Spinning Magnets Do Your Dice Rolling For You

June 28, 2024 by Dan Maloney 6 Comments

Dice are about the simplest machines possible, and they’ve been used since before recorded history to generate random numbers. But no machine is so simple that a little needless complexity can’t make it better, as is the case with this mechanical spinning dice. Or die. Whatever.

Inspiration for the project came from [Attoparsec]’s long history with RPG and tabletop games, which depend on different kinds of dice to generate the randomness that keeps them going — that and the fortuitous find of a seven-segment flip-dot display, plus the need for something cool to show off at OpenSauce. The flip-dot is controlled by an array of neodymium magnets with the proper polarity to flip the segments to the desired number. The magnets are attached to an aluminum disk, with each array spread out far enough to prevent interference. [Attoparsec] also added a ring of magnets to act as detents that lock the disk into a specific digit after a spin.

The finished product ended up being satisfyingly clicky and suitably random, and made a good impression at OpenSauce. The video below documents the whole design and build process, and includes some design dead-ends that [Attoparsec] went down in pursuit of a multiple-digit display. We’d love to see him revisit some of these ideas, mechanically difficult though they may be. And while he’s at it, maybe he could spice up the rolls with a little radioactivity.

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What’s Black, White, And Red On 20 Sides?

May 22, 2023 by Michael Shaub 11 Comments

You won’t need to pack a full set of dice for your next game with this DIY Multifunctional Eink Gadget. [Sasa Karanović] brings us a fun device that combines a few essential aspects of tabletop gaming, D6, D12, and D20 dice rolling and a hero dashboard. While they have grand plans for a BLE networked future application, we admire the restraint to complete a V1 project before allowing scope-creep to run amok. Well played!

For this project, [Sasa] realized it needed to be battery powered and just choosing the right display for a battery powered application can be daunting. Even if you aren’t building this project, the video after the break includes a nice intro to electronic ink and low power microcontrollers for the uninitiated. We even see a graph of the completed board’s power draw from the button wake up, display refresh, and low power sleep. The project has some neat tips for building interaction into case design with the use of the display and a flexible bezel as integrated buttons. Continue reading “What’s Black, White, And Red On 20 Sides?” →

NE555-Based Electronic Dice

December 11, 2022 by Dave Walker 14 Comments

It has become a bit of a running joke in the Hackaday community to suggest that a project could or should have been done with a 555 timer. [Tim] has rather taken this to heart with his latest Electronic Dice project, which uses three of the venerable devices.

If three seems like a lot of 555s to make an electronic die, then it may be worth considering that the last time we shared his project he was using 22 of them! Since then, [Tim] has been busy optimising his design, whilst keeping within the constraints of an old-school through-hole soldering kit.

Maybe the most surprising thing about this project is the purpose to which the NE555 devices are pressed. Rather than using them for their famous oscillation properties, they are in actual fact just being used as Schmitt Triggers to clean up the three-phase ring oscillator that is constructed from discrete transistors and passives.

scope trace of the electronic dice ring oscillator — Simulation trace of the three-phase ring oscillator before Scmitt Trigger stages

The ring oscillator cleverly produces three phase-shifted square waves such that a binary combination of the three phases offers six unique states. Six being the perfect number for a dice throw, all that then remains is to figure out which LEDs need to be switched on in which state and wire them up accordingly.

To “roll” the dice, a push-button powers up the oscillator, and stops it again when it is released, displaying the random end-state on the LEDs.

It can be fun to see what can be done using old technology, and educational to try to optimise a design down to the fewest parts possible.

[Tim]’s earlier project is here if you want to see how the design has evolved. The documentation on both of these iterations is excellent and well worth a read.

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Roll The Radioactive Dice For Truly Random D&D Play

November 2, 2022 by Dan Maloney 22 Comments

When you have a bunch of people gathered around a table for a “Dungeons & Dragons” session, you have to expect that things are not always going to go smoothly. After all, people who willingly create and immerse themselves in an alternate reality where one bad roll of the dice can lead to the virtual death of a character they’ve spent months or years with can be traumatic. And with that trauma comes the search for the guilty — it’s the dice! It’s always the dice!

Eliminating that excuse, or at least making it statistically implausible, is the idea behind this radioactively random dice roller. It comes to us from [Science Shack] and uses radioactive decay to generate truly random numbers, as opposed to the pseudorandom number generators baked into most microcontrollers. The design is based on [AlphaPhoenix]’s muon-powered RNG, but with a significant twist: rather than depending on background radiation, [Science Shack] brought the power of uranium to the party.

