Microcontroller measuring converter of capacitance based on transients in RC circuit

Abstract

The performed work relates to measuring techniques, in particular, to devices for metering physical quantities by capacitive sensors built on microcontroller-based interfacing circuit. One of the major capacitive sensor application areas in agriculture are the technological processes connected to humidity control and management. There is a problem in the need of development software for implementing Arduino-based algorithms that allow the analysis and synthesis of technical solutions for measuring the sensor capacitance using transients in an RC circuit. An algorithm that implements the dependence of the Microcontroller Measuring Converter binary code on the sensor capacity is proposed. An analytical expression that allows calculating the values of quantities necessary for effective interfacing of the capacitive sensor's sensing element with the microcontroller is given. The study results of the Microcontroller Measuring Converter for capacitance varying in the range from 100 to 500 pF are presented. Experimental studies were performed on the basis of Atmel's 8-bit ATmega328P microcontroller using the Arduino platform. The results obtained in this work are necessary for designing capacitive intelligent microcontroller-based sensors.