LM35 temperature sensor library for Arduino

This is an accurate LM35 analog temperature sensor library for Arduino with noise cancellation.

Library features

• Synchronous 10-bit unsigned temperature read
• Temperature range: 0.0 .. 110.0 degree Celsius
• Accuracy: 0.1 degree Celsius
• Noise cancellation
• Small footprint

Hardware

Supported hardware

• All ATmega328P MCU (Arduino UNO, Micro, Nano, etc)
• All ATmega32U4 MCU (Arduino Leonardo, Pro Micro, etc)
• Arduino ATmega2560

Notes:

• This library changes analog pins to ADC 1.1V internal reference voltage which affects all analog pins.
• The function analogReference() may not be supported with other non-AVR MCU's.

Arduino UNO - LM35 example

LM35	Arduino UNO
GND	GND
Vs	5V (or 3.3V)
Vout	A0 (ANALOG pin)

Notes:

• Keep wires short to prevent noise.

LM35 pins

LM35 specifications

• Supply voltage: 3.3V .. 30V
• Low power: Around 65uA
• Analog voltage interface

Examples

Arduino IDE | Examples | Erriez LM35 analog temperature:

• ErriezLM35

Documentation

• Doxygen online HTML
• Doxygen PDF
• LM35 datasheet

Usage

Initialization

#include <ErriezLM35.h>
  
// Connect LM35 data pin to Arduino DIGITAL pin
#define LM35_PIN   A0
  
LM35 lm35 = LM35(LM35_PIN);

Read temperature and humidity

void loop()
{
  // Read unsigned temperature from sensor
  uint16_t lm35_temp = lm35.readTemperature();
  
  // Print temperature
  Serial.print(F("LM35: "));
  Serial.print(lm35_temp / 10);
  Serial.print(F("."));
  Serial.print(lm35_temp % 10);
  Serial.println(F(" *C"));
  
  // Wait some time
  delay(2000);
}

Serial output

Analog LM35 temperature sensor example
  
LM35: 18.1 *C
LM35: 18.2 *C
LM35: 18.2 *C
  
...

Library dependencies

• None

Library installation

Please refer to the Wiki page.

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