LM35 Temperature Sensor

“Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language”. Using the Arduino I will show you how to get the analog input from the LM35 temperature sensor and display the information in the serial window as raw data, celsius and fahrenheit.

For the purpose of the post I will assume that you already know how to download and install the Arduino software and load a sketch onto it.

Step 1: What You Need

What you will need:

Arduino UNO, Leonardo or equivalent

Breadboard

Jumper Wires

USB Cord

LM35 temperature sensor Data Sheet

Step 2: Wiring:

Wire up the breadboard as depicted in this picture.

Step 3: Code

The code can be downloaded here.

or Copy and paste this into the arduino sketch.

/*<br>Simple Temperature uses the lm35 in the basic centigrade temperature configuration
*/
float temp;
int tempPin = 2; // analog input pin
int sampleTime = 1000; // 1 second dafault 

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

void loop()
{
  //gets and prints the raw data from the lm35
  temp = analogRead(tempPin);
  Serial.print("RAW DATA: ");
  Serial.print (temp);
  Serial.println(" ");
  //converts raw data into degrees celsius and prints it out
  // 500mV/1024=.48828125
  temp = temp * 0.48828125;
  Serial.print("CELSIUS: ");
  Serial.print(temp);
  Serial.println("*C ");
  //converts celsius into fahrenheit 
  temp = temp *9 / 5;
  temp = temp + 32;
  Serial.print("FAHRENHEIT: ");
  Serial.print(temp);
  Serial.println("*F");
  delay(sampleTime);

}

Load the code into to your board and open the serial monitor you should see both fahrenheit and celsius.