thermister_threshold.pde

double Thermister(int RawADC) {
 double Temp;
 Temp = log(((10240000/RawADC) - 10000));
 Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp ))* Temp );
 Temp = Temp - 273.15;            // Convert Kelvin to Celcius
 Temp = (Temp * 9.0)/ 5.0 + 32.0; // Convert Celcius to Fahrenheit
 return Temp;
}

boolean debug = false;

int led = 13;

int up = 2;
int down = 3;

double threshold = 85; // Fahrenheit

boolean triggered = false;

void setup() {
 if(debug) Serial.begin(115200);
 pinMode(led, OUTPUT);
 pinMode(up, INPUT);
 pinMode(down, INPUT);
 digitalWrite(led, LOW);
}

void loop() {
 double temp = Thermister(analogRead(0));
 
 if (digitalRead(up) == HIGH) {
   threshold++;
   triggered = false;
 }
 if (digitalRead(down) == HIGH) {
   threshold--;
   triggered = false;
 }
 
 if(debug){
   Serial.print(int(temp));  // display Fahrenheit
   Serial.print("|");
   Serial.println(int(threshold));
 }
 if (temp > threshold) triggered = true;
 
 if(triggered) digitalWrite(led, HIGH);
 else digitalWrite(led, LOW);
 delay(100);
}