Glitching LED Display Proves Crowd Favorite

There’s something enchanting about the soft glow of a properly diffused LED, and this is only improved by greater numbers of LEDs. [Manoj Nathwani] was well aware of this, setting out to build a large display using ping-pong balls for their desirable optical qualities.Unfortunately, not everything went to plan, but sometimes that’s not all bad.

The matrix, built back in 2016 for EMF Camp, was sized at 32×18 elements, for a total of 576 pixels. This was achieved with the use of 12 WS2811 LED strips, with the lights set out on a 50mm grid. Cheap knock-off pingpong balls were used for their low cost, and they proved to be excellent diffusers for the LEDs.

With everything wired up to a NodeMCU, basic testing showed the system to be functioning well. However, once the full matrix was assembled in the field, things started to fall over. Basic commands would work for the first 200 LEDs or so, and then the entire matrix would begin to glitch out and display random colors. Unable to fix the problem in the field, [Manoj] elected to simply run the display as-is. Despite the problems, passers-by found the random animations to be rather beautiful anyway, particularly at night.

After the event, [Manoj] determined the issue was due to the excessive length of the data line, which in the final build was 48 meters long. While the problem may be rectified when [Manoj] revisits the project, the audience seemed to appreciate the first revision anyway.

LED displays will be a hacker staple until the heat death of the universe. Ping pong balls will also likely retain their position as a favorite diffuser. If you’ve got a great LED build of your very own, be sure to hit up the tips line!

A Chrome Extension For Configuring RGB LEDs

Like pretty much all of us, [Andy Schwarz] loves RGB LEDs. Specifically he likes to put them on RC vehicles, such as navigation lights on airplanes or flashers and headlights on cars. He found himself often rewriting very similar Arduino code for each one of these installations, and eventually decided he could save himself (and all the other hackers in the world) some time by creating a customizable Arduino firmware specifically for driving RGB LEDs.

The software side of this project, which he’s calling BitsyLED, actually comes in two parts. The first is the firmware itself, which is designed to control common RGB LEDs such as the WS2812 or members of the NeoPixel family. It can run on an Arduino Pro Mini with no problems, but [Andy] has also designed his own open hardware control board based on the ATtiny84 that you can build yourself. Currently you need a USBASP to program it, but he’s working on a second version which will add USB support.

With your controller of choice running the BitsyLED firmware, you need something to configure it. For that, [Andy] has developed a Chrome extension which offers a very slick user interface for setting up colors and patterns. The tool even allows you to create a visual representation of your LEDs so you can get an idea of what it’s going to look like when all the hardware is powered up.

RGB LEDs such as the WS2812 are some of the most common components we see in projects today, mainly because they’re so easy to physically interface with a microcontroller. But even though it only takes a couple of wires to control a large number of LEDs, you still need to write the code for it all. BitsyLED takes a lot of the hassle out of that last part, and we’re very interested to see what the hacker community makes of it.

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Addressable 7-Segment Displays May Make Multiplexing A Thing Of The Past

[Sean Hodgins] has a knack for coming up with simple solutions that can make a big difference, but this is one of those “Why didn’t I think of that?” things: addressable seven-segment LED displays.

[Sean]’s design is basically a merging of everyone’s favorite Neopixel RGB LED driver with the ubiquitous seven-segment display. The WS2811 addressable RGB driver chip doesn’t necessarily have to drive three different color LEDs – it can drive three segments of the same display. With three of the chips on a single board, all seven segments plus the decimal point of a display can be controlled over a single data line. No more shift registers, no more multiplexing. And as a nice touch, individual displays can be ganged together with connectors on the back of each module. [Sean] has some code to support the display but is looking for someone to build a standalone library for it, so you might want to pitch in. Yes, he plans to sell the boards in his shop, but as with all his projects, this one is open source and everything you need to build your own is up on GitHub. The brief video below shows a few daisy-chained displays in action.

Like many of [Sean]’s designs, including this Arduino rapid design board, this is a simple way to get a tedious job done, and it wrings a lot of functionality from a single IO pin.

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LEDs And Pi Let You Virtually Decorate This Online Christmas Tree

Anyone who has decorated a Christmas tree knows that the lights are what really make the look. But no matter how many strings you wrap around it, there never seems to be enough. Plus the standard sets either sit there and do nothing, or just blink on and off at regular intervals. Yawn.

