LPED

Highly customizable Low-power Electronic Playing Dice

This project started as a bachelors thesis, the original repository can be found here

Features

• Separate charging station for charging the dice via pogo-pins
• Changing the dice shape with custom sleeves
• The dice can be configured to support any shape with up to 60 sides
• Up to 10 profiles can be saved onboard

Hardware

• The dice uses a nRF52810 microcontroller with FXLS8974CF accelerometer
• Instead of battery it uses hybrid super-capacitor with 20 F capacity that provides up to 8 hours of game time with charging time of 15 minutes
• The 3D models of the charging dock have been optimized for 3D printing and they do not require any supports
  • However, one heat inserts and 4 magnets (6x6x2mm) are necessary for the assembly

Firmware

• The dice transmits the landed numbers via BLE broadcast advertisement
  • To ensure they get to the client application, they are sent multiple times with unique identifier
• For configuration it is necessary to connect to the dice
  • It provides all the necessary parameters via characteristics in custom GATT service
• It saves the whole configuration in the FLASH memory of the dice, making it independent on the used client application
• Each side can have its own physical position on the dice and its own number, making it possible to create dice with custom non-standard shapes

Project structure

• /hardware - schematics, 3D models and PCB design files for dice, charger and programming adapter
  • The schematics and PCB designs were made in KiCad
  • The printable models were made in FreeCAD
• /firmware - Zephyr firmware running on the dice

Versioning info

• Repository uses major.minor format
  • major is incremented with each major hardware revision or significant firmware update that causes the implementation to be incompatible with previous version
  • minor is used for firmware fixes and patches that don't affect backwards compatibility
• PCBs have their own version code on them that follows standard major.minor format
  • major is used for drastic changes to the boards, such as MCU swap or change of pinout
  • minor is used for hardware fixes and patches