Suggestions for components to read and respond to Voltage input

Hi all,

Looking for any suggestions on a simple item that can read a 0-5V signal and then ouput a response (i.e. trigger a relay) based on reaching or exceeding a pre-set voltage. More specifically, I would like to be able to tap into an existing output wire of a variable rheostat and read the voltage as it increases and decreases. Depending on what those actual voltages are, which will need to be read and determined, “program” or set the item to trigger a connected relay once the voltage exceeds roughly 90% of the max voltage that has been set.

I am somewhat new to building electronics for these types of purposes. I have been trying to sift through the information provided on the site, but there are so many items and possibilities, that it is hard to narrow down or understand exactly what may be needed to do this. Thanks in advance to anyone that may be able to provide any insight or suggest further reading more specific to this purpose.

Look at the LM311 comparator (https://www.sparkfun.com/products/13950) Feed your voltage into the positive input and feed the negative input from a pot set up as a voltage divider to set the trip point.

/mike