DHT22 (AM2302) High-Precision Digital Temperature & Humidity Sensor Module

Product Description The DHT22 (also known as AM2302) is a professional-grade, high-precision digital environmental sensor designed for accurate measurement of ambient temperature and relative humidity. Compared to its predecessor (DHT11), this "Pro" version offers a much wider measurement range, higher accuracy, and better resolution, making it suitable for scientific data logging and industrial climate control. The sensor features a high-performance 8-bit microcontroller internally that handles the analog-to-digital conversion and outputs a calibrated digital signal. Its reliable single-bus serial interface ensures easy integration with Arduino, ESP32, and Raspberry Pi, providing stable environmental data for smart home systems and weather stations.

Key Features

• Ultra-High Accuracy: Delivers precise humidity readings within ±2% and temperature within ±0.5°C for critical monitoring.

• Full-Range Humidity Detection: Capable of measuring relative humidity from 0% to 100%, ideal for greenhouse and bathroom automation.

• Calibrated Digital Output: Every sensor is factory calibrated in a precision humidity chamber, with calibration coefficients stored in internal OTP memory.

• Long-Distance Transmission: Optimized for signal integrity over cable lengths up to 20 meters, allowing for remote sensor placement.

• Excellent Long-Term Stability: Features a high-quality capacitive humidity sensing element and a high-precision thermistor for consistent performance over years.

Technical Details

• Sensor Element: Utilizes a polymer capacitive humidity sensing element and a NTC high-precision temperature measurement component.

• Digital Communication: Employs a single-wire bi-directional serial interface (Single Bus), reducing the number of I/O pins required.

• Internal Processing: An integrated 8-bit MCU handles complex signal processing and data transmission protocols.

• Operating Current: Draws minimal power of approximately 1.5mA during active data acquisition and 40µA to 50µA in standby.

• Data Resolution: Provides 16-bit resolution for both temperature and humidity, outputting data in 0.1 increments.

• Measurement Cycle: Requires a minimum sampling interval of 2 seconds between consecutive readings for maximum accuracy.

• Interchangeability: High consistency between units allows for direct replacement without the need for additional software calibration.

• Power Supply Independence: Functions perfectly between 3.3V and 5.5V, making it compatible with both low-power and standard logic boards.

• Signal Pull-up Requirement: The data line requires a pull-up resistor (typically 4.7k to 10k) for proper logic transition during communication.

• Anti-Interference Design: Built-in signal processing helps filter out noise from high-frequency electromagnetic sources.

• Compact Housing: Features a white plastic ventilated enclosure that protects the internal elements while allowing optimal airflow.

• PCB Build: Comes as a pre-mounted module with a built-in pull-up resistor and filter capacitor for immediate use.

• Environmental Tolerance: Designed to operate reliably in non-condensing environments across the full industrial temperature spectrum.

• Response Time: Features a fast response time to changes in environmental conditions, typically reaching stability in 6 to 20 seconds.

• Logic Compatibility: Standard TTL digital output is compatible with 3.3V and 5V logic families without level shifters.