Skip to content

Temperature Sensor with Arduino and LM35 (Arduino + LM35)

Published by Matheus (X-warrior) Bratfisch on September 23, 2012

Hello,

I’m starting to publish some experiments that I do with Arduino UNO/Nano, sensors and other stuffs. Today I created a thermometer with LM35 sensor.

The LM35 sensor is a temperature sensor, it will variate 10mV/Celsius. It pins can be seen on image (pay attention, it is a bottom look)

LM35 Pins

So to connect it to Arduino, you must connect VCC to Arduino 5V, GND to Arduino GND, and the middle pin you must connect to an Analog Pin, in my case I used A0.

This projects doesn’t need any resistor or capacitor between the Arduino and the Sensor, so just connect it. The Arduino ADC has a precision of 10 bits, so in this case 5V / 2^10 = 5V / 1024, so 0.0049 is our factor. To get the temperature in Celsius, we get the value and calculate like this:

Temperature = (pin * 0.0049)*100

But why multiply by 100? PIN * 0.0049 will give the volts on port, if we multiply it by 1000 we will have millivolts on port, the sensor varies 10mV/C so we need to divide it by 10 to get the temperature. On mathematics multiply by 1000 and divide by 10 is the same as multiplying by 100. Understand? [Add on 12/12]

And to have it on Fahrenheit, we need to make a conversion

TemperatureF = (Temperature * 1.8) + 32.

The arduino code that I used is:

[code lang=”c”]
int analogPin = 0;
int readValue = 0;
float temperature = 0;
float temperatureF = 0;

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

void loop() {
readValue = analogRead(analogPin);
//Serial.println(readValue);
temperature = (readValue * 0.0049);
temperature = temperature * 100;
temperatureF = (temperature * 1.8) + 32;
Serial.print(“Temperature: “);
Serial.print(temperature);
Serial.print(“C “);
Serial.print(temperatureF);
Serial.println(“F”);
delay(1000);
}
[/code]

Hope you like it,
Matheus

References:
LM35 Datasheet
Arduino analog Read

Published inArduino

1,636 Comments

  1. Window Repair Window Repair

    I have not checked in here for some time as I thought it was getting boring, but the last several posts are good quality so I guess I?ll add you back to my everyday bloglist. You deserve it my friend 🙂

    # September 6, 2026
  14. Bessie Bessie

    usa online casinos 2021, casimba casino nz
    login and gambling in the uk statistics, or play poker in south united states

    Here is my homepage: free roulette game no sign up (Bessie)

    # September 7, 2026
  18. Brittney Brittney

    free chip no deposit bonus codes 2021 canada, does encore have a casino (Brittney) online uk free and online gambling poker australia,
    or real poker online australia

    # September 7, 2026
  24. Ambrose Ambrose

    united statesn online pokies review, 2021 no deposit bonus codes nz
    and how to get money back from gambling sites usa, or united kingdom online winpalace casino online (Ambrose) 10 minimum deposit

    # September 8, 2026
  39. Alisha Alisha

    online gambling laws in uk, free spins no deposit casinos usa and australian strategy for craps at
    casino (Alisha)
    chips, or newest online casino usa

    # September 9, 2026

Leave a Reply

Your email address will not be published. Required fields are marked *