Big Clive Hacks LED Bulbs With OpenSCAD

April 8, 2021 by Chris Lott 11 Comments

After accidentally crushing the plastic envelope on a cheap LED light bulb, [bigclivedotcom] figured out he could make custom ones using OpenSCAD in any shape he wants. He previously hacked a bunch of these inexpensive LED bulbs last month, discovering they all shared a similar circuit topology. All the ones he experimented with drove the LEDs hard, something that’s bound to reduce bulb lifetime. By reverse engineering the current control regulator, it turns out it is easy to adjust the drive current by changing a resistor or two. Reducing the current should not only increase lifetime, but could allow repurposing the bulb for other uses, such as decorative lighting.

Three OpenSCAD scripts are provided which generate what he calls diamond, obelisk, and globe styles. Basic parameters for each style can be tweaked by the user, such as feature sizes and number of facets. He mentions the lack of OpenSCAD customizers in his script — this can easily be added as shown in the following example (this section of the User Manual on customizers explains the syntax). Note that you can’t make the slider generate real numbers, only whole numbers, which is why the scaling factor is multiplied by 10.

Adding Parameter Customization Sliders is Easy

These fancy globes can be used as night lights and possibly outdoor lighting, if you can make a good seal with the base. Custom chandeliers, anyone? Indicator lamps for very large panels? Any other ideas? If you want to explore the LED lifetime issue further, inveterate tinkerer Ted Yapo wrote a deep dive into the mythical 100,000 hour LED bulb. Thanks to [Cliff Claven] for the tip.

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Hiding Behind The Silkscreen: The Carolinacon 2021 Badge Has A Secret

April 4, 2021 by Jenny List 7 Comments

The pandemic may have taken away many of our real-world events, but as they’ve gone online their badge teams have often carried on regardless. One of these comes from Carolinacon, and it’s decided to eschew the bleeding edge of electronic wizardry and instead push slightly at the boundaries of PCB art. It contains a hidden message in a copper layer behind a band of white silkscreen, which is revealed by a set of LEDs on the reverse of the board shining through the translucent FR4.

Electronics-wise it’s a pretty simple design, sporting only an ATtiny microcontroller and a photoresistor alongside the LEDs, and with the secret message being triggered when the badge is placed in the dark. The conference’s pig logo is eye-catching, but it has no pretences towards being a dev board or similar. The technique of LEDs behind copper and silkscreen is an interesting one though, and something that we think could bear more investigation in future designs. It’s pleasing to see that there are still new avenues to be taken in the world of PCB-based art.

This isn’t the first time this event has had an eye-catching badge, we’ve covered one of their previous offerings.

This Vintage LED Matrix Lives In A Gold Bathtub

April 3, 2021 by Donald Papp 9 Comments

Early LED displays came in all sorts of configurations. Because the LED was fairly new technology, all kinds of ideas were getting tried, and with all that work there was plenty of opportunity for hardware that didn’t make the cut to fall into obscurity. That’s exactly what happened to the Hewlett-Packard 5082-7002, a 5×7 LED matrix display with something many of its brethren didn’t: an oversized gold tub to sit in.

It doesn’t seem that these displays were ever used in any actual products, and its origins are a mystery, but the device itself was nevertheless assigned an HP part number. Beyond that, not much is known about them, but [Industrial Alchemy] reminds us that many early LED devices were poorly documented and never produced in any real quantities. They became forgotten hardware, waiting to be rediscovered.

The 5082-7002 has a oversized gold tub that makes the 5×7 LED matrix mounted inside look puny by comparison, and reading any display made from these units would be difficult because the large size of the device would mean a lot of empty space between each character or digit. But it’s definitely got a striking look to it, no doubt about that.

What’s neat is that the 5802-7002 actually showed up in a video we featured with a look back at cool old LED technology. If you would like to (briefly) see the HP 5802-7002 a bit closer under a microscope, here is a link to the video, cued to 2:19.

You Can Now Build Your Own Glowing LED D20 (with A Whopping 2,400 LEDs)

April 3, 2021 by Lewin Day 9 Comments

The D20, or twenty-sided die, is most commonly known in the shape of a regular icosahedron. It’s a fantastic, enchanting geometry, and one that has held the balance of fate in innumerable tabletop roleplaying games over the years. It was this sacred geometry that [Greg Davill] chose to bless with the glory of glowing RGB LEDs. Now, [Greg] has shared the files so you can build your own.

The development blog of the D20 is a great read, highlighting the challenges of creating such a compact item that glows so brilliantly. The design uses a full 2400 1.5 mm x 1.5mm LEDs, in the old-school RGB style, split evenly between the twenty sides. That’s right, there’s no fancy self-addressing smart LEDs here — each LED is manually controlled directly by [Greg]’s hardware. A SAMD51 and ICE40UP5K FPGA are put to work running the displays. Each panel is held together in a barely-there 3D printed frame, linked together with ribbon cables to keep things compact. A Sony camera battery is slotted inside the tight confines of the frame to supply the necessary power.

