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);
 
 }