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.