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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Building A Panel Mount OLED Display

There are a million and one cheap OLED display modules out there. The only problem is, they’re all assembled on bare PCBs with slight differences, and that frustrates efforts to mount them in a clean and tidy manner. [Galopago] decided to build a small OLED module that solved this frustrating problem.

The idea to pursue this came from off-the-shelf panel displays commonly used for power supply builds and other such equipment. These come in relatively standard sizes and are designed from the outset to slot neatly into a panel with a bezel that covers any ugly edges or awkward gaps.

The build began with a 48 x 29 mm enclosure grabbed from an off-the-shelf power panel meter. There are two PCBs—one holding the regulator and other equipment to run the display, the other carrying a set of screw terminals that make it easy to wire up the display to a piece of equipment. The SSD1306-compatible OLED screen itself connects to the first board with a flat flex cable, as is the norm.

If you find yourself often wanting to pop a small display into a piece of custom test equipment, this might be relevant to your interests. Files are on GitHub for the curious.

We’ve featured some other fun OLED hacks over the years, like this interesting effort to whip up displays from scratch in a home lab. If you’ve got nifty usability hacks of your own in the works, don’t hesitate to let us know.

Building A 2-Way Holographic Display

Holographic displays sound very fancy but you can build various simple types yourself at home. [Julius Makes] whipped up a neat design that shows a different image depending on the position from which you view it. 

Running the show is a Wemos D1 devboard equipped with the ESP8266 microcontroller. It’s hooked up to a pair of OLED displays over I2C. The displays are placed in a 3D printed assembly that aims each one at a beam-splitter cube. This bounces light projected into one face through 90 degrees, and out another face. By leveraging this, it’s possible to aim each display at one face and bounce it out another, such that looking at either side of the beamsplitter cube shows a different image. Since the beamsplitter cube also allows some light to be transmitted directly through as well, the image from each display appears to float in space.

[Julius] notes that this setup is being used in a puzzle box game, while wondering whether there’s any other fun ways to leverage this technique. We’ve seen some other neat holographic displays before, too, like this neat Holochess build.

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Jacket Turned Cyberpunk Wearable OLED Display

If you’ve played Cyberpunk 2077, you might have seen the rad jacket that has a screen in the collar. Once upon a time, such a thing would be solely the preserve of science fiction—you certainly wouldn’t be achieving that look with cathode ray tubes, that much is for sure. However, technology has advanced to the point where [Zibartas] was able to produce just such a jacket in real life.

The key to the build is the advent of the flexible OLED screen. [Zibartas] was able to source four such panels in a smartphone-like aspect ratio, which came in at the hefty price of $300 each. Two Raspberry Pi 4s were enlisted to drive two screens each. The older model Pi was chosen as it was capable of achieving a neat hack to better play smooth video across two displays. A rudimentary sync system was whipped up using GPIO pins to keep video from both Pis playing together. From there, it was simply a matter of figuring out how to create a structure to hold the screens within the large collar of the scratch built cyberpunk-styled jacket. As it turns out they don’t actually flex much in the final install, as they’re held in a 3D printed structure to keep them safe from damage.

The final result is quite something, very accurately recreating the jacket from the game itself. While technically a simple build, actually pulling it off required some delicate work and smart design decisions to make it practical to wear. We’ve featured some other fun jackets over the years, too.

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Real LED TVs Are Finally Becoming A Thing

Once upon a time, the cathode ray tube was pretty much the only type of display you’d find in a consumer television. As the analog broadcast world shifted to digital, we saw the rise of plasma displays and LCDs, which offered greater resolution and much slimmer packaging. Then there was the so-called LED TV, confusingly named—for it was merely an LCD display with an LED backlight. The LEDs were merely lamps, with the liquid crystal doing all the work of displaying an image.

Today, however, we are seeing the rise of true LED displays. Sadly, decades of confusing marketing messages have polluted the terminology, making it a confusing space for the modern television enthusiast. Today, we’ll explore how these displays work and disambiguate what they’re being called in the marketplace.

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These Ultra-Cute, Handsfree Walkie-Talkies Are Built For Cycling

Walkie-talkies are great fun, and [RealCorebb]’s bbTalkie project takes the concept a step further by adding some extremely cool features to make a highly refined, self-contained ESP32-based communicator. bbTalkie completely does away with a push-to-talk button by implementing robust voice detection that works reliably even in noisy environments. It was all designed with cycling in mind, so hands-free operation that stands up to noise is a big plus.

Hands-free, wireless, self-contained digital walkie-talkies that can connect in a group. What’s not to like?

The core of communication is done over ESP-NOW, which is Espressif’s own protocol for direct device-to-device broadcasting. This removes the need to involve any sort of external service like SIM cards or internet access to transmit voice. Performance is best with an external antenna, naturally, but ESP-NOW doesn’t actually require anything other than the existing on-board hardware.

We’ve seen ESP-NOW used to make digital walkie-talkies before, but bbTalkie is a really evolved take on the concept, not least of which due to its hands-free operation.

Because volume-based automatic triggers are highly susceptible to noise, voice detection is done with the help of VADNet, a neural network-based model implemented locally on the device. This system can reliably detect human speech, even in noisy environments. This lets bbTalkie switch between transmit and listen modes automatically and hands-free, without false triggers.

Even when doing all that, there’s still spare capability to play with. Further to the goal of making bbTalkie useful for cyclists in a group, [RealCorebb] added a system that can recognize specific voice commands (like “turn left” for example, or “wait for me!”) which trigger synchronized animations to play on the displays of all connected units. There’s even some experimental support for controlling a camera over Bluetooth, though currently it only supports hardware from Sony.

Watch a tour of it in the video below (Chinese language, English captions available). The OLED screens and animations are adorable, and are great visual feedback of what the unit is doing at any given moment.

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Live Train Departure Screens Keep You Abreast Of Transit Developments

If you want to know when the train is coming, you could pull up a webpage on your phone, or walk all the way to the station to look at the displays there. Or, like [eastfamilyreddish], you could build a neat little train info display to decorate your desktop instead.

The build is based on the work of [gadec-uk]—who developed a train information display some time ago. It’s based around an ESP32 D1 Mini, paired with a 256 x 64 OLED screen to display relevant train information. It accesses a National Rail API for train status information—known as the Darwin LDBWS (Live Departure Board Webservice). Configuration is via a web GUI hosted by the ESP32 itself.

[eastfamilyreddish] took the concept further by adapting this hardware into a more pleasing form. The ESP32 and OLED screen are built into a neat little hanging sign setup that apes one you might expect to see at a real railway station. You might expect that 3D printing was involved, but instead, this was achieved with lasercut parts and resin casting to create something with a beautiful finish. They even went so far as to include a wireless phone charging module in the base, making the device extra useful to really earn its place on the desktop.

The fact is, around these parts we love both trains and the displays you find around them. If you’ve got a railway-adjacent project, or you’ve just built your own awesome railway, don’t hesitate to let us know on the tipsline!