Arduino DHT11 Temperature and Humidity Monitor with LCD

Arduino DHT11 Temperature and Humidity Monitor with LCD

This project demonstrates a simple yet effective temperature and humidity monitoring system using an Arduino, a DHT11 sensor, and a Liquid Crystal Display (LCD). It allows real-time monitoring of environmental conditions—ideal for learning sensor integration and basic display outputs.

🔧 Key Features

  • Real-time temperature and humidity readings with DHT11
  • Visual output on a 16x2 LCD display
  • Temperature threshold alert system (30°C)
  • Data also sent to Serial Monitor

📋 Components Required

  • Arduino Uno or Mega
  • DHT11 Sensor
  • 16x2 LCD (with I2C or pins)
  • Breadboard and Jumper Wires

🔌 How It Works

  1. The DHT11 continuously measures temperature and humidity.
  2. Arduino reads these values and shows them on the LCD screen.
  3. If the temperature ≥ 30°C, an alert can be triggered.
  4. The same data is logged to the Serial Monitor for debugging or extension.

📷 Schematic

Arduino DHT11 Schematic

💻 Code


#include <Wire.h>
#include <LiquidCrystal.h>
#include <DHT.h>

#define DHTTYPE DHT11
#define DHTPIN A0

DHT dht11(DHTPIN, DHTTYPE);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2, 10, 9, 8, 7);
const int THRESHOLD = 30;

void setup() {
  Wire.begin();
  lcd.begin(16, 2);
  lcd.print("DHT11 Sensor");
  dht11.begin();
}

void loop() {
  float t = dht11.readTemperature();
  float h = dht11.readHumidity();

  if (t >= THRESHOLD) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Temp:"); lcd.print(t);
    lcd.setCursor(0, 1);
    lcd.print("Humidity:"); lcd.print(h);
  }

  delay(2000);
}

🛠 Optional Components

If you need components for this project, here are some helpful links: