My idea is based on the PIC controlled version from Frits K.

Instead of a PIC/X9C103 i'm using a DS1803 with Arduino. So far so good. Controlling the DS1803 is not a problem.
But when I measure the ohm output of the DS1803, it's fluctuating (a little bit).
When I connect the DS1803 to my thermostat it's continuous adjusting the temperature (18C > 18,5C > 18C > 17,5C > 18C etc).
Any idea how to solve this?
Albert
