Study On Water Film Sensor Based On Microelectrodes

It is particularly important to get the weather information in a timely manner, because of the annual rain and snow and other severe weather will cause a large number of casualties. The water film sensor plays a c key role as an important part of the road sensing system. However, the current domestic market is basically monopolized by European countries and detection technology also heteronomy, so the main work of this paper is to study a cheap and practical water film thickness measuring device.This paper develops a kind of contact type sensor for measuring the thickness of water film on road surface. By the microelectronic manufacturing process, the microelectrode spacing was processed to 0.5mm and the single detection electrode area was processed to 0.2mm2. The changes of the thickness of water film output in the form of voltage signal and the AC voltage signal is rectified into DC signal by hardware circuit, then the filter calibration is amplified into the A/D acquisition. The driving signal of the common electrode is improved, which is the positive and negative alternating 1MHz pulse signal.The electrode corrosion is improved by reducing the corrosion potential difference between the electrodes and the impedance matching in the high end of the detection electrode to reduce current. Through the comparison experiment of the electrode material and analysis of the instability of measurement data of water film sensor, the more stable platinum is selected.The collected data is interpolated by interpolation algorithm, and then the least square method is used to retrieve the results. Finally, the error of the water film sensor is less than 0.6%, the measuring range of the sensor is 0-80mm, and the measurement accuracy is 0.5mm.Through the static calibration experiment, the reliability and the temperature stability of the sensor are analyzed and evaluated.