hello. we did this project and our supply V- = -5v and
V+ = +5v. but why does the input voltage in pin1 is in negative??
Vref= -3.5v)
pls help us. this is for our project study.. thank you!!! 
What is a max038? Don't you think you should be the one to supply a link?
Why are you feeding negative voltages to the Arduino? That's a good way to destroy it.