// EPOCH PROJECT#20: "ACTIVE AND PASSIVE BUZZERS"
// IN THIS PROJECT WE'LL LEARN HOW TO USE THE ACTIVE AND PASSIVE BUZZERS
// CONNECTIONS:
// CONNECT THE ADCK (ANALOG KEYPAD PIN) TO THE A5 ANALOG PIN ON CHIP-A
// CONNNECT GPIO PIN#2 ON CHIP-A TO ONE OF THE TWO BUZZER CTRL PINS ON THE LOWER LEFT SIDE OF THE EPOCH. 
// SET THE BUZZER SELECT JUMER TO SHORT "ACT" OR "PASS" 

#define buzzer 2            // OUR BUZZER WILL CONNECT TO GPIO PIN#2 ON CHIP-A
int time = 0;               // WE'RE GOING TO USE THIS INTEGER TO STORE TIME INFORMATION IN OUR PASSIVE() FUNCTION
int hold = 0;               // WE'LL STORE OUR ANALOG KEYPAD SAMPLING DATA IN THIS INTEGER

void setup() 
{
  pinMode(buzzer,OUTPUT);   // DECLARE OUR BUZZER AS AN OUTPUT           
}



void loop() 
{
hold = analogRead(5);       // SAMPLE THE KEYPAD ANALOG DATA, AND PLACE THE RESULT IN hold
if(hold > 500)              // IF A BUTTON ON THE KEYPAD IS BEING PRESSED, CHECK TO SEE IF IT IS BUTTONS 7 TOUGH 9 AND 0.
{
 active();                  // IF SO, CALL THE active() FUNCTION SEEN BELOW
}  
else if(hold > 25)          // IF BUTTONS 1-5 ARE BEING PRESSED, CALL THE passive() FUNCTIONS SEEN BELOW.  IF THE ADC KEYPAD VALUE IS LESS THAN 25, DO NOTHING.
{
  passive();                // IF HIGHER THAN 25, BUT LOWER THAN 500, CALL THE passive() FUNCTION
}
} // THIS IS THE END OF VOID LOOP

void active()               // WHEN THIS FUNCTION IS CALLED, WE SET THE BUZZER OUTPUT TO TURN ON FOR HALF A SECOND, AND THEN OFF FOR HALF A SECOND.  MAKE SURE THAT THE "ACT" BUZZER IS SELECTED 
{
  digitalWrite(buzzer,HIGH);
  delay(500);
  digitalWrite(buzzer,LOW);
  delay(500);
}

void passive()                      // WHEN THIS FUNCTION IS CALLED, WE SET THE BUZZER TO OUTPUT A CONSTANTLY CHANGING SIGNAL WITH VARIED DUCY CYCLE AND FREQUENCY.  MAKE SURE THAT THE "ACT" BUZZER IS SELECTED 
{
  time = 1000;                      // SET THE time INTEGER TO 1000
  for(int i = 0 ; i <= 1000 ; i++)  // THE FOLLOWING for LOOP WILL EXECUTE 100 TIMES
  {
  digitalWrite(buzzer,HIGH);        // TURN THE BUZZER ON
  delayMicroseconds(time);          // delayMicroseconds() AND delay() WORK SIMILARLY.  ONE IS A us (Microsecond delay), while the other is a ms (Millisecond).  When we place (time) in the delay value brackets, the value of time will be the delay
  digitalWrite(buzzer,LOW);         // TURN OFF THE BUZZER
  delayMicroseconds(time);          // THIS DELAY IS THE SAME AS THE DELAY ABOVE
  time = time - 1;                  // SUBTRACT 1 FROM time.  BECAUSE THIS for LOOP EXECUTES 1000 TIMES, THE time DELAY IS ALWAYS CHANGING BECAUSE OF THIS LINE OF CODE
  }
  //                                // LET'S REVERSE THE ORDER OF THINGS NOW.  IN THE ABOVE for LOOP, WE STARTED time AT A VALUE OF 1000.  NOW WE'LL START IT AT A VALUE OF 0.
  time = 0;                         // SET time TO 0
    for(int i = 1000 ; i > 0 ; i--) // NOTE THAT THIS TIME THE for STATEMENT WORKDS DIFFERENTLY.  ACTUALLY, IT WORKS THE EXACT SAME AS THE for STATEMENT ABOVE.  IT JUST OPERATES DIFFERENTLY.  WE START i AT 1000, AND USE i-- TO SUBTRACT AFTER EACH LOOP
  {
  digitalWrite(buzzer,HIGH);        // TURN THE BUZZER ON
  delayMicroseconds(time);          // THE VALUE IN THE time INTEGER IS THE DELAY IN MICROSECONDS.  IT STARTS AT 0, AND ENDS AT 1000 WHEN THE for LOOP ENDS
  digitalWrite(buzzer,LOW);         // TURN THE BUZZER OFF
  delayMicroseconds(time);          // THE VALUE IN THE time INTEGER IS THE DELAY IN MICROSECONDS.  IT STARTS AT 0, AND ENDS AT 1000 WHEN THE for LOOP ENDS
  time = time + 1;                  // THIS TIME WE ADD 1 TO time.  ABOVE WE SUBRTACTED 1 FROM time
  }
}   // BOOM.  DONE.

// NOTES
// for(int i = 0 ; i <= 1000 ; i++) and for(int i = 1000 ; i > 0 ; i--) both execute 1000 times.  They just operate differently.  
// The first FOR loop starts with i equalling 0, and the loop ends when i is greater or equal to 1000.  After every single loop, 1 is added to i (i++).  i++ means increment i or i = i + 1
// The second FOR loop starts with i equalling 1000, and the loop ends when i = 0.  After every single loop, 1 is subtracted from i (i--).  i-- means decrement i, or i = i - 1
// If you don't have the TONE.h library, try downloading it and playing with it.  
// Also try messing around with the for loops.  See if you can generate different sounds!