Pertains for design, construction and testing of sensitive protective devices where the device is used to detect pedestrians including in particular applications, slow moving elderly persons, slow moving disabled persons and children who may be exposed to injury by power operated doors, gates and barriers, electrically powered from a public supply and intended for installation in areas in the reach of persons, and for which the main intended uses are giving safe access for goods and vehicles accompanied or driven by persons in industrial, commercial, public or residential premises.