A portable analyzer based on a novel optical structure for urine dry-chemistry analysis

摘要

A portable urine analyzer, based on a novel optical structure, a high-performance 32- bit microcontroller STM32F103VE and a WiFi module, is put forward for urine dry-chemistry analysis in this paper. In the analyzer, the optical structure, made up of optical fiber bundles, is helpful to control the spread path of light and to reduce influence of ambient light on test results effectively. Meanwhile, through our designed optical structure, the intensity of both irradiating light from white LED and reflected light from urine reagent strip can be measured synchronously by two color sensors. And this is useful to enhance the degree of automation availably and to further improve test accuracy of the urine analyzer. Furthermore, a temperature sensor is also used to measure environment temperature for calibrating the test results of the analyzer. In addition, a high-precision reference voltage chip, LM4132A-3.0, which provides a reference voltage for analog-digital and digital-analog converters integrated in STM32F103VE, is adopted to improve both the measurement precision of light intensity and the control accuracy of outputted analog signals. Consequently, by the 14-item urinalysis reagent strip, the analyzer is able to obtain fourteen indexes of human urine, to display and print the composite reflectivity or semi-quantitative result of each test item. Besides, it also can output all results, covering above mentioned two kinds of results, each color-component reflectivity and all original data of the latest tested strip throughWiFi module. To validate the performance of the analyzer, 200 real human urine samples were tested by our designed analyzer and a commercial one simultaneously. The results show that the urine analyzer has a good stability and a great consistency with the commercial one. Therefore, our designed analyzer has a good application prospect in the communities and families.