Abstract: A circuit for energizing an annunciator or warning device is actuated whenever a door or the like is in any position other than in proximity to preselected locations such as the two ends of intended travel. Proximity detectors arranged in conformity with the limits of intended travel effect electrical switching so as to interrupt the annunciator circuit whenever the door is within acceptable distance of the limits. The proximity detectors can be provided by a dual magnetic arrangement with one magnet associated with travel and the other permanently affixed relative to a reed switch or the like. The fixed magnet maintains the reed switch closed except when its magnetic field is effectively cancelled by the movable magnet.