DHT22 AM2302 Temperature sensor and humidity sensor

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Introduction

The DHT22 (also known as the AM2302) is a highly accurate digital temperature and humidity sensor. It is widely used in applications requiring precise environmental measurements, such as weather stations, HVAC systems, and smart home devices. The sensor uses a capacitive humidity sensor and a thermistor to measure the surrounding air, providing calibrated digital output.

Features

High Accuracy: Accurate temperature and humidity readings.
Wide Measurement Range: Supports a broad range of temperature and humidity measurements.
Stable and Reliable: Provides stable performance and long-term reliability.
Digital Output: Easy to interface with microcontrollers and other digital systems.
Low Power Consumption: Efficient design suitable for battery-powered applications.

Specifications

Operating Voltage: 3.3V to 6V
Temperature Range: -40°C to 80°C
Humidity Range: 0% to 100% RH
Temperature Accuracy: ±0.5°C
Humidity Accuracy: ±2% RH
Output: Digital signal via a single-bus interface
Sampling Rate: 0.5 Hz (one reading every 2 seconds)

Pinout

VCC: Power supply pin (3.3V to 6V)
GND: Ground pin
DATA: Serial data pin for digital output
NC: Not connected (some versions may have this pin)

Dimensions

Size: 15.1mm x 25mm x 7.7mm
Weight: 2.4g

How to Use

Power the Sensor: Connect the VCC pin to a power supply (3.3V to 6V) and the GND pin to ground.
Connect the Data Pin: Connect the DATA pin to a digital input pin of your microcontroller to read temperature and humidity data.
Use Pull-up Resistor: Place a 4.7kΩ pull-up resistor between the DATA and VCC pins to ensure proper communication.
Library and Code Example: Use an appropriate library to read data from the sensor. The following example demonstrates how to use the DHT22 sensor with an Arduino.

// Example code for Arduino

#include "DHT.h"

#define DHTPIN 2     // Digital pin connected to the DHT sensor
#define DHTTYPE DHT22   // DHT22 (AM2302) sensor type

DHT dht(DHTPIN, DHTTYPE);

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

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

  // Read temperature as Celsius
  float t = dht.readTemperature();
  // Read humidity
  float h = dht.readHumidity();

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

  // Print the results
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.println(" *C");
}

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Last updated 3 months ago

// Example code for Arduino #include "DHT.h" #define DHTPIN 2 // Digital pin connected to the DHT sensor #define DHTTYPE DHT22 // DHT22 (AM2302) sensor type DHT dht(DHTPIN, DHTTYPE); void setup() { Serial.begin(9600); dht.begin(); } void loop() { // Wait a few seconds between measurements delay(2000); // Read temperature as Celsius float t = dht.readTemperature(); // Read humidity float h = dht.readHumidity(); // Check if any reads failed and exit early (to try again). if (isnan(t) || isnan(h)) { Serial.println("Failed to read from DHT sensor!"); return; } // Print the results Serial.print("Humidity: "); Serial.print(h); Serial.print(" %\t"); Serial.print("Temperature: "); Serial.print(t); Serial.println(" *C"); }