The icosaLEDron Is an LED-Lit Regular Platonic Solid That Anyone Can Build!

Jason Coon shows us what goes inside his amazing icosaLEDron — a 20-sided, LED-faceted fidget toy that is freakin' awesome!

If we've seen a definite trend we've seen over the past year, it's safe to say that people love LEDs, and more so when they are presented in a tactile format that welcomes interaction.

We were truly overwhelmed with content to cover in the heady days of the 2020 LED cube rush, when the advent of low-cost, iCE40 FPGA-based designs used LED panels as a go-to "hello world" project.

Shortly thereafter, ol' Greg Davill threw his hat into the ring, with his take on what a LED cube should look like, and before long, once again, when he decided to very much up the game, by releasing his truly magnificent LED icosahedron for us all to drop our jaws at.

Thing is, myself very much included, not all of us have Davill's steady hand, nor patience for such painstaking board assemblies. This thought apparently resonated with Jason Coon, and with that in mind, we happily present his take on the luminous LED icosahedron — a study into the development of a "low-resolution", pixel-per-face redux of similar builds that we have seen, aptly named the icosaLEDron.

Boiling this design down to the bare minimum, the icosaLEDron is a 20-sided shape, with 20 LEDs — one per face. That meets the functional definition for such a name, and drops the complexity by several orders of magnitude — not only in terms of assembly, but in functional operation as well!

The initial version of Coon's icosaLEDron, which can be seen seen spinning above, kept things as simple as they needed to be. 20 triangular boards, each featuring a single WS2812B-Mini 3535 addressable RGB LED.

These 3535 packaged parts are a nice halfway-house for makers looking for a digital serial LED solution that can be placed in layouts where the conventional 5050 package would take up too much board real estate. For such situations, a 1515 or 2020 LED case might be a tad too tiny for those without stencil and reflow capabilities — the 3535 packages can still be hand soldered!

More often than not now, we are pleased to see the inclusion of 3D printing jigging and support tooling within a build. Seen below, the idea to use a simple assembly fixture is a well thought out one.

It might look simple, but even the small features — such as the rounded mountain pegs, mean that the jig can easily be removed after the soldering operation, without the need to flex the soldered connections too much.

Speaking of soldered connections, now's a pretty good time to touch on the fact that all of these boards are identical. That's more interesting than it initially seems, because it indicates how much effort Coon has put into the thinking behind the signal routing within this icosaLEDron.

Those little solder jumpers sat above each LED are able to control the direction in which the LED serial data stream exits out of the board, left or right — meaning that Coon can snake a way for data to pass through the sculpture, without the need for custom wiring, etc. Clever!

This handy little jig enables Coon to move around the assembly, board by board, likely constructing two or three "sub assemblies," which are the bought together in order to eventually take on their final form.

icosaLEDron Rev 2?

With the signal routing and general tessellated assembly method standing as a rousing proof of concept, Coon now turns his eye to a more refined revision 2, featuring a few tricks to make this little triangular faceted finger toy a bit more robust in the hands of many a bright eyed user!

From the start, it's always good to frame your aspirations — and when it comes to a project that's going to be fidgeted with, spun about, and likely dropped more than a few times, there's one thing you can do, first and foremost, in order to make your design a darn sight more robust — and that's build it upon a firm frame, one that can stand the forces that the project will likely be facing during the course of its lifetime!

Building on his obvious affinity for 3D printing, Coon throws a flashback to the build of Davill, with a nifty "press-fit" fixture system that is as clever as the magnetic solution Davill used in his cube.

This presents Coon with the option to 3D print some segmented parts, forming an "outer shell" that can click into place over the triangular LED boards, affording the delicate LEDs a huge amount more protection than if they were laid bare.

Scaling it up!

The more recent of the two builds, the larger variant on the original, set of triangular LED boards features a few modifications in contrast to the original spec.

Notably, their larger dimensions mean that this second icosaLEDron has an internal volume that can now accommodate a reasonably-sized LiPo cell, along with an Adafruit nRF52840 Sense development board.

When you look at just all of features and functionality that this tricked-out dev board can bring to any design, well, the addition of the Adafruit nRF52840 Sense board makes a good deal of... sense to any project!

The nRF52840 Sense is packed to the brim with inputs and outputs, meaning that the mere substitution of this board into any other Feather-form factor base is enough to bring some superhuman sensing peripherals to any project.

