Interfacing LM75 Temperature Sensor Module with Arduino

Contents hide

1 Introduction

2 LM75 Temperature Sensor Module

3 Hardware Required

4 Circuit Diagram

5 Arduino Code

6 Working Explanation

7 Code Explanation

Introduction

Temperature sensors are electronic devices that convert temperature into electrical signals and are used to detect temperature. This might be air temperature, liquid temperature, or solid matter temperature. There are several types of temperature sensors available, and each uses a distinct technology and concept to monitor the temperature. In this tutorial will be “Interfacing LM75 Temperature Sensor Module with Arduino”.

LM75 Temperature Sensor Module

The LM75 sensor is a popular temperature sensor and is used in many tiny electronics projects. Hardware overview, The pin configurations, and features, connecting with Arduino are described below:

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Hardware Overview

The NXP LM75 Temperature IC is used in this LM75 Temperature Sensor module, which comprises a delta-sigma analog-to-digital converter as well as a digital over-temperature detector. The LM75 module has five pins, i.e. VCC, GND, OS, SCL, and SDA. The SCL and SDA pins are linked with 4.7K ohms pull-up resistors.

Pin Configuration

Pin Name	Description
VCC	The Vcc pin powers the module, typically with +5V
GND	Power Supply Ground
OS	Over-temperature Shutdown Pin
SCL	Serial Clock Input. Open drain. Connected through a pullup resistor
SDA	Serial-Data Input/Output Line. Open drain. Connect through a pullup resistor

LM75 Temperature Sensor Features

Operating Voltage: 3.3V to 5V DC
Range: -25°C~125°C
Supply Current: 250uA
Maximum Supply Current: 1mA
OS Sink Current: 10mA
Delta-sigma Resolution: 8-bits
TOS temperature: 80°C
THYST temperature: 75°C
Low Operating Supply Current: 250µA
I²C Bus Interface
Easy to use with Microcontrollers or even with normal Digital/Analog IC
Small, cheap, and easily available

Hardware Required

S.no	Component	Value	Qty
1.	Arduino	UNO	1
2.	USB Cable Type A to B	–	1
3.	Temperature Sensor Module	LM75	1
4.	Jumper Wires	–	–

Circuit Diagram

LM75 Temperature Sensor module interfacing with Arduino

Connection Table

Arduino UNO	LM75 Temperature Sensor Module
GND	GND
3.3v	Vcc
A4	SDA
D5	SCL

Arduino Code

#include <inttypes.h>
#include <Wire.h>
#include <lm75.h>
 
TempI2C_LM75 Temperature = TempI2C_LM75(0x48,TempI2C_LM75::nine_bits);
 
void setup()
{
Serial.begin(9600);
Serial.println("Start");
Serial.print("Actual temp ");
Serial.print(Temperature.getTemp());
Serial.println(" oC");
delay(2000);
}
 
void loop()
{
Serial.print(Temperature.getTemp());
Serial.println(" oC");
delay(2000);
}

Working Explanation

Interfacing LM75 Temperature Sensor Module with Arduino, connect the circuit according to the connection table and diagram provided. Copy and paste the provided code into the Arduino IDE, then upload it to the Arduino board. After compilation and uploading, the temperature value will be shown on the Arduino serial monitor.

Code Explanation

First, we include the necessary libraries, such as Wire.h for I2C protocol support and LM75.h for temperature sensor support. Additionally, to obtain the temperature reading from the LM75 sensor module, establish a TempI2C LM75 object named Temperature.
The Serial monitor is set up in the void setup with a 9600bps baud rate. Furthermore, it will show the welcome messages on the Arduino serial monitor screen.
We obtain a temperature sample from the LM75 inside the void loop and print it on the Arduino serial display every two seconds.