Arduino - Display Temperature from LM35 Sensor on LCD

In this tutorial, we are going to learn how to read the temperature from LM35 sensor and display it on an LCD 16x2 I2C.

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B
1	×	LCD I2C
1	×	LM35 Temperature Sensor
1	×	Jumper Wires
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Optional) Screw Terminal Block Shield for Arduino

One of the following breadboard:

1	×	Full-sized 830-Point Breadboard
1	×	Half-sized 400-point Breadboard
1	×	Mini-sized 170-point Breadboard
1	×	All-sized Breadboard Kit

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About LM35 Temperature Sensor and LCD I2C

If you do not know about LM35 Temperature Sensor and LCD I2C (pinout, how it works, how to program ...), learn about them in the following tutorials:

Arduino - LCD I2C tutorial
Arduino - LM35 Temperature Sensor tutorial

Wiring Diagram

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Arduino Code - LM35 Temperature Sensor - LCD I2C

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-display-temperature-from-lm35-sensor-on-lcd */ #include <LiquidCrystal_I2C.h> // LCD I2C library #define ADC_VREF_mV 5000.0 // in millivolt #define ADC_RESOLUTION 1024.0 #define PIN_LM35 A0 // pin connected to LM35 temperature sensor LiquidCrystal_I2C lcd(0x3F, 16, 2); // LCD I2C address 0x27, 16 column and 2 rows void setup() { Serial.begin(9600); lcd.init(); // initialize the lcd lcd.backlight(); // open the backlight } void loop() { int adcVal = analogRead(PIN_LM35); // convert the ADC value to voltage in millivolt float milliVolt = adcVal * (ADC_VREF_mV / ADC_RESOLUTION); // convert the voltage to the temperature in Celsius float tempC = milliVolt / 10; float tempF = tempC * 9 / 5 + 32; // convert Celsius to Fahrenheit lcd.clear(); lcd.setCursor(0, 0); // start to print at the first row lcd.print(tempC); // print the temperature in Celsius lcd.print("°C"); lcd.setCursor(0, 1); // start to print at the second row lcd.print(tempF); // print the temperature in Fahrenheit lcd.print("°F"); // print the temperature to Serial Monitor Serial.print(tempC); Serial.print("°C ~ "); Serial.print(tempF); Serial.println("°F"); delay(500); }

Quick Steps

Open Arduino IDE, Go to Tools Manage Libraries

Search “LiquidCrystal I2C”, then find the LiquidCrystal_I2C library by Frank de Brabander
Click Install button to install LiquidCrystal_I2C library.

Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to Arduino
Put the sensor on hot and cold water, or grasp the sensor by your hand
See the result on LCD and Serial Monitor

※ NOTE THAT:

The I2C address of LCD can vary according to the manufacturers. In the code, we used 0x27 that is specified by DIYables manufacturer

Video Tutorial

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