This is my first time doing any arduino build, and I'm planning to build a digital hydrometer/thermometer for home brewing. I'd like to either run a simple webserver on the arduino or transmit the information to a small server that I'll be setting up. In order for it to fit into my fermentation vessels, the device needs to be less than 2 inches in diameter, although length is not too constraining. This limits me to the Arduino Nano or Fio and smaller modules. I'm thinking of going with the Fio, since the 3.3v output on the Nano isn't powered when running from external power. For Wifi on the Fio, I'm looking at either the XBee Wifi module or the WiFly GSX breakout board. Are there any advantages to one versus the other?
On a more general note, is the Fio a good choice for this project? I'll need to be pulling information from a temperature sensor (I haven't begun researching this yet, so any recommendation of favorite sensors/methods would be welcome) and the following liquid level sensor (http://www.sparkfun.com/products/10221
). The project will also need to be battery powered.