Lesson #9: Binary Counting

/*
* Binary Counter
*
* This example uses 6 LEDs to count in binary from 0 to 63.
*
* There are two buttons. One button will add 1 to the count
* each time it is pressed, while the other button will
* subtract 1 from the count.
*
* The 6 LEDs are connected to digital pins 2 through 7.
* The "add" button is connected to digital pin 12.
* The "subtract" button is connected to digital pin 13.
*
*/

// Here we set some global constants
// In other words, variables whose values do not change

const int add_button=12,
          subtract_button=13,
          NumberOfBits=6;



// Here we set some global non-constant variables.
// In other words, variables whose values can change throughout execution.

int OurSixBitNumber[]={0,0,0,0,0,0}, LED_Selector, ButtonIsPressed;

void setup() {

  pinMode(2,OUTPUT);
  pinMode(3,OUTPUT);
  pinMode(4,OUTPUT);
  pinMode(5,OUTPUT);
  pinMode(6,OUTPUT);
  pinMode(7,OUTPUT);

  pinMode(add_button,INPUT);
  pinMode(subtract_button,INPUT);

}

void loop() {

  ButtonIsPressed = digitalRead(add_button); // Equals 1 if button being pressed, 0 if not.
  if(ButtonIsPressed == 1) { addButtonPressed(); }

  delay(100); // To prevent spamming

  ButtonIsPressed = digitalRead(subtract_button);
  if(ButtonIsPressed == 1) { subButtonPressed(); }

  resetSelector();
  writeLEDs();

}

/**************************/

/*

/*  ADDITIONAL FUNCTIONS:

/*     addButtonPressed()
/*     subButtonPressed()
/*     writeLEDs()
/*     resetSelector()
/*
/**************************/

void addButtonPressed() {

  while(digitalRead(add_button) == 1) { /* do nothing until let go of button */ } //AKA: Add Button being held down still

  delay(100); //Delay for 100 milliseconds to prevent spamming of buttons
  resetSelector();

  while(LED_Selector >= 0 && ButtonIsPressed != 0)
  {
    if(OurSixBitNumber[LED_Selector] == 1)
    {
      OurSixBitNumber[LED_Selector] = 0;
      LED_Selector--;
    }
    else
    {
      OurSixBitNumber[LED_Selector] = 1;
      ButtonIsPressed = 0;
    }
  }
}

void subButtonPressed() {

  while(digitalRead(subtract_button) == 1) { /* do nothing until let go of button */ } //AKA: Subtract Button being held down still

  delay(100); //Delay for 100 milliseconds to prevent spamming of buttons

  resetSelector();

  while(LED_Selector >= 0 && ButtonIsPressed != 0) // While the LED Selector is greater than zero and the subtract button is 1, then starting from the last LED to the first, do the following:

  {
    if(OurSixBitNumber[LED_Selector] == 0) // IF that LED is OFF, turn it on, and continue to the next LED (aka the one before because backwards)
    {
      OurSixBitNumber[LED_Selector] = 1; // Turning LED on
      LED_Selector--; // Continuing to the next (aka the one before because going backwards) LED
    }
    else // ELSE (the LED is ON) turn off the LED and set the button state to NOT pressed.
    {
      OurSixBitNumber[LED_Selector] = 0; // Turn it off
      ButtonIsPressed = 0; // Reset Button State
    }
  }
}

void writeLEDs() {

  for(int temp = 0; temp < NumberOfBits; temp++)
  {
    if(OurSixBitNumber[temp] == 1)
    {
      digitalWrite(NumberOfBits - temp + 1, HIGH);
    }
    else
    {
      digitalWrite(NumberOfBits - temp + 1, LOW);
    }
    LED_Selector--;
  }
}

void resetSelector() {
 LED_Selector = NumberOfBits - 1; // because arrays start at 0;
}