Arduino Temperature Sensor Using LM35




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The LM35 series are precision integrated-circuit temperature devices with an output voltage linearly proportional to the Centigrade temperature. LM35 is three terminal linear temperature sensor from National semiconductors. It can measure temperature from -55 degree Celsius to +150 degree Celsius. The voltage output of the LM35 increases 10mV per degree Celsius rise in temperature. LM35 can be operated from a 5V supply and the stand by current is less than 60uA. The pin out of LM35 is shown in the figure below.


• Calibrated Directly in Celsius (Centigrade)

• Linear + 10-mV/°C Scale Factor

• 0.5°C Ensured Accuracy (at 25°C)

• Rated for Full −55°C to 150°C Range

• Suitable for Remote Applications

• Low-Cost Due to Wafer-Level Trimming

• Operates from 4 V to 30 V

• Less than 60-μA Current Drain

• Low Self-Heating, 0.08°C in Still Air

• Non-Linearity Only ±¼°C Typical

• Low-Impedance Output, 0.1 Ω for 1-mA Load

PinOuts Of LM35 is Shown in image.

You can download the datasheet from below file.

Step 1: Hardware Required and Circuit Diagram

Connect the Circuit as shown in image and upload the following code.

Step 2: Programming the Arduino

/*Code designed by Sujay Alaspure in SA Lab */

const int sensor=A5; // Assigning analog pin A5 to variable 'sensor'

float tempc; //variable to store temperature in degree Celsius

float tempf; //variable to store temperature in Fahreinheit

float vout; //temporary variable to hold sensor reading

void setup() {

pinMode(sensor,INPUT); // Configuring sensor pin as input



void loop() {

vout=analogRead(sensor); //Reading the value from sensor


tempc=vout; // Storing value in Degree Celsius

tempf=(vout*1.8)+32; // Converting to Fahrenheit

Serial.print("in DegreeC=");



Serial.print(" ");

Serial.print("in Fahrenheit=");




delay(500); //Delay of 1 second for ease of viewing }

Step 3: Output Result

See the result on Serial Moniter....

First of all, I would like to thank you for reading this guide ! I hope it helps you.

If You have any queries I am happy to help you.....

Drop a Comment. Your feedback is valuable for me.



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    3 Discussions


    Question 9 months ago

    Hi Sujay, thanks for posting this! Quick question: I did this schematic but the temperature is not showed correctly. I got variations between 120-202 Celsius on room temperature.

    I actually tried several schematics with LM35 but I got the same results. I'm using an arduino nano with atmel 328P chipset if matters.

    Any idea why is not working correctly? Thank you!

    1 more answer

    Answer 8 months ago

    you should check LM35 pin outs properly. if you connect it in wrong manner. it will not give proper output. Else there should not any issue.


    Nice tutorial. You should enter this in the Arduino contest.