DHT22/AM2302B Digital Temperature & Humidity Sensor

Description

The DHT22 (also designated as AM2302B) is a low-cost, factory-calibrated digital temperature and humidity sensor designed for reliable environmental monitoring in hobbyist, educational, and light industrial applications. It combines a capacitive humidity sensing element and an NTC thermistor with an integrated 8-bit microcontroller that performs analog-to-digital conversion and outputs a calibrated digital signal over a single-wire interface . The sensor is fully interchangeable, requires no external calibration, and communicates using a proprietary single-bus protocol that minimizes wiring complexity. Compared to the earlier DHT11, the DHT22 offers a wider measurement range, higher resolution, and improved accuracy, making it suitable for weather stations, HVAC monitoring, greenhouse control, and indoor environmental data logging .

Features

• Factory Calibrated: Each sensor is individually calibrated in a precision chamber, with calibration coefficients stored in OTP memory; no user calibration is required .

• Digital Single-Wire Output: Temperature and humidity values are transmitted as a 40-bit serial data packet over one data line, reducing wiring and pin requirements .

• Wide Measurement Range: Operates across -40°C to 80°C and 0% to 100% relative humidity, suitable for diverse environments .

• Low Power Consumption: Typical measuring current of 0.3 mA and standby current of 60 µA support battery-powered and low-energy designs .

• Long Transmission Distance: Reliable signal transmission up to 20 meters with appropriate pull-up resistor and cable .

• Simple Microcontroller Interface: Compatible with Arduino, Raspberry Pi, ESP32, STM32, and other MCUs via readily available libraries and straightforward timing protocols .

Technical Specifications