“In this instructable, I will show you how I made this set of electronic dice. This is a small handheld device that contains 5 individual die with a button that initiates a random roll. The switch is used to turn each die on or off so depending on the game one is playing, 1-5 dice can be used.
The inspiration for this project came during quarantine when many of the card and board games we own were running out of fun. For something different, I wanted to play a dice game called Liars Dice which is a fun, strategic, betting game. The problem is that each player needs 5 dice and a place to roll/cover their die. So, I decided to design and build an electronic set of dice. Pocket Dice was originally designed around the game Liars dice but its functionality can be extended to all games that use 1-5 dice.
When coming up with this idea, I had a few design challenges and requirements:
Make the overall design as compact as possible which would require the use of mostly surface mount components. I wanted to utilize an Attiny85 microcontroller which is fairly robust in its functionality for its size. Because the number of I/O pins are limited by the Attiny, I needed to find a suitable LED driver IC. The one I settled on was a MAX7219 chip which can drive up to 64 LEDs with only 3 inputs! It had to be battery powered to maintain its portability. Because I was replacing traditional die, I wanted to make the look and feel of the electronic die as real as possible. With all of these design requirements in mind, a custom PCB was essential and I utilized easyEDA and JLCpcb for the design and fabrication. Follow along for the build process and list of supplies below. The focus of this project will be on the PCB design and will be helpful for anyone that may be new to this process!
Attiny85 and Datasheet
U1V10F5 5V Step up voltage regulator
3.7V 420 mAh lipo battery
35x 0603 Red LED
5 position SPST piano DIP switch
SPDT mini slide switch
6mm tactile push button
10 Kohm 0603 resistor
32.4 Kohm 0603 resistor
Tiny AVR programmer
3D printer (optional)
Black and White PLA filament
solder/ solder paste