You have seen temperature and humidity display board from your childhood right??So let us build now.
Prerequisites - basic knowledge of C and Arduino programming and hardware interfacing(basic). I have used the DHT22 sensor for temperature and humidity display. It is highly accurate.For a cheaper sensor you can go for DHT11. The schematics and code are given at the Fritzing file.Before opening it,download the free software Fritzing first. It is very nice.I have attached a 16*2 display board for the temperature and humidity display.Now I have added a Bluetooth feature so that user can also connect to mobile and get the same data as shown on the display board.This project is nice for those hobbyist with a little knowledge of arduino and sensors.This will help in future projects taking this as a reference.