analogReference usage

Forum 2005-2010 (read only) Hardware Interfacing
1

there were two main threads on the subject, listed bellow, but as of v11 it is exposed.
leaving me with following question...

i set up a voltage divider for the arduino 5v to 2.5 for my sharp range finder
(which goes from 0.5v to 3v).

i used an offline voltage devider calculator, which is nice. i currently lack the resistors needed for a 5v to 3v so i set the AREF to 2.5. (using the calculator i found i need something in the ratio of 10k and 6.8k)

what will happen if the input goes above the AREF? will it blend? :-/

the analogReference page
thread on AREF
and another one on AREF usage

2

i admit the original question was rather silly. it just caped at 2.5

now i want to bias my sensor to get it down to 0.v-2.5v from 0.5v-3.0v .