Building An Edge Lit Sign From The Scrap Pile

April 22, 2022 by Tom Nardi 3 Comments

Whether in a shop window or mounted to the top of consoles in NASA’s Mission Control Center, edge lit acrylic is a popular choice for making high visibility signs. Partly because of their striking hologram-like appearance, but also because they’re exceptionally cheap and easy to produce. Just how cheap and easy? Take a look at this recent video from [Hack Modular] for a perfect example.

Now you might think you’d need something like a CNC router to produce a sign like this, and for more complex images, that’s arguably the case. But if you’re only concerned with text, and have a fairly steady hand, you can pull off the etching step with nothing more exotic than a printed template and a razor blade. Of course, the LCD style font that [Hack Modular] picked for this sign is particularly well suited to hand cutting — if you’re interested in edge lit calligraphy, this method probably isn’t what you’re looking for.

This linear LED provides a more consistent light.

With the text carved into the acrylic, the only missing ingredient is light. For that, [Hack Modular] is using a 12 volt linear LED strip light. That is, instead of being dotted with individual LEDs like traditional strips, it provides a continuous band of light that’s perfect for this application. That gets stuck down to a scrap piece of wood, and a rusty angle bracket from an old Meccano set is used to hold the acrylic right on the center-line. If you think the final product looks like something that was created from trash, don’t feel bad, that was the intent.

The end result looks great. In fact, if we’re being honest, it’s a lot better than we would have thought was possible using hand tools. Granted the choice of font has a lot to do with that, but then again, we wouldn’t mind if all our edge lit acrylic signs ended up looking like big seven-segment displays either.

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2022 Sci-Fi Contest: A Very Star Wars Door

April 22, 2022 by Lewin Day No comments

Every fan of the original Star Wars trilogy knows the plight of Han Solo, who was so cruelly frozen in carbonite by Imperial forces. [erv.plecter] came into possession of a replica Solo, this time frozen in polyurethane, and set about using it as the door for a home theater setup.

Just like in the movie, there are a series of controls and lights on the side of the door, clearly intended to represent the state of the carbonite block and the smuggler trapped within. This was achieved with the use of a SAMD51 microcontroller, which controls five meters of WS2812B LED strip along with a small OLED display.

There’s also an amazing little smoke effect, built using a vape inhaler. These devices have proved popular for all kinds of theme builds and costumes, as it turns out. They’re a great way to produce a visible fog or smoke in a tiny, compact package.

[erv.plecter] was kind enough to share plenty of details on the build, including how the polyurethane cast was assembled into the door. The final result looks remarkably authentic, and would surely prove a hit at any Star Wars movie night. Just don’t spoil things by forcing everyone to sit through Revenge of the Sith. Video after the break. Continue reading “2022 Sci-Fi Contest: A Very Star Wars Door” →

2022 Sci-Fi Contest: Glowing LED Cubes Make Captivating Artifacts

April 20, 2022 by Lewin Day 3 Comments

LED cubes were once an exercise in IO mastery, requiring multiplexing finesse in order to drive arrays of many LEDs. Going RGB only increased the challenge. This build from [DIY GUY Chris] shows how much easier it is these days, when every LED has a smart addressable controller on board, and serves as a great sci-fi prop to boot.

Yes, the build relies on the venerable WS2812B addressable LEDs, soldered up in 5×5 grids on each of the six faces of the cube. Running the show is the Raspberry Pi RP2040 microcontroller, sourced here as an individual part rather than in its development board form. An SPI memory chip is on board for the code, along with a USB-C connector for programming. Signals pass around the cube via soldered connections along the edges of the custom PCBs that make up the faces of the solid.

Sitting on its 3D printed stand, the cube glows brightly while drawing a full 2 amps of power. [Chris] coded up a variety of animations, from simple color breathing routines to frantic dazzle animations sure to captivate any cyberpunk thieves that come to steal your magic glowing artifact.

If rectangular prisms aren’t your fancy, though, you can always consider building yourself a glowing D20 instead. Video after the break.

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Cute Oscilloscope Uses LEDs For Display

March 29, 2022 by Lewin Day 29 Comments

Oscilloscopes were once commonly called CROs, for the fact that they relied on cathode ray tubes for display. Since then, technology has moved quickly, and oscilloscopes these days almost entirely rely on modern screens like LCDs. However, [lonesoulsurfer] went a different route with this fun DIY build, creating an oscilloscope with a low-resolution LED display.

