Example Code for Arduino-Temperature Alarm

Wiring Diagram

Sample Code

/*
   Temperature Alarm
*/
float sinVal;
int toneVal;
unsigned long tepTimer ;

void setup(){
    pinMode(8, OUTPUT);
    Serial.begin(9600);
}

void loop(){
    int val;
    double data;
    val=analogRead(0);
    data = (double) val * (5/10.24);  // convert the voltage to temperture

    if(data>27){        // If the temperture is over 27 degree, buzzer will alarm.
          for(int x=0; x<180; x++){
            sinVal = (sin(x*(3.1412/180)));
            toneVal = 2000+(int(sinVal*1000));
            tone(8, toneVal);
            delay(2);
     }
    } else {    // If the temperturn is below 27 degree, buzzer will not alarm
           noTone(8);
    }

    if(millis() - tepTimer > 500){     // output the temperture value per 500ms
             tepTimer = millis();
             Serial.print("temperature: ");
             Serial.print(data);
             Serial.println("C");
       }
}