Humidity and Temperature Sensor

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. 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. 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.
Features
    Low cost
    3 to 5V power and I/O
    Good for -40 to 125°C temperature readings ±0.5°C accuracy
    Good for 0-100% humidity readings with 2-5% accuracy