LM35 Temperature Sensor

The LM35 is a precision analog temperature sensor IC that provides an accurate and linear voltage output corresponding to the temperature in degrees Celsius. Here's detailed information about the LM35 sensor:

Features:
 

1. Temperature Range:
   • Operating: 0°C to +100°C
   • Calibrated: -55°C to +150°C
2. Output Voltage:
   • Linearly proportional to temperature: 10 mV/°C
3. Accuracy:
   • Typically ±0.5°C at +25°C, and ±3/4°C over the full -55°C to +150°C range.
4. Low Impedance Output:
   • The output impedance is low, allowing it to drive other devices directly without additional circuitry.
5. Power Supply:
   • Operates from 4V to 30V DC, making it suitable for a wide range of applications.
6. Temperature Calibration:
   • Factory calibrated to provide a precise output voltage for a given temperature range.
      

Applications:
 

• Temperature Measurement: Widely used in applications where accurate temperature sensing is required, such as climate control systems, industrial process monitoring, and automotive applications.
• Temperature Compensation: Often used in circuits requiring temperature compensation, such as in analog circuits and sensor modules.
• Portable Devices: Due to its low power consumption and small size, it is suitable for integration into handheld and portable devices.

Example Circuit:
 

Here's a basic example of how you might connect an LM35 sensor to an Arduino for temperature measurement:

const int lm35Pin = A0;  // LM35 analog pin connected to Arduino analog input A0

void setup() {
  Serial.begin(9600);    // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(lm35Pin);  // Read analog input
  float voltage = sensorValue * (5.0 / 1023.0);  // Convert analog reading to voltage (assuming 5V Arduino)
  
  // Convert voltage to temperature using LM35 formula (10 mV/°C)
  float temperatureC = voltage * 100.0;  // LM35 outputs 10 mV per degree Celsius
  
  // Print temperature to serial monitor
  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" °C");
  
  delay(1000);  // Delay before next reading
}

Explanation:
 

• Connect the LM35 sensor's Vout pin to Arduino's analog input pin (A0 in this example).
• In the Arduino sketch, read the analog voltage from the sensor using analogRead() function.
• Convert the analog reading to voltage using the formula (sensorValue * (5.0 / 1023.0)), assuming a 5V Arduino.
• Use the LM35 formula voltage * 100.0 to convert voltage to temperature in degrees Celsius, as the LM35 outputs 10 mV per degree Celsius.
• Print the temperature readings to the Serial Monitor.

This example demonstrates how to interface the LM35 sensor with Arduino for temperature measurement. Adjust the code as needed based on your specific setup and requirements.