DHT22 / AM2302 Temperature and Humidity Sensor

Name: DHT22 / AM2302 Temperature and Humidity Sensor
Brand: ESP32
Price: 5 USD
Availability: InStock

DHT22 / AM2302 Temperature and Humidity Sensor image

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Overview

The DHT22 is a versatile and affordable sensor for measuring temperature and humidity. It provides calibrated digital output and is easy to interface with microcontrollers. With a temperature measurement range of -40°C to 80°C and humidity range of 0% to 100%, the DHT22 is suitable for a variety of applications, including environmental monitoring and HVAC systems.

Quick Navigation

📋 Specs 📍 Pinout 🔌 Wiring 🔧 Debug

Code Examples

Arduino

C++ Framework

ESP-IDF

Native Framework

ESPHome

YAML Configuration

PlatformIO

IDE & Toolchain

MicroPython

Python Framework

About DHT22 / AM2302 Temperature and Humidity Sensor

The DHT22, also known as AM2302, is a low-cost digital sensor designed for precise temperature and humidity measurement. It uses a capacitive humidity sensor and a thermistor for reliable data collection and communicates via a single-wire digital interface, ensuring easy integration with ESP32, Arduino, and other microcontrollers.

⚡ Key Features

Improved Accuracy & Range – More precise than DHT11, with a wider measurement range.
Single-Wire Communication – Simple interfacing with microcontrollers.
Capacitive Humidity Sensing – Ensures stable and long-term performance.
Ideal for Demanding Applications – Used in weather stations, HVAC systems, and industrial monitoring.

With its affordability and high accuracy, the DHT22 is a great choice for climate monitoring and smart home applications. 🚀

Where to Buy

Get Your DHT22 / AM2302

DHT22 / AM2302 Temperature and Humidity Sensor

Starting from

$5 per unit

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💡 Prices are subject to change. We earn from qualifying purchases as an Amazon Associate.

Technical Specs

DHT22 / AM2302 Specifications

Complete technical specification details for DHT22 / AM2302 Temperature and Humidity Sensor

📊 Technical Parameters

Operating Voltage 3.3V to 5.5V

Temperature Range -40°C to 80°C

Humidity Range 0% to 100% RH

Temperature Accuracy ±0.5°C

Humidity Accuracy ±2% RH

Sampling Rate 0.5 Hz (once every 2 seconds)

Dimensions 15.1mm x 25mm x 7.7mm

Download Full Datasheet

Pin Configuration

DHT22 / AM2302 Pinout

The DHT22/AM2302 uses the same 4-pin layout as the DHT11, with improved accuracy and wider measurement range.

Visual Pinout Diagram

Pinout Diagram Primary

DHT22 / AM2302 Temperature and Humidity Sensor pinout

Total Pins

Pin Types

Power

Communication

Control

Quick Tips

🔌

Uses proprietary single-wire digital protocol,⚠️ Requires 5kΩ to 10kΩ pull-up resistor on DATA pin

💡

Higher accuracy than DHT11 (±0.5°C vs ±2°C),⏱️ Can be read once every 2 seconds

❄️

Operates in wider temperature range (-40°C to 80°C)

Pin Descriptions

Pin Name	Type	Description	Notes
1 VCC	Power	Power supply input (3.3V to 6V)	Works with both 3.3V and 5V logic levels
2 DATA	Communication	Digital signal output	Single-wire digital interface for data transmission
3 NC	Control	Not connected	Leave this pin unconnected
4 GND	Power	Ground connection	Connect to ESP32 ground

Connection Guide

Wiring DHT22 / AM2302 to ESP32

Connect the DHT22/AM2302 using the single-wire digital interface with a pull-up resistor for stable readings.

Visual Wiring Diagram

Wiring Diagram Recommended

DHT22 / AM2302 Temperature and Humidity Sensor wiring with ESP32

Connections

Connection Status

Required

Protocol

OneWire

Pin Connections

DHT22 / AM2302 Pin	ESP32 Pin	Description
1 VCC Required	3.3V	Power supply (3.3V to 6V supported)
2 GND Required	GND	Ground connection
3 DATA Required	GPIO4	Digital data line
4 DATA (Pull-up) Required	5kΩ to VCC	Pull-up resistor for reliable communication

💡

Any GPIO pin works - GPIO4 is commonly used

🔧

5kΩ pull-up resistor recommended (10kΩ also works)

