In an exemplary embodiment, a security sensor is present in a POS terminal between the keypad and a processor. The security sensor is configured to detect an unauthorized probe through the keypad and implement a security protocol. In an exemplary embodiment, the security sensor is a serpentine conductive circuit screen printed on the polyester film. The serpentine conductive circuit may cover almost all of the polyester film. For example, the serpentine conductive circuit may cover 90% to 100% of the film. Furthermore, in an exemplary embodiment, the serpentine conductive circuit limited to a section of the polyester film. For example, the serpentine conductive circuit may be on only ¼ of the film. This embodiment has the advantage of printing the serpentine conductive circuit on the critical security areas and leaving the non-critical areas with blank polyester film.