DHT22 is a popular temperature and humidity based digital sensor. This is the upgraded version of the DHT11 temperature and humidity sensor. The sensor uses a capacitive humidity sensor and a thermistor based temperature sensor to measure the ambient humidity and temperature. The humidity sensing ranges from 0% to 100% with ±1% accuracy and the temperature sensing ranges from -40 degrees to the 80 degrees Celcius with ±0.5°C accuracy. The sampling time of this sensor is 2 seconds almost.
This Temperature and Humidity Sensor uses digital pins to communicate with the microcontroller unit and does not have any kind of analog pins. The module also has the inbuilt pull-up resistor and additional filter capacitor to support the DHT22 sensor. Thus the module is available in ready to go mode and can be directly connected with the microcontroller unit without using any kind of additional components.
The above image is showing the pinout of the DHT22 sensor. Connect 3-5V in the VCC (+) pin and ground on the GND(-) pin. Connect the middle pin which is a digital output of the sensor module with a microcontroller digital I/O pin. Use the referenced library that is given below of this page for interfacing the sensor with the microcontroller unit.
DHT22 Sensor Specifications
-
Operating Voltage: 3.5V to 5.5V
-
Digital I/O
-
5 Hz sampling rate (Once every 2 Seconds)
-
Measuring current: 0.3mA
-
Low power consumption
-
Temperature range: -40 to 80 degree C
-
Humidity range: 0% to 100%
-
Accuracy: ±0.5°C and ±1%
-
Dimension: 5x 4 x 2 cm
Additional Resources:
DHT22 Sensor Datasheet
Arduino Library-DHT22-Adafruit
Automatic Fan control using DHT22
Sending Temperature and Humidity sensor data to Firebase Real-Time Database using NodeMCU ESP8266
Log Temperature Sensor Data to Google Sheet using NodeMCU ESP8266
