Video:

https://www.youtube.com/watch?v=NsjoV-Hwcoc

Description:

Back in 2017 I attended a gaming convention called Gameholecon and watched a game of Dungeons and Dragons run by Chris Perkins, game designer and master, er game-master.  It was a game titled “Tortle Annihilation” because the main characters were of the Tortle race.  The game was for charity and had many celebrities from the role-playing game space.  Afterwards they auctioned off everyone’s dice and I purchased Chris Perkins' dice. I wanted to make a an awesome display to show off these prize dice so I got around to quickly designing a 3D printed base to house and light up these dice… and then the project sat until March of this year until I got my hands on a Pi Pico and thought it was a good time to learn some Python.

BOM:

5.5x2.1 Barrel Jack

5V DC Adapter

Pimoroni Tiny2040 Pi Pico board

3D Printed base (2 pieces)

Adafruit BiColor matrix with I2C backpack

Awesome Chris Perkin’s dice - Crystal Caste Giant Dice

Chessex Large Figure box - stand in for Chris’ signed box

Small piece of vellum or paper to diffusing LEDs

Process:

I designed the base in Fusion 360 and hand painted the details using acrylic paints. 

I wired the barrel jack to the Pico and the matrix and wired the I2C between them.

I laser cut images onto the dice box to pick up the light from the base, more on that later.

For the code, the display runs like a 16x8 display but 8 of the columns overlap for red and green.  I created a frame (array) for the overall display and then frames for the red, green, and orange, with orange just being red and green on at the same time.  To create animations I went into excel and created 8 representations of the display for each color with varying bits turned on and off, red being most coverage, orange being less coverage as it’s a hotter color towards the center, and some small green pixels just to add variety.  In my code I randomly select a red, orange, and green frame every cycle through and update them to the display.  I then sleep for a random amount of time to give a natural flame flicker look.

Onto the laser etching.  Chris signed the dice box in marker, I wanted it to stand out more so I opted to laser etch it.  I did this by scanning the box and signature on a flatbed scanner.  I cleaned up the signature in GIMP and then converted to a path in Inkscape.  I decided on not having just one laser etched side and found a few other pictures online to engrave.  To keep the original box pristine I ordered some extra boxes to be laser etched instead of the original.  I believe the boxes are polycarbonate and not acrylic so they do etch a little weird as they don’t vaporize, instead they leave a melted rough surface which is actually kind of neat.

Once the box was etched I added a piece of vellum (paper) to diffuse the LEDs and everything was good to go!  It looks impressive in person and was a great way to show off my celebrity dice!