A Tiny LED Matrix Is Better With Friends

When we last heard from [lixielabs] he was building Nixie tube replacements out of etched acrylic and LEDs. Well he’s moved forward a few decades to bring us the Pixie, a chainable, addressable backpack for tiny LED matrix displays.

Each Pixie module is designed to host two gorgeous little Lite-On LTP-305G/HR 5×7 LED dot matrix displays, which we suspect have been impulse purchases in many a shopping cart. Along with the displays there is a small matrix controller and an ATTINY45 to expose a friendly electrical interface. Each module is designed to be mounted edge to edge and daisy chained out to 12 or more (with two displays each) for a flexible display any size you need. But to address the entire array only two control pins are required (data and clock).

[lixielabs] has done the legwork to make using those pins as easy as possible. He is careful to point out the importance of a good SDK and provides handy Arduino libraries for common microcontrollers and a reference implementation for the Raspberry Pi that should be easy to crib from to support new platforms. To go with that library support is superb documentation in the form of a datasheet (complete with dimensions and schematic!) and well stocked GitHub repo with examples and more.

To get a sense of their graphical capabilities, check out a video of 6 Pixie’s acting as a VU meter after the break. The Pixie looks like what you get when a hacker gets frustrated at reinventing LED dot matrix control for every project and decided to solve it once and for all. The design is clean, well documented, and extremely functional. We’re excited to see what comes next! Continue reading “A Tiny LED Matrix Is Better With Friends”

Slim RGB Matrix Puts LEDs Inside The PCB

Sometimes all that’s required to build something interesting is to put the same old pieces together differently. [Sayantan Pal] did this for the humble RGB LED matrix, creating an extra-thin version by recessing WS2812b NeoPixel LEDs inside a PCB.

The popular WS2812B is 1.6 mm in height, which happens to be the most commonly used PCB thickness. Using EasyEDA, [Sayantan] designed a 8×8 matrix with modified WS2812B footprints. A slightly undersized cutout was added to create a friction-fit for the LEDs, and the pads were moved to the back side of the panel just outside the cutout, and their assignment were flipped. The PCB is assembled face down, and all the pads are soldered by hand. Unfortunately this creates rather large solder bridges which slightly increases the overall thickness of the panel, and is probably also unsuitable for production with conventional pick-and-place assembly.

We’ve seen some similar methods with PCB assemblies that use layered PCBs. Manufacturers are starting to even embed components inside multilayer PCBs.

Slot Machine Has A Handle On Fun

For some reason, when slot machines went digital, they lost their best feature — the handle. Who wants to push a button on a slot machine, anyway? Might as well just play video poker. [John Bradnam] seems to agree, and has built an open-source three-color matrix slot machine complete with handle.

In this case, you’ll be losing all of your nickels to an Arduino Pro Mini. The handle is an upgrade to an earlier slot machine project that uses three 8×8 matrices and a custom driver board. When the spring-loaded handle is pulled, it strikes a micro switch to spins the reels and then snaps back into place. Between each pull, the current score is displayed across the matrix. There’s even a piezo buzzer for victory squawks. We only wish the button under the handle were of the clickier variety, just for the feels. Check out the short demo video after the break.

If you’re not a gambler, you could always turn your slot machine into a clock.

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ARM And X86 Team Up In No Compromise Cyberdeck

Over the last couple of years the cyberdeck community has absolutely exploded. Among those who design and build these truly personal computers there are no hard rules, save perhaps making sure the final result looks as unconventional as possible. But one thing that’s remained fairly consistent is the fact that these machines are almost exclusively powered by the Raspberry Pi. Unfortunately, that means they often leave something to be desired in terms of raw performance.

But [MSG] had a different idea. His cyberdeck still has the customary Raspberry Pi inside, but it also has an i7 Intel NUC that can be fired up at the touch of a button. He says it’s the best of both worlds: an energy efficient ARM Linux platform for mobile experimentation, and a powerful x86 Windows box for playing games working from home. It’s the hacker equivalent of business in the front, party in the back.

With a KVM connected to the custom Planck 40% mechanical keyboard and seven inch LCD, [MSG] can switch between both systems on the fly. Assuming he’s got the juice anyway; while the Raspberry Pi 4 and LCD is able to run on a pair of 18650 batteries, the cyberdeck needs to be plugged in if he wants to use the power-hungry NUC. If he ditched the Pi he could potentially load up the case with enough batteries to get the Intel box spun up, but that would be getting a little too close to a conventional laptop.