Yes, the signals are shown on a 10×10 matrix made up of red LEDs. The individual pixels look nicely diffused and chunky thanks to the fact that [lonesoulsurfer] was able to source square 5mm LEDs for the build. The whole project only uses four ICs – a decade counter and a LM3914 LED driver to run the display, a 555 timer for clock input, and an LM386 op-amp for amplifying incoming signals.

With a mic fitted onboard, the oscilloscope can act as a simple music visualizer, or be used with a probe to investigate actual circuits. It may not be of great enough resolution or precision for fine work, but it’ll at least tell you if your microcontroller’s clock is running properly if you’re scratching your head about the function of a simple project.

We’ve seen some great DIY oscilloscopes over the years, like this neat Arduino-based build. Video after the break.

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LED Kaleidoscope Uses Induction Power Magic

March 29, 2022 by Lewin Day 4 Comments

The kaleidoscope was first invented back in the early 1800s, with the curio known for showing compelling psychedelic patterns as light passes through colored glass and is reflected by mirrors in a tube. [Debra] of Geek Mom Projects recently gave the classic toy a thoroughly modern twist with her own build. (Thread Reader Link).

[Debra]’s kaleidoscope still relies on the typical mirror-tube construction to create reflections upon reflections which generate symmetrical patterns for the viewer. However, instead of colored glass beads lit by external light, she replaced these with so-called “wireless LEDs.” These little bead-like LEDs are fitted with small coils that allow them to be inductively powered without wires when they are placed in the magnetic field generated by a powered coil. Thus, [Debra]’s kaleidoscope works day or night, even in a dark room, since the light is coming from the little beady LEDs themselves.

It’s a great demonstration of wireless LED technology; there’s something almost magical about the tiny free-moving glowing beads. If you don’t want to buy them off the shelf, you can even make your own! Video after the break.

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Finally, A Mapping Tool For Addressable LED Strings

March 23, 2022 by Lewin Day 30 Comments

Addressable LED strings have made it easier than ever to build fun glowable projects with all kinds of exciting animations. However, if you’re not going with a simple grid layout, it can be a little difficult to map your strings out in code. Fear not, for [Jason Coon] has provided a tool to help out with just that!

[Jason]’s web app, accessible here. is used for mapping out irregular layouts when working with addressable LED strings like the WS2812B and others that work with libraries like FastLED and Pixelblaze. If you’re making some kind of LED globe, crazy LED tree, or other non-gridular shape, this tool can help.

The first step is to create a layout of your LEDs in a Google Sheets table, which can then be pasted into the web app. Then, the app handles generating the necessary code to address the LEDs in an order corresponding to the physical layout.

[Jason] does a great job of explaining how the tool works, and demonstrates it working with a bowtie-like serpentine layout with rainbow animations. The tool can even provide visual previews of the layout so you can verify what you’ve typed in makes sense.

It’s a great tool that we recently saw put to use on [Geeky Faye’s] excellent necklace project. Video after the break. Continue reading “Finally, A Mapping Tool For Addressable LED Strings” →

Breathe Easy With This LED Air Sensor Necklace

March 23, 2022 by Lewin Day 8 Comments

When you’re building wearables and glowables, sometimes a flashy rainbow animation is all you need. [Geeky Faye] likes to go a little further, however, and built this impressive necklace that serves to inform on the local air quality.

The necklace consists of a series of Neopixel LED strips, housed within a tidy 3D printed housing made with flexible filament. A dovetail joint makes putting on and removing the necklace a cinch. A TinyPico V2, based on the ESP32, runs the show, as it’s very small and thus perfect for the wearable application. A USB power bank provides power to the microcontroller and LEDs.

The TinyPico uses its WiFi connection to query a server fed with air quality data from a separate sensor unit. The necklace displays a calm breathing animation as standard in cool tones. However, when air quality deteriorates, it shows warmer and hotter colors in a more pointed and vibrant fashion.

It’s a neat project that shows off [Geeky Faye]’s abilities at both electronics and tasteful wearable fabrication. It’s not always easy to build projects that are both functional and comfortable to wear, but this one works on both counts. Both the 3D files for the necklace and the microcontroller firmware code is included in the GitHub repo for those keen to dive in to the nitty gritty.

We’ve seen some great necklaces over the years, including those that rely on some beautiful PCB art. Video after the break.
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