Patent Number: 6,310,540

Title: Multiple signal audible oscillation generator

Abstract: A microcontroller is used to drive a piezoelectric transducer. Certain pins on the microcontroller are indicative of selection signals. The selector can be activated either by a user directly (e.g., by pushing buttons), by an offboard actuator (e.g., another microcontroller), or by any method known in the art for activating switches. In one embodiment, an output pin of the microcontroller acts as output for a high-low oscillator. The oscillation amplitude toggles between 0 and 5 volts in a square wave fashion. The output pin is coupled to the base of a bipolar junction transistor so that the transistor turns on and off as a switch in response to the high-low oscillations. As the transistor turns on and off, supply voltage is routed through a network of logic inverters, after first passing through a current limiting impedance means such as a resistor, to the piezoelectric transducer in a manner designed to provide a voltage swing at the transducer on the order of two times the supply voltage for each oscillation. In another embodiment, instead of using a single pin on the microcontroller to alternately forward and reverse bias a single transistor, the microcontroller actuates predetermined pins that are connected to different RC oscillators. The RC oscillators are then connected to the driving circuit. The circuit includes a voltage regulator connected at an input to the supply voltage and at an output to the power supply pin of the microcontroller.

Inventors: Burnett; George A. (Coatesville, IN), Leonard, Jr.; Robert L. (Indianapolis, IN)

Assignee: Yosemite Investiment Inc.

International Classification: G08B 3/00 (20060101); G08B 3/10 (20060101); G08B 003/10 ()

Expiration Date: 10/30/2018