LEDice is a compact, battery-powered device that uses an ATtiny85 microcontroller and a MAX7219 8x8 LED matrix module to simulate dice rolls.
- Simulates dice roll with a press of a button
- Supports multiple dice types: D4, D6, D8, D10, D12 and D20 (shown on the left in the image below)
- Can display up to 4 dice at once (shown on the right in the image below)
- Adjustable display brightness
The runtime is around 45 hours on the lowest brightness level, which is most commonly used.
At maximum brightness, battery life can decrease to about 7 hours, but this can vary significantly depending on the selected dice.
See this flowchart illustrating the features of the device:
You can also increase the brightness of the display by holding down buttons while powering it on:
| ROLL Button | MODE Button | Brightness Level |
|---|---|---|
| No | No | Lowest |
| Yes | No | Low |
| No | Yes | High |
| Yes | Yes | Highest |
I designed two PCBs: The Main PCB and the Battery PCB.
The contents of the main PCB can be viewed in the schematic below. The Pinheaders will be connected to the display and the Pins on the bottom left are soldering pads to connect the external buttons and the battery that is located on the other PCB.
Don't forget to add the switch between one of the wires that connects the Baterry PCB to the Main PCB.
Below is the main PCB. There are boards available that already handle all the display wiring to make it easier to use with a microcontroller. I basically integrated the circuit of those modules into my PCB to save space inside the case.
The Battery PCB. It is a very simple PCB with the intention to make switching the battery easy.
You can use the gerber files gerber-LEDice-v0.3.zip gerber-Battery.zip for PCB fabrication. You can order them from companies like PCBWay.
The PCB dimensions are 32mm x 32mm with a thickness of 1mm.
You can find the 3D model on MakerWorld.
The custom PCBs are optional, but you will need them if you want to use this case.
- ATtiny85 microcontroller including a socket
- Display control components (you can buy all these components together via unsoldered DIY kits).
- MAX7219CN
- MAX7219 compatible 8x8 display
- 10μF Capacitor
- 0.1μF Ceramic Capacitor
- 10KΩ Resistor
- Two 8x1 Pin sockets for the display
- CR2032 Battery
- Battery holder that fits the holes on the PCB
- 2 push buttons
- 1 small switch
The provided links are for reference, not necessarily the cheapest or best options for you.
Please note, you'll need a programmer for the ATtiny85 microcontroller.