Build an Ultra Tiny Smart RGB LED Display Matrix with the SAM D21

German-based electrical engineer Alex took to Hackaday to introduce a new project he’s been working on that he calls an “ultra tiny smart USB RGB LED display/matrix,” which is a complete overhaul of his first endeavor — 192:LED, the “extreme smart RGB LED display/matrix.”

The project came about when he pondered what to do with a handful of leftover 0404 RGB LEDs lying around: The goal is to build a very tiny 8x8 RGB LED matrix. This matrix will be controlled by UART and/or I2C (not decided yet). Besides this, there will be some ‘demo modes’ for a standalone operation.”

For the extreme version of the project, Alex soldered together a series of 0404 LEDs on a custom four-layer PCB and controlled the lot using a microcontroller (unknown) and multiplexing. Beyond the MCU and LEDs, Alex equipped the tiny matrix with a 2016-sized crystal oscillator with a pair of 0201 capacitors, 3X 0402 buffer capacitors (for Vcc), and a solder bridge to disconnect MOSI for programming.

Alex’s 192:LED redesign, however, is more streamlined than the original, and most of the hardware has been replaced with better electronics — including WS28112 LEDs in a 1515 package, and a SAM D21 MCU that’s more than capable of driving the display/matrix. He also designed an ingenious platform to program the tiny board, which consists of a 3D-printed jig, a Trinket-M0-USB-Bootloader, and an Atmel-ICE programming and debugging tool.

Alex’s Ultra tiny smart USB RGB LED display/matrix project is still a work in progress, and those interested can follow his work in the link listed above.