It’s holiday time again! And that means it’s time to break out the soldering iron and the RGB LEDs! If you’re going to make a custom PCB to put those LEDs on, you’ll notice that you get few copies of your PCB in your order, so, might as well design it such that you can combine them all together into a single Sierpinski Christmas Tree, just like [Landon Carter] did.

Each PCB “tree” has three connections which can be used as either inputs or outputs by soldering one of two bridge connections on the PCB. The power and signal goes up and down through the tree, rather than across, so the connections go one on the top of the tree and two on the bottom. This way, each tree in the triangle can easily be connected, and each triangle can be easily connected to another. Each individual tree has three WS2812b-mini addressable RGB LEDs and the tree is controlled by an external Arduino.

The first order of 10 PCBs came in, which makes a 9 member tree – next up is a 27 member tree. After that, you’re going to need some pretty high vaulted ceilings in order to put these on the wall. On the upside, though, once the holidays are over, everything can be easily disconnected and packed away with the rest of the decorations. If you, too, are interested in RGB LED decorations, there are a few on the site for your perusal.

The human body does plenty of cool tricks, but one of the easiest to take advantage of is persistence of vision (POV). Our eyes continue to see light for a fraction of a second after the light goes off, and we can leverage this into fun blinkenlight toys like POV staffs. Sure, you can buy POV staffs and other devices, but they’re pretty expensive and you won’t learn anything that way. Building something yourself is often the more expensive route, but that’s not the case with [shurik179]’s excellent open-source POV staff.

There’s a lot to like about this project, starting with the detailed instructions. It’s based on the ItsyBitsyM4 Express and Adafruit’s Dotstar LED strips. You could use the Bluetooth version, but it’s already quite easy to load images to the staff because it shows up as a USB mass storage device. We like that [shurik179] added an IMU and coded the staff so that the images look consistent no matter how fast the staff is spinning. In the future, [shurik179] might make a Bluetooth version that’s collapsible. That sounds like quite the feat, and we can’t wait to see it in action.

As cool as it is to wave a POV staff around, there’s no real practical application. What’s more practical than a clock?

Just when we think we’ve seen all possible combinations of 3D printing, microcontrollers, and pretty blinkenlights coming together to form DIY clocks, [Mukesh_Sankhla] goes and builds this geometric beauty. It’s kaleidoscopic, it’s mosaic, and it sorta resembles stained glass, but is way cheaper and easier.

The crucial part of the print does two jobs — it combines a plate full of holes for a string of addressable RGB LEDs with the light-dividing walls that turn the LEDs into triangular pixels. [Mukesh] designed digits for a clock that each use ten triangles. You’d need an ESP8266 to run the clock code, or if you’d rather sit and admire the rainbow light show unabated by the passing of time, just use an Arduino Uno or something similar.

Most of the aesthetic magic here is in the printed pieces and the FastLED library. It has a bunch of really cool animations baked in that look great with this design. Check out the demo video after the break. The audio is really quiet until the very end of the video, so be warned. In our opinion, the audio isn’t necessary to follow along with the build.

The humble clock takes many lovely forms around here, including pop art.

Reading is big in Québec, and [pepelepoisson]’s young children have access to a free mini library nook that had seen better days and was in dire need of maintenance and refurbishing. In the process of repairing and repainting the little outdoor book nook, he took the opportunity to install a few experimental upgrades (link in French, English translation here.)

The mini library pods are called Croque-Livres, part of a program of free little book nooks for children across Québec (the name is a bit tricky to translate into English, but think of it as “snack shack, but for books” because books are things to be happily devoured.)

After sanding and repairs and a few coats of new paint, the Croque-Livres was enhanced with a strip of WS2812B LEDs, rechargeable battery with solar panel, magnet and reed switch as door sensor, and a 3.3 V Arduino to drive it all. [pepelepoisson]’s GitHub repository for the project contains the code and CAD files for the 3D printed pieces.

The WS2812B LED strip technically requires 5 V, but as [pepelepoisson] found in his earlier project Stecchino, the LED strip works fine when driven directly from a 3.7 V lithium-polymer cell. It’s not until around 3 V that it starts to get unreliable, so a single 3.7 V cell powers everything nicely.

