1200 Addressable LEDs Make For The Perfect First Dance

The first dance of a newly married couple at the wedding reception is both a sentimental and memorable event, so why not make it even more so with something a bit special? Hackaday alumnus [Brett Haddoak] and his wife [Rachelle] certainly achieved that, with 1200 addressable LEDs turning her wedding dress into a real-life reproduction of Princess Aurora’s color changing dress from Disney’s Sleeping Beauty.

Tradition dictates that a groom must not see the dress before the Big Day, thus the LEDs were fixed to a petticoat and bustier that go underneath. The design would need so many LEDs that it crossed the limit that an Arduino can address, thus there were two Arduinos to control the whole. Electronics and batteries were worn in a pair of polo shorts, and after some nail-biting moments involving flaky connections, the whole thing came to life. The result can be seen in the video below the break, and certainly comes with a significant wow factor!

We would like to wish the happy couple all the best for the future, and we hope that this won’t be their last such electronic collaboration. If you’re hungry for more, it’s not the first light-up wedding outfit we’ve brought you.

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Image showing differences between WS2815 and WS2813 LED strips - the WS2815 strip lighting is more uniform throughout the strip's length.

Teaching You Everything You Might Have Missed About Addressable LEDs

Often, financial motivation results in people writing great educational material for hackers. Such is absolutely the case with this extensive documentation blog post on addressable LEDs by [DeRun]. This article could very be named “Addressable LEDs 101”, and it’s a must-scroll-through for anyone, whether you’re a seasoned hacker, or an artist with hardly any technical background and a desire to put LEDs in your creations.

This blog post is easy to read, painting a complete picture of what you can expect from different addressable LED types, and with apt illustrations to boot. Ever wonder which one of the addressable strips you should get from your retailer of choice, and what are the limitations of any specific type? Or, perhaps, you’d like to know – why is it that a strip with a certain LED controller is suspiciously cheap or expensive? You’re more than welcome to, at least, scroll through and fill into any of your addressable LED knowledge gaps, whether it’s voltage drops, color accuracy differences, data transfer protocol basics or dead LED failsafes.

Addressable LEDs have a special place in our hearts, it’s as if the sun started shining brighter after we’ve discovered them… or, perhaps, it’s all the LEDs we are now able to use. WS2812 is a staple of the addressable LED world, which is why we see them even be targets of both clone manufacturers and patent trolls. However, just like the blog post we highlight today mentions, there’s plenty of other options. Either way do keep coming cover a new addressable LED-related hack, like rewriting their drivers to optimize them, or adding 3.3V compatibility with just a diode.

We thank [Helge] for sharing this with us!

Tutorial Teaches You To Use Neopixels With Micropython

Addressable LEDs are wonderful things, with products like Neopixels making it easy to create all kinds of vibrant, blinking glowables. However, for those without a lot of electronics experience, using these devices can seem a bit daunting. [Bhavesh Kakwani] is here to help, with his tutorial on getting started with Neopixels using the MicroPython environment. 

The tutorial flows on from [Bhavesh’s] Blink example for MicroPython, and is aimed at beginners who are learning for the first time. It explains the theory behind RGB color mixing that allows one to generate all manner of colors with WS2812B-based LED strings, and how to code for the Raspberry Pi Pico to make these LEDs do one’s bidding.

The guide even covers the use of the Wokwi simulation tool. This is a great way for beginners to test their projects before having to play with actual hardware. This is useful for beginners, because it’s a great way to catch mistakes – is there a software problem, or did they push the soldering iron through the microcontroller? It’s also a technique that pays dividends when working on more complicated projects.

Whether you’re entirely new to the embedded world, or just want to learn the intricacies of talking to addressable LEDs and make sense of color mixing theory, this tutorial will serve you well. Before you know it, you’ll be building glowing projects with the best of them!

 

DIY All-Transistor Addressable Pixel

By now most readers should be used to addressable LEDs, devices that when strung out in a connected chain can be individually lit or extinguished by a serial data stream. Should you peer at one under a microscope you’ll see alongside the LED dies an integrated circuit that handles all the address decoding. It’s likely to be quite a complex device, but how simply can its functions be replicated? It’s a theme [Tim] has explored in the TransistorPixel, and addressable LED board that achieves addressability with only 17 transistors.

It uses a surprisingly straightforward protocol, in which a pulse longer than 500ns enables the LED while a shorter one turns it off. Subsequent pulses in a train are passed on down the line to the next device. A 20µs absence of a pulse resets the string and sets it to wait for the next pulse train. Unlike the commercial addressable LEDS there is only a single colour and no suport for gradated brightness, but it’s still an impressive circuit.

Under the hood is some very old-school RTL logic, a monostable to detect the pulse and a selection of gates and a latch to capture the state and forward to the chain. It’s laid out on a PCB in order of circuit function, and while we can see that maybe it’s not a practical addresssable LED for 2021, it’s likely that it could be made into a much smaller PCB if desired.

Perhaps unsurprisingly given the ready availability of addressable LEDs, we’ve not seen many home made ones. This addressable 7-segment display may be the closest.

Discrete LEDs Make A Micro Display

Few things excite a Hackaday staff member more than a glowing LED, so it should be no surprise that combining them together into a matrix really gets us going. Make that matrix tiny, addressable, and chainable and you know it’ll be a hit at the virtual water cooler. We’ve seen [tinyledmatrix]’s work before but he’s back with the COPXIE, a pair of tiny addressable displays on one PCBA.

The sample boards seen at top are a particularly eye catching combination of OSH Park After Dark PCB and mysterious purple SMT LEDs that really explain the entire premise. Each PCBA holds two groups of discrete LEDs each arranged into a 5×7 display. There’s enough density here for a full Latin character set and simple icons and graphics, so there should be enough flexibility for all the NTP-synced desk clocks and train timetables a temporally obsessed hacker could want.

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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”

New Part Day: SK6812 Mini-E. A Hand Solderable Neopixel Compatible LED!

Normally when we give you a New Part Day piece, it concerns a component that you will have never seen before. The subject of this find by [Robert Fitzsimons] then is a slight departure from that norm, given that the SK6812 Mini-E is a WS2812 or Neopixel compatible multi-colour LED of a type that has been available for a while now.

What makes this component new though is its packaging. The Mini-E variant of the SK6812 only appeared last year and has now found its way through to smaller order quantities on AliExpress. Its special feature is that it has a set of flat leads rather than the usual pads on the underside of the package. This means that unlike its predecessors it is readily hand solderable, as he demonstrates by attaching a set of leads to one.

The leads emerge halfway up the side of the device, which seems designed to be mounted recessed within a PCB hole. He demonstrates this with a piece of stripboard, and remarks that they would make a good choice for many small projects such as Shitty Add-On boards.

We’ve touched the leadless SK6812s a few times before, along the way remarking that in some respects they are better than the WS2812 they follow.

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