DHT22 Humidity and Temperature Sensor Module (AM2302)
What It Is
The DHT22 (also called AM2302) is a digital temperature and humidity sensor that uses a capacitive humidity sensing element and a thermistor to measure the environment and output calibrated digital readings.
It's an upgrade over DHT11 offering wider range and better accuracy.
Key Features
Digital Output: Sends temperature and humidity data over a single digital data line no analog conversion needed. Wide Temperature Range: Measures from about 40C to +80C. Wide Humidity Range: From 0% to 99.9% relative humidity. High Accuracy: Temperature: about 0.1C (temp) and 0.1% RH (humidity) Power Supply: Typically 3.3V to 5.5V DC, suitable for Arduino, Raspberry Pi, ESP32, etc. Low Power Consumption: Good for battery'powered systems.
How It Works
The module reads temperature and humidity with internal sensors and outputs digital data in a simple protocol.
Only one pin (data) is used for communication with your controller but it's not Dallas One'Wire compatible, so each sensor needs its own data pin in multi'sensor setups.
Updates are available roughly once every 2 seconds (about 0.5Hz sampling rate).
Typical Applications
Weather Stations & Environmental Monitoringms Greenhouse & Agriculture Climate Monitoring IoT Devices and Smart Sensors Consumer Electronics & Appliances
Important Notes
Sampling Limitation: You can request new readings only about once every 2 seconds. Careful Timing: Code must handle timing correctly to read data. Environmental Limitations: Direct water or heavy condensation contact can affect humidity performance sensors are best used where moisture won't settle directly on them. Better Alternatives: For higher accuracy and fast