⚡

Use 3.3V for ESP32, sensor supports up to 6V

⏱️

Minimum 2 second interval between readings

🌡️

Better accuracy than DHT11 for demanding applications

Help & Support

DHT22 / AM2302 Troubleshooting

Common issues and solutions to help you get your sensor working

Common Issues

Debugging Tips

Additional Resources

Datasheet

Technical specifications and guidelines

Code Examples

DHT22 / AM2302 Programming Examples

Ready-to-use code examples for different platforms and frameworks

#include "DHT.h"

#define DHTPIN 4     // Digital pin connected to the DHT sensor
#define DHTTYPE DHT22   // DHT 22 (AM2302)

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  Serial.println("DHT22 Sensor Example");

  dht.begin();
}

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

  // Reading temperature or humidity takes about 250 milliseconds!
  float humidity = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float temperature = dht.readTemperature();

  // Check if any reads failed and exit early (to try again).
  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print(" %	");
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");
}

This Arduino sketch demonstrates how to interface with the DHT22 sensor. It initializes the sensor on digital pin 4 and reads the temperature and humidity every 2 seconds. The readings are then printed to the Serial Monitor. The code includes checks to ensure that the sensor readings are valid.

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "dht.h"

#define DHT_PIN GPIO_NUM_4

void app_main() {
    setDHTgpio(DHT_PIN);

    while (1) {
        printf("Reading DHT22 sensor...\n");

        int ret = readDHT();
        errorHandler(ret);

        printf("Humidity: %.1f%%\n", getHumidity());
        printf("Temperature: %.1f°C\n", getTemperature());

        vTaskDelay(2000 / portTICK_PERIOD_MS);
    }
}

This ESP-IDF example demonstrates how to read data from the DHT22 sensor using GPIO pin 4. The `readDHT()` function reads the sensor data, and the humidity and temperature values are retrieved using `getHumidity()` and `getTemperature()` functions, respectively. The readings are printed to the console every 2 seconds.

sensor:
  - platform: dht
    pin: GPIO4
    model: DHT22
    temperature:
      name: "Living Room Temperature"
    humidity:
      name: "Living Room Humidity"
    update_interval: 60s

The ESPHome configuration utilizes the `dht` platform to define the DHT22 sensor. The `pin` specifies the GPIO pin where the sensor's DATA pin is connected (e.g., GPIO4). The `model` is set to `DHT22` to ensure accurate data interpretation. Two sensor entities are defined: one for temperature and one for humidity, each assigned a user-friendly name like 'Living Room Temperature' and 'Living Room Humidity.' The `update_interval` is set to 60 seconds, meaning the sensor will update the readings every minute.

platformio.ini

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
lib_deps = 
    adafruit/DHT sensor library @ ^1.4.2
monitor_speed = 115200

main.cpp

#include <DHT.h>

#define DHTPIN 4
#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

void setup() {
    Serial.begin(115200);
    Serial.println("DHT22 Sensor Example");

    dht.begin();
}

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

    // Reading temperature or humidity takes about 250 milliseconds!
    float humidity = dht.readHumidity();
    // Read temperature as Celsius (the default)
    float temperature = dht.readTemperature();

    // Check if any reads failed and exit early (to try again).
    if (isnan(humidity) || isnan(temperature)) {
        Serial.println("Failed to read from DHT sensor!");
        return;
    }

    Serial.print("Humidity: ");
    Serial.print(humidity);
    Serial.print(" %	");
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");
}

This PlatformIO sketch demonstrates how to use the DHT22 sensor with an ESP32 board. It initializes the sensor on GPIO pin 4 and reads temperature and humidity data every 2 seconds. The results are printed to the Serial Monitor. The code includes checks to ensure the sensor data is valid, retrying if the readings are invalid.

from machine import Pin
from time import sleep
import dht

# Initialize the DHT22 sensor
sensor = dht.DHT22(Pin(4))

print('DHT22 Sensor Example')

while True:
    sensor.measure()
    temperature = sensor.temperature()  # Temperature in Celsius
    humidity = sensor.humidity()  # Relative Humidity in %

    print('Temperature: {} °C'.format(temperature))
    print('Humidity: {} %'.format(humidity))

    sleep(2)

This MicroPython code uses the `dht` module to interact with the DHT22 sensor. It initializes the sensor on GPIO pin 4, reads temperature and humidity every 2 seconds, and prints the results to the console. The `sensor.measure()` function is used to fetch the data from the sensor, and the `temperature()` and `humidity()` methods are used to extract the values.

Summary

Wrapping Up DHT22 / AM2302

The ESP32 DHT22 / AM2302 Temperature and Humidity Sensor is a powerful environment sensor that offers excellent performance and reliability. With support for multiple development platforms including Arduino, ESP-IDF, ESPHome, PlatformIO, and MicroPython, it's a versatile choice for your IoT projects.