You may be better off getting a hall switch instead of a full linear analog device, then you just have to have it close enough and you'll get a definitive 0 or 5v
don't forget you need a pullup and that pay attention to the pinout the smd is different than the thru hole one, I've burnt one before I figured that out
with your sensor you will have to detect the peak and besides analog reading take more time
Google or ebay search hall sensor switch, they are usually cheaper actually (I bought by accident once thinking they were the linear kind)