Issue with an LM35 sensor and LCD backlight

Using Arduino Sensors
2

the backlight might draw too much current from your Arduino.

  1. use a separate power supply for the backlight
  2. connect it to Vin (with an additional resistor !! to be determined by a potmeter)

Where does this formula comes from ?

( 4.91 * sensorReading * 100.0) / 1024.0;

can be shortened.