|Humidity sensor||Polymer humidity capacitor|
|Supply voltage||3.3 to 5.5V DC|
|Operating range||humidity 0 to-100 % RH , temperature - 40 to 80 deg Celsius|
|Output signal||digital signal via 1- wire bus|
|Resolution or sensitivity||humidity 0.1% RH ; temperature 0.1 Celsius|
|Repeatability||humidity +/- 1% RH; temperature +/- 0.2 Celsius|
|Sensing period||Average: 2 s|
|Accuracy||humidity +/- 2 % RH (Max +/- 5 % RH) ,|
|Sensor Length (millimetre)||small size 14 x 18 x 5.5 mm; big size 22 x 28 x 5 mm|
The DHT22 is a basic, low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and spits out a digital signal on the data pin (no analog input pins needed).
Simply connect the first pin on the left to 3-5V power, the second pin to your data input pin and the right most pin to ground. Although it uses a single-wire to send data it is not Dallas One Wire compatible! If you want multiple sensors, each one must have its own data pin.
Compared to the DHT11, this sensor is more precise, more accurate and works in a bigger range of temperature/humidity, but its larger and more expensive.
Comes with a 4.7K - 10K resistor, which you will want to use as a pullup from the data pin to VCC.