Get accurate temperature from LM35 on Arduino - Correctly!

After using some online examples I noticed that the temperature was always a little off with my weather station at home. Reading to some examples I came across two fixes: - divide the analogRead by 1023 not 1024. There are 1024 values but that includes 0. - Use analogReference(INTERNAL). This gives a higher accuracy. I've combined these two in the following example: Download example

float tempC;
float tempF;

int reading;
float referenceVoltage;

int tempPin = 0; //Analog pin connected to LM35


void setup()
{
  
 Serial.begin(9600);

 // Set Analog reference to 1.1V this gives more accuracy since the sensor will output 0-1 V
 // This only available on ATmega168 or ATmega328)
 // For more information see: http://arduino.cc/en/Reference/AnalogReference
 analogReference(INTERNAL);
 referenceVoltage = 1.1; //Set to 5, 3.3, 2.56 or 1.1 depending on analogReference Setting
 
}

void loop()
{
  reading = 0;
  
  for(int i = 0; i < 10; i++) { // Average 10 readings for accurate reading
     reading += analogRead(tempPin); 
     delay(20);
  }


  // A lot of examples divide the sensor reading by 1024. This is incorrect and should be 1023. There are 1024 values including 0 so this should be 1023.
  tempC =  (referenceVoltage * reading * 10) / 1023; 
  
  // Convert to Fahrenheit
  tempF = (tempC * 9 / 5) + 32;
  
  Serial.print(tempC, 1); //Print one decimal, it's not accurate enough for two
  Serial.println(" C");
  Serial.print(tempF, 1); //Print one decimal, it's not accurate enough for two
  Serial.println(" F");
  
  Serial.println(" ");
  delay(1500);
}