const int TEMP_SENSOR_PIN = A0;    
const int GAS_SENSOR_PIN  = A1;    
const int BUZZER_PIN      = 8;     
const int LED_PIN         = 13;    

const float THR_TEMP = 40.0;
const int THR_GAS = 400;


void setup() {
  pinMode(TEMP_SENSOR_PIN, INPUT);
  pinMode(GAS_SENSOR_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);

  Serial.begin(9600);

  digitalWrite(BUZZER_PIN, LOW);      
  digitalWrite(LED_PIN, LOW); 

  Serial.println("=== Safety Monitoring System Started ===");
  Serial.println("Monitoring temperature and gas levels...");
  Serial.println();
}

void loop() {
  int tempRaw = analogRead(TEMP_SENSOR_PIN);
  int gas  = analogRead(GAS_SENSOR_PIN);

  //float voltage = tempRaw * (5.0 / 1023.0);

  //float tempC = map(tempRaw, 0, 1023, 0, 100);


  int tempC = map(tempRaw, 650, 420, 25, 60);

  Serial.print("temp in C: ");
  Serial.print(tempC);
  Serial.print( " C | gas level: ");
  Serial.print(gas);

  if (tempC > THR_TEMP) {
    tone(BUZZER_PIN, 1000);
    Serial.print("TEMP ALERT!!!");
  }
  else {
    noTone(BUZZER_PIN);
  }

  if (gas > THR_GAS) {
    digitalWrite(LED_PIN, HIGH);
    Serial.print(" Gas Alert!!!");
  }
  else {
    digitalWrite(LED_PIN, LOW);
  }

  Serial.println();
  delay(500);
}