It is already December 1st, and time for a new Advent Calendar. This year the design includes birch plywood with PMMA, SK6812 RGBW LEDs running with a Raspberry Pi Pico board, building a small village.

The small buildings are cut out of 4 mm plywood with laser engraved PMMA inlets.

A Raspberry Pi Pico runs the show:

The board hosts an optional debug interface (see “Getting Started: Raspberry Pi Pico RP2040 with Eclipse and J-Link“), a navigation switch plus two SK6812 RGBW LEDs on it.

Using the navigation switch, one can change the color theme, brightness and of course change the ‘counter’: from 1 to 24, one building for each number.

The small buildings can be filled with items (sweets), and nicely cover the bottom LED. And with the item removed, the buildings let the light shine through.

All the PCBs are placed on the bottom side. Originally I wanted to use the mounting holes on each PCB, but it was easier just to glue them to the back side with some plywood pieces. Looks kind of messy, but works :-).

The firmware runs on the Pico with FreeRTOS, and it features different color modes. From warm white, candle flickering, up/down dimming up to random color modes.

The settings are stored in the on-chip flash using MinINI, so settings are persistent. And the UF2 bootloader of the Pico makes it easy to provide a new firmware just in case, or for next year.

Originally, I wanted to produce three of it, but I was running out of time. So for now this is the only one, and today it will be donated to a family who deserves it :-).

Happy Adventing 🙂

Links

• Laser Cut Advent Calendar 2020
• Advent Calendar for 2021