World’s Smallest 384-Pixel LED Cube

DIY GUY Chris made what may be the world’s smallest 64-pixel-per-face LED cube.

Jeremy Cook
5 months agoLights

How many addressable LEDs can you fit on the surface of a 20x20x20mm PCB cube? As DIY GUY Chris shows in this tiny LED cube project, using WS2812B-1010 addressable LEDs (featuring a 1x1mm footprint), it’s possible to fit 8x8, or 64 LEDs on each PCB side, giving a total of 384 LEDs on the cube.

The cube not only arranges and connects LEDs on each outer surface, but also houses an ATmega328P microcontroller and battery charging circuitry on the back side of one of the PCBs. A tiny 3.7V lithium-ion battery is hidden inside the assembled cube for portable power. Because of the addressable function of the WS2812Bs used, a single MCU output controls the entire chain of LEDs, passing signals from one light source to the next.

To properly solder all of these tiny LEDs, DIY Guy Chris used a tiny stencil for applying solder paste, making application relatively straightforward. Ensuring the correct LED orientation was a bit of a challenge, however, and after the LEDs were applied the control board had to be flipped to solder on the MCU/etc with a heat gun. Each board was then soldered together with the help of a 3D-printed internal structure, forming this beautiful little LED cube.

Charging is provided by a pair of pins, while a second pair of pins is jumpered together to turn it on. Be sure to check out the build process, and a demo of it shining away in the video below.

*Note that 20x20mm appears to be the surface area of each PCB, potentially making the cube’s assembled full volume a bit larger than 20x20x20mm. It’s still impressive, and a good illustration of how at such a tiny scale the vertical dimensions of components, the joint structure, and board thickness are non-negligible design considerations. For another really tiny–and possibly also world’s smallest–device, check out my 1-inch MIDI controller featured here.

Jeremy Cook
Engineer, maker of random contraptions, love learning about tech. Write for various publications, including Hackster!
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