Added Heat Index & Dew Point calculations
Added Barometric Pressure Sensor
I wanted to set up a home web server that could monitor indoor and outdoor temperature, humidity levels, and even monitor for indoor freezing or flooding conditions (and other security, appliance or environmental alerts). The approach I took consists of a Arduino and a Ethernet shield, running a tiny web server sketch, and for this example, I'm using the popular DHT-11 Temperature / Humidity module. You can interface this to smoke / heat sensors, CO and other gas sensors, and a whole lot more.
For this example you will need:
Ethernet Shield (this could be done with wifi as well with some code changes)
DHT-11 Temp/Humidity Module
10k Ohm Resistor
Optional: BMP-085 Barometric Pressure Sensor
A internet router and home internet access
Step 1: The DHT-11 Temperature / Humidity Sensor
The ethernet shield uses pins A0, A1, D4, and D10-D13
The DHT-11 is using D2, but can be changed.
The BMP180 uses A4 & A5.