Volumetric OLED Display Shows Bladerunner Vibe, Curious Screen Tech

March 4, 2021 by 39 Comments

[Sean Hodgins] is out with his latest video and it’s a piece of art in itself. Beyond a traditional project show and tell, he’s spun together a cyberpunk vibe to premiere the volumetric display he built from an OLED stackup. Update: He’s also documented the build.

The trick of a volumetric display is the ability to add a third dimension for positioning pixels. Here [Sean] delivered that ability with a stack up of ten screens to add a depth element. This is not such an easy trick. These small OLED displays are all over the place but they share a common element: a dark background over which the pixels appear. [Sean] has gotten his hands on some transparent OLED panels and with some Duck-Duck-Go-Fu we think it’s probably a Crystalfontz 128×56 display. Why is it we don’t see more of these? Anyone know if it’s possible to remove the backing from other OLED displays to get here. (Let us know in the comments.)

The rest of the built is fairly straight-forward with a Feather M4 board driving the ten screens via SPI, and an MPU-6050 IMU for motion input. The form factor lends an aesthetic of an augmented reality device and the production approach for the video puts this in a Bladerunner or Johnny Mnemonic universe. Kudos for expanding the awesome of the build with an implied backstory!

If you can’t find your own transparent displays, spinning things are a popular trend in this area. We just saw one last week that spun an LED matrix to form cylindrical display. Another favorite of ours is a volumetric display that spins a helix-shaped projection screen.

Unique LED Display Inspired By Fighter Jet Dashboard

August 22, 2020 by 6 Comments

Last year, [Mangy_Dog] was asked by a few friends to consult on a project they were working on. The goal was to build an authentic replica of an F-18 cockpit, apparently for the purposes of creating a film. The project never materialized, but it did inspire him to take a hard look at the 1970s era alphanumeric displays utilized in the real aircraft. One thing lead to another, and he ended up using his own take on the idea to build his own “starburst” digit display.

As [Mangy_Dog] explains, while the faces of these original displays might have been quite small, there was a lot going on behind the scenes. Due to the technical limitations of the time, each alphanumeric character was made up of an array of incandescent light bulbs and fiber optic cables. This worked well enough, but was bulky and complex to manufacture.

Today, we can do better, even on the hobbyist level. As it turns out, 0402 LEDs are just about the right size to recreate the segments of the original starburst displays. So [Mangy_Dog] came up with a simple PCB design to not only align the LEDs properly, but drive them with a 74HC595 shift register and an array of MOSFETs. While assembly wasn’t without its challenges, he made good use of his custom built reflow oven to get all the diminutive components in place.

He went through a few different ideas for the diffuser, but eventually settled on black plastic with tiny holes drilled through courtesy of his laser cutter. Behind each set of three holes is a small pocket that got filled from both sides with transparent UV resin, which was then sanded down after curing. The end result isn’t perfect as you can still tell the center dot is brighter than its peers, but the overall effect is still very nice and definitely has a sort of faux-retro appeal.

The military naturally has access to some incredible technology, though they have a tendency to hold onto it for decades. That an individual with a meager budget and homemade tools can improve upon a piece of hardware installed in a $60+ million airplane is a testament to just how fast things are moving.

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Clock Uses Custom LED Displays To Keep Myst Time

January 28, 2020 by 17 Comments

The Myst fans in the audience will love this project because it displays the 25-hour timekeeping system of the D’ni. The hardware hackers will lean a little closer to their screen because it does so with custom made 25-segment LEDs, and the precision obsessed will start breathing heavily when they hear it maintains an accuracy of 0.001 seconds. As for which of those camps creator [Mike Ando] most identifies with, we can’t say. But we definitely respect his style.

We’ll spare you the in-depth description of the base-25 number system apparently used in the Myst franchise. If you’re interested enough you can click on through to the project’s Hackaday.io page and learn how to actually read the clock. Presumably you’ll then come back here and leave your comment in Klingon.

Let’s instead jump right to the part that really gets us excited, those custom displays. To create them, [Mike] cut the face out of black acrylic with a laser, and filled each void with a mixture of clear resin and very fine gypsum plaster. Getting the mix right can be a little finicky as the plaster can clump up, but the end result diffuses the light nicely. The acrylic front panel and a couple of cardboard “gaskets” to keep the light from leaking onto adjacent segments is then stacked on top of a PCB with corresponding 0603 SMD LEDs.

Beyond the soul-crushing number of wires required to hook everything up internally, the rest of the project is relatively straightforward. It uses a WeMos D1 Mini to connect to the WiFi network and pull the current time down from the geographically closest NTP server every couple of hours. Rather than putting a temperature controlled oscillator on the board, [Mike] has decided to pin his accuracy on a constantly on Internet connection and aggressive synchronizations.

From impressive curved bar graph modules to displays segmented with household items, we’ve seen our fair share of custom indicators. But we have to admit that building 25-segment LED displays for the alphabet of a fictional interstellar species sets the bar pretty high.

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Chaining Together A 16×2 Bubble LED Display

December 10, 2019 by 27 Comments

We’ve recently noticed an uptick of interest in so-called “bubble displays”: vintage alphanumeric LEDs which are probably best remembered as being used in watches and calculators before the LCD took over. Today they’re available as surplus or even salvage for literally pennies, but unfortunately they only provide four or five characters to work with. Or rather they did, until [sjm4306] built a board that chains them into a 16×2 array.

