Characterizing acoustic impedance of several saline solution utilizing range finder acoustic sensor

Nowadays, acoustic technology Is used In many sectors of human life. One of acoustic benefit is to know mechanical property of material, such kind of liquid and solid. One of mechanical property is acoustic impedance. Several methods are used to estimate acoustic impedance of material. Most of them use high focused ultrasound transducer, and utilize pure water as a common coupling material. However, this type of transducer is still expensive. Another type of ultrasound so called range finder ultrasound (RFU) is very cheap transducer. It is usually use to measure distance and place localization for its applications. Since RFU utilizing air as a coupling material, RFU became to a very sensitive sensor. Small displacement and small difference of distance from the sensor will produce a massive different of measurement. Hence, an accurate and precision method should be built for best result of measurement. In this paper, we utilized range finder ultrasound (RFU) sensor to estimate acoustic impedance of several saline solutions. Based on theoretical, the denser the solution the higher the acoustic impedance. From the experiment, it can be obtained that the higher the acoustic impedance of saline solutions the higher the echo signal that is received by receiver transducer. A characterization conversion curve was successfully developed from the experiment. However, assuming one plane wave for this type of transducer produced significant error. Detail discussion related to this research is presented in this paper.