DHT22 Temperature/Humidity Sensor
This little device is a great measurement instrument, it requires 5v to operate and provides temperature and humidity as digital signal output. Each one must have unit must have its own data line.
Arduino Library:
Extract the file after downloading the zip and drop into your Arduino sketch folder. Window users check my document>Arduino>library then open Arduino ide.
https://github.com/adafruit/DHT-sensor-library
Pinout:
First pin on the left is 5v VCC, second pin is data pin connect to 2 if using above library, third pin is NC and last pin on the right is GND.
WARNING
