Patent ID: 8674817
Filing Date: 2014-03-18
Classification: G08B,H04R

Abstract:
1. An audible signal device comprising a voltage supply circuit; a controller; a transducer connected to the controller, and including an oscillating element, and at least first and second inputs to which voltage can be applied, causing the oscillating element to deform; at least one feedback output connected to one side of the oscillating element which, in cooperation with at least one of the inputs detects a voltage produced by deformation of the element; a transducer driver having a plurality of logic gates, an inverter connected to an output of each of at least two of the logic gates, with an output of a first inverter connected to one of the inputs to the transducer, and with an output of a second inverter connected to another of the inputs to the transducer; an input to the controller from the voltage supply circuit; a second input to the controller from a programmer; a first output from the controller and connected to an input of the first and second logic gates; an output from the first gate connected to an input of the second logic gate; and an input to the first logic gate for selectively receiving a voltage from the feedback output.