Built upon a Raytac Corporation MDBT50Q module, that is itself in turn, based upon one of the ever popular Nordic Semiconductor nRF5x series of parts — the powerhouse nRF52840, the module alone is a feature-filled spec-sheets go all the way down!

With the nRF52840 offering a hefty Cortex-M4+, clocked at 64MHz, with a built-in FPU and HW DSP support, 1MB of FLASH and 256KB of SRAM, it's a worthy processor, before you even consider the on-chip communication peripheral set.

Native USB communications, NFC, and the obvious Bluetooth Low Energy give you a wide range of interfaces over which to sling your bits and bytes about. With further support for other 2.4GHz interfaces — including Bluetooth Mesh, Thread, ANT+, and Zigbee — these devices look pretty well covered for future communication protocols.

Raytaq Corp takes that powerful little chipset, and wraps it up into a much more easy to work with (although, admittedly still an LGA footprint...), FCC-certified module, complete with chip antenna —the MDBT50Q module.

This module based offering removes the need for the designer to get jiggy with the voodoo that is RF layout — and more importantly perhaps, for any aspiring product, can help simplify the certification of the design — something that will be needed before any product using such a module can be sold on the consumer market.

It's important to note that using a FCC pre-certified module does not remove the need for you to have your design subsequently tested for compliance, but it can make the whole ordeal a lot, lot easier - read - cheaper!

Finally, Adafruit takes that pre-certified Raytaq Corp module, and drops it into the Feather form factor that we all know and love, and absolutely cram whatever board real estate is left open and free, with a suite of sensors that let you get an insight into the environment the board sits inside.

With the obligatory motion sensor load out going above and beyond a basic accelerometer, we find an STMicroelectronics LSM6DS33 tri-axial accelerometer + gyroscope combination, coupled with an additional ST part, the LIS3MDL tri-axial magnetometer, which rounds out a full 9-DoF motion sensing solution.

Coon has already put those parts to good use, in mapping the various motion components to lighting parameters, as seen below — making this for a fun fidget gadget already!

If you want to lend an ear — perhaps over BLE? — there's a part for that on board. Another ST part steps in to play, the MP34DT01-M MEMS PDM microphone, offers up some interesting options for sound reactive lighting, especially maybe when put into practice producing data for the Cortex-M4 DSP functions to tear through!

It's fitting that a device that dishes out dazzling displays of color might have some sense of feedback in its feature list, if perhaps not yet implemented — it's certainly a nice option to have for future functionality.

The Broadcom APDS-9960 allows for such feedback — and a whole, whole lot more. Crammed into a single 8-pin SMD package, this diminutive (3.94 x 2.36 x 1.35 mm) device is three sensors in one: an RGBC light sensor, proximity sensor, and gesture detector.

There's a myriad possibilities for integrating that data into your light show, I've already lost count of the ideas spawning from this part!

What about... environmental LED ornaments?

The final feature set of the Sense board fixates around the parameters that often feature heavily in our perception of the "comfort factor" of our surroundings.

With a SHT30 from Sensirion offering metrics on temperature and relative humidity parameters, the Bosch Sensortec BMP-280 lets us keep tabs on barometric pressure levels — from which we can derive our altitude.

(In no way am I suggesting that it's a good idea to have such an delicate,ornate device perhaps able to sense the height to which it could be thrown... but you know... it's all possible with these parts!)

Reduce, reuse, recycle!

I'm quite fond of the cut-out feature found on the larger, rev 2 LED boards. With it serving to provide access to the USB port of the Feather board on one face, it's also been used to provide access to the SPST switch, for switching the device on and off.

Little design tips and tricks like this allows the overall complexity of the assembly to be reduced, just by taking the time to think what could work elsewhere.

Coon is cracking on ahead with the pre-production and verification of his larger, framed design, and I can't wait to see this icosaLEDron — or several of them! — rolling around, showing off the data they are sensing from the world around them.

If you want to dive into this awesome build, Jason has a project page here with further details.

Make sure you're up to date with the latest from Coon by checking out the development thread he's sharing over on Twitter, or if you'd prefer, take a gander over at his GitHub for all the goodies!

Tom Fleet
Hi, I'm Tom! I create content for Hackster News, allowing us to showcase your latest and greatest projects for the world to see!
Latest articles
Sponsored articles
Related articles
Latest articles
Read more
Related articles