Design of moisture real-time detection system for grain dryer

Abstract STM32 MCU is used as the core control chip, and the parallel plate is designed as the data acquisition terminal of capacitance sensor. The parallel plate is a capacitive sensor to collect the moisture data of grain in the dryer, through AD conversion, signal processing. Through RS485 communication, the signal will be transmitted to the top computer for real-time display. The operator can calibrate grain moisture in real time through the upper computer. The influence of grain temperature and volume on capacitance was studied, and a mathematical model describing capacitance and moisture content was established, and the model was verified. Through field experiments, the reliability of the system was confirmed, and the accuracy of online monitoring could reach within 0.5%, which fully met the requirements.