Thin film detector for presence detection

A transducer (800) is provided where a membrane (830) is formed over a front substrate (615); and a piezoelectric layer (820) is formed over the membrane (830) at an active portion (821) and peripheral portions located adjacent the active portion (821). A patterned conductive layer including first and second electrodes (840, 845) is formed over the piezoelectric layer (820). Further, a back substrate structure is provided having supports (822, 824) located at the peripheral portions adjacent the active portion (821). The height (826) of the supports (822, 824) is greater than a combined height (828) of the patterned piezoelectric layer and the patterned conductive layer. Many transducers may be connected to form an array, where a controller may be provided for controlling the array, such as steering a beam of the array, and processing signals received by the array, for presence or motion detection and/or imaging, for example.