Assembly of harness and sensor substrate plates for monitoring vital signals of a patient is provided. More specifically, the present invention provides a harness, a sensor substrate plate, and related devices for non-invasively monitoring vital signals of a patient. The sensor substrate plate provides removable attachment to the skin of a patient to measure vital signals of the patient. The sensor substrate plate comprises an elongated main body comprising an upper surface and an under surface. The upper surface is configured to removably contact the skin surface of the patient. Further, a plurality of slots on the upper surface of the main body is mechanically and electrically configured to hold sensors or electrodes for monitoring biometric parameters of the patient. The upper surface also includes a first through hole mechanically and electrically configured to hold an electrical connector; and a first end and a second end of the main body.