How to use LM35 Temperature Sensor with Arduino | arduino tutorials

lm temp sensor

Lm35 temperature sensor is used as input to measure External temperature in analog values. This is the quick tutorial about lm35 arduino. The arduino tutorials and how and why to use lm35 sensor. We will discuss how to interface lm35 temperature sensor with arduino. lm35 temperature sensor code for arduino.This is the quick tutorial series about arduino tutorials and arduino programming tutorial.

How to Interface LM35 Temperature Sensor with arduino

Welcome, Everyone
Here is the first Tutorial in the series of Learn by Doing.Learn Arduino by Doing projects.There is a long list of 100+ amazing Arduino projects.So we are going to start with some basic concepts.There are almost 10 first tutorials on Sensors then we will move towards doing amazing and cool projects.
In all these tutorials we will understand each and every component, circuit diagrams and complete Arduino codes.Stay connected on YouTube and follow for step by step Guide and source codes.
So let’s start with the basic LM35 temperature sensor.


  1. Introduction to LM35 Temperature Sensor
  2. Components List
  3. LM35 with Arduino Circuit Diagram
  4. code for arduino

Lm35 temperature sensor:

Lm35 is a Temperature Sensor that works with the variations in temperature.The internal structure of Lm35 consists of transistors, amplifier, and few resistors.The integrated circuit and the resistors are calibrated in the factory to produce the accurate temperature.

The Lm35 has 3 pins:

  • Input
  • Output
  • Ground
The output of Lm35 is in volts.Every 10 mv change is equal to 1 degree Celsius.
The Exact Equation to convert voltage into degree Celsius is:

( THE SUPPLY_VOLTAGE x 1000 / 1024) / 10 where  THE SUPPLY_VOLTAGE is 5.0Volts )

 1000 is used for changing the unit from Volts to mV
10 is constant and Each 10 mV is directly proportional to 1 degree Celcius.
5 is the supply voltage.

The final Equation is: [(5.0 * 1000 / 1024) / 10  ] = 0.4882

Components for lm35 arduino:

  1. Arduino Board with USB Cable
  2. LM35 Temperature sensor
  3. Bread board (for practice)
  4. Arduino jumper wires

Lm35 sesor with arduino circuit diagram:

  1. Connect first pin with 5v on Arduino
  2. Second with analog pin of Arduino A0
  3. Third with GND on Arduino

Code for Arduino:

float temp;                                        //Defining the temp float variable
int sensor = 0;                                 // The output pin of LM35 on arduino analog pin 0 it could be A0
void setup()
{Serial.begin(9600);                                    //start the serial monitor
void loop(){
temp = analogRead(sensor);                     //assigning the analog output to temp
float mv = ( temp/1024.0)*5000;             // Converting equation for voltage to Celsius
float celsius = mv/10;
Serial.print("The temperature is :");       //Display the results on serial monitor
Serial.println("deg. Celsius");
delay(1000);                                          //1 second delay to avoid overloop
There will be more on Lm35 temperature sensor. How to display Temperature on LCD and Weather displaying box Arduino Project.Stay connected and subscribe on YouTube for video Tutorials.Learn by Doing.Stay motivated and always have faith on yourself.
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