They obtained a sample of autunite, a weird-looking phosphate mineral that contains a decent amount of uranium, perfect for stimulating the Geiger counter built into the dice roller. Autunite also has the advantage of looking very cool under UV light, taking on a ghostly “fuel rod glow,” in the [Homer Simpson] sense. The decay-powered RNG at the heart of this build is used to simulate throws of every standard D&D die, from a D4 to a D100. The laser-cut hardboard case holds all the controls and displays, and also has some strategically placed openings to gaze upon its glowing guts.

We really like the design, but we have to quibble with the handling of the uranium ore; true, the specific activity of autunite is probably pretty low, but it seems like at least some gloves would have been in order.

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Hackaday Prize 2022: Digital Dice Towers Built In Beautiful Retro Cases

July 26, 2022 by Lewin Day 5 Comments

Retro hardware often looks fantastic, but we may find we no longer need it for its original function. [John Anderson] found that to be the case with some old Heathkit gear, and set about giving them a fun overhaul.

With the help of AVR microcontrollers, the devices have been repurposed into electronic dice towers for playing Dungeons & Dragons. A seed is generated based on the chip’s uptime, and supplied to a pseudorandom number generator that emulates dice rolls. The devices can be configured to roll a variety of dice, including the usual 6, 8, 10, and 20-sided varieties. Plus, they can be set to roll multiple dice at a time — useful when you’re rolling complicated spells and attacks in combat.

[John] has converted a variety of Heathkit devices, from Morse code trainers to digital multi-meters. They provide their beautiful cases and a great retro aesthetic, and we think they’d make fitting table decoration for retro cyberpunk tabletop games, too.

Creating your own electronic dice is a great way to get familiar with programming microcontrollers. Video after the break.

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Electronic Dice Is Introduction To Microcontroller Programming

May 27, 2022 by Bryan Cockfield 10 Comments

By now most of us are familiar with the Arduino platform. It’s an inexpensive and fairly easy way into the world of microcontrollers. For plenty of projects, there’s no need to go beyond that unless you have a desire to learn more of the inner workings of microcontrollers in general. [Cristiano] was interested in expanding some of his knowledge, so he decided to build this electronic dice using a PIC microcontroller instead of the Arduino platform he was more familiar with.

As a result, this project is set up as a how-to for others looking to dive further into the world of microcontrollers that don’t have the same hand-holding setup as the Arduino. To take care of the need for a random number for the dice, the PIC’s random number generator is used but with the added randomness of a seed from an internal timer. The timer is started when a mercury tilt switch signals the device that it has been rolled over, and after some computation a single digit number is displayed on a seven-segment display.

While it might seem simple on the surface, the project comes with an in-depth guide on programming the PIC family of microcontrollers, and has a polish not normally seen on beginner projects, including the use of the mercury tilt switch which gives it a retro vibe. For some other tips on how to build projects like this, take a look at this guide on how to build power supplies for your projects as well.

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555 Timer On Its Own In Electronic Dice

January 8, 2022 by Bryan Cockfield 18 Comments

One of the most common clichés around here is that a piece of equipment chosen for a project is always too advanced. If a Raspberry Pi was used, someone will say they should have used an Arduino. If they use an Arduino, it should have been an ATtiny. And of course, if an ATtiny was used, there should have simply been a 555 timer. This time, however, [Tim] decided to actually show how this can be done by removing some of the integrated circuits from an electronic dice and relying entirely on the 555 timer for his build.

The electronic dice that [Tim] has on hand makes use of two main ICs: a NE555 and a CD4017 which is a decade counter/divider used for cycling through states. In order to bring the 555 to the forefront of this build, he scraps the CD4017 and adds an array of 555 timers. These are used to generate the clock signals necessary for this build but can also be arranged to form logic circuits. This comes at a great cost, however. The 555 chips take up an unnecessarily large area on the PCB (even though these are small surface-mount chips), consume an incredible amount of power, and are very slow. That’s fine for an electronic dice-rolling machine like this one, but that’s probably where [Tim] will leave this idea.

The 555 timer is a surprisingly versatile chip, and this project shows that there is some element of truth to the folks claiming that projects need naught but a few 555s. We’ve seen entire CPUs built using nothing but 555s, and even a classic project that uses a 555 timer to balance a robot.