// Source          :: Chapter08.Digital Hourglass
// Description     :: Digital Hourglass, Chapter 8, Arduino Projects Book
// Programmed by   :: Douglas Vieira Ferreira / 03-11-2024 

/*
IN THIS PROJECT, I'VE BUILT A DIGITAL HOURGLASS THAT TURNS ON AN LED EVERY TEN MINUTES OR 5 SECONDS.
*/


const int switchPin = 8;

unsigned long previousTime = 0;  // store the last time an LED was updated
int switchState = 0;             // the current switch state
int prevSwitchState = 0;         // the previous switch state
int led = 2;                     // a variable to refer to the LEDs

int notes[] = { 330, 660, 750, 900}; // some buzzer notes to choose from

// 600000 = 10 minutes in milliseconds
// 5000 = 5 second intervals
long interval = 5000;

void setup() {
  // set the LED pins as outputs
  for (int x = 2; x < 8; x++) {
    pinMode(x, OUTPUT);
  }
  // set the tilt switch pin as input
  pinMode(switchPin, INPUT);
}

void loop(){                     
  // store the time since the Arduino started running in a variable
  unsigned long currentTime = millis();

  // compare the current time to the previous time an LED turned on
  // if it is greater than your interval, run the if statement
  if(currentTime - previousTime > interval) {
    // save the current time as the last time you changed an LED
    previousTime = currentTime;
    // Turn the LED on
    digitalWrite(led, HIGH);
    // increment the led variable
    // in 10 minutes the next LED will light up    
    led++;                       
    if(led == 7){
      tone(7, notes[2]);      
    }
  }

  // read the switch value
  switchState = digitalRead(switchPin);
  
  // if the switch has changed
  if(switchState != prevSwitchState){

    // turn all the LEDs low
    for(int x = 2;x<8;x++){
     digitalWrite(x, LOW);        
    }

    // reset the LED variable to the first one
    led = 2;

    //reset the timer
    previousTime = currentTime;
  }

  // set the previous switch state to the current state
  prevSwitchState = switchState;
}