For the princely sum of 71 cents each, [sjm4306] picked up ten HPDL-1414 displays, each capable of showing four characters. He then designed a PCB that would accept eight of the displays at once, and even thought ahead to use headers so they could be pulled out and swapped as needed. Of course mounting them is only half the battle, you still need to drive the things.

Each display has its own dedicated driver chip on board, but trying to address each one individually would take far too many pins. So [sjm4306] opted to use a trio of 74HC595 shift registers, allowing him to toggle the three dozen pins necessary over SPI from a microcontroller. He’s even written up a little library and some example code that you can grab on the project’s Hackaday.io page.

Unfortunately, after all his hard work, tragedy struck. As these displays were a couple decades old given their date code, [sjm4306] thought he would clean them up with a bit of alcohol before their big video debut. But whatever plastic the clear panels are made of didn’t take kindly to the IPA, and they all shattered. They still work, but it’s definitely a quirk to keep in mind if you pick up some of these vintage displays to play with yourself.

In the past we’ve seen a much smaller PCB that allowed similar displays to more easily be interfaced with modern microcontrollers; perfect if you just want to bang out a few retro LED characters with a minimum of fuss.

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Glitching LED Display Proves Crowd Favorite

September 17, 2019 by 9 Comments

There’s something enchanting about the soft glow of a properly diffused LED, and this is only improved by greater numbers of LEDs. [Manoj Nathwani] was well aware of this, setting out to build a large display using ping-pong balls for their desirable optical qualities.Unfortunately, not everything went to plan, but sometimes that’s not all bad.

The matrix, built back in 2016 for EMF Camp, was sized at 32×18 elements, for a total of 576 pixels. This was achieved with the use of 12 WS2811 LED strips, with the lights set out on a 50mm grid. Cheap knock-off pingpong balls were used for their low cost, and they proved to be excellent diffusers for the LEDs.

With everything wired up to a NodeMCU, basic testing showed the system to be functioning well. However, once the full matrix was assembled in the field, things started to fall over. Basic commands would work for the first 200 LEDs or so, and then the entire matrix would begin to glitch out and display random colors. Unable to fix the problem in the field, [Manoj] elected to simply run the display as-is. Despite the problems, passers-by found the random animations to be rather beautiful anyway, particularly at night.

After the event, [Manoj] determined the issue was due to the excessive length of the data line, which in the final build was 48 meters long. While the problem may be rectified when [Manoj] revisits the project, the audience seemed to appreciate the first revision anyway.

LED displays will be a hacker staple until the heat death of the universe. Ping pong balls will also likely retain their position as a favorite diffuser. If you’ve got a great LED build of your very own, be sure to hit up the tips line!

Giant LED Display Is 1200 Balls To The Wall

August 29, 2019 by 10 Comments

When you’re going to build something big, it’s often a good idea to start small and work out the bugs first. That’s what [bitluni] did with his massive 1200-pixel LED video wall, which he unveiled at Maker Faire Hanover recently.

We covered his prototype a while back, a mere 300 ping pong ball ensconced-LEDs on a large panel. You may recall his travails with the build, including the questionable choice of sheet steel for the panel and the arm-busting effort needed to drill 300 holes with a hand drill. Not wanting to repeat those mistakes, [bitluni] used the custom hole punch he built rather than a drill, and went with aluminum sheet for the four panels needed. It was still a lot of work, and he had to rig up some help to make the tool more comfortable to use, but in the end the punched holes appear much neater than their drilled counterparts.

[bitluni] mastered enough TIG welding to make nice aluminum frames for the panels, making them lightweight and easy to transport. 1200 ping pong balls, a gunked-up soldering iron, and a package of hot glue sticks later, the wall was ready for electronics. It took a 70-amp power supply and an ESP32 to run everything, but that’s enough horsepower to make some impressive graphics and even stream live video – choppy and low-res, but still usable.

We love the look this wall and we appreciate the effort that went into it. And it’s always good to see just how much fun [bitluni] has with his builds – it’s infectious.

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New PCB Revives Ancient Bubble LED Displays

June 11, 2019 by 14 Comments

For those of us who remember LED calculators, the HP 5082-7400 series red “bubble” displays hold a special charm. Available in 3, 4, or 5-digit varieties, these multiplexed 7-segment displays provided countless hours of entertainment to those who would spell upside-down words on their pocket calculators. In case you happen to be lucky enough to have access to a few of these beautiful vintage display sticks, [Gigawipf] has designed a small driver PCB that lets you easily interface them to a modern microcontroller.

At the heart of the board, aimed at either the 5082-7405 or 5082-7415 5-digit modules, are a pair of 74HC595 shift registers in tiny QFN packages. Five lines from one register drive one of the common cathodes for the selected digit, while the other register drives the eight anode lines through 330-Ohm resistors. The boards are slightly smaller than the width of the displays allowing you to stack them seamlessly for more digits, and eight header pins on each allow you to plug them into solderless breadboards for prototyping. The result is easy to drive with some simple code, and [Gigawipf] provides an example for Arduino as part of the project. The Eagle design files are supplied, as well as Gerbers for those who just want to have some boards made. This sounds like a great way to get some of these vintage displays going again.

If you can’t find any of these displays to play, with, you can try making some larger digits from individual surface-mount LEDs.