Foldable OLED Displays And The Bane Of Dust

Much like Apple’s once vaunted super-slim butterfly keyboard, today’s range of portable devices featuring flexible OLED displays – which can fold said display into a much smaller form factor – are a marvel of engineering.

The foldable phone after a dusty encounter. (Credit: iFixit, YouTube)
The foldable phone after a dusty encounter. (Credit: iFixit, YouTube)

Unfortunately engineering can only do so much against fundamental flaws. In the case of both these flexible OLEDs and butterfly keyboards the main issue is that of dust intrusion, with a recent teardown by [iFixit] going over the reasons for this.

As test subject we got a Galaxy Z Fold 8, as an example of a modern-day foldable smartphone-tablet hybrid. This phone has an IP48 rating, meaning that it’s water-resistant, but not dust-resistant for particles smaller than 1 mm. To test this, [iFixit] used UV-reactive dust particles, making sure that they got literally everywhere inside the phone’s hinge mechanism.

After this treatment, trying to fold the phone caused the hinge mechanism to make absolutely horrific crunching noises, confirming that it’s reached dust-under-butterfly-keycap levels of unusable. During the subsequent teardown a quick pass with the UV lamp showed that not much of the dust had penetrated into the two halves of the device at least, but the hinge mechanism wasn’t as lucky.

Getting to the hinge is sadly rather destructive, as it involves removing the flexible OLED. Once the hinge was exposed and subjected to UV light the spectacle was something to marvel at, as can be seen in the above screenshot. With the dust caking literally every part of the mechanism, it was little wonder that the hinge had ceased to work.

Although this was obviously an extreme case of dust exposure, and the average flexible OLED screen’s hinge won’t see nearly as much dust, one can’t help but feel slightly disconcerted at that crunching noise, knowing that it’s just one big dust exposure away.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

3D Printering: Why Is My PLA So Brittle?

Over the years poly(lactic acid) (PLA) – also known as polylactide – has become a popular thermoplastic for a variety of reasons. One of these reasons is that it’s easily produced from a renewable resource, i.e. lactic acid, with the resulting polymer even being compostable if you assume that your compost pile hits a steady 65°C or more, well above the polymer’s glass transition temperature (Tg).

That said, PLA by itself is a pretty crummy material, being exceedingly brittle and inferior to common alternatives like PET(G) in many metrics. Over the decades much research has gone into figuring out this material, its amorphous and crystalline states, as well as how to use plasticizers, copolymers, mechanical manipulation and PLLA/PDLA blends to produce more useful variants of PLA.

Today’s spools of thermoplastic filament that gets marketed as ‘PLA’ are the result of such engineering, though with plenty of remaining issues, as anyone who has struggled through a spool of brittle PLA filament can attest to. Although you can find plenty of tips online about how you should ‘just’ toss said spool into an filament dryer, oven or similar to bake it – with accusing fingers pointed at moisture intrusion, hydrolysis and kin – it helps to understand the fundamentals of how PLA works, and how it degrades.

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Miniaturizing The Atari 2600 Console

For as popular as Atari was in their heyday, it wasn’t until well after they were on their famous decline that they released their first handheld, the Atari Lynx. In retrospect, competing with the Game Boy was not going to be a recipe for success even without considering their other problems as a company, and as a result was their penultimate console before exiting the market completely. But [Nick]’s most recent project asks what the world would have been like with an Atari handheld from their golden era, and has been working on this miniaturized version of the 2600.

Unlike any modern emulators which can easily handle Atari 2600 games in almost any form factor today, this console is doing it all with as much original hardware as possible. It uses much smaller switches and buttons compared to the original, and omits some other unnecessary hardware for today’s world like the RF modulator. [Nick] has also designed a custom PCB that reduces the overall footprint considerably as well, and has relocated the cartridge port in preparation for its eventual handheld shape. The result is a console using original hardware that’s less than half the footprint of the original.

Although there were around 30 million Atari 2600 consoles sold and the system is unlikely to be a real collector’s item anytime soon, [Nick] makes sure to note that no real 2600 hardware was harmed in this build. And, as far as its handheld nature, this is a stepping stone on the path to that eventual goal. We’ll look forward to an eventual system that integrates a screen and controller as well as a port for the original cartridges. In the meantime, here’s another handheld 2600 that fits completely inside one of those cartridges.

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An Early History Of Space Stations: The Brick Moon Made Real

People have lived in space stations for decades now, but something is wrong with them. Where are the big rotating wheels? You know the ones. They show up in old paintings of the future and, perhaps most memorably, in 2001: A Space Odyssey. Spin a great wheel in space, and people can stroll around inside with something that feels suspiciously like gravity. It seems like an obvious idea.

It is also an old idea. Much older than actual spaceflight, in fact. But to find the beginning of the space station, we have to go back to a time when powered aircraft were still several decades in the future.

A Moon Made of Bricks

In 1869, Edward Everett Hale published The Brick Moon in The Atlantic Monthly. The moon in question wasn’t natural. Hale imagined building a 200-foot-diameter sphere made from bricks and putting it into orbit as a navigation aid. Sailors could sight it and use its known orbit to determine their longitude. There was only one small problem: the thing was accidentally launched with people aboard.

