If you needed a reason to dress up for your next Dungeons & Dragons adventure this is surely it. Not only will this attractive wrist adornment go right along with your medieval theme, but the gauntlet doubles as a multi-sided digital die.
Sparkfun whipped up this tutorial which details the build. Yep, they’re hawking their own goods but we must say this is one of the few projects using sewable electronics which we thoroughly enjoy. It calls for several Lilypad modules, including an Arduino board, accelerometer, and slide switches. The switches let you select the number of sides for the die you are about to roll. The accelerometer starts the fun when you shake your wrist back and forth (that’s what she said). The project is powered by a rechargeable battery, which we always like to see, and uses a four-digit seven segment display located where the face of a wristwatch is normally found.
Of course, you could get the shaking action and use no batteries at all if you wish.
If you’re gaming on the road, or just don’t have a die with the right number of sides on hand, an electronic polyhedral die will be quite handy. [Marcus] built this using a printed circuit board of his own design, and we think an electronically simple project like this is a great way to get your feet wet with PCB fab house techniques. He suggests Seeed Studios’ service, or the DorkBotPDX group PCB order. But this would not be a hard project to build on perfboard as well.
The concept is simple. A two-digit 7-segment display shows the value of the top face of your die. when it’s time to roll, just pick up the box and tip it over. A tilt switch senses this action and rolls the die by displaying the next pseudo-random number. The single button, seen here with a pyramid die glued to it, lets you select between die with different number of sides; from 2 (like a coin flip) all the way up to 100.
We like [Marcus’] projects. He’s the same guy that built a scoring system in a game storage box.
[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.
[Mike Shegedin] makes full use of an 8-pin microcontroller with this ATtiny13-based dice project. With a maximum of six I/O pins (that includes using the reset pin as I/O) he needed a couple of tricks in order to drive 14 LEDs and use a momentary push button for user input. We’re certainly familiar with the concepts here, but it still took quite a while to figure out what is going on with the schematic that [Mike] posted.
You’ve probably already guessed that he’s using Charlieplexing to drive more LEDs than he has pins. But when we started looking at the layout we thought he had drawn the schematic wrong, because there are six pairs of LEDs where the two diodes in each pair a not reverse biased, but hooked up in parallel. That, plus the fact that his battery is hooked up backwards. After several minutes of study the light bulb finally clicked on. Dice add pips (the dots on each side of a die) in pairs with the exception of the center pip. That means that you only need to control four total lines for each die (three pairs plus the center pip). There’s two ways to handle this, you could use four rows and two columns with traditional multiplexing, or you can reverse bias the two sets of LEDs for each die and use Charlieplexing. The former is a bit easier to program, the latter saves you one I/O pin and meant that [Mike] didn’t need to use the reset pin as I/O.
This is a clever addition to the collection of dice projects we’ve seen like the battery-less die, and the ATtiny2313 powered dice.
A pair of 6-sided electric dice (original in Dutch, here’s the Google Translate link) was sent in on the tip line for our ATtiny hacks theme. We really appreciate the simplicity of the circuit; it really shows how the complexity of discrete components can be cut down with a simple microcontroller.
The circuit is very simple – An ATtiny26 serves as the core of the project. Fourteen LEDs are connected to fourteen pins on the micro. The tiny26 might be a bit overkill. With Charlieplexing, we suspect this build could have been completed with an 8-pin micro like an ATtiny25. The code for the build (written in BASIC with BASCOM-AVR), board files and schematics have all been posted.
We’ve seen a few electronic dice builds before. this build uses an ATmega328 in a hugely overwrought circuit. Compared to what can be done with a 555, the ATtiny26 build provides a very nice middle ground.
Thanks [Roeland] for sending this in.
[Gadre] built his own ATtiny project without using any batteries. It’s an electronic Dice (or die if you’re being critical) which uses induction to charge a storage capacitor to act as the power source. The voltage generator is made from a tube of Perspex which houses a set of rare-earth magnets. At the enter of the tube [Gadre] machined a channel wich accepts about 1500 windings of 30 AWG magnet wire. When someone shakes the tube back and forth the magnet passes the wire, inducing a current. The product is stored in a 4700 uF capacitor, which feeds a boost converter to power the rest of the circuit.
The ATtiny13V that controls the circuit is running its internal RC oscillator at 128 kHz, the lowest setting possible in order to minimize power consumption. After a good shake the user can press a button to roll the die, which is then displayed for several seconds on a group of seven LEDs. See for yourself in the video after the break.
Continue reading “ATtiny Hacks: Look Ma, no batteries!”
If you happen to be in the market for some designer dice or need a set of custom dice for a game you have created, you could pay a ton of money to have them made, or you can do it yourself.
[Dicecreator] runs a blog dedicated to the ins and outs of creating DIY game and collector’s dice. This subject is not something that we would normally be interested in, but one particular item caught our interest – DIY toner transfer dice. Very similar to the process of creating a toner transfer PCB, he walks through the steps required for making your own dice with very little overhead.
The steps are likely quite familiar to those who have fabricated your own PCBs at home. He starts out with blank dice, sanding the sides down with increasingly fine sandpaper until they are ready for the transfer process. An image is printed on glossy inkjet photo paper, which is then applied to each die with a standard clothes iron. After a bit of soaking in water to remove the excess paper, the die is ready to go.
Sure it’s not exactly rocket science, but it is a cool little trick that would work quite well if you are trying to replace a lost die or if you simply want to make a fun gift for a friend.