Arduino sends messages every second to Serial Monitor, which display them.
Values indicates us that they are over the threshold one (30°C), so red LED pin on Arduino, connected to digital pin 13, is On.
A video test follows, showing the temperature grow quickly when sensor is covered and decrease slowly when uncovered.
Tricks:
- a resistor put between signal out and ground could prevent overheating (in this case is not necessary);
- changing function to get Celsius degrees, you can obtain other temperature sizes (Kelvin, Farenheit, etc...) but always knowing tha LM35DZ is scaled natively to Celsius degrees.