The DHT22 sensor is used to measure the temperature and humidity. It is also known as the AM2302. This sensor is cheap and also has better accuracy.
• Temperature range is from -40 to 125 degree Centigrade with accuracy of ±0.5 ͦ C.
• Humidity range is from 0 to 100% with accuracy of ± 2-5%.
• Sampling rate is 0.5 Hz.
• Operating Voltage is 3-5V.
• Maximum Current while measuring is 2.5mA.
• The first pin is the VCC pin which requires 3-5V to operate.
• The second pin is the data pin which will be connected to the digital pin of the Arduino.
• The third pin is not used.
• The last pin is the ground pin.