I recently helped a client move their office which included setting up a new computer room.
I wanted them to be able to check the temperature and humidity of the room both by checking an LCD display in the room and also via a web page. I put together an Arduino with a DHT11 sensor, 16x2 LCD display and ENC28J60 Ethernet module. I did the project in stages first getting the DHT11 portion working using the DHT11 library and examples from Adafruit
, then adding an LCD display and finally adding Ethernet using the EtherCard library and modifying their example code . This makes troubleshooting a lot easier and I could build/learn the code as I went along. I have taken code from the various examples provided with the necessary libraries.
This instructable will go through the steps to prototype this.
Note: the DHT11 sensor isn't very accurate - about plus and minus 2 degrees Celsius and 5% accuracy for humidity. I'll probably be changing to a DHT22 which is plus and minus .5 degrees Celsius and between 2% and 5% for humidity. The good news is it's an easy change in the code.