A Presentation onUltrasonic TransducerProf. Sajid Naeem (DOES – PC)
Ultrasonic SensorAn ultrasonic transducer is a device that converts energy intoultrasound, or sound waves above the normal range ofhuman hearing.Systems typically use a transducer which generates soundwaves in the ultrasonic range, above 18,000 hertz, by turningelectrical energy into sound, then upon receiving the echoturn the sound waves into electrical energy which can bemeasured and displayed.
Ultrasonic sensors (also known as transceivers when theyboth send and receive) work on a principle similar to radar orsonar which evaluate attributes of a target by interpreting theechoes from radio or sound waves respectively. Ultrasonicsensors generate high frequency sound waves and evaluatethe echo which is received back by the sensor. Sensorscalculate the time interval between sending the signal andreceiving the echo to determine the distance to an object.
Construction of Ultrasonic SensorPiezoelectric crystals are used forthis conversion process.Piezoelectric crystals willoscillate at high frequencieswhen electric energy is applied toit. The reverse is also true. Thesepiezoelectric crystals willgenerate electrical signals onreceipt of ultrasound. Thesesensors are capable of sendingultrasound to an object andreceive the echo developed bythe object. The echo is convertedinto electrical energy for onwardprocessing by the control circuit.
Interfacing & Features •description: ultrasonic transducer - receiver •max. input voltage: 20Vrms •operating temperature: -20 C to +85 C •range: 0.2 to 6m •nominal frequency: 40kHz •sensitivity: -67dB min. •sound pressure: 112dB min.
This technology can beused for measuring: windspeed and direction,fullness of a tank andspeed through air or water.For measuring speed ordirection a device usesmultiple detectors andcalculates the speed fromthe relative distances toparticulates in the air orwater. To measure theamount of liquid in a tank,the sensor measures thedistance to the surface ofthe fluid.