Weather Station using DHT11 and I2C LCD Display with Arduino, it’s EASY

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In this step-by-step tutorial, we’ll guide you through creating a Weather Station using DHT11 and I2C LCD Display with arduino. This simple yet effective project is perfect for anyone interested in real-time environmental monitoring. With the DHT11 and I2C LCD Display, you’ll be able to measure and showcase temperature and humidity levels in real-time, ideal for use at home, greenhouses, or any indoor space that benefits from consistent climate monitoring.

The DHT11 sensor is a reliable and affordable component for measuring temperature and humidity, producing easy-to-read digital data compatible with microcontrollers like Arduino. To present this data in a structured way, we’ll use a 20×4 I2C LCD display. The I2C interface minimizes the wiring, as it only requires two pins to connect the LCD to the Arduino.

This project is an excellent introduction to using the DHT11 and I2C LCD Display with Arduino. You’ll learn essential skills, from capturing sensor data to displaying it, which will set the foundation for more complex Arduino projects. By the end of this tutorial, you’ll have built a functional weather station that displays live temperature and humidity data, providing valuable insights into your environment.

COMPONENTS REQUIRED

DHT11
The DHT11 is a basic, ultra-low-cost digital temperature and humidity sensor. It can measure temperature and humidity in the surrounding air.

20×4 LCD Display (with I2C module)
This display module will show the temperature and humidity readings. The I2C version requires only two pins for communication, making it a convenient option.

Arduino or ESP32
Either microcontroller can be used for this project. We will provide code that works with both.

Jumper Wires
To connect the components.

required libraries

Before starting, make sure to install the following libraries in your Arduino IDE:

  1. DHT Sensor Library by Adafruit
    This library allows you to interface with the DHT11 or DHT22 sensor.
  2. LiquidCrystal I2C Library by Frank de Brabander
    This library is necessary for controlling the 20×4 I2C LCD display.

You can easily install these libraries from the Arduino IDE’s Library Manager. Go to sketch-> Include Library-> Library Manager and search the names of library to install.

WIRING DIAGRAM

DHT11 and I2C LCD Display Wiring Diagram with arduino

Here’s how to wire everything together:

DHT11 Sensor:

  • VCC connects to 3.3V or 5V (depending on your board and sensor).
  • GND connects to GND.
  • Data Pin connects to a digital pin (for example, D2).

20×4 LCD (I2C):

  • SDA connects to GPIO 21 on ESP32 / A4 on Arduino.
  • SCL connects to GPIO 22 on ESP32 / A5 on Arduino.
  • VCC connects to 5V.
  • GND connects to GND.

Finding LCD Display I2C Address

Note: Use your own wiring diagram here. I2C address is typically 0x27, but make sure to check your specific LCD module’s I2C address with this I2C scanner sketch

#include <Wire.h>
 
 
void setup()
{
  Wire.begin();
 
  Serial.begin(9600);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}
 
 
void loop()
{
  byte error, address;
  int nDevices;
 
  Serial.println("Scanning...");
 
  nDevices = 0;
  for(address = 1; address < 127; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
 
    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");
 
      nDevices++;
    }
    else if (error==4)
    {
      Serial.print("Unknown error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");
 
  delay(5000);           // wait 5 seconds for next scan
}

LCD Display I2C Address

We got the address of 0x3F for our LCD with the above given sketch. In the main code, On line#13 you can update the I2C address if your LCD got different address.

LiquidCrystal_I2C lcd(0x3F, 20, 4);

If you want to get detailed tutorial you can follow: Arduino | How to Scan and Detect I2C Addresses | Adafruit Learning System

code for DHT11 and I2C LCD Display

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include "DHT.h"

// Define DHT pin and type (DHT11 or DHT22)
#define DHTPIN 2      // Pin where the DHT sensor is connected
#define DHTTYPE DHT11 // Change to DHT11 if using DHT11

// Initialize DHT sensor
DHT dht(DHTPIN, DHTTYPE);

// Initialize the LCD with I2C address 0x3F
LiquidCrystal_I2C lcd(0x3F, 20, 4);  // 20x4 LCD

void setup() {
  // Start Serial Monitor
  Serial.begin(115200);
  
  // Initialize DHT sensor
  dht.begin();
  
  // Initialize the LCD
  lcd.init();
  lcd.backlight();

  // Display initial message
  lcd.setCursor(0, 0); 
  lcd.print("Weather Station by");
  
  lcd.setCursor(0, 1); 
  lcd.print("   ArduinoYard");
  
  lcd.setCursor(0, 2);
  lcd.print("Temperature: ");
  
  lcd.setCursor(0, 3);
  lcd.print("Humidity: ");
}

void loop() {
  // Wait a few seconds between measurements
  delay(2000);

  // Read temperature and humidity values
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();

  // Check if any reads failed and exit early
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor!");
    lcd.setCursor(0, 3);
    lcd.print("Sensor error      ");
    return;
  }

  // Print temperature to the LCD
  lcd.setCursor(12, 2);  // Column 6, Row 1
  lcd.print(temperature);
  lcd.print((char)223);  // Print the degree symbol
  lcd.print("C  ");

  // Print humidity to the LCD
  lcd.setCursor(10, 3);  // Column 10, Row 2
  lcd.print(humidity);
  lcd.print("%  ");
}

DEMONSTRATION

Below is an image demonstrating the DHT11 and I2C LCD Display in action. The display shows real-time temperature and humidity readings captured by the DHT11 sensor and presented clearly on the 20×4 I2C LCD screen.

DHT11 and I2C LCD Display Working Demonstration

CONCLUSION

This project showcases how to effectively use the DHT11 and I2C LCD Display to create a compact and reliable temperature and humidity monitoring system. By combining the DHT11 sensor (or DHT22 for more accuracy) with a 20×4 I2C LCD, you can easily display real-time environmental data, making it perfect for applications like home automation, greenhouses, or personal weather stations.

The DHT11 and I2C LCD Display setup provides a simple yet powerful foundation that can be expanded further. You might consider adding data logging, setting alarms for specific temperature or humidity thresholds, or even implementing wireless data transmission to a web dashboard.

If you have questions or need additional help, feel free to ask in the comments!

Thank You!!!

You can find more Arduino projects on this website:

Useful Automatic Room Light Control Using Arduino And PIR Sensor HC-SR501 – ArduinoYard

Autonomous Edge-Detection Robot With Arduino – ArduinoYard

Arduino MP3 Player With Voice Control Using HC-05 Bluetooth Module And DFplayer Mini – ArduinoYard

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