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.
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.
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.
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.
[Jeremy Cook] writes to us about a project of his – a bouquet of LED cube flowers. The flowers are PCB cubes made out of small castellated PCBs, each of those having an individually addressable LED in its center. Castellations hold the cubes together mechanically, and thanks to a cleverly chosen pinout, only two different kinds of PCB need to be ordered for building such a flower!
As a vase for these flowers, he decided to use a glass bottle – which would need a cutout to fit a ESP8266-powered NodeMCU board, a controller of choice for the project. After a few different approaches for cutting glass all resulted in the bottles cracking, he gave up on the “clean cut” idea and reused one of the broken bottles, gluing it back together well enough for the aesthetic to work.
[Jeremy] tells us that he’s had help from a hack we covered back in 2017 – using a diode for level shifting, as the ESP8266’s 3.3 V level signals aren’t a good match for WS2812 inputs. From there, the WLED firmware for the ESP8266 ties everything together beautifully. It’s clear that [Jeremy] had a field day designing this, toying with all the ideas and approaches!
As you might expect, the release of last year’s Ghostbusters: Afterlife has not only lead to renewed interest in the old 1980s toys and tie-in merchandise, but has spawned a whole new generation of blinking plastic gadgets to delight children of all ages. Of course, for folks like us, that means more hardware to hack on.
In a recent post to the official Ghostbusters YouTube channel, professional prop maker [Ben Eadie] shows off some of the tricks of the trade when he takes a $15 USD “PKE Meter” toy from Hasbro and turns it into a screen-quality prop. Even if you’re not looking to get an early start on your Halloween costume, the techniques demonstrated in this video could be easily adapted to other projects. For those whose next ideal home improvement is a fireman’s pole and an ectoplasmic laser-confinement grid, you might want to grab a couple of these toys while they’re still cheap for eventual conversion.
Uncovering the silver makes the piece look worn down.
The biggest takeaway from the video is probably the finishing techniques, as they could be used on any sort of realistic prop build. [Ben] starts by using a cabinet scraper to smooth out the lines on the plastic toy, and any holes are filled with the familiar baking soda and cyanoacrylate glue trick. Once the surfaces have been prepped, all the principle parts are sprayed with an adhesion promoter, followed by a coat of silver, and then the final black color.
This allows him to create a convincing “chipped paint” effect by strategically sanding or scraping through the top coat. Dabbing some toothpaste where you want the device to look worn down before spraying the final coat makes the process even faster, as it will prevent the top coat from sticking to the silver in the first place.
Unfortunately [Ben] doesn’t spend a whole lot of time explaining the electronics side of things, but it doesn’t look like there’s anything too complex going on. All the original gear is stripped, and it gets replaced with a microcontroller which we believe is an Adafruit ItsyBitsy nRF52840 Express. This is connected to two strings of tiny APA102 addressable LEDs which are run down the “wings” (we especially like the 3D printed lenses used to replace the original solid pips), and one that’s used to provide the iconic sine-wave display.
Everyone loves LED matrices, and even if you can’t find what you like commercially, it’s pretty easy to make just what you want. Need it big? No problem; just order a big PCB and some WS2812s. Need something tiny? There are ridiculously small LEDs that will test your SMD skills, as well as your vision.
But what if you want a small matrix that’s actually a big matrix in disguise? For that, you’ll want to follow [elliotmade]’s lead and incorporate fiber optics into your LED matrix. The build starts with a 16×16 matrix of WS2812B addressable LEDs, with fairly tight spacing but still 160 mm on a side. The flexible matrix was sandwiched between a metal backing plate and a plastic bezel with holes directly over each LED. Each hole accepts one end of a generous length of flexible 1.5-mm acrylic light pipe material; the other end plugs into a block of aluminum with a 35 by 7 matrix of similar holes. The small block is supported above the baseplate by standoffs, but it looks like the graceful bundle of fibers is holding up the smaller display.
A Raspberry Pi Pico running a CircutPython program does the job of controlling the LEDs, and as you can see in the video below, the effect is quite lovely. Just enough light leaks out from the fibers to make a fascinating show in the background while the small display does its thing. We’ve seen a few practical uses for such a thing, but we’re OK with this just being pretty. It does give one ideas about adding fiber optics to circuit sculptures, though.
