Spinning Magnets Do Your Dice Rolling For You

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.

6 thoughts on “Spinning Magnets Do Your Dice Rolling For You

  1. I’m wondering if fixed magnets and display with a moveable flux path to do the rolling would be the best way to approach this concept – though that is a rabbit hole of design I’ve not dived into enough to have any real feeling for and would certainty be more challenging to design/make it seems like it could make a more compact version plausible.

    1. Oh but this is a great fun project, looks really neat and quite satisfying to play with so I wish I’d had the chance. Just not sure if it is really the best method to achieve the goal here.

      (Realised almost as soon as I posted that the comment could sound overly negative – really wasn’t meant to this is great fun!)

  2. Interesting project and using obsolete technology in a new way. The device looks quite satisfying to use, similar to a wheel of fortune. If I’d build one, I’d attempt to fit more digits on the wheel in a de Bruijn sequence way. But that’ll certainly reduce the effect.

  3. This sounds great, I can imagine it’s very satisfying in person!

    I think the magnetic pipes should be viable, but the distance between the rods should probably be larger than the total airgap from the magnet to the display element. The rods can probably be a lot thinner, which would make bending easier.

    Alternatively, you could try 3D printing a part with channels, and filling those with iron or ferrite powder with some kind of binder (such as Arabic gum).

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