//Thermometer with thermistor
 
/*thermistor parameters:
 * RT0: 10 000 Ω
 * B: 3977 K +- 0.75%
 * T0:  25 C
 * +- 5%
 */
 
//These values are in the datasheet
#define RT0 10000   // Ω
#define B 3977      // K
//--------------------------------------
 
 
#define VCC 5    //Supply voltage
#define R 10000  //R=10KΩ
 
//Variables
float RT, VR, ln, TX, T0, VRT;
const int ledpin = 13;
 
void setup() {
  Serial.begin(9600);
  T0 = 25 + 273.35;                 //Temperature T0 from datasheet, conversion from Celsius to kelvin
  pinMode(ledpin, OUTPUT);
};
 
void loop() {
  VRT = analogRead(A0);              //Acquisition analog value of VRT
  VRT = (5.00 / 1024.00) * VRT;      //Conversion to voltage
  VR = VCC - VRT;
  RT = VRT / (VR / R);               //Resistance of RT
 
  ln = log(RT / RT0);
  TX = (1 / ((ln / B) + (1 / T0))); //Temperature from thermistor
 
  TX = TX - 273.35;                 //Conversion to Celsius 
 if (TX > 40) { digitalWrite(ledpin, HIGH); // Turn on LED } else { digitalWrite(ledPin, LOW); // Turn off LED } delay(500);
 
 }else { digitalWrite(ledpin, LOW);} ;// Turn off LED }
  Serial.print("Temperature:");
  Serial.print("\t");
  Serial.print(TX);
  Serial.print("C\t\t");
  Serial.print(RT);        //Conversion to Kelvin
  Serial.print("Ω\t\t");
  
  delay(500);
 
}