Hacking a scale

So I've got a cheap platform scale. The platform on the left is about the right size to stand a keg on and it connects to the display via a phone headset type connector. So I have interrupted the connection and sent it via the breadboard and Arduino to try and see what's going on. Four wires one ground one 2.3v and two that have the signal but pressing the scale gives almost no change in the signal. I think it needs amplifying to be able to be any use. Off to read about op amps....