Point of purchase advertising system

Claim 1

An announcement system, comprising: means for selectively and repeatedly giving desired announcements; and motive means operably coupled with said announcement-giving means for operation thereof to give said desired announcements in their entirety, said motive means including-- actuator means for re-actuating said announcement-giving means following each completion of an announcement by the announcement-giving means and only in response to ongoing movement of a person within a region adjacent the announcement-giving means; apparatus for preventing said re-actuation of the announcement-giving means during a pause of predetermined duration immediately following completion of each announcement, whereby to provide time for a person having just received the announcement to leave the region without re-actuating the announcement-giving means, said actuator means being operable to re-actuate said announcement-giving means only during a functional time period of variable duration between said pause and commencement of the next announcement; ultrasonic sending transducer means operable for sending ultrasonic signals into said region, said signals after said sending thereof being alterable by ongoing movement of a person within the region; ultrasonic receiving transducer means operable for receiving ultrasonic signals from said sending transducer means, and for generating output signals in response to said receipt of said ultrasonic signals, said output signals having varying ampltiudes when a person is moving within said region and the receiving transducer means receives altered ultrasonic signals, as compared to the constant amplitude of the output signals when no person is moving within the region and the receiving transducer means receives unaltered ultrasonic signals, said actuator means being operably coupled with said receiving transducer means and said announcement-giving means for re-actuating the announcement-giving means only in response to the amplitude variations of output signals, resulting from ongoing movement of a person within said region being sufficiently high during said functional time period of the actuator means, said actuator means being disposed for preventing operation of the announcement-giving means in response to the constant amplitude output signals resulting from no movement of a person within said region during the functional time period of the actuator means, or resulting from amplitude variations which are sufficiently high but do not occur during said functional time period of the actuator means; and structure for maintaining the operation of said announcement-giving means after initiation of operation thereof for a period of time until a desired announcement is completed.