I'm new to using the Arduino w/ ethernet. All my previous projects have just been standalone UNO or Micro boards. I have an UNO with an ethernet shield stacked on top of it. I'd like to run the finished project with PoE. However, I see there are two different modules, a 5V and a 12V? Which should I use? Does it make a difference?
A little about the project...I'm building time keeping and access control systems that will be add on modules to a web-based business solution I've written. Each access unit (comprised of an UNO and ethernet shield) will be used with an RFID reader and relay. The time keeping units will be the same but with a 20x2 LCD instead of the relay.