A sensor module includes a housing and a sensor assembly disposed within the housing. The sensor assembly includes a base having at least one energy emitter and at least one energy detector, and a guide layer overlying the base in face-to-face relationship. The guide layer has at least one protrusion extending outwardly to accommodate the at least one energy emitter, and a plurality of outwardly extending stabilizing members. The housing has at least one first opening through which the at least one protrusion extends, and a plurality of second openings through which the stabilizing members extend. Some of the stabilizing members have an outwardly extending length that is greater than an outwardly extending length of the at least one protrusion. Some of the stabilizing members are substantially cylindrical and have a circular cross-sectional profile, and some of the stabilizing members are partially cylindrical and have a partially circular cross-sectional profile.