A paper counting system based on capacitive digital/frequency converter FDC2214 is designed to solve the problem of traditional paper counting machines in printing industry

such as high power consumption

high cost and insufficient intellectualization.The number of papers between the two parallel polar plates of the system affects the capacitance and then adjusts the resonant frequency.FDC2214 chip converts the received frequency into digital quantity to communicate with the control center STM32 MCU in I~2C mode.The MCU preprocesses on collected data with Kalman filtering algorithm

and then adopts dynamical threshold algorithm to realize the measurement and calibration at the same time

and the system is intelligent and real-time.The experimental results show that the accuracy of the system for measuring standard A4 paper is 100 % within 87 sheets

always above 93 % within 90 sheets

and the measurement response time is less than 200 ms.