Microcontroller-based control system for safe grain storage in silo

Abstract

This study developed a control system that could continuously monitor temperature and relative humidity, measure moisture content non-destructively, and control storage condition to a safe level. The developed control system used Arduino program because it is an open source and the components of the hardware are locally available. It was evaluated using small-scale metal silo during wet season at the University of the Philippines - Los Baños, Laguna, Philippines. During the evaluation, the average temperature, relative humidity, and dewpoint temperature of the ambient air were 27 °C, 87 %, and 24 °C respectively. These parameters are not favourable for safe grain storage, however, the developed control system monitors the storage condition inside the silo and regulate the environment by switching on and off a fan and heater. The average temperature and water activity of the stored grains were 34°C and 0.65 respectively. Though there was an increase in relative humidity and decrease of temperature inside the silo, the condition was still within the safe level for storage. This was proven by the low moisture content (12.0%) of the stored grains in the controlled silo. During the evaluation period, the moisture content of the grains stored in the conventional silo was maintained at its initial 14% moisture however, it showed a fluctuation trend. The developed device which also reads moisture content with a mean difference value of 0.25% meets the acceptable tolerance