There are already temperature and humidity sensors commercially available in the market for both industrial and home solutions.
You will find numerous climatic sensor solutions on the internet. For example, ONSET is one such company providing Temperature and Relative Humidity Data Loggers & Sensors. To know about it, visit http://www.onsetcomp.com/products/data-loggers-sensors/temperature-relative-humidity-rh.
One of the advantages about choosing a complete sensor solution rather than individual and standalone sensors is that sensor-based solutions are well packaged and come with extensive documentation and support. For example, the following is a TEMPERATURE-HUMIDITY SENSOR + EXTRAS known as DHT22:
Figure 2: DHT22 Temperature and humidity sensor; source: www.adafruit.com
This is a low cost and basic temperature and humidity sensor, which...