DHT22 main chip is AM2302 high sensitivity temperature humidity sensor. Single bus digital signal output, bidirectional serial data.4 Pins Sequence Number: Pin1-VDD(Power 3.3V-5.5V); Pin2-SDA, serial data interface, two-way interface; Pin3-NC, no connection; Pin4-GND(Ground).DHT22 is a reliable sensor for determining temperature and humidity. The output is serialized as a digital bit sequence. The sensor is ideal for monitoring the room climate or for building a weather station.Each AM2302 sensor is calibrated in a very accurate humidity calibration room. The calibration coefficients are stored in the OTP memory in the form of programs where the calibration coefficients are called within the sensor during signal processing.Single-wire serial interface, system integration becomes simple and fast. Ultra-small size, low power, signal transmission distance up to 20 meters, which makes it the best choice for all kinds of applications and even the most demanding applications. The products are 4-pin single row pin package, easy to connect.