Random Number Generator with 8x8 LED Matrix and Arduino © CC BY-NC-ND

/*
   Project:   Random Number Generator
   Author:    LAGSILVA
   Hardware:  Arduino UNO-R3, MAX72XX LED Matrix (8x8)
   Date:      20.Jul.2019
   Revision:  2.0
   License:   CC BY-NC-ND 4.0
              (Attribution-NonCommercial-NoDerivatives 4.0 International)
*/

#include <LedControl.h>                 // Library for LED Display - MAX72XX

// Global Variables
byte pDown = 10, pUp = 9, pMode = 8;
String shuffleDezenas, dezenas;
byte row, col, mode = 3;
byte btnMode, btnUp, btnDown;
byte totGrupo = 6, totDez = 60;
float timer = 1;
unsigned long ti, tf;

/*
  Pin numbers of Arduino to be connected into MAX72XX (LED Matrix controlled by MAX72XX)
  pin 5 is connected to the DataIn (DIN)
  pin 6 is connected to LOAD (CS)
  pin 7 is connected to the CLK (CLK)
*/

LedControl lc = LedControl(5, 7, 6, 1); // LedControl(int dataPin, int clkPin, int csPin, int numDevices)


void setup() {

  pinMode(pUp, INPUT_PULLUP);
  pinMode(pDown, INPUT_PULLUP);
  pinMode(pMode, INPUT_PULLUP);

  // Setup of Display "0"
  lc.shutdown(0, false);                // Wakeup Display "0"
  lc.setIntensity(0, 8);                // Set the Brightness of Display (0 to 15)
  lc.clearDisplay(0);                   // Clear Display "0" (Hour)

  randomSeed(analogRead(A1));
  numbers();

}


void shuffle() {            // Shuffling routine
  byte k, n;
  String tempSeq = dezenas;
  shuffleDezenas = "";
  for (k = 0; k < totGrupo; k++) {
    n = random(tempSeq.length() / 2);
    shuffleDezenas = shuffleDezenas + tempSeq.substring(n * 2 , n * 2 + 2);
    tempSeq.remove(n * 2, 2);
  }
}


void numbers() {          // Numbers to be drawn
  dezenas = "";
  for (byte k = 1; k <= totDez; k++) {
    if (k < 10) {
      dezenas = dezenas + "0" + k;
    }
    else {
      dezenas = dezenas + k;
    }
  }
}


void plot(byte tot) {
  byte row, col;
  if (tot > 4) {
    row = (12 - tot % 8) % 8;
    col = (tot + 3) / 8;
  }
  else {
    row = 6 - tot;
    col = 0;
  }
  lc.setLed(0, row, col, true);
}


void loop() {

  btnMode = digitalRead(pMode);
  btnUp = digitalRead(pUp);
  btnDown = digitalRead(pDown);

  if (btnMode == LOW) {
    mode = (mode + 1) % 4;            // Modes: 0 (N = Population Size)) / 1 (n = Sample Size) / 2 (Manual Draw)) / 3 (Timer of Draw)
    lc.clearDisplay(0);
    if (mode <= 1) {
      lc.setLed(0, 7 - mode, 0, true);
    } else {
      lc.setLed(0, 3 - mode, 0, true);
    }
    delay(150);
    if (mode == 0) {
      plot(totDez);
    }
    if (mode == 1) {
      plot(totGrupo);
    }
  }

  if (mode == 0 && btnUp == LOW) {    // Mode 0: Setup of Population (Increase mode)
    lc.clearDisplay(0);
    lc.setLed(0, 7, 0, true);
    totDez += 1;
    if (totDez > 60) {
      totDez = 1;
    }
    plot(totDez);
    numbers();
    delay(150);
  }

  if (mode == 0 && btnDown == LOW) {  // Mode 0: Setup of Population Size (Decrease mode)
    lc.clearDisplay(0);
    lc.setLed(0, 7, 0, true);
    totDez -= 1;
    if (totDez < 1) {
      totDez = 60;
    }
    plot(totDez);
    numbers();
    delay(150);
  }

  if (mode == 1 && btnUp == LOW) {    // Mode 1: Setup of Sample Size (Increase mode)
    lc.clearDisplay(0);
    lc.setLed(0, 6, 0, true);
    totGrupo += 1;
    if (totGrupo > 60) {
      totGrupo = 1;
    }
    plot(totGrupo);
    delay(150);
  }

  if (mode == 1 && btnDown == LOW) {  // Mode 1: Setup of Sample Size (Decrease mode)
    lc.clearDisplay(0);
    lc.setLed(0, 6, 0, true);
    totGrupo -= 1;
    if (totGrupo < 1) {
      totGrupo = 60;
    }
    plot(totGrupo);
    delay(150);
  }

  if (mode == 2 && (btnUp == LOW || btnDown == LOW)) {    // Mode 2: Manual Draw of Number
    for (byte s = 1; s <= 20; s++) {
      lc.clearDisplay(0);
      lc.setLed(0, 1, 0, true);
      shuffle();
      for (byte k = 0; k < totGrupo; k++) {
        byte dez = (shuffleDezenas.substring(k * 2, k * 2 + 2)).toInt();
        plot(dez);
      }
      delay(25);
    }
  }

  if (mode == 3 && btnUp == LOW) {      // Mode 3: Increase the time lapse
    lc.clearDisplay(0);
    lc.setLed(0, 0, 0, true);
    timer += 1;
    if (timer > 60) {
      timer = 0;
    }
    plot(timer);
    delay(150);
    ti = millis();
  }

  if (mode == 3 && btnDown == LOW) {    // Mode 3: Decrease the time lapse
    lc.clearDisplay(0);
    lc.setLed(0, 0, 0, true);
    timer -= 1;
    if (timer < 0) {
      timer = 60;
    }
    plot(timer);
    delay(150);
    ti = millis();
  }

  if (mode == 3) {                      // Automatic draw of numbers by timer
    if (timer == 0) {
      timer = 0.050;
    }
    tf = millis() - ti;
    if (tf >= timer * 1000) {
      lc.clearDisplay(0);
      lc.setLed(0, 0, 0, true);
      shuffle();
      for (byte k = 0; k < totGrupo; k++) {
        byte dez = (shuffleDezenas.substring(k * 2, k * 2 + 2)).toInt();
        plot(dez);
        ti = millis();
      }
    }
  }

}