This Digital Die Built with an Adafruit Feather Is Perfect for Rolling D20s

People who have never played a tabletop role-playing game like Dungeons & Dragons or Pathfinder may assume that the famous d20 is the only die involved in the games. In actuality, it’s just one of many required to play those kinds of games. The particular die you need to roll depends on the situation, and you often need to roll multiple dice and add up the results. Caleb Everett’s Digital Die makes that easy, and removes all of that pesky math from the equation.

The Digital Die resembles a pocket calculator, but all of its functions were designed specifically for games like Dungeons & Dragons. The user can perform simple functions, like rolling a d20 or a d100. But, they can also roll more elaborate sets of dice, along with modifiers, like “4d20 + d4 + 4.” Anyone you’re playing with be naturally suspicious of the device, so there is a test function to prove that it’s a fair die. There is even a “gambler’s fallacy mode” that forces a roll distribution that feels more like what our statistically-impaired human minds expect.

The whole thing is controlled by an Adafruit Feather M0 Express, and the results of the die rolls are shown on a 2.3" 128x32 OLED screen. The buttons are knockoff Cherry MX keyswitches, like what you’d find in a decent mechanical keyboard. A 2200mAh lithium-ion battery powers it all, and everything is fitted into a thin 3D-printed enclosure. If you want to build your own Digital Die for your next gaming session, Everett has provided his code and STL files for printing your own case.