Abstract: A bio metric sensor device (1) comprises: —a thin, flexible, layered sensor body (2); —a conductive sense plate (21); —a first non-conductive layer (41) between the sense plate and an outer surface (7); —a conductive shield plate (53) having a passage opening (54), overlaying the sense plate; —a second non-conductive layer (51) between the sense plate and the shield plate; —conductive circuit lines (73) on an inner surface (6); —a non-conductive separation layer (61, 71) between the shield plate and the circuit lines; —a signal processing circuit (100) mounted on the inner surface (6), the circuit (100) comprising a differential amplifier (110) having an input (111); —a conductive interconnector (82) crossing the second non-conductive layer (51) and the separation layer (61, 71), extending through the passage opening (54) of the shield plate (53), coupling the sense plate (21) and said input (111) of said amplifier (110).