[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.
Hackaday reader [Daid] posted in our forums showing off a set of electronic dice he recently constructed. Back in January, we featured a similar set of electronic dice built with an Arduino that was way overpowered as far as [Daid] was concerned. Not satisfied with simply saying it could be done better, he put his money where his mouth is – something we would love to see more of.
He used an ATTiny2313 to provide the device’s logic, outputting the dice values on a set of four 7 segment displays. The whole setup is controlled by a single push button that serves triple duty rolling the dice, configuring how many sides the dice have, as well as selecting how many dice are being thrown.
He admits that the wiring job is a bit of a mess, but he was going for function over form, and it works just fine. He also says that he would have finished it far sooner if it hadn’t been for
those meddling kids some broken 7 segment displays.
We think he did quite a nice job, though we’re all ears if you think you can do it better.
While most dice games are based on luck and chance more than anything else, [Mike] decided he wanted to create a dice game that took a little more skill to play. He built a replica of a game found in Ian Stewart’s “The Cow Maze”, a book of mathematical stories and puzzles.
The theory behind the game is as follows:
A number is randomly drawn and is considered the “heap”. Players take turns reducing the heap, using the die to represent the number they would like to remove. The only restrictions placed on moves are that you cannot re-use the same number chosen by your opponent in the preceding move, nor can you use the number on the die face opposite that number. The winner of the game is the individual reducing the heap to exactly zero, though you can also lose the game automatically if you reduce the heap to a negative number.
The game operates using a magnet-loaded wooden die and hall sensors built into the playing surface. The sensors relay the value of the die’s face to the ATmega chip he used to run the game. His code provides the logic for your computer opponent as well as for keeping score.
The whole project is wrapped up in a nice-looking wooden box that gives it a bit of old time-y charm, micro controller and LCD aside.
Be sure to check out the video below to see a few rounds of the game being played, and swing by his site for more details.
Continue reading “Interactive dice game pits man against machine”
Most of the dice related hacks we run into have to do with pseudo random number generation, but today we saw something different. This sleek looking jumbo die is actually a prize holding box opened by a secret sequence of rotations. Using an accelerometer and an ATmega 328 with a sub-micro servo to control the locking mechanism. Worried about the batteries going flat and losing your treasure indefinitely? Good news! The batteries are accessable without giving away the secret inside.
It also turns out that this is an update to an earlier project from the same laboratory, so be sure to check that out as well to see where this build came from. Code is available for anyone looking to make their own, as well as a useful parts list.
[via Hacked Gadgets]