/****************************************/
#include <math.h>
/****************************************/
const int relayPin = 8;
const int ThermistorPin = A0;
double Thermistor(int RawADC) {
 double Temp;
 Temp = log(10000.0*((1023.0/RawADC-1))); 
 Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
 Temp = Temp - 273.15;          
 Temp = (Temp * 9.0)/ 5.0 + 32.0; 
 return Temp;
}
/****************************************/
void setup() {
  Serial.begin(9600);
  pinMode(relayPin, OUTPUT);
}
void loop() {             
  int val;                
  double temp;            
  val=analogRead(ThermistorPin);      
  temp=Thermistor(val);   
  Serial.print("Temperature = ");
  Serial.print(temp);   
  Serial.println(" F");
  if (temp >= 81){
    digitalWrite(relayPin, LOW);
  }
  else {
    digitalWrite(relayPin, HIGH);
  }
  delay(1000);            
}