The D20, or twenty-sided die, is most commonly known in the shape of a regular icosahedron. It’s a fantastic, enchanting geometry, and one that has held the balance of fate in innumerable tabletop roleplaying games over the years. It was this sacred geometry that [Greg Davill] chose to bless with the glory of glowing RGB LEDs. Now, [Greg] has shared the files so you can build your own.
The development blog of the D20 is a great read, highlighting the challenges of creating such a compact item that glows so brilliantly. The design uses a full 2400 1.5 mm x 1.5mm LEDs, in the old-school RGB style, split evenly between the twenty sides. That’s right, there’s no fancy self-addressing smart LEDs here — each LED is manually controlled directly by [Greg]’s hardware. A SAMD51 and ICE40UP5K FPGA are put to work running the displays. Each panel is held together in a barely-there 3D printed frame, linked together with ribbon cables to keep things compact. A Sony camera battery is slotted inside the tight confines of the frame to supply the necessary power.
We first covered the project late last year, and it’s great to see it out there now in a form that’s readily reproduced. Assembly of such a board is not for the faint of heart, however, with plenty of fine SMD parts to tangle with. We suspect this is just yet another salvo in the ongoing arms race of LED glowables, and we can’t wait to see what [Greg] — and the rest of the community — comes out with next. If you’ve got a lead on the new glowing hotness, let us know. Video after the break.
Many of us have become familiar with the distinctive sound of multirotor toys, a sound frequently punctuated by sharp sounds of crashes. We’d then have to pick it up and repair any damage before flying fun can resume. This is fine for a toy, but autonomous fliers will need to shake it off and get back to work without human intervention. [Zha et al.] of UC Berkeley’s HiPeRLab have invented a resilient design to do so.
We’ve seen increased durability from flexible frames, but that left the propellers largely exposed. Protective bumpers and cages are not new, either, but this icosahedron (twenty sided) tensegrity structure is far more durable than the norm. Tests verified it can survive impact with a concrete wall at speed of 6.5 meters per second. Tensegrity is a lot of fun to play with, letting us build intuition-defying structures and here tensegrity elements dissipate impact energy, preventing damage to fragile components like propellers and electronics.
But surviving an impact and falling to the ground in one piece is not enough. For independent operation, it needs to be able to get itself back in the air. Fortunately the brains of this quadcopter has been taught the geometry of an icosahedron. Starting from the face it landed on, it can autonomously devise a plan to flip itself upright by applying bursts of power to select propeller motors. Rotating itself face by face, working its way to an upright orientation for takeoff, at which point it is back in business.
We have a long way to go before autonomous drone robots can operate safely and reliably. Right now the easy answer is to fly slowly, but that also drastically cuts into efficiency and effectiveness. Having flying robots that are resilient against flying mistakes at speed, and can also recover from those mistakes, will be very useful in exploration of aerial autonomy.
We all have our own preferences when it comes to travel souvenirs — that little something that brings back the memories and feelings of a past holiday every time we look at it, whether it’s the cliché fridge magnet, some local speciality, or just the collection of photos we took. But then there are those journeys that can’t be summarized into a single item and may require a bit more creativity. For [Jonathan], it was last year’s trip around the world that took him and [Maria] to locations all over Europe, Asia, and Oceania, and he found a great way to remember it: an interactive, laser-cut travel globe displaying all the places they went to.
Building a sphere is of course a bit tricky with a laser cutter, so [Jonathan] went for the icosahedron shaped Dymaxion map projection (think of a large d20 dice) and burnt the world onto it. Inside the globe is an ESP8266, an MPU-6050 IMU, and a bunch of LEDs to light up the travel locations using the WLED library. Taking the data from the IMU, he customized the WLED library to determine which way the globe is positioned, and highlights the top-facing location in a different color.
This is a great way to reminisce about a memorable journey even years down the road, and while it may not be flexible to extend, it seems like the kind of trip that deserves a standalone device anyway. Plus, the Dymaxion map is definitely an interesting projection — so here’a a foldable one, just because. And If you like tracking things on a globe, here’s one that shows the location of the ISS.
[janth]’s build relies on semitransparent acrylic mirrors for the infinity effect, lasercut into triangles to form the faces of the icosahedron. The frame is built out of 3D printed rails which slot on to the acrylic mirrors, and also hold the LED strips. [janth] chose high-density strips with 144 LEDs per meter for a more consistent effect, and added frosted acrylic diffusers to all the strips for a clean look with less hotspots from the individual LEDs.
An ESP32 runs the show, and the whole assembly is epoxied together for strength. The final effect is very future disco, and it’s probably against medical advice to stare at it for more than 5 minutes at a time.
Like the original, [noniq]’s version is laser cut and engraved, and uses some 3D printed parts. But it does away with the fasteners (that’s 60 pairs of nuts and bolts), and instead uses neodymium magnets to make all the triangle pieces snap together to form the icosahedron globe. The hinges are simply some pieces of gaffer-tape.
This design improvement creates a cleaner globe and also addresses some of the concerns posted in the comments of the earlier build. The design files are available for download on [noniq]’s blog — you need to 3D print some magnet holders and stopper plates, and laser cut the 20 triangle tiles. The stopper plates help ensure that the angle between tiles when it is put together is limited to 138 degrees, making it easier to assemble the globe.
Check out the video after the break to hear the satisfying “thunk” of neodymium magnets snapping together.
Tired of balls that are just balls, and not glowing geometric constructions of electronics and wonderment? Get yourself an IcosaLEDron, the latest in Platonic solids loaded up with RGB LEDs.
The folks at Afrit Labs wanted a fun, glowy device that would show off the capabilities of IMUs and MEMS accelerometers. They came up with a ball with a circuit board inside and twenty WS2812B RGB LEDs studded around its circumference
The frame of the ball is simply a set of twenty tessellated triangles that can be folded up during assembly. The outer shell of the ball is again printed in one piece, but fabricated out of transparent NinjaFlex, an extraordinarily odd, squishy, and likely indestructible material.
Inside the IcosaLEDron is a PCB loaded up with an ATMega328p, an accelerometer, a LiPo battery charger, and quite a bit of wiring. Once the ball is assembled and locked down, the squishy outer exterior is installed and turned into a throwable plaything.
If 20 sides and 20 LEDs aren’t enough, how about a an astonishing 386-LED ball that’s animated and knows its orientation? That’s a project from Null Space Labs, and looking at it in person is hypnotic.
While city engineers were setting up the multicolored ball of lights in Times Square this year, [Phil] at adafruit was busy designing the X2 Time Ball, a disco icosahedron perfect for celebrating the new year.
The ball is made of 20 acrylic triangles zip-tied together into an icosahedron. On each face, six RGB pixels light up via commands from an Arduino. The entire project is able to be controlled remotely thanks to the help of a pair of XBees. [Phil] whipped up a Processing sketch to control the LED ball any way we could possibly imagine.
Although it may be a little late to build an LED disco ball for this year’s New Year’s Eve party, that doesn’t mean we couldn’t use it the other 364 days of the year. It’s perfect for parties, weddings, and our weekly lightswitch raves. Check out the action video of the Time Ball after the break.