A physiological parameter sensor system includes a housing with a first cell and a plurality of second cells. A first sensor system element (either an emitter or a detector) resides in the first cell. Second sensor system elements reside in at least some of the second cells. If the first sensor system element is an emitter, each second sensor system element is a detector, and vice versa. The housing is conformable to the contours of a patient to ensure that the sensor system elements are closely coupled to the patient's skin. The system identifies the emitter which yields the best quality signal at the detector (or the detector which receives the best quality signal from the emitter). The system then uses only the identified emitter/detector pair. The system is compact, places only modest demands on battery power, and tolerates being positioned at a nonoptimal loactions on the patient's body.