Abstract: Embodiments relate generally to an ultrasonic detector, and methods of making the ultrasonic detector. The ultrasonic detector may comprise a piezoelectric element operable to convert the pressure of sound waves from mechanical energy into electric signal; a protective cover; a hot melt adhesive; one or more layers of solder; one or more perforated metal electrodes comprising openings filled with the solder; and one or more support elements. The ultrasonic detector may also comprise one or more casing elements operable to enclose and house the other elements of the ultrasonic detector; a printed circuit board (PCB) operable to receive ultrasonic data from the piezoelectric element and electrodes, wherein the electrodes connect to, or contact, the PCB; and an insulator located in proximity to the electrodes, and operable to prevent shorting between the metal electrodes and the metal casing elements.

Abstract: Embodiments relate generally to an explosion proof ultrasonic detector. The explosion proof ultrasonic detector comprises a metal enclosure configured to face ultrasound pressure waves, a sense element, wherein the sense element is attached to the metal enclosure via solder, a compression element configured to contact the sense element, and a printed circuit board configured to compress the compression element and to connect electrically to the sense element.

Abstract: Embodiments relate generally to an ultrasonic detector, and methods of making the ultrasonic detector. The ultrasonic detector may comprise a piezoelectric element operable to convert the pressure of sound waves from mechanical energy into electric signal; a protective cover; a hot melt adhesive; one or more layers of solder; one or more perforated metal electrodes comprising openings filled with the solder; and one or more support elements. The ultrasonic detector may also comprise one or more casing elements operable to enclose and house the other elements of the ultrasonic detector; a printed circuit board (PCB) operable to receive ultrasonic data from the piezoelectric element and electrodes, wherein the electrodes connect to, or contact, the PCB; and an insulator located in proximity to the electrodes, and operable to prevent shorting between the metal electrodes and the metal casing elements.

Abstract: A hazard detector has an electronic circuit with a start-up program for causing emission of a local indicator signal, such as a flashing signal from a LED, if power and ground terminals of the detector are connected with proper orientation, i.e. polarity, to power and ground lines of a power supply. Through this means, a person installing the hazard detector can tell immediately after connection if the detector has been connected with proper orientation, and avoids the need for introducing a hazard such as heat or smoke to test the operation of the detector. A variation uses a more sophisticated program that disables, during a test mode, complex filtering algorithms that are used by detectors to block false alarm signals; if such filtering is not disabled, impedes normal testing of the detectors.