- Stock: In Stock
- Model: T181.DHT22
DHT22 AM2302: A High-Precision Digital Temperature and Humidity Sensor Module
The DHT22, alternatively known as the AM2302, is a highly precise digital sensor for temperature and humidity measurements. This sensor is an enhanced version of the DHT11, offering superior accuracy and a broader measurement spectrum.
General Information:
The DHT22 is engineered to digitally record and output both temperature and humidity data. It employs a capacitive humidity sensor and a thermistor to measure the surrounding air, providing a digital signal on the data pin.
Key Features:
- Temperature Range: -40 to +80°C with an accuracy of ±0.5°C.
- Humidity Range: 0 to 100% RH with an accuracy of ±2-5% RH.
- Resolution: 0.1 for both temperature and humidity.
- Power Supply: 3.3V to 6V.
- Low Power Consumption: Ideal for battery-powered applications.
- Digital Output: Single-wire communication protocol.
- Response Time: Typically less than 2 seconds.
- Long-Term Stability: Good long-term stability.
Pin Configuration:
The DHT22 sensor generally has four pins, but frequently only three are utilized:
- VCC: Power supply (3.3V to 6V).
- GND: Ground.
- DATA: Data pin for digital signal output.
- NC: Not connected (optional).
Applications:
- Weather Stations: For measuring ambient temperature and humidity.
- HVAC Systems: For monitoring and controlling heating, ventilation, and air conditioning systems.
- Home Automation: For environmental monitoring.
- Agriculture: To monitor greenhouse conditions.
- Industrial Applications: For monitoring environmental conditions in factories and warehouses.
Wiring:
To interface the DHT22 with an Arduino:
- Connect the VCC pin of the DHT22 to the 5V pin of the Arduino.
- Connect the GND pin of the DHT22 to the GND pin of the Arduino.
- Connect the DATA pin of the DHT22 to a digital pin (e.g., pin 2) on the Arduino.
- A pull-up resistor (4.7kΩ to 10kΩ) is required between the VCC and DATA pins.
Example Code:
To utilize the DHT22 with an Arduino, the DHT library by Adafruit can be installed via the Library Manager in the Arduino IDE.
#include "DHT.h"// Define the type of sensor and the pin it's connected to
#define DHTTYPE DHT22 // DHT 22 (AM2302)
#define DHTPIN 2 // Digital pin 2DHT dht(DHTPIN, DHTTYPE);void setup() {
Serial.begin(9600);
Serial.println("DHT22 (AM2302) test!"); dht.begin();
}void loop() {
// Wait a few seconds between measurements
delay(2000); // Reading temperature and humidity values
float humidity = dht.readHumidity();
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;
} // Print the results
Serial.print("Humidity: ");
Serial.print(humidity);
Serial.print(" % ");
Serial.print("Temperature: ");
Serial.print(temperature);
Serial.println(" *C");
}
Calibration and Usage Tips:
- Ensure the sensor is placed in an area with good airflow for accurate readings.
- Avoid placing the sensor in direct sunlight or near heat sources to prevent false readings.
- Periodically check and recalibrate the sensor if used in critical applications.
The DHT22 (AM2302) is a reliable and accurate sensor suitable for various applications requiring precise temperature and humidity measurements. It is favored for its accuracy, stability, and ease of integration into projects.
