Christian Iannella's ATtiny85-Based Keychain Dice Get You Ready for Gaming Wherever You May Be
Built with a minimum of components, this keychain-ready electronic gadget replaces a physical d6 in the game of your choice.
Italian maker Christian Iannella has built a compact yet entirely self-contained electronic die which fits neatly on a keychain, powered by a Microchip ATtiny85 microcontroller — and boasting "many months" of battery life.
"This little keychain is composed of an ATtiny85 (SOIC 8 [packaged]), a button on the IO2 pin (pin seven), a CR2032 battery slot, and seven LEDs," Iannella explains of the compact PCB. "With this device, you can simulate a dice, and with deep sleep mode, the keychain will work for many months."
Using the device couldn't be simpler: once programmed — Iannella recommends the use of his ATtiny85-compatible Arduino UNO programming shield — the gadget responds to a button press by randomly lighting up the LEDs in a pattern designed to match those of the faces of a traditional six-sided die, from one in the dead center all the way through to three across each side to make the six.
Iannella's electronic die is hardly the first of its kind, though it's one of the most compact we've seen of late — noticeably thinner than Emiliano Valencia's tinyDice, which were built using a vinyl cutter to produce the PCB mask. It's also unlikely to be the most genuinely random: that accolade goes to a Dungeons & Dragons electronic dice tower built by The Science Shack which houses real uranium ore to drive a true random number generator (TRNG).
Iannella has published the design files and source code for the project on GitHub under an unspecified open source license; fully-assembled units can be purchased for $10 each on his Tindie store.