When the door is opened, the LED strip lights up with a brief animation, then displays the battery voltage as a bar graph. After that, the number of times the door as been opened is shown on the LED strip in binary. It’s highly visual, interactive, and there’s even a small cheat sheet explaining how binary works for anyone interested in translating the light pattern into a number. How well does it all hold up? So far so good, but it’s an experiment that doesn’t interfere at all with the operation of the little box, so it’s all good fun.

Anyone who has done anything with RGB LEDs knows that their ability to display pretty much any color is somehow both the best and worst thing about them. How do you get it right? How do you make your results repeatable? [Thomas] has the answer. He dug around in the ol’ parts cupboard, found a few pots, and got to work making this stay-home stew of a project — an on-demand RGB LED color mixer.

Three cleverly color-coded potentiometers and an Arduino let [Thomas] step through 0-255 to mix various values of red, blue, and green. The shade that gets made is displayed live on a set of 10 individual NeoPixels that are laid out under a frosty diffusing panel. Each of the RGB values are also shown on an 16×2 LCD.

This is one of those projects that hits a sweet spot of being simple, useful, and fun. It’s even nice-looking and compact. What more could you want from a project cobbled together from ingredients on hand? [Thomas] is even giving away the code recipe.

Once you dial in your ideal colors, why not make a gesture-controlled lamp?

Looking to sterilize something? Give it a good blast of the old UV-C. Ultraviolet radiation in the shortest wavelength band breaks down DNA and RNA, so it’s a great way to kill off any nasties that are lurking. But how much UV-C are you using? [Akiba] at Hackerfarm has come up with the NukeMeter, a meter that measures the output of their UV-C sterilizer the NukeBox. It is built around a $2.50 sensor and a $3 Arduino.

The NukeMeter is built around a GUVA-S12SD UV sensor breakout board. This sensor is really designed for UV-A detection, but a quick look at the spec sheet revealed that it is sensitive to UV across all of the bands. So, it can be used as a UV-C sensor if you know how sensitive it is to this particular frequency band.

However, the sensor is not that sensitive to UV-C light, so [Akiba] had to do a bit of minor surgery on the circuitry that surrounds the sensor to tweak the output. The sensor was designed to measure relatively low levels of UV light (such as sunlight), and now they are blasting it with a shedload of radiation, so they have to effectively disable one of the op-amps that normally scales the output up, which involves replacing a couple of resistors. That’s a bit of a pain to do with surface mount components, but it is doable with a steady hand and a small tip soldering iron.

Next, an Arduino takes the voltage output of the sensor and converts it into a light level. The mathematics of how this works are all well detailed in the post, but it isn’t complicated, and the source code is here.

Using this, [Akiba] was able to measure how the lights performed, how quickly they warmed up and how much the light level varies along the length of the fluorescent tube.

One caveat to bear in mind here: [Akiba] designed this to measure the output of the low-pressure mercury vapor lamps they are using at Hackerfarm, which output a very narrow frequency band, peaking at 250 nM. This design would not work for a more broadband output or for one which mixed UV-C with UV-A and UV-B. For that, you would need a more sophisticated design that would probably cost more than $5.

SAFETY NOTE: Don’t mess with UV-C light sources unless you have a good idea of what you are doing and are sure that the light is contained, e.g. in a sealed box, maybe with interlocks. Remember that you also rely on DNA, and inadvertently zapping your own DNA can cause all sorts of unpleasantness.  

When we last saw [isaac879]’s levitating RGB time fountain, it was made of wood which meant that it would absorb water and didn’t really show off the effect very well. His new version solves this problem with an acrylic case, new PCB and an updated circuit.

Like the original, this project drops water past strobing RGB LEDs creating an illusion of levitating, undulating colored water droplets. The pump at the top creates the droplets, but the timing has a tendency to drift over time. He thus implemented a PID controller to manage the pump’s drip rate, which was done by having the droplets pass by an infrared diode connected to an ATTiny85. The ’85 used the diode and PWM to control the pump motor speed and communicated to the Arduino over I2C.

The video shown below shows the whole process of designing and building the new time fountain. Everything from circuit and PCB design to 3D printing to assembly is shown along with narration describing what’s going on in case you want to build one yourself. If you do, all the files and components required are listed in the info section of the video.

