lesson_03_original.ino

const int sensorPin = A0;
const float baselineTemp = 20.0;
void setup()
{
  // put your setup code here, to run once:
  Serial.begin(9600);
  for(int pinNumber = 2; pinNumber < 5; pinNumber++)
  {
    pinMode(pinNumber, OUTPUT);
    digitalWrite(pinNumber, LOW);
  }
}
void loop()
{
  // put your main code here, to run repeatedly:
  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+2)
  {
    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(5000);
}