555 Timer On Its Own In Electronic Dice

One of the most common clich├ęs around here is that a piece of equipment chosen for a project is always too advanced. If a Raspberry Pi was used, someone will say they should have used an Arduino. If they use an Arduino, it should have been an ATtiny. And of course, if an ATtiny was used, there should have simply been a 555 timer. This time, however, [Tim] decided to actually show how this can be done by removing some of the integrated circuits from an electronic dice and relying entirely on the 555 timer for his build.

The electronic dice that [Tim] has on hand makes use of two main ICs: a NE555 and a CD4017 which is a decade counter/divider used for cycling through states. In order to bring the 555 to the forefront of this build, he scraps the CD4017 and adds an array of 555 timers. These are used to generate the clock signals necessary for this build but can also be arranged to form logic circuits. This comes at a great cost, however. The 555 chips take up an unnecessarily large area on the PCB (even though these are small surface-mount chips), consume an incredible amount of power, and are very slow. That’s fine for an electronic dice-rolling machine like this one, but that’s probably where [Tim] will leave this idea.

The 555 timer is a surprisingly versatile chip, and this project shows that there is some element of truth to the folks claiming that projects need naught but a few 555s. We’ve seen entire CPUs built using nothing but 555s, and even a classic project that uses a 555 timer to balance a robot.

Handheld Farkle Really Sparkles

Farkle is a classic dice game that only requires 6 dice and a way to write down scores based on the numbers rolled. Even so, this type of game isn’t inherently portable — it would be fairly difficult to play on a road trip, for instance. [Sunyecz22] decided that Farkle would make an excellent electronic game and got to work designing his first PCB.

This little game has everything you could want from a splash screen introduction to a handy scoring guide on the silkscreen. After choosing the number of players, the first player rolls using the momentary button and the electronic dice light up to indicate what was rolled. As long as the player rolled at least one scoring die, they can take the points by selecting the appropriate die/dice with the capsense pads, and either pass or keep going. The current player’s score is shown on the 7-segment, and the totals for each player are on the OLED screen at the bottom.

The brains of the operation is an Arduino Pro Mini. It controls two MAX7219s that drive the 42 LEDs plus the 7-segment display. A game like this is all in the code, and lucky for us, [Sunyecz22] made it available. We love how gorgeous the glossy 3D printed enclosure looks — between the glossy finish and the curved back, it looks very comfortable to hold. In the future, [Sunyecz22] plans to make a one player versus the computer mode. Check out the demo and walk-through video after the break.

The capsense modules are a great touch, but some people want a little more tactility in their handheld games. We say bring on the toggle switches.

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Dice Roller Keeps Germs Out Of Your Snake Eyes

Do you need a to find a more sanitary way to roll the dice at your next socially-distanced board game gathering? [CJA3D]’s pop-o-matic mason jar dice roller can roll the bones two different ways — either by hitting that big, inviting arcade button, or though a web app that everyone can access on their own phones.

We think this looks great, and is a great reuse of a glass jar. The brains of this operation is an ESP8266, which drives a continuous-rotation servo underneath the dice. Push the button or use the web app and the servo disturbs the plate, moving the dice around.

Besides the sanitary aspect, one benefit of using the web app is that there are four different speed presets for the servo. As a bonus, [CJA3D] included the files for a pair of printed 6-sided dice. Click through to the project to see it in action.

We know you take games seriously, and so do we. Just look at this dice roller that uses machine vision to ensure fairness.

The Most Expensive D20 You’ll See Today

Roll your negotiation skill, because this d20 is a hefty one. The Tweet is also below. We are charmed by [Greg Davill]’s twenty-sided LED contraption, but what do we call it? Is it a device? A sculpture? A die? Even though “d20” is right on his custom controller PCB, we don’t think this will grace the table at the next elf campaign since it is rather like taking a Rolls Royce to the grocery store. Our builder estimates the price tag at $350 USD and that includes twenty custom PCB light panels with their components, a controller board, one battery pack, and the 3D printed chassis that has to friction-fit the light faces.

Power and communication for all the panels rely on twenty ribbon cables daisy-chained throughout the printed scaffolding, which you can see in the picture above. [Greg] made a six-sided LED cube last year, and there are more details for it, but we suspect he learned his lesson about soldering thousands of lights by hand. There are one-hundred-twenty LEDs per panel, times twenty, that is over two-thousand blinkenlights. We don’t yet have specs on the controller, but last time he used a SAMD51 processor to support over three-thousand lights. We don’t know where he’ll go next, but we’re game if he wants to make a chandelier for Hackaday’s secret underground lair.

(Editor’s Note: If you were at Supercon last year, and you got to play with this thing in the flesh, it’s worth it!)

