Discreet CO2 Monitor Hides Elegant Internal Layout

Outwardly, this sleek CO2 monitor designed by [Daniel Gernert] might look like something cooked up in Amazon’s consumer electronics division. But open up that 3D printed case, and you’ll find a surprisingly low parts count that’s been cleverly packed in so as to make the most of the enclosure’s meager internal dimensions.

No wasted space here.

There are, if you can believe it, just three principle components to this device: a Seeed Studio Seeeduino XIAO microcontroller, a Infineon S2GO PAS CO2 sensor board, and a ring of WS2812B LEDs. You could even delete the ring altogether and replace it with a single addressable LED to accomplish the same goal, but we’d say the full ring is money-well-spent if you’re going to spin up your own copy.

Functionality is very straightforward — the LED ring will indicate the detected CO2 concentration by lighting up green and working its way through yellow and onto red. The sensor has no wireless capability, but if you plug it into your computer, you can get a local readout of current conditions.

We love environmental monitoring solutions here almost as much as we love intricately designed 3D printed enclosures. If you’d like to see another project where those two concepts aligned, check out this printable ESP8266 sensor enclosure.

Throwback: Designing Addressable LEDs From Scratch

These days, addressable LEDs are all the rage. A little chip paired with each LED receives signals and modulates the light output as needed. [John Peterson] was working on a project along these very lines, designing his Curilights back in 2008!

[John] wasn’t the first to come up with the idea; he designed the Curilights to replicate a string of programmable LEDs he’d seen called Triklits. His design involved each RGB LED being fitted with a Microchip PIC 16F688 microcontroller, which could receive serial data and control the LED channels with PWM. These LEDs could then be strung up to create an addressable chain. It’s fundamentally the same concept as the WS2812, just in a larger format and built by hand. His design also had the benefit of non-volatile memory onboard the PICs, so animations could be stored even after power off. [John] later went on to build a controller for his lights, complete with sensors. It could be triggered by a motion sensor or light sensor, and would run animations on the string without the use of a computer.

While [John]’s design didn’t go on to bigger things or commercial success, it did win first place at the Third Annual Lantronix Wireless Design Contest. It also goes to show that many people will come around to the same idea when it makes good sense!

If you’re interested in the wider world of addressable LEDs, check out our breakdown on some of the products out there. Meanwhile, if you’re brewing up your own flashing, glowing projects, be sure to notify the tipsline!

Big Audio Visualizer Pumps With The Music

A spectrum analyzer is a great way to create exciting visuals that pulse in time with music. [pyrograf] wanted a big one as a display piece, so set about whipping up something of their very own.

An ESP32 microcontroller serves as the heart of the build, with its high clock rate and dual cores making it a highly capable choice for the job. Audio from a microphone is amplified and pumped into the ESP32’s analog input. Core 0 on the ESP32 then runs a Fast Fourier Transform on the input audio in order to determine the energy in each frequency band. The results of this FFT are then passed to Core 1, which is used to calculate the required animations and pipe them out to a series of WS2812B LEDs.

Where this build really shines, though, is in the actual construction. Big chunks of acrylic serve as diffusers for the LEDs which light up each segment of the spectrum display. Combine the big pixel size with a nice smooth 30 Hz refresh rate on the LEDs, and the result is a rather large spectrum analyzer that really does look the business.

We’ve seen some similar builds over the years, too. Video after the break.

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Easy Network Config For IoT Devices With RGBeacon

When you’re hooking up hardware to a network, it can sometimes be a pain to figure out what IP address the device has ended up with. [Bas Pijls] often saw this problem occurring in the classroom, and set about creating a simple method for small devices to communicate their IP address and other data with a minimum of fuss.

[Bas] specifically wanted a way to do this without adding a display to the hardware, as this would add a lot of complexity and expense to simple IoT devices. Instead, RGBeacon was created, wherin a microcontroller flashes out network information with the aid of a single RGB WS2812B LED.

In fact, all three colors of the RGB LED are used to send information to a computer via a webcam. The red channel flashes out a clock signal, the green channel represents the beginning of a byte, and the blue channel flashes to indicate bits that are high. With a little signal processing, a computer running a Javascript app in a web browser can receive information from a microcontroller flashing its LEDs via a webcam.

It’s a neat hack that should make setting up devices in [Bas]’s classes much easier. It needn’t be limited to network info, either; the code could be repurposed to let a microcontroller flash out other messages, too. It’s not dissimilar from the old Timex Datalink watches which used monitor flashes to communicate!

2022 Sci-Fi Contest: CyberGlove Tests Your Reactions

Since the 1980s, we’ve seen innumerable attempts to revolutionize the way we interact with computers. Since the advent of keyboards and mice, we’ve seen everything from magic wands to electric gloves, with [Deemo Chen]’s project fitting into the latter category.

The build takes on a cyberpunk aesthetic, with addressable LEDs installed along each digit. The various digits light up randomly, and the wearer of the glove must tap a button on the corresponding digit in order to test their reaction times. An Arduino Uno runs the show, and keeps track of the score, displaying the results on an attached HD44870-compatible LCD.

The mess-o’-wires aesthetic, with bare electronics hanging off the glove, goes a long way to making this look like a proper bit of sci-fi kit. The lurid, colorful glow is a key part of this look, and something we’ve seen on many projects over the years.

Overall, the reaction trainer served as a great freshman project for [Deemo], along with their chums [Dhruv] and [Ryan]. Along the way, the team clearly picked up skills in microcontroller programming, as well as learning how to work with LCD displays and addressable LEDs. Master these skills and you can pull off some impressive feats. Video after the break.

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Finally, A Mapping Tool For Addressable LED Strings

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”

fiber matrix

Big LED Matrix Becomes Tiny LED Matrix Thanks To Fiber Optics

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.

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