Patent ID: 7817500

Claim:
A shock-activated switch device comprising: a piezoelectric element having a body, a first terminal connected to a power source, and a second terminal outputting an electrical output signal in response to a mechanical shock applied to the body, the second terminal also receiving an electrical input signal for outputting of an audible sound by the piezoelectric element; a reactive electrical circuit element fixedly electrically connected to the first and second terminals of the piezoelectric element and thereby electrically connected in parallel with the piezoelectric element; an output circuit connected to the second terminal of the piezoelectric element and converting the electrical output signal, output in response to a mechanical shock applied to the body, into a logic signal for controlling an electronic circuit, wherein the output circuit comprises an amplifying element having an input coupled to the second terminal of the piezoelectric element for amplifying the electrical output signal, output in response to a mechanical shock applied to the body, and producing an amplified output signal, a temperature compensation element connected between the input of the amplifying element and ground, compensating for changes in temperature of the amplifying element, and a shaping circuit receiving and shaping the amplified output signal into the logic signal, the shaping circuit comprising at least one biasing resistor, and only a single electronic switch that is connected to the at least one biasing resistor and closed only when the amplified output signal is applied to the single electronic switch, the single electronic switch supplying a direct current voltage to an output terminal as the logic signal; and an input circuit connected to the second terminal for receiving a beep control signal and, in response to receiving a beep control signal, applying the electrical input signal to the piezoelectric element so that, in response to the electrical input signal, the piezoelectric element generates the audible sound.