We first covered the project late last year, and it’s great to see it out there now in a form that’s readily reproduced. Assembly of such a board is not for the faint of heart, however, with plenty of fine SMD parts to tangle with. We suspect this is just yet another salvo in the ongoing arms race of LED glowables, and we can’t wait to see what [Greg] — and the rest of the community — comes out with next. If you’ve got a lead on the new glowing hotness, let us know. Video after the break.

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Over-Engineered Incandescent Numerical Display Shows Great Workmanship

April 1, 2021 by Donald Papp 18 Comments

Back before LED technology came into its own, displays used incandescent bulbs. These vintage incandescent displays weren’t necessarily big; the Eaton 925H-C fiber optic display, for example, has numbers barely 7 mm tall and packs two of them into a tiny area. Of course, the depth of the display module itself is huge by today’s standards; those components have got to go somewhere, after all.

This particular device is, in [Industrial Alchemy]’s words, “[d]ripping with the spending excess that only a bottomless military budget can provide… the Eaton 925H-C may not be a practical device, but it is certainly an impressive one.”

The way the display works is this: individual incandescent bulbs light up fiber optic light guides, which terminate on the face of the display in small dots to make up a numerical display. With only fourteen bulbs, the dots we see here clearly aren’t individually addressable; the two digits are most likely broken up into seven segments each, with three dots making up each segment.

No expense seems spared in the design and manufacture of these displays. Even the incandescent lamps have individual shock absorbers.

The sheer amount of workmanship in these displays is remarkable, and their design makes them easy to retrofit with LED technology instead of replacing the tiny incandescent lamps. In a stark contrast to all of the machined aluminum and gold plated contacts seen here in the Eaton 925H-C, take a look at this Soviet-era seven-segment incandescent display whose construction is far less sophisticated, but shows off its own clever engineering. We’ve also seen more modern DIY takes on the concept, using LED light sources and cured UV resin light pipes to get that vintage look to the displays.

Oh Brother, Would You Look At This Cistercian Clock

March 29, 2021 by Kristina Panos 18 Comments

We were beginning to think we’d seen it all when it comes to RGB clocks, but [andrei.erdei] found a fast path back into our hearts and minds. This clock is a digital representation of an ancient numeral system used by 13th century Cistercian monks before the Indo-Arabic system that we know and love today took over. It’s a compact system (at least for numbers 1-9,999) that produces numerals which sort of look like 16-segment displays gone crazy.

Every numeral has a line down the middle, and the system uses the four quadrants of space around it to display the ones, tens, hundreds, and thousands positions starting in the upper right corner.

[andrei] adapted the system to show time by assigning tens of hours to the thousands quadrant in the bottom left, hours to the hundreds quadrant in the bottom right, tens of minutes in the upper left, and minutes in the top right. The tricky part is that the system has no zero, but [andrei] just darkens the appropriate quadrant to represent zero.

The timekeeping is done with an ESP-01, and there are a total of 31 RGB LEDs including the middle bit, which blinks like a proper digital clock and doubles as a second hand. As usual, [andrei] has provided everything you’d need to build one of these for yourself. We admit that the system would take a little time to learn, but even if you never bothered to learn, this would make a nice conversation piece or focal point for sitting and staring. Take a minute to check it out in action after the break.

We love a good clock build no matter how it works. Sink your teeth into this clock that’s driven by a tuning fork.

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Building An LED Etch-A-Sketch

March 11, 2021 by Lewin Day 14 Comments

The Etch-A-Sketch was a toy that demanded mastery. Some grew capable of creating masterful artworks, while others struggled to do more than a jumbled mess of angry, angular lines. The inherent limitations of being able to only draw a singular, connected line are all part of the fun, of course, and [gatoninja236] recreated that in a modern, LED form.

The build uses a Raspberry Pi to run the show, with a 64×64 LED matrix hooked up to the GPIO pins serving as a display. Two encoders are used to recreate the famous Etch-A-Sketch interface, hooked up to an Arduino Nano that then communicates encoder data to the Pi over I2C, due to the limited GPIOs available. There’s also an MPU6050 accelerometer board, used to enable the intuitive shake-to-clear functionality.

The final result is a fun LED toy that, unlike a real Etch-A-Sketch, you can play in the dark. We’ve seen other sneaky hacks on the classic toy before, too – like this Samsung TV cleverly hidden in a lookalike shell. Video after the break. Continue reading “Building An LED Etch-A-Sketch” →