Normal interface surface mating sensor

A method comprising:

• providing a power source including a first terminal and a second terminal;
• providing at least one of:
• an ammeter connected to the first terminal of the power source to measure electrical current at the first terminal;
• or
• a voltmeter connected in parallel with the first terminal and the second terminal of the power source to measure voltage across the power source;
• providing a plurality of electrically conductive sensing elements coupled to the first terminal of the power source and positioned on a first contact face of a surface of an external first body, flush with the first contact face, and are arranged in a pattern such that a spatial location of each sensing element among the plurality of electrically conductive sensing elements forms a normal interface surface mating sensor (NISMS) that generates an electrical signal when a conductive area on an opposing contact face of an external second body physically contacts the first contact face of the first body at the spatial location of the NISMS;
• outputting measurements from the provided at least one of the ammeter or the voltmeter as a contact event indicator that includes a conductivity measurement corresponding to the electrical signal generated by the physical at a sequence of the NISMSs with the conductive area on opposing contact face;
• and
• providing a set of return elements asymmetrically arranged in the pattern and positioned on the opposing contact face of the external second body, and including a continuity return element characterized by a wider diameter than non-aligned return elements among the set of return elements.