Abstract: Smoke detector, comprising a housing the length side of which is several times greater than the width side thereof, incorporating a sensor and a power source; a U-shaped bracket having a base mounted turnable on the top of the housing, and downwardly directed arms, one of which carries a second sensor interconnected with the first sensor and the power source, which is rotatable from a position adjacent the width sides of the housing into a position of parallel spaced relationship to the length side thereof, for accommodation of an upper door edge between the space within the sensor carrying arm and the length side of the housing.