| 摘要 |
A method and device for generating alerting sounds and broadcasting the same into the interior of a building so that an occupant can be made aware of the presence of a visitor at a door to the building. The sounds are generated by an exciter feature of a transducer held in a case, able to be gripped in one hand of a user, the exciter feature being able to be pressed against an exterior surface of the door by the user moving the case to a position adjacent to the door. The transducer vibrates its exciter feature in correspondence with audio signals transmitted to the transducer to broadcast corresponding sounds into the interior of the building by resonance induced in the door by the vibrating exciter feature. The sounds can resemble conventional alerting sounds such as a knocking or ringing sounds, and/or can be a spoken message either prerecorded in an audio source or created contemporaneously by being spoken by the user into a microphone. The device may be hand carried door to door as by delivery personnel and emergency workers and used to effectively alert occupants and eliminate the need for hand knocking or yelling a message through the door. |
