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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Trap Chess Keeps Players On Their Toes

Chess is a game that originated so long ago, we don’t have concrete information as to its origins. Rules have changed throughout history, and many continue to study and experiment with the game. [Yann Guidon] has a neighbour, [Bob], who is just one such enthusiast, and together, they built a working Trap Chess game.

What is trap chess, you may ask? It’s a variant of chess where pieces randomly fall into traps at the change of turns. This is easy to simulate in a digital game, but that wasn’t enough for [Bob]. Enlisting [Yann] for his electrical skills, the duo built a board with ten trapdoors built in. Whenever the timer is hit, there’s a chance a trapdoor can open, removing a piece from the game.

The build relies on a PIC16F818, an 8-bit microcontroller from Microchip. This helps interface between the timer and servos and generally runs the whole show. The board is built into a table, and we’re impressed by the fit and finish of the final product. From a distance, it’s difficult to notice anything is awry, and it would make a great prank when playing with an unsuspecting mark. Just make sure there’s no money on the table first.

We’ve seen other impressive chess hacks before — like this board that can move the pieces for you. Video after the break. Continue reading “Trap Chess Keeps Players On Their Toes”

Spice Up Your Dice With Bluetooth

There’s no shortage of projects that replace your regular board game dice with an electronic version of them, bringing digital features into the real world. [Jean] however goes the other way around and brings the real world into the digital one with his Bluetooth equipped electronic dice.

These dice are built around a Simblee module that houses the Bluetooth LE stack and antenna along with an ARM Cortex-M0 on a single chip. Adding an accelerometer for side detection and a bunch of LEDs to indicate the detected side, [Jean] put it all on a flex PCB wrapped around the battery, and into a 3D printed case that is just slightly bigger than your standard die.

While they’ll work as simple LED lighted replacement for your regular dice as-is, their biggest value is obviously the added Bluetooth functionality. In his project introduction video placed after the break, [Jean] shows a proof-of-concept game of Yahtzee displaying the thrown dice values on his mobile phone. Taking it further, he also demonstrates scenarios to map special purposes and custom behavior to selected dice and talks about his additional ideas for the future.

After seeing the inside of the die, it seems evident that getting a Bluetooth powered D20 will unfortunately remain a dream for another while — unless, of course, you take this giant one as inspiration for the dimensions.

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Simulating Snakes And Ladders For Fun, Not Profit

A great many of you will remember the game of Snakes and Ladders from your youth. It’s a simple game, which one grows to realise involves absolutely no skill – it’s purely the luck of the dice. [Alex Laratro] noticed that without player decisions to effect the outcome, the game was thus a prime candidate for simulation. 

[Alex] wanted to dive into the question of “Who is winning a game of Snakes and Ladders?” at any given point in the gameplay. A common approach would be to state “whoever is in front”, but the ladders might have something to say about that. [Alex] uses Markov analysis to investigate, coming to some interesting conclusions about how the game works, and how this compares to the design of more complex games like Mario Kart and Power Grid.

Overall, it’s a breakdown of a popular game that’s simple enough to really sink your teeth into, but has some incredibly interesting conclusions that are well worth considering for anyone designing their own board games. We love seeing math applied to novel and fun problems – and it can solve important problems, too.

Full Size Star Wars Holochess Build

The quality and attention to detail seen in [Ian Martin]’s build is impressive regardless of his choice to build a functioning holochess set. We’re not to take away from the nerd-gasm this build invokes, but we’d rather draw to attention the craftsmanship of the builder. Sadly [Ian] doesn’t have a proper blog or product page but you can view everything he posts about the project on his social networking page and get his take on the finished work in the video below.

This build is not just a well engineered mechanical design, the electronics that run the controls and indicators are [Ian]’s home brew Arduino Mega shields. A complete game requires two sets of electronics, one for each side of the table so rolling his own shield was probably a space saving decision.

Each of the figures used as game pieces were hand sculpted and painted (is that a Rancor to the right?). User controls are presented in true-to-form fashion with 54 buttons, 26 lights, 10 knobs, and an LCD screen with custom bezel to display custom monster status. Nope, the monsters aren’t animated holograms but to make up for that [Ian] built in ambient noises so you know which are still alive. This is our first time discovering that there is a name other than “Holochess” for the game: Dejarik. We’ll leave it up to the reader to figure out how it’s played.

This is an impressive build and we can’t wait to see what else [Ian] comes up with in the future. We have covered Star Wars builds before and some interesting board game builds but never where the two meet before this.

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