Design Of An FPGA Precipitation Particle Measurement System Based On Piezoelectric Effect

Precipitation particle measurement is an important sector in meteorological observation. This paper proposes a new method of measurement, which is based on piezoelectric sensors. An FPGA-based precipitation particle signal acquisition and processing system has been designed. This system acquires the signal through synchronized multi-channel analog-to-digital converters. When implementing the measurement and signal processing, the response functions of the multiple channels and the response functions of the particles are both applied in the algorithm that determines particle diameters. The system not only covers the full span of the signal but also reduces nonlinearity error. The characterization results indicate that the error of this system is less than±0.1mm in particle diameter, and that the system features wide span, high precision, fast response and accurate particle sizing.This article first introduces the background and significance of this research, the principles of piezoelectric effect and characteristic analysis of piezoelectric sensors and characteristics of precipitation particle.Secondly, it provides the system hardware structure. The system core of controlling and processing is based on an FPGA primarily, and on an MCU as an auxiliary processor. FPGA is the main control, data acquisition and processing device. As the core of system, it is responsible for driving the ADC data acquisition, smoothing preprocessing, feature extraction to determine measurement, SD card storage and MCU communication, etc.The MCU as an auxiliary device, completes external communications, packing and uploading data, system tracing and environmental temperature detection. In addition, The system hardware also includes matching circuits placed in front of the output signal of the piezoelectric device.Thirdly, this paper covers the system software design, including the program design of the FPGA and the corresponding auxiliary function programming of the MCU.Then, the paper describes the system test environment and analyzes the data collected from the experiments.Finally, this paper summarizes the development of the system, and points out the advantages and disadvantages in this system.