A Maker named Walter recently created an entropy library for Atmel AVR microcontrollers (MCUs) to ensure a reliable source of truly arbitrary numbers.
As HackADay’s Brian Benchoff reports, the electronic dice generate random numbers by taking advantage of the watchdog timer’s natural jitter.
“[This isn’t] fast by any means but most sources of entropy aren’t that fast anyway,” Benchoff explains. “By sampling a whole lot of AVR chips and doing a few statistical tests, it turns out this library is actually a pretty good source of randomness, at least as good as a pair of dice.”
According to Benchoff, the circuit itself employs a pair of 8×8 LED matrices from Adafruit, an Atmel-based Arduino board and a pair of buttons.
Supported modes (11 total)?
- 2d6
- 2d4
- 2d8
- 2d10
- 1d12
- 1d20
- Deck of cards
- Single hex number
- Single 8-bit binary number
- 8 character alphanumeric password
Interested in learning more? You can watch the video above or check out the project’s official page here.
Atmel | Bits & Pieces 