// Week 12 - Input Devices
// Author: Kati Pitkänen, April 30, 2018
// Temperature calculation made by Ari Vuokila
#include <math.h>

int LED=PB2                       // Define the threshold value
int TEMPERATURE=PB3;              // Define LED in the pin PB2 as an OUTPUT
int threshold=22;                 // Define the threshold value

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(TEMPERATURE, INPUT);
  digitalWrite(LED,HIGH);
}
void loop() {                     // Main code to run repeatedly:

  float reading;                                // Define the variable to store the sensor value data
  reading = analogRead(TEMPERATURE);            // Read and store the analog input value coming from the temp sensor pin
  double Temp, T;                               // Define the variables to show the temperature data
  double R = 10000 / (1023.0 / readng - 1);     // Steinhart - Hart    /// Resistance = 10 k ohm
  double loka = 10000 / R;                      // loka = R0/R // 10000/R = ReferenceResistance/ NominalResistance = ResistanceInNominalTemperature25oC)
  T = (0.0033540164 + 0.00026666666 * log(L));  // Steinhart-Hart 1/T=1/T0 + 1/B*ln(R0/R)
  T = 1/T;
  Temp = T - 273.15;              // To get degrees Celcius Temperature = T - 273.15 (degrees Kelvin) 


  if(Temp>threshold){             // If the current temperature is higher than the threshold value
    digitalWrite(LED,LOW);        // Turn ON the LED (because of pull-up resistor the value is LOW=0)
  }
  else{
    digitalWrite(LED,HIGH);       // Else, turn OFF the LED (because of pull-up resistor the value is HIGH=1)
  }
delay(1000);                      // Delay time before starting the loop again
}