Hi Clifford,
To start off, check out my site at
http://paago.org/aquaponics. The greenhouse is all driven with a Raspberry Pi.
The Raspberry Pi is configured with some temperature and humidity sensors and a webcam. To track all of the stats, I am using an IoT service called Xively. My next step will be to add some relays to control the greenhouse fan and perhaps a grow light.
I looked at using an Arduino board at first. Unfortunately, you pretty much have to write an Operating system to deal with all of the potential multitasking issues. The RPI has a very thick and rich software stack available and is pretty easy to set up.
Here are some articles on how I configured everything.
http://paago.org/xively/83/measuring-te ... spberry-pihttp://paago.org/xively/81/measuring-relative-soundI hope this is helpful.