sometime i wonder how much trouble one will ge through to save a buck.
i'd say just use LM34 temperature to voltage cost $1.25 USD and the
a/d and uart build into the pic16c74. i did a project like this that
displays all eight readings and controls relays and even changes setpoints
by reading switch contact inputs. it was lots of fun and done only with
the software simulator DOS version cause it works best.

michael