#define writeV 12

#define readV A0

int roomTemp = 0;

void setup() {

  Serial.begin(9600);

  pinMode(writeV, OUTPUT);

  pinMode(readV,INPUT);

 roomTemp = analogRead(readV);

}

void loop() {

    int threshold = roomTemp-35;

    int val = analogRead(readV);

    Serial.println(val);

  if(val < threshold){

        digitalWrite(writeV, HIGH);

  }else{

    digitalWrite(writeV, LOW);

  }

}