There’s more that [isaac879] wants to do to improve the time fountain, but V2 looks great. It’s sleeker and smaller than the original and solves some of the design issues of the first. For more inspiration, check out some of the other levitating water fountain projects that have been posted over the years.

If everything goes according to plan, Elon Musk says the first generation of SpaceX’s massive Starship will make an orbital flight before the end of 2020. That’s a pretty bold claim, but when you’ve made landing rockets on their tails as in the old science fiction pulp magazines seem routine, we suppose you’ve earned the right to a bit of bravado. We’re excited to see the vehicle evolve over the next several months, but even if the real one stays grounded, we’ll gladly take this “flying” Starship model from [Chris Chimienti] as a consolation prize.

Feeling a bit let down by the 3D printable models of the Starship he found online, [Chris] set out to build his own. But it wasn’t enough to just make his bigger, stronger, and more accurate to Starship’s current design; he also wanted to make it a bit more exciting. Some RGB LEDs an Arduino embedded in the “cloud” stand the rocket sits on was a good start, and the landing pad inspired by SpaceX’s real autonomous spaceport drone ship Just Read the Instructions looks great all lit up.

But this is Starship we’re talking about, a vehicle that could literally push humanity towards being a multi-planet species. To do it justice, you’ve really got to knock it out of the park. So [Chris] found a magnetic levitation module online that could support a few hundred grams, and set to work on making his plastic Starship actually hover over the landing pad.

As you might imagine, it was a bit tricky. The first versions of the rocket looked great but came out too heavy, so he switched over to printing the model in so-called “spiral vase mode” which made it entirely hollow. Now far lighter and with a magnetic plate fit into the bottom, it was stable enough to float on its own. For the final touch, [Chris] added some red LEDs and a coin cell battery to the base of the Starship so it looks like the sleek craft is performing a last-second landing burn with its “impossible” full-flow staged combustion engines.

This isn’t the first time we’ve seen a model rocket with an electronic glowing cloud under it, but it’s certainly the first one we’ve seen that could levitate in mid-air. While this little rocket might not make it all the way to Mars, we wouldn’t be surprised to see it touching down on the desks of other hackers and makers in the near future.

Inspired by the over-the-top stage lighting and pyrotechnics used during e-sport events, [Hans Peter] set out to develop a scaled-down version (minus the flames) for his personal Counter-Strike: Global Offensive sessions. It might seem like pulling something like this off would involve hacking the game engine, but as it turns out, Valve was kind enough to implement a game state API that made it relatively easy.

According to the documentation, the CS:GO client can be configured to send out state information to a HTTP server at regular intervals. It even provided example code for implementing a simple state server in Node.js, which [Hans] adapted for this project by adding some conditional statements that analyze the status of the current game.

These functions fire off serial commands to the attached Arduino, which in turn controls the WS2812B LEDs. The Arduino code takes the information provided by the HTTP server and breaks that down into various lighting routines for different conditions such as wins and losses. But things really kick into gear when a bomb is active.

[Hans] wanted to synchronize the flashing LEDs with the beeping sound the bomb makes in the game, but the API doesn’t provide granular enough data. So he recorded the audio of the bomb arming sequence, used Audacity to precisely time the beeps, and implemented the sequence in his Arduino code. In the video after the break you can see that the synchronization isn’t perfect, but it’s certainly close enough to get the point across in the heat of battle.

With the special place that Counter-Strike occupies in the hearts of hackers and gamers alike, it’s little surprise people are still finding unique ways to experience the game.

[Peterthinks] admits he’s no cabinet maker, so his projects use a lot of hot glue. He also admits he’s no video editor. However, his latest video uses some a MAX7219 to create a 600 character scrolling LED sign. You can see a video of the thing, below. Spoiler alert: not all characters are visible at once.

The heart of the project is a MAX7219 4-in-1 LED display that costs well under $10. The board has four LED arrays resulting in a display of 8×32 LEDs. The MAX7219 takes a 16-bit data word over a 10 MHz serial bus, so programming is pretty easy.

The MAX chip can decode for seven-segment displays or just allow you to light up the outputs directly, which is what the code here does. You can cascade the chips, so it is possible to string more than one of these modules together.

The code is available on Dropbox. The code is extremely simple due to the use of the Parola library and a MAX72XX library. We’ve seen a number of projects based around this chip. Some of the uses are pretty novel.