int buzzerPin = 7;
float start = 0;
bool once = true;
float total_time = 45.0;


void setup() {
  pinMode(buzzerPin, OUTPUT);
  start = millis();
  Serial.begin(115200);
  Serial.println("Bomb has been planted!");
}

float getBPS(float c_time, float exp_time)
{
  float time = 45.0 * c_time / exp_time;
  float n = (0.00000542275012008209 * time) + (0.000000000871011529375232 * time * time);
  float bps = 1.04865094758501 * exp(n);
  return bps;
}

void playFor(int freq, int duration)
{
  tone(buzzerPin, freq);
  delay(duration);
  noTone(buzzerPin);
}

void loop() {
  float time = (millis() - start);

  if(time < total_time * 1000.0)
  {
    playFor(4000,125);
    delay(1000.0/getBPS(time, total_time));
  }

  else
  {
    if(once){
      Serial.println("\nBOOOM!");
      for(int i = 1500; i <10750;i+=22 ) {
        tone(buzzerPin,i);
        delay(5);
      }
      for(int i = 0; i < 6;i+=1) {
        playFor(3400,50);
        delay(50);
        playFor(3360,50);
        delay(50);
      }
    once = false;
    }
    else
    {
      noTone(buzzerPin);
    }
  }
}