int is_alarm = 0;
const float BETA = 3950; // should match the Beta Coefficient of the thermistor
void setup() {
  pinMode(8, OUTPUT); // buzzer
  pinMode(7, OUTPUT); // red led
  pinMode(2, OUTPUT); // green led
  digitalWrite(2, HIGH);
  Serial.begin(9600);

}

void alarm(){
  tone(8, 500 , 1000);
  digitalWrite(7, HIGH);
  digitalWrite(2, LOW);
}

void turnOff(){
  digitalWrite(7, LOW);
  digitalWrite(2, HIGH);
}

void loop() {
  int analogValue = analogRead(A3);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  Serial.print("Temperature: ");
  Serial.print(celsius);
  Serial.println(" ℃");

  if(celsius > 50){
    alarm();
    is_alarm = 1;
  }else if(is_alarm){
    turnOff();
  }

  delay(1000);

}