot of hassle by just building this moon and tide clock from [pjdines1994] instead.
The build is based on a Raspberry Pi Pico W, which is hooked up to a real-time clock module and a Waveshare 3.7-inch e-paper display. Upon this display, the clock draws an image relevant to the current phase of the moon. As the write-up notes, it was a tad fussy to store 24 images for all the different lunar phases within the Pi Pico, but it was achieved nonetheless with a touch of compression. As for tides, it covers those too by pulling in tide information from an online resource.
It’s specifically set up to report the local tides for [pjdines1994], reporting the high tide and low tide times for Whitstable in the United Kingdom. If you’re not in Whitstable, you’d probably want to reconfigure the clock before using it yourself. Unless you really want to know what’s up in Whitstable, of course. If you so wish, you can set the clock up to make its own tide predictions by running local calculations, but [pjdines1994] notes that this is rather more complicated to do. The finished result look quite good, because [pjdines1994] decided to build it inside an old carriage clock that only reveals parts of the display showing the moon and the relevant tide numbers.
We’ve featured some other great tide clocks before, like this grand 3D printed design. If you’ve built your own arcane machine to plot the dances of celestial objects, do be sure to let us know on the tipsline!
We’ve all been there. You’ve found a beautiful piece of older hardware at the thrift store, and bought it for a song. You rush it home, eager to tinker, but you soon find it’s just not working. You open it up to attempt a repair, but you could really use some information on what you’re looking at and how to enter service mode. Only… a Google search turns up nothing but dodgy websites offering blurry PDFs for entirely the wrong model, and you’re out of luck.
These days, when you buy an appliance, the best documentation you can expect is a Quick Start guide and a warranty card you’ll never use. Manufacturers simply don’t want to give you real information, because they think the average consumer will get scared and confused. I think they can do better. I’m demanding a new two-tier documentation system—the basics for the normies, and real manuals for the tech heads out there.
Want to know if somebody is lying? It’s always so hard to tell. [dbmaking] has whipped up a fun little polygraph, otherwise known as a lie detector. It’s nowhere near as complex as the ones you’ve seen on TV, but it might be just as good when it comes to finding the truth.
The project keeps things simple by focusing on two major biometric readouts — heart rate and skin conductivity. When it comes to the beating heart, [dbmaking] went hardcore and chose an AD8232 ECG device, rather than relying on the crutch that is pulse oximetry. It picks up heart signals via three leads that are just like those they stick on you in the emergency room. Skin conductivity is measured with a pair of electrodes that attach to the fingers with Velcro straps. The readings from these inputs are measured and then used to determine truth or a lie if their values cross a certain threshold. Presumably, if you’re sweating a lot and your heart is beating like crazy, you’re telling a lie. After all, we know Olympic sprinters never tell the truth immediately after a run.
Does this work as an actual, viable lie detector? No, not really. But that’s not just because this device isn’t sophisticated enough; commercial polygraph systems have been widely discredited anyway. There simply isn’t an easy way to correlate sweating to lying, as much as TV has told us the opposite. Consider it a fun toy or prop to play with, and a great way to learn about working with microcontrollers and biometric sensors.
A mosquito has a very finely tuned proboscis that is excellent at slipping through your skin to suck out the blood beneath. Researchers at McGill University recently figured that the same biological structure could also prove useful in another was—as a fine and precise nozzle for 3D printing (via Tom’s Hardware).
Small prints made with the mosquito proboscis nozzle. Credit: research paper
To achieve this feat, the research team harvested the proboscis from a female mosquito, as only the female of the species sucks blood in this timeline. The mosquito’s proboscis was chosen over other similar biological structures, like insect stingers and snake fangs. It was prized for its tiny size, with an inside diameter of just 20 micrometers—which outdoes just about any man-made nozzle out there. It’s also surprisingly strong, able to resist up to 60 kPa of pressure from the fluid squirted through it.
Of course, you can’t just grab a mosquito and stick it on your 3D printer. It takes very fine work to remove the proboscis and turn it into a functional nozzle; it also requires the use of 3D printed scaffolding to give the structure additional strength. The nozzle is apparently used with bio-inks, rather than molten plastic, and proved capable of printing some basic 3D structures in testing.
Amusingly, the process has been termed 3D necroprinting, we suspect both because it uses a dead organism and because it sounds cool on the Internet. We’ve created a necroprinting tag, just in case, but we’re not holding our breath for this to become the next big thing. At 20 um, more likely the next small thing.
Playing the drums requires a lot of practice, but that practice can be incredibly loud. A nice workaround is presented by [PocketBoy], in converting an acoustic kit to electronic operation so you can play with headphones instead.
A sensor installed inside a floor tom.
It might sound like a complicated project, but creating a basic set of electronic drums can actually be quite simple if you’ve already got an acoustic kit. You just need to damp all the drums and cymbals to make them quieter, and then fit all the individual elements with their own piezo sensors. These are basically small discs that can pick up vibrations and turn them into electricity—which can be used to trigger an electronic drum module.
[PocketBoy]’s build started with a PDP New Yorker kit, some mesh heads to dull the snares and toms, and some low-volume cymbals sourced off Amazon. Each drum got a small piezo element, which was soldered to a 6.5mm jack for easy hookup. They’re installed inside the drums on foam squares with a simple bracket system [PocketBoy] whipped up from hardware store parts. A DDrum DDti interface picks up the signals from the piezo elements and sends commands to an attached PC. It’s paired with Ableton 12 Lite, which plays the drum sounds as triggered by the drummer.
[PocketBoy] notes it’s a quick and dirty setup, good for quiet practice but not quite gig-ready. You’d want to probably just run it as a regular acoustic kit in that context, but there’s nothing about the conversion that prevents that. Ultimately, it’s a useful project if you find yourself needing to practice the drums quietly and you don’t have space for a second electric-only kit. There’s lots of other fun you can have with those piezos, too. Video after the break.
Asbestos is a nasty old mineral. It’s known for releasing fine, microscopic fibers that can lodge in the body’s tissues and cause deadly disease over a period of decades. Originally prized for its fire resistance and insulating properties, it was widely used in all sorts of building materials. Years after the dangers became clear, many countries eventually banned its use, with strict rules around disposal to protect the public from the risk it poses to health.
Australia is one of the stricter countries when it comes to asbestos, taking great pains to limit its use and its entry into the country. This made it all the more surprising when it became apparent that schools across the nation had been contaminated with loose asbestos material. The culprit was something altogether unexpected, too—in the form of tiny little tubes of colored sand. Authorities have rushed to shut down schools as the media asked the obvious question—how could this be allowed to happen?
