Battery-less electronic dice for all your D&D needs


[Anthony] is a big fan of Dungeons & Dragons, but he thought the game would be far more fun to play with an electronic die rather than the traditional fare. Electronic dice are nothing new around here, though we can’t help but like his design.

He wanted to keep his electronic die as small as possible while ensuring it would last an entire gaming session, so rather than use a battery to power it, he opted for a super capacitor instead. His 1F 5.5V cap keeps the PIC18 and 22 SMD LEDs chugging along quite nicely without ever requiring a break in the action for a charge.

The electronic die looks great, and give him the choice of rolling a 4, 6, 8, 10, 12, and 20 sided die with a simple push of a button. While a bit less interactive than tossing a die on the table, we certainly wouldn’t mind having one.

42 thoughts on “Battery-less electronic dice for all your D&D needs

  1. You know what would be REALLY REALLY REALLY cool?

    Imagine an electronic dice device that can read your brainwaves so you can use your thoughts to influence the outcome.

    That would be a great help when dealing with a kibbitzing assasin who wants to roleplay a dweeb who is out to kill EVERYBODY.

    Saving throw against being turned into a 6″ tall little crap-flinging butt monkey… FAILED!

    1. So wait let me see if I have this right.

      A small micro on a tiny board powered by a cap that can be charged in minutes and used for hours is overkill compared to a java-based cell phone with a fat processor and batteries that take hours to charge?

      I just wanted to make sure I had all the crazytalk straight.

    2. Actually any phone running any operating system that allows apps to be written for it, or any phone that has access to the web, could do this job.

      Not sure what Java has to do with that. :-p

    1. I’ve had a set for ages, they look like these –

      Not the best picture, it’s these – but round and with a flat bottom.

      There’s a little spring that acts as a switch, when dropped it causes the LEDs to flash with beeping.

      Powered by 2 button cells, and after all these years they still work. Neat. I think they were about $5, money well spent I think.

      1. Nothing to stop you making a set.

        They’re a nice little design, about the size of a walnut. The batteries are at the bottom (the flat bit) but don’t quite have enough weight for it to always roll face up.

        A bit non-trivial to build due to the case, but if you used 10mm LEDs you could have one the size of tennis ball.

        As a bonus you could add wireless charging, hack up one of those glowing ball things.

  2. On his site, he says: “If anyone is interested in buying one to play with, I have plenty that need a good home and i’d love to have some funding for a better revision!”

    How do we get in touch with Anthony? We can’t leave comments or email him if the captcha image never loads…

    If Anthony is reading these comments, I’d like 4 please! Let me know how much I owe you.

    1. I looked at the email he sent us, and unless he’s a big fan of confusing, hard to remember email addresses composed of random strings of letters, we don’t have a valid way to contact him.

      Hopefully he’ll notice the influx of traffic to his site (most people do) and swing by to see the requests for more info.

  3. I know… Use an Arduiono and XBee to communicate with with an ATtiny tied to a 3 axis accelerometer inside a 6 sided cube with a 7 segment led on each face. Using the earths gravity as a reference, you can light up the appropriate number depending on how it falls…

  4. Blargh! The reCaptcha forms on the contributor’s website appear to be broken, so it’s not possible to leave comments or contact him about the seemingly broken reCaptcha’s.

    Hackaday team, if you still have his email, shoot him a note about this, would you?

  5. Very cool. Now, instead of having to charge it by plugging it in, it would be awesome to charge it by shaking the dice! Just like you do normal dice.

    So, just need a little energy harvester on there and you’re good to go!

  6. Wow. You are right. Electronic dice. But since people are so used to reading regular dice, the electronic dice should have pips on them! And the rolling action should be used as a seed for the randomization routine!

    Yeah, thats the ticket.

  7. I have to say I’m disappointed that some of you want a shake dice. That’s so last century. The Dev should put one of these puppies on it with the super-cap. No more battery problems.

    I know what you’re thinking — “but $35 is waaayyy too much for this project!” Well after adding this, you can market this as being Green, self-sustaining, and perfect for the geeks that will buy it to ogle over. Besides, those power chips are made for projects exactly like this.

    1. I really like all the wonderful ideas… Power was the BIGGEST consideration for the project. I agree with all of you, plugging the thing in SUCKS! But, i have to need everything on the PCB, and it’s pretty well stuffed. I actually have an OLDER revision of this board that has a large coil for inductive charging, i have the boards and parts lying around, just never assembled it. I also wanted to keep costs as LOW as possible, right now, with everything costs are around ~20$ with the custom boards.

    2. (From the datasheet) 50mA (maximum) charging current… That’s going to lead to abysmal (to say the least) charging times.

      >> I know what you’re thinking — “but $35 is waaayyy too much for this project!”

      Yes, yes that’s correct. No need to attempt to sell us on a sevenfold price increase for a negligible nonexistent sustainability argument.

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