But hackers aim higher, and [leo.currie]’s interactive “paintable” Christmas tree takes the lighting game a step beyond. The standard light strings are replaced with strings of WS2811 RGB LEDs which are wired to an ESP8266. A camera connected to a Raspberry Pi is setup up to stream images of the tree to all and sundry on the Interwebz, but with a special twist: it also creates a map of every light on the tree. That allows the lights to be controlled individually in response to user inputs on a web page hosted on the Pi. The upshot is that you can paint the tree with any color you like in real time, or upload various animated GIFs to display on the tree. You can play with the tree directly, or watch a replay on the video below when that Pi inevitably gets hugged to death.

Imagine the possibilities with this. Why not hang a lot of LED strings vertically from the eaves of your house and make a huge, low-resolution display? We’ve featured plenty of large, interactive LED Christmas displays before, and we’d love to see what you come up with.

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Engineer’s Primer On DIY Christmas Light Shows

Each year brings new Christmas light shows, with synchronised music and wild blinking decorations to light your eyeballs ablaze. Now, many of us have dabbled in the dark arts of blinken, tinkering with LEDs or flashing a neon bulb or two. There’s plenty of tutorials on how to control all manner of lights, but they’re often written for novices. Learning the basics of electronics for the nth time when you just need to know the specifics of a protocol or what IC you need can be a total drag. That’s why [Bill Porter] has written the Engineer’s Guide to DIY Computer Controlled Holiday Lights.

[Bill] covers the topic from start to finish – not just the technical side of things, but practical considerations about where to source components, and timescales for keeping your project on track. It’s no coincidence this is coming out in January – if you want to get something big up and running for Christmas, it’s time to start now! The guide gives links to forum communities that put in large group orders for parts early, and ship them slow to save money.

Other areas covered include software for creating advanced sequences for your lighting setup, which allow you to map animations over your entire layout. There’s also tips on which controller hardware to use for incandescent lights and the now-ubiquitous WS2811 strings. Even better, [Bill] shares specific tips on how to avoid common problems like voltage drop over long pixel runs and communication issues.

It’s a testament to [Bill] and his experience – the guide is an excellent way to get right up to speed with the state of the art in DIY Christmas light shows, and will save you from all manner of pitfalls. If you need to build something big this year and don’t want to reinvent the wheel, this is for you.

It’s not the first time we’ve heard from [Bill] either – check out his stunning wedding invitations or his repair of a science museum exhibit.

Driving 16 WS2812B Strips With GPIOs And DMA

[Martin Hubáček] wrote in with his WS2812 LED library for the STM32F3 series processors. [Martin]’s library takes the same approach as [Paul Stoffregen]’s OctoWS2811 for the Teensy, and [Erich Styger]’s for the Freescale FRDM-K64F board. That is, it uses three DMA channels to get the signal out as fast as possible.

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Using WS2811 Chip To Drive Incandescent Lamps

What makes the WS2812-style individually addressable pixel LEDs so inviting? Their rich colors? Nope, you can get RGB LEDs anywhere. Their form factor? Nope. Even surface-mount RGBs are plentiful and cheap. The answer: it’s the integrated controller. It’s just so handy to speak an SPI-like protocol to your LEDs — it separates the power supply from the data, and you can chain them to your heart’s desire. Combine this controller and the LEDs together in a single package and you’ve got a runaway product success.

But before the WS2812, there was the WS2811 — a standalone RGB controller IC. With the WS2812s on the market, nobody wants the lowly WS2811’s anymore. Nobody except [Michael Krumpus], that is. You see, he likes the old-school glow of incandescent, but likes the way the WS2812 strings are easy to drive and extend. So he bought a bag of WS2811s and put the two together.

The controller IC can’t handle the current that an incandescent bulb requires, so he added a MOSFET to do the heavy lifting. After linking a few of these units together, he discovered (as one does with the LED-based WS2812s eventually) that the switching transients can pull down the power lines, so there is a beefy capacitor accompanying each bulb.

He wanted each bulb to be independently addressable, so he only used the blue line of the RGB controller, which leaves two outputs empty. I’m sure you can figure out something to do with them.

Needless to say, we’ve seen a lot of WS2812 hacks here. It’s hard to pick a favorite. [Mike] of “mike’s electric stuff” fame built what may be the largest installation we’ve seen, and this hack that effectively projection-maps onto a randomly placed string of WS2812s is pretty cool. But honestly, no project that blinks or glows can go far wrong, right?

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