Abstract: The sound producing device is composed of three independent parts: (1) a push-button for generating a sound-wave; (2) an assembly comprising a sound-wave sensing switch, a magnet and magnetic-reed switch, an integrated circuit amplifier and a door bell; and (3) a fixed magnet. The three parts have their own self-sticking glue, so that no wire is required when installed, and it can be adhered on the front of the door, inside the door, and by the side of the door frame, respectively. Dry cells may be located in the interior of the assembly. The device serves several functions because it notifies people (1) that the door is not well closed, (2) that a burglar is trying to get into the house and (3) it serves the normal function of a door bell.