We decided the most efficient route for cleaning the room would be by utilising a spiral pattern, especially with the furniture in the room grouped in the centre.  Our approach involved a robot (henceforth referenced as Dennis) with six infra-red distance sensors around the front of it arranged in such a manner as to detect all the obstacles it might find in front of it.  We explored several methods for navigation, initially using odometry for turning but then moving on to employing a compass sensor instead.  We also investigated using infra-red sensors to map the obstacles in the room in advance rather than avoiding them as they were encountered.