Steinhardt-Hart Equation for computing temperature from a thermistor.

steinhardt.ino

  float R1 = 10000; // resistance value of the fixed resistor
  float RT; // resistance value of thermistor
  float T; // final temperature value
  int therm_val; // where you will store the value from analogRead()

  // get the value
  /* INSERT CODE HERE TO RETRIEVE THE ANALOG VALUE & STORE IT IN therm_val */

  // this is the math equation for computing the resistance of thermistor
  RT = R1 * (1023 - therm_val) / therm_val;

  // compute temperature in Celsius
  // RT is the resistance across the thermistor
  float c1 = 1.009249522e-03, c2 = 2.378405444e-04, c3 = 2.019202697e-07;
  T = (1 / (c1 + c2*log(RT) + c3*log(RT)*log(RT)*log(RT))) - 273.15;
  
  // now convert the temperature from Fahrenheit to Celsius