A sensor or detector device includes a box in the form of a tubular hollow body, through whose opening a connecting cable passes and that is sealed by a connected plug. The device also includes a card or an analogous substrate, carrying the electronic components of the sensor or detector and mounted in the box, by being coated by an insulating filler material filling approximately the entire remaining inside volume of the latter. The Device (1) is characterized in that it includes a mechanical element for the positioning with wedging of the card (6) in the box, preferably along a median plane or with longitudinal symmetry (PM) of the latter, with at least a portion of the element being integrated in the plug (5).