Shorting two wires via wifi

It took me a little time to get my hands on a multimeter, but I tested the wires, and they fluctuate between 2 and 3 volts dc. My brother said it fluctuates because the gate opener has a battery backup. Can you suggest what hardware I should buy? Would this work for me instead of buying an arduino and an ethernet shield separately? http://arduino.cc/en/Main/ArduinoBoardEthernet