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’75 Nixie Multimeter As Digital Dice

For the casual Monopoly or Risk player, using plain six-sided dice is probably fine. For other games you may need dice with much more than six sides, and if you really want to go overboard you can do what [John] did and build electronic dice with a random number generator if you really need to remove the pesky practice of rolling physical dice during your games of chance.

The “digital dice” he built are based on a multimeter from 1975 which has some hardware in it that was worth preserving, including a high quality set of nixie tubes. Nixies can be a little hard to come by these days, but are interesting pieces of hardware in their own right. [John] added some modern hardware to it as well, including an AVR microcontroller that handles the (pseudo) random number generation. A hardware switch tells the microcontroller how many sides the “die” to be emulated will need, and then a button generates the result of the roll.

This is a pretty great use for an old piece of hardware which would otherwise be obsolete by now. [John] considers this a “Resto-Mod” and the finish and quality of the build almost makes it look all original. It’s certainly a conversation piece at the D&D sessions he frequents.

These Dice Know If You’re Cheating

Fans of D&D are surely aware of the significance of a good pair of dice. What if your dice were not only stylish, but smart? For anyone who’s ever had to deal with playing board games with less than reputable siblings or friends, the electric die just might be your savior.

The dice are configured via Bluetooth, tracking rolls and stats over the course of gameplay captured by an accelerometer.

The PCB had to have a flexible surface – specifically in the shape of an unfolded icosahedron – in order to form the shape of the die which constrains the design to two layers. Each face contains an LED facing outwards to light up the number on that side. The LEDs are directly powered by a rechargeable battery, which uses a small coil for wireless inductive charging. Rather than opting for a Qi charger chipset, which regulates the maximum amount of power transmitted if the efficiency falls below a threshold, [Jean Simonet] uses a simpler charger setup using a full bridge rectifier, capacitors, and a linear regulator to create a stable 5V supply for the receiving end.

While the initial design for the die required an injection molded plastic shell, an easier solution was to simply cast the designs in resin. The electronics are placed into a dice mold and cast just as a regular die would be.

This luckily also solved the issue of needing to fit the components inside a screw-on container with a removable lid, which presented a hassle in terms of finding a battery that would fit the dimensions. The LEDs – purchased for cheap on Alibaba – are daisy chained to reduce the complexity of the routing.

One issue with the LEDs, however, is that the internal PWMs modulating the intensity remain on even at an intensity of 0, constantly drawing 21 mA (for the 21 LEDs on the die). This causes the battery to die after 2-3 hours. The solution [Simonet] used was to add a transistor to cut off power to the LEDs and to have the MCU toggle the transistor when the LEDs are turned off. Even this solution didn’t solve the entire problem since the LEDs still drain current from the data and clock lines, so those lines had to be low before going to sleep.

There were some stability issues with using a small buck converter to bring the LiPo voltage down to 3.3V, so the power regulation was done directly by the MCU instead. Switching the die off is controlled by a magnetic switch connected to a power buck converter that turns off logic when a magnet is present. This initially caused the LED control lines to become floating when power was turned off, turning the LEDs to arbitrary colors. The solution was to wire the output of the magnetic sensor to the MCU and to allow the software to handle the LEDs as well.

Maybe it’s because creator [Simonet] happens to be a game developer as well, but the early development stages of the electronic die (CAD, circuit schematics, prototyping, hand soldering components) were streamed on Twitch, adding some interactivity to even the build phase. The end result may be small, but these dice certainly have large brains!

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Dice Reader Brings Tech To Your Craps Game… Or, Ya Know, D&D

There are truisms about dice that you’ve probably already heard: if you have just one of them it’s called a “die”, opposite faces of each die always add up to seven, and those dots that you’re adding together are known as “pips”. But what about the infrared properties of those pips? It turns out they reflect less IR than the white body of the die and that trait can be used to build an automatic die reader.

Great projects have a way of bubbling to the surface. The proof of concept comes from way back in 2009, and while the source blog is now defunct, it’s thankfully been preserved by the Internet Archive. In recreating the project based on that barebones description, [Calvin] reached for a set of five IR transmitter/receiver pairs. Take a close look and you’ll see each transmitter is hidden under its partnered receiver. The light shines up through the receiver and the presence of the pip is detected by measuring how much of it bounces back.

This board is only the sensor portion of the design. A 595 shift register provides the ability to control which IR pair is powered, plus five more signals heading out to the analog pins of an Arduino Uno to monitor how much light is being detected by the receivers. Hey, that’s another interesting fact about dice, you only need to read five different pips to establish the value shown!

We wish there were a demo video showing this in action, but alas we couldn’t find one. We were amused to hear [Calvin] mentioned this was a sorting assignment at University and the team didn’t want to build yet another candy sorter. Look, we love an epic M&M sorter just as much as the next electronic geek, but it’s pretty hard to one-up this dice-based random number generator which rolls 1.3 million times each day.