Temperature and Humidity Sensor (DHT11/DHT22)

Overview

DHT11 and DHT22 are popular digital temperature and humidity sensors that measure ambient temperature and humidity levels. These sensors are ideal for weather stations, climate control systems, and environmental monitoring projects. They provide calibrated digital output and are easy to interface with microcontrollers like Arduino and ESP32.

Technical Specifications

DHT11 vs DHT22 Comparison

Feature DHT11 DHT22

Temperature Range 0-50°C -40-80°C

Temperature Accuracy ±2°C ±0.5°C

Humidity Range 20-90% 0-100%

Humidity Accuracy ±5% ±2-5%

Operating Voltage 3-5.5V 3.3-6V

Sampling Rate 1Hz (1s) 0.5Hz (2s)

Key Features

Digital output with calibrated values
Single-wire communication protocol
Low power consumption
Long-term stability
No external components required
Easy Arduino library support
Cost-effective solution
Compact size for easy integration

Wiring Diagram

Basic Connection (Arduino Uno)

DHT Pin → Arduino Pin

VCC → 5V (or 3.3V)

GND → GND

DATA → Digital Pin 2

Note: Add a 10kΩ pull-up resistor between DATA and VCC pins for reliable communication.

Common Applications

Weather Stations

Local weather monitoring and data logging

Climate Control

HVAC systems and smart thermostats

Greenhouse Monitoring

Plant growth environment optimization

Indoor Air Quality

Home and office environmental monitoring

Quick Info

Difficulty: Beginner

Price Range: ₹50-350

Interface: Digital (Single-wire)

Compatible Boards

Sample Code

#include "DHT.h"

#define DHTPIN 2
#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  dht.begin();
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print("%  Temperature: ");
  Serial.print(t);
  Serial.println("°C");
  
  delay(2000);
}