The whole plurality theme doesn’t stop at the computing devices, either. In addition to the primary LCD, there’s also a 2.13 inch e-paper display and a retro-style LED matrix courtesy of a Pimoroni Micro Dot pHAT. With a little Python magic behind the scenes, [MSG] is able to display things like the system temperature, time, and battery percentage even when the LCD is powered down.

In a post on the aptly-named Cyberdeck Cafe, [MSG] talks about how seeing the VirtuScope built by [bootdsc] inspired him to start working towards his own personal deck, and where he hopes to take the idea from here. The unique USB expansion bay behind the screen holds particular promise, and it sounds like a few add-on modules are already in the works. But of course, it wouldn’t be a true cyberdeck if it wasn’t constantly being improved and redesigned. Come to think of it, that makes at least two rules to live by in this community.

Lo-Fi Art On A 32×32 Matrix

Display technology has improved by leaps and bounds over the last few years, thanks in no small part to the smartphone revolution. High-resolution LCD panels are dirt cheap and easy to interface with. There’s absolutely no logical reason to try and show images on a 32×32 array of RGB LEDs. But that didn’t stop [Felix Spöttel] from doing it anyway.

The project, which he calls thirtytwopixels, was designed to work in conjunction with MPD (Music Player Daemon) to show the album art for whatever is currently playing. The ultra-low resolution display added a certain element of abstractness to the artwork, which [Felix] said made it an interesting conversation starter. Guests would try and guess what the album art was depicting given the sparse rendition shown on the matrix.

[Felix] gives an excellent explanation of how to get the server and client-side software up and running should you want to recreate his setup, but his Python scripts also have a function where you can push an arbitrary image to the display if you don’t want to connect everything up to the MPD backend.

On the hardware side, thirtytwopixels uses the Raspberry Pi Zero W, a Adafruit RGB Matrix Bonnet, and a 32×32 LED matrix that uses the HUB75 interface. Even a relatively small LED matrix like this can get pretty thirsty, so [Felix] is using a 5 volt power supply that can deliver 4 amps to keep the electronics happy.

If you wanted to keep the low resolution aesthetic but make the display larger, we’ve seen WS2812B LED strips and 3D printed frames used to make a custom jumbo matrix which could surely be adapted for this concept.

Clock Is Not Readable By Humans

Not every build needs to be immediately useful or revolutionary. Plenty of builds are just for fun, for education, or even purposefully useless but still challenging. This clock, for example, might fit into all three categories. It’s a clock that displays time through a QR code, making it completely inscrutable unless you have a device which likely has its own readable clock on it already.

The QR Code clock comes to us from [Aaron] and is based on the now-ubiquitous ESP32 WiFi chip. The ESP32 is connected to a 64×64 LED matrix which is updated every second with a code for the current time. With single-second resolution that means that even with a method for reading a QR code by hand, like you sometimes can with barcodes, there’s no way to read it without a smartphone since it changes so rapidly.

Of course [Aaron] recognizes the flaw in his design in his video in which he notes tongue-in-cheek that with this clock you would never have to look at a smartphone again, since the clock is right there on the wall. We appreciate the humor and also that [Aaron] has made all of his source code available in case you would like to use this as an example project for using QR codes for more useful purposes. For now, though, we’ll just forward you along to some other useless machines.

Thanks to [willmore] for the tip!

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The Hurricanes Are Coming

It’s hurricane season in the northern hemisphere right now, and plenty of news and weather organizations remain dedicated to alerting people if a storm is about to impact their area. There’s no shortage of ways to receive this information, either. We all have our favorite weather app or forecasting site, and there are emergency alerts to cell phones, TV, and radio stations as well. If none of that suits you, though, you can also roll out your own weather alert readerboard.

[Damaged Dolphin] built a weather alert readerboard using a Raspberry Pi and a 64×128 LED matrix. The Raspberry Pi runs Raspbian and uses a HAT from Adafruit, and once connected to the internet pulls down weather information for a specific area using custom python code. From there it can display any emergency weather alerts instantly on the readerboard screen including alerts for hurricanes. It does rely on data from the National Weather Service though, so if that is not available in your area some modifications will need to be made to the code.

While he notes that you probably shouldn’t rely on his non-professional python code exclusively when getting weather information, it would still be a good way of retrieving information about weather events without having to refresh a browser all the time. Once the storms have passed though, be sure you’re prepared for the days following.

Thanks to [b00tfa|l] for the tip!

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