Giant D20 Is A Critical Hit in More Ways than One

[Mikael Vejdemo-Johansson] is a member of the NYC Resistor hackerspace and an avid fan of a D&D themed improv theatre called The Campaign. To show his appreciation, he decided to gift them a Christmas present: a giant D20. The original plan called for integrated LEDs to burst alight on a critical hit or miss, or let out pulses if it landed on another face. Cool, right? Well, easier said than done.

[Vejdemo-Johansson] figured a circle of 4 tilt sensors mounted on the one and twenty face would be enough to detect critical rolls. If any of the switches were tilted beyond 30 degrees, the switch would close. He mounted eight ball-tilt switches and glued in the LEDs. A hackerspace friend also helped him put together an astable multivibrator to generate the pulses for non-critical rolls.

This… did not work out so well. His tilt sensor array proved to be a veritable electronic cacophony and terribly sensitive to any movement. That and some other electronic troubles forced a shelving of any light shows on a critical hit or miss. [Vejdemo-Johansson] kept the pulsing LEDs which made for a cool effect when shining through the mirrored, red acrylic panes he used for the die faces. Foam caulk backer rods protect as the die’s structure to stop it from being shattered on its first use.

Before The Campaign’s next show, [Vejdemo-Johansson] managed to stealthily swap-out of the troupe’s original die with his gift, only for it to be immediately thrown in a way that would definitely void any electronic warranty. Check out the reveal after the break (warning, some NSFW language)!

Oh well, it’s the thought that counts, right? Hot glue to the rescue.

A more durable die might be found in the form of a bracer, but for those longer game sessions, you might want an electronic die that that doesn’t need batteries!

[Thanks for the tip, Bonnie Eisenman!]

17 thoughts on “Giant D20 Is A Critical Hit in More Ways than One

  1. 1.Use accelerometer to activate circuit on die throw.
    2.Circuit uses photosensitive component of choice and decrees electronics to check light levels on faces.
    3.If face polar opposite twenty (one) is covered, then critical. If twenty is covered, then critical failure. Else, pulse.
    Or, that’s how I would have tried to do it.

      1. Maybe one could have just a motion-activated flashlight inside a suitably weighted piece of foam, that would tumble about inside the D20. Hopefully it would land on the bottom and point to the opposite face.

          1. On second thought, your idea might work if the weighted light source were a weighted sphere separated by a liquid from the outter D20 shell. Or perhaps something along the lines of a magic 8 ball design…though I wouldn’t want that determining my fate.

    1. Maybe like one of those Lego projects that roll multiple dice, i.e. embed a real D20 in a Trouble like bubble inside the larger D20; then the electronics detect which side the actual D20 landed on and light up the outter face with a number accordingly? Would be complicated I think, but that would disconnect any major outter shell inconsistencies from having a direct influence on the fairness I think other than smoothness of the bubble holding it…unless iit was really off balance and always rolled a hard left or something.

    1. Couple that with my Lego comment above? Large D20 is just a wireless prop that receives a signal for rolled number from an off-stage actual D20 roll. Everyone’s favorite ESP serving to receive and display the rolled number.

      This might address several problems actually.
      1. Random() won’t be trusted by everyone
      2. You can easily swap out smaller D20 if challenged
      3. You could even automate averaging of multiple off-stage D20 for increased fairness.
      4. You can more easily integrate display of rolled number to the audience…a challenge with simply lighting the face they can’t naturally see.
      5. The wireless D20 prop could use choice of circuit to signal roll action to off-stage rolled.

      Sorry, just an interesting challenge to comment on.

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