Introduction: Truly-Random Digital Die

Picture of Truly-Random Digital Die

Dice are subject to tampering and potential defected products. However, a digital die, generating a roll from a digitally randomized result produces a truly random result at each roll. This project uses 6 different coloured LEDs to make a digital die, wherein the Arduino processes the input to find a random number from 0 to 6. This number is then displayed on the die. In addition, the die will roll for a random amount of time, showing the different random die number that is rolling before it eventually stops.

Step 1: Tools and Materials

Picture of Tools and Materials
  • Arduino Uno
  • Breadboard
  • 6 LEDs
  • 6 pieces of 100Ω Resistors
  • Jumper Cables
  • Push button
  • 10K Ω Resistor

Step 2: Connecting the LEDs to the Arduino

Picture of Connecting the LEDs to the Arduino

1. Connect each of the LED's anodes to a 100Ω resistor.

2. Connect each of the LED's cathodes to ground.

3. Connect the open-end of the resistor to digital pins 3, 4, 7, 8, 9, 11 of the Arduino.

Step 3: Connecting the Push Button to the Arduino

Picture of Connecting the Push Button to the Arduino

4. Connect one pin of the push button to ground.

5. Connect the remaining pin to a 10K Ω resistor which then connects to the 3.3V power rail.

6. Connect the same pin to pin 2 on the Arduino.

7. Then, connect the 3.3V pin from the Arduino to the 3.3V power rail on the breadboard

8. Finally, complete the circuit by connecting the ground pin from the Arduino to the common ground rail on the breadboard.

Step 4: Coding

Picture of Coding
int ledPins[7] = {2, 3, 4, 7, 8, 9, 11};<br>
int dicePatterns[7][7] = {
{0, 0, 0, 0, 0, 0, 1}, // 1
{0, 0, 1, 1, 0, 0, 0}, // 2
{0, 0, 1, 1, 0, 0, 1}, // 3
{1, 0, 1, 1, 0, 1, 0}, // 4
{1, 0, 1, 1, 0, 1, 1}, // 5
{1, 1, 1, 1, 1, 1, 0}, // 6
{0, 0, 0, 0, 0, 0, 0} // BLANK
};
int switchPin = 10;
int blank = 6;
void setup()
{
for (int i = 0; i < 7; i++)
{
pinMode(ledPins[i], OUTPUT);
digitalWrite(ledPins[i], LOW);
}
randomSeed(analogRead(0));
}
void loop(){
  if (digitalRead(switchPin))
{
rollTheDice();
}
delay(100);
}
void rollTheDice()
{
int result = 0;
int lengthOfRoll = random(15, 25);
for (int i = 0; i < lengthOfRoll; i++)
{
result = random(0, 6); // result will be 0 to 5 not 1 to 6
show(result);
delay(50 + i * 10);
}
for (int j = 0; j < 3; j++)
{
show(blank);
delay(500);
show(result);
delay(500);
}
}
void show(int result)
{
for (int i = 0; i < 7; i++)
{
digitalWrite(ledPins[i], dicePatterns[result][i]);
}
}

Step 5: Demo

When the push button is pressed, the die is rolled for a random time, to generate a digitally randomized LED pattern corresponding to a number rolled by the die. In the demo, I rolled a four.

Comments

Magnelectrostatic (author)2017-07-28

"True Random" has a special meaning. Arduino's random() function generates what's called a pseudorandom number - it looks random to us, and it can usually work if you need a random number, but it isn't actually random. The numbers are generated by a set algorithm, so if you use the same seed, you'll actually get the same 'random' number sequence! Similarly, in theory you could figure out the pattern of numbers if you watched them long enough, and then you could predict the next one (this happened with some electronic slot machines recently - a group of people figured out the pattern and found out how to always win).

True Random Number Generators (TRNG, or HRNG - H for hardware) use some kind of noise source for their number generation. Typically the noise source will be an electrical component like a diode, and the noise comes from random flow of electrons whose stems from quantum mechanical processes.

That being said, pseudorandom is good enough for plenty of things.

On another note, I really like the rolling animation! Nice touch.

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