A new time-domain measurement method for determining the capacitance and resistance values of lossy relative humidity capacitive sensors is presented. The method is based on a direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators and timers. The interface circuit consists only of four reference resistors (two reference resistors if a microcontroller includes a voltage reference source), a given sensor and a microcontroller. A systematic error correction algorithm based on a correction dictionary and the M-multiple measurement approach are also proposed in the paper. Experimental investigations were carried out using a prototype device based on an 8-bit ATXmega32A4 microcontroller. The experimental research confirmed that the relative errors of measurement of capacitance introduced by the interface circuit are less than 0.71% (for capacitance values 100 – 286 pF), and the relative errors of measurement of resistance are less than 0.74% (for resistance values 1 – 10 MΩ).

提出了一种新的时域测量方法，用于确定有损相对湿度电容传感器的电容和电阻值。该方法基于具有内部模拟比较器和计时器的微控制器的直接传感器到微控制器接口。接口电路仅由四个参考电阻（如果微控制器包括电压参考源，则为两个参考电阻），给定的传感器和微控制器组成。基于校正字典和M的系统误差校正算法本文还提出了多种测量方法。使用基于8位ATXmega32A4微控制器的原型设备进行了实验研究。实验研究证实，接口电路引入的电容测量的相对误差小于0.71％（对于电容值100 – 286 pF），电阻测量的相对误差小于0.74％（对于电阻值1 – 10MΩ）。