That makes The Brick Moon generally regarded as not only the first fictional artificial satellite, but also the first fictional space station. Hale followed it in 1870 with Life on the Brick Moon, describing how the accidental colonists got along up there.

Hale didn’t have rockets. He proposed flinging the thing into the sky with giant flywheels, but, then again, it was 1869, so we’re inclined to cut him some slack. As the 19th century turned into the 20th, however, people started doing the math.

Konstantin Tsiolkovsky is best remembered for putting rocket flight on a sound theoretical footing. The Russian schoolteacher wrote extensively about orbital flight and space habitation, envisioning people living in orbit long before anyone had demonstrated that a liquid-fueled rocket actually worked. His ideas included rotating habitats to provide artificial gravity.

Hermann Oberth’s 1923 book Die Rakete zu den Planetenräumen — The Rocket into Planetary Space — Oberth went beyond fiction and seriously considered a permanently inhabited station. He envisioned it being periodically supplied by smaller rockets, serving as an observation and communications platform, and even acting as a jumping-off point for trips farther into space. He also suggested spinning the station to give the crew artificial gravity.

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Teardown Shows Low-Fi Microphone Is Surprisingly Sophisticated

The Ting FX EP-2350 by Teenage Engineering is a standalone microphone with a few extras, including samples and built-in effect presets that can be modified by the user. It also has a distinctive design, and [Sam Holland] does an in-depth teardown that offers some insights that are worth keeping in one’s back pocket. The large, side-mounted lever in particular is an interesting bit, but more about that in a moment.

Inside the device is a single PCB, which has a cutout in the middle for a pair of AAA cells. A Raspberry Pi 2350 drives the device’s functions, supported by various components which [Sam] identifies, although he mostly looks at everything from the perspective of a mechanical engineer as he critiques the design. It’s a clean-looking, intentionally low-fi design that belies how complex the device really is.

The multi-function, chunky, spring-loaded side lever is of particular interest. It has three sensors: two switches and a potentiometer. One switch detects when the lever is at rest, or depressed by any amount at all. The potentiometer mates with the pivot point of the lever, allowing the device to directly sense how far the lever is pushed. The last switch triggers when the lever is pushed all the way in. Together, it forms an intuitive input that combines powering on (the device wakes up from sleep mode as soon as the lever is pressed) with the ability to adjust effects in proportion with how far the lever is pressed, while also bottoming out with a distinct click that itself acts as an input signal.

One other interesting bit is the light pipes that carry light from multiple indicator LEDs to the outside of the device. A textured surface acts as a diffuser and helps the lit surface look smooth, while a coating of silver paint prevents light bleed and (probably) maximizes light transmission through the plastic. Hot glue makes a pretty good light pipe material but if DIY light pipes end up in your next project, sanding the exit surface and giving the rest a coating of silver paint just might be worth a shot. Continue reading “Teardown Shows Low-Fi Microphone Is Surprisingly Sophisticated”

Reading Isn’t Rocket Science… But In This Case…

While Hackaday’s bread and butter is, of course, hacks, we sometimes cover things that most of us are interested in that are probably out of reach for the typical hacker. Space, for example, is undeniably cool, even though your chances of putting yourself or even your own rover on the Moon aren’t very good at the moment (but, of course, give it time). If you are looking for something to put on your e-reader and you are also interested in space, save your money and get some downloadable books directly from NASA.

There’s something for everyone on the site. The site has four main categories: aeronautics, Hubble, science, and NASA history. Aeronautics has two volumes of “NASA’s Contributions to Aeronautics,” a book on the X-15, and a book about aviation pressure suits. Want to know more about the giant wind tunnel at Langley?

For the Hubble, you’ll find titles that have great images, of course, but also a book with an overview of the telescope or, if you prefer, about gravitational lensing.

The science titles go really deep with books on black holes, Landsat, the Cassini mission, and the Spitzer telescope. If you prefer history, there’s everything from a history of near-Earth object research to lessons from the Columbia tragedy for engineers, managers, and leaders. We were also interested in the book “Archaeology, Anthropology, and Interstellar Communication.”

The books are typically available in EPUB or PDF, and they are all free. Just what you need for your next plane trip or to round out your Calibre library.

We do love free books, we just can’t get enough.

Quick Share Implemented On A Kindle

Quick Share is a useful tool for flipping files between Android smart phones in a fuss-free wireless manner. [unrealJune] has now implemented the feature on Kindle devices.

You’ll need a jailbroken Kindle to use this, which is running the Kindle Unified Application Launcher and KOReader as well. You’ll also want SSH access, and a machine that has Go and Docker for you to build the project. [unrealJune] steps through the steps to compile and install the Quick Share plugin to KOReader, as well as explaining how it works. Notably, it’s receive only—so you can spit files onto the Kindle, but you can’t send them from the Kindle to other devices. The Kindle will also automatically accept files, which is worth noting if you’re security conscious. If there’s no network, the Kindle is also able to appear as its own AP if needed.

Think of this as a nifty convenience if you find yourself regularly trying to truck files on to your jailbroken Kindle. It’s also a neat to see a Quick Share implementation from the open source world. Between-device sharing still sucks, as we’ve discussed before, but there are at least attempts being made to make it better. That’s something!