An intelligent measuring system for the refractive index of liquids

An intelligent measuring system for the refractive index of liquids is developed, with the purpose of controlling adulteration in liquids of everyday use. In this system, there are two parts: the photo-translating system and the data processing, digital display system. The lateral displacement of a laser beam that passes obliquely through a rectangular cell filled with the measured liquid is accurately determined by a position-sensitive detector in the first part. Then according to the output current of the position-sensitive detector, the refractive indexes of liquids are worked-out by the single chip microcomputer system, and the calculating result is showed in the digital display. In the software design, the digital filter is adopted, which makes the hardware structure simple and the result more accurate. Finally, The errors that can be obtained in this system are analyzed.