const int sensorPin=A0;
const float baselineTemp=20.0;
void setup(){
  Serial.begin(9600);
  for(int pinNumber=2;pinNumber<5;
      pinNumber++){
      pinMode(pinNumber,OUTPUT);
      digitalWrite(pinNumber,LOW);
}
}

void loop(){
  int sensorVal=analogRead(sensorPin);
  Serial.print("Sensor Value:");
  Serial.print(sensorVal);
  float voltage=(sensorVal/1024.0*5.0);
  Serial.print(",Volts:");
  Serial.print(voltage);
  Serial.print(",degrees C:");
  float temperature=(voltage-.5)*100;
  Serial.println(temperature);
  if(temperature<baselineTemp);
  {
    digitalWrite(2,LOW);
    digitalWrite(3,LOW);
    digitalWrite(4,LOW);
  }else if(temperature>=baselineTemp+2&&
  temperature<baselineTemp+4){
    digitalWrite(2,HIGH);
    digitalWrite(3,LOW);
    digitalWrite(4,LOW);
  }else if(temperature>=baselineTemp+4&&
  temperature<baselineTemp+6){
    digitalWrite(2,HIGH);
    digitalWrite(3,HIGH);
    digitalWrite(4,LOW);
  }else if(temperature>=baselineTemp+6){
    digitalWrite(2,HIGH);
    digitalWrite(3,HIGH);
    digitalWrite(4,HIGH);
  }
    delay(1);
}