Rolling Your Own LED Matrix Driver, With Copper Foil Tape To The Rescue

May 30, 2020 by Donald Papp 1 Comment

It all started when [Damien Walsh] got his hands on some surplus LED boards. Each panel contained 100 mini-PCBs hosting a single bright LED that were meant to be to be snapped apart as needed. [Damien] had a much better idea: leave them in their 20×5 array and design a driver allowing each LED to be controlled over WiFi. He was successful (a brief demo video is embedded down below after the break) and had a few interesting tips to share about the process of making it from scratch.

The first hurdle he ran into was something most of us can relate to; it’s difficult to research something when one doesn’t know the correct terms. In [Damien]’s case, his searches led him to a cornucopia of LED drivers intended to be used for room lighting or backlights. These devices make a large array of smaller LEDs act like a single larger light source, but he wanted to be able to individually address each LED.

Eventually he came across the IS32FL3738 6×8 Dot Matrix LED Driver IC from ISSI which hit all the right bases. Three of these would be enough to control the 100-LED panel; it offered I2C control and even had the ability to synchronize the PWM of the LEDs across multiple chips, so there would be no mismatched flicker between LEDs on different drivers. As for micontroller and WiFi connectivity, we all have our favorites and [Damien] is a big fan of Espressif’s ESP32 series, and used the ESP32-WROOM to head it all up.

LED pads bridged to copper tape, with Kapton (polyimide) tape insulating any crossovers.

The other issue that needed attention was wiring. Each of the LEDs is on its own little PCB with handy exposed soldering pads, but soldering up 100 LEDs is the kind of job where a little planning goes a long way. [Damien] settled on a clever system of using strips of copper tape, insulated by Kapton (a super handy material with a sadly tragic history.) One tip [Damien] has for soldering to copper tape: make sure to have a fume extractor fan running because it’s a much smokier process than soldering to wires.

A 3D-printed baffle using tracing paper to diffuse the light rounds out the device, yielding a 20 x 5 matrix of individually-controlled rectangles that light up smoothly and evenly. The end result looks fantastic, and you can see it in action in the short video embedded below.

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Dim Hallway Gets Lighting Upgrade

May 27, 2020 by Lewin Day 13 Comments

There’s nothing worse than a lightswitch that’s nowhere near where it should be, leaving you fumbling around in the dark. [supersquirrel72] had just this problem, and decided to put an Arduino to work instead.

Rather than using the original mains lighting that was poorly positioned and not enough to light the hall, instead 2 meters of white LED strip was chosen. The form factor is perfect for lighting a long, thin space – far better than running a series of seperate bulbs. The strip was rigged up to an Arduino Uno, that triggers the lights when movement is detected with a simple PIR motion sensor. After some feedback from the other occupants of the house, it was decided to tweak things further. An RTC was implemented to allow the Arduino to keep things dimmer after 9PM, so as to not wake others when making a trip to the kitchen for a midnight snack.

It’s a simple solution which brightens up the hallway nicely. We imagine this could just be the first step to a yet-more-integrated lighting solution in [supersquirrel72]’s house. Whether it’s IOT lights or something more festive, we can’t wait to see what’s next.

From Zero To LED Cube In Less Than Seven Months

May 22, 2020 by Dan Maloney 17 Comments

We know that LED video cubes are so last year, but that doesn’t mean we don’t still love to see them. Any project that incorporates over 24,000 LEDs is bound to be impressive, after all. But the more interesting bit about [Mike Cann]’s self-contained LED cube has more to do with the process he chose to get to the finished product.

There are two ways to approach a new project, especially when you’re new to hardware hacking like [Mike] is. One is to jump in with both feet and just see what happens, for good or for ill. The other is is to ease into it with a starter project, to find out where your limitations lay and work around them gradually. [Mike Cann] wisely chose the latter approach with his LED cube project, starting with an LED sand toy. The single 64 x 64 LED panel was a bit easier to work with, and got him up to speed on the care and feeding of such hardware, as well as the code needed to drive it. The video below tells the tale of scaling that project up by a factor of six to make the cube, a process that had its share of speedbumps. Everything ended up fitting together great, though, letting [Mike] get on to the software side. That’s where this project really shines — the smartphone app running the cube is really slick, and the animations are great.

There’s clearly room for new features on [Mike]’s cube, so here’s hoping he can carve out some time to make a great build even better. For inspiration he might want to check out this side-scrolling Castlevania cube, or perhaps read up on the finer points of OpenGL for LED cubes.

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LED Matrix Takes You Down To Nixieland

May 20, 2020 by Sven Gregori 2 Comments

It’s said that imitation is the sincerest form of flattery. Sure, there are some who might simply sugarcoat blatant plagiarism with fancy quotes, but there are still cases that come from well-intended, genuine admiration. The Nixie tube with its ember-like glow is a component that definitely gets a lot of such admiration, and being a fond LED enthusiast, [tuenhidiy] saw a perfect opportunity to imitate them with a RGB LED Matrix and build a virtual Nixie clock from it.

What may sound like just displaying images of Nixie tubes on a LED matrix, is actually exactly that. Using the UTFT library and converter, [tuenhidiy] turned pictures of individually lit-up Nixie tube digits into arrays of 16bit RGB values, and shows the current time on an ESP32-controlled 64×64 matrix with them. Providing two different image sizes, you can either place two tubes next to each other, or in a 3×2 arrangement, and of course have plenty of flexibility for future extensions. In the demo video after the break, you can see the two options in action while displaying both the full time, and only the seconds.

Unfortunately, it’s always difficult to judge an LED project through the lens of a camera, especially when looking for the characteristic color of a Nixie tube, but we take [tuenhidiy]’s word that it resembles it a lot better in reality. On the other hand, the pixelated look certainly adds its own charm, so you might as well go completely overboard with the colors — something we’ve seen with a different LED-themed Nixie alternative a little while back.

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Weather Display Is Cloudy With A Chance Of ESP8266

May 19, 2020 by Tom Nardi 2 Comments

[Mukesh Sankhla] writes in to share this unique weather display that looks to be equal parts art and science. Rather than show the current conditions with something as pedestrian as numbers, this device communicates various weather conditions to the user with 25 WS2812B LEDs embedded into the 3D printed structure. It also doubles as a functional planter for your desk.

So how does this potted plant tell you if it’s time to get your umbrella? Using a NodeMCU ESP8266 development board, it connects to openweathermap.org and gets the current conditions for your location. Relative temperature is conveyed by changing the color of the pot itself; going from blue to red as things heat up. If there’s rain, the cloud over the plant will change color and flash to indicate thunder.

[Mukesh] has made all of the STL files for the printed components available, as well as the source code for the ESP8266. You’ll need to provide your own soil and plant though, there’s only so much you can send over the Internet. Incidentally, if the clever way he soldered these WS2812B modules together in the video catches your eye, you’ll really love his “RGB Goggles” project that we covered earlier.

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Jumbo LED Matrix Brings Classic Sprites To Life

May 18, 2020 by Tom Nardi 9 Comments

Despite all the incredible advancements made in video game technology over the last few decades, the 8-bit classics never seem to go out of style. Even if you weren’t old enough to experience these games when they were new, it’s impossible not to be impressed by what the early video game pioneers were able to do with such meager hardware. They’re a reminder of what can be accomplished with dedication and technical mastery.

The grid has been split up for easier printing.

If you’d like to put a little retro inspiration on your desk, take a look at this fantastic 16 x 16 LED matrix put together by [Josh Gerdes]. While it’s obviously not the only thing you could use it for, the display certainly seems particularly adept at showing old school video game sprites in all their pixelated glory. There’s something about the internal 3D printed grid that gives the sprites a three dimensional look, while the diffused glow reminds us of nights spent hunched over a flickering CRT.

The best part might be how easy it is to put one of these together for yourself. You’ve probably got most of what you need in the parts bin; essentially it’s just a WS2812B strip long enough to liberate 256 LEDs from and a microcontroller to drive them. [Josh] used an Arduino Nano, but anything compatible with the FastLED library would be a drop-in replacement. You’ll also need a 3D printer to run off the grid, and something to put the whole thing into. The 12×12 shadowbox used here looks great, but we imagine clever folks such as yourselves could make do with whatever might be laying around if you can’t nip off to the arts and crafts store right now.

Beyond looking great, this project is a fantastic reminder of how incredibly handy WS2812 LEDs really are. Whether you’re recreating iconic game sprites or fashioning your own light-up sunglasses, it’s hard to imagine how we managed before these little wonders hit the scene.

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PCB Jewelry Never Looked So Good

May 16, 2020 by Orlando Hoilett 8 Comments

[Gautchh] wanted to make something nice for his girlfriend. Being the DIY enthusiast he is, he thought a hand-made gift would resonate with her better than something he could pick up from the store. Enter NeckLight, a glow in the dark PCB necklace. He was first inspired by another project he ran across on Instructables, then decided to put his own little spin on the design. It’s cool how that works. Interestingly enough, it was his first time using Fusion 360, but you probably wouldn’t know that if you took a look at the results.

Aside from soldering, the trickiest part of this project was trying to get the LED intensities just right. [Gautchh] found the best way to do this was experimentally by testing each LED color with a series of resistors. He wanted to ensure he could get the color intensity and the LED current just right. Finally, with a touch of acetone, he was done (though he might want to try some alternatives to acetone next time).

[Gautchh] also thinks that this project would be a really nice way for beginners to learn surface mount (SMD) soldering. We’ve seen a few cool SMD LED projects before. Who could forget those competitive soldering challenges over at DEF CON?

Anyway. Thanks, [Gautchh]. We hope your girlfriend, and your dog, enjoyed their gifts.