基于电容传感器的纸张计数器设计

Paper counter design based on capacitive sensor

本文利用电容式传感器FDC2214设计制作了一个纸张计数器。待计数的纸张放置并被压紧于平行板电容器的两金属极板间,电容值随板间距(纸张厚度)变化,从而引起计数器前端谐振回路谐振频率变化。该传感器将感测到的谐振频率变化数字化,并送处理器进行中值平均滤波以降低噪声影响。系统将采样值与前期校准学习预存数据进行比对匹配,从而得到纸张计数值,并对计数结果进行液晶显示和语音播报输出。

A paper counting instrument is designed and fabricated using capacitive sensor FDC2214 in this paper.The paper to be counted is placed and pressed between the two metal plates of the parallel plate capacitor,and the capacitance value varies with the plate spacing(paper thickness),thereby causing the change of the resonant frequency of the counter front end circuit.The sensor digitizes the sensed resonant frequency change and sends it to the processor for median averaging filtering to reduce the effects of noise.The system compares the sampled value with the pre-stored data to obtain the paper counting value,and output the counting result to liquid crystal display and voice broadcast.