The use of Temperature and Relative Humidity Sensors to Estimate the Final Moisture Content of the Drying Process

Abstract

The estimation of the paddy moisture content during the drying process was important to retain the moisture level properly for trade (15%wb) or storage. In general, the agriculturists estimated moisture content by using a moisture detector (Riceter F512). This allowed the user to determine the moisture level, once the drying process was completed. The objective of this paper was to estimate the final moisture content (FMC) of the paddy drying process by using the mass balance method. The temperature and relative humidity sensor were installed at two locations, one for surrounding air (DHT22-sensor) and another one to exhaust air (EE31-sensor) of the dryer in order to read and record data values. Arduino microcontroller was used as the main processor that receives the property of air from a DHT22, EE31 sensor. After that, the processor would calculate the humidity ratio of air and send the signal output to indicate the moisture level of the paddy that was reduced. Besides, the moisture reduction was compared with the traditional method by using a moisture detector. The drying condition used in this study was set: paddy initial moisture content (IMC) range 20-21%wb, rotary valve speed of 2 rpm (equivalent to 60 kg/h), the average hot-air temperature of 130 °C, hot-air velocities of 2 m/s and the average eccentric speed of 110 RPM. The results showed that the system could estimate and display moisture content of the paddy that was a reduction from IMC to FMC and the average error values of 4.3 percent when compared with a moisture detector.