Hewlett-Packard used to make some pretty cool LED displays, many of which appeared in their iconic pocket calculators back in the 1970s and 1980s. [Upir] tracked down some of these classic bubble displays and used them with a microcontroller. We love the results!

The displays featured here, the HPDL-1414, aren’t quite what would have been found in an HP-35, of course. These displays have 16 segments for reasonably legible approximations of most of the ASCII character set. Also, these aren’t just the displays; rather, a pair of the bubble-topped displays, each with four characters, is mounted to a module that provides a serial interface. [Upir] found these modules online, but despite the HP logo on the PCB silkscreen, it’s not really clear who made them. The documentation was a bit thin, to say the least, but with a little translation help from Google, he figured out the serial parameters and the character encoding. The video below shows him putting these modules through their paces.

Unusually for [upir], who has made a name for himself hacking displays to do things they weren’t designed to do, he stuck with the stock character set baked into this module. We think it would be fun to get one of these modules and hack the firmware to provide alternative character sets or even get a few of the naked displays and build a custom interface. Sounds like a fun rainy-day project.

This reminded us of another HP display project we saw a while back. Or, roll your own displays.

We’re big fans of unusual timepieces here at Hackaday, so it didn’t take long before somebody called our attention to the gloriously luminescent watch that [Henner Zeller] was wearing at this year’s Supercon.

He calls it the Glowtape, and it uses a dense array of UV LEDs and a long strip of glow-in-the-dark material to display the time and date, as well as images and long strings of text written out horizontally to create an impromptu banner. It looked phenomenal in person, with the energized areas on the tape glowing brightly during the evening festivities in the alleyway.

The text and images would fade fairly quickly, but in practice, that’s hardly a problem when you’re just trying to check the current time. If there was something to limit the practicality on this one, it would have to be the meter-long piece of material that you’ve got to keep pushing and pulling through the mechanism — but it’s a price we’re willing to pay.

Want one of your own? [Henner] has shared all of the source code for the wearable, from the OpenSCAD scripts to generate the 3D printed enclosure to the C firmware for the RP2040 that runs the show. The LED array itself is actually a spin-off of his Glowxels project, which is worth checking out if you’d like to recreate this concept on a much larger scale.

This isn’t the first time we’ve seen this technique used for this kind of thing, but it may be the most compact version of the concept we’ve seen so far.

Let’s say you’ve got a fun little organization that does things together under a collective branding or banner. Maybe you want to celebrate that fact with some visually appealing signage? Well, that’s pretty much how [Jack] of the Purdue Hackers felt, so he and the gang put together a sizable logo sign to advertise their makerspace.

[Jack] explains that The Sign, as it is known, embodies the spirit of the Purdue Hackers. Basically, it’s about making something cool and sharing it with the world. He then outlines how they came to develop a “shining monument” to their organization with the use of LEDs and 3D printed components. The blog post explains how the group began with small prototypes, before stepping up to build a larger version for display in their makerspace window. It also chronicles the twists and turns of the project, including budget snarls and PCB errors that threatened to derail everything.

Ultimately, though, the Purdue Hackers prevailed, and The Sign has been shining bright ever since. Files are on GitHub for the curious, because it’s all open source! Meanwhile, if you’ve been cooking up your own neat signage projects, don’t hesitate to drop us a line!

Volumetric displays are simply cool. Throw some LEDs together, take advantage of persistence of vision, and you’ve really got something. [Nick Electronics] shows us how its done with his neat little volumetric lamp build.

The concept is simple. [Nick] built a little device to spin a little rectangular array of LEDs. A small motor in the base provides the requisite rotational motion at a speed of roughly 6000 rpm. To get power to the LEDs while they’re spinning, the build relies on wire coils for power transmission, instead of the more traditional technique of using slip rings.

The build doesn’t do anything particularly fancy—it just turns on the whole LED array and spins it. That’s why it’s a lamp, rather than any sort of special volumetric display. Still, the visual effect is nice. We’ve seen some other highly capable volumetric displays before, though. Video after the break.