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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 | × | Breadboard | |
| 4 | × | Jumper Wires |
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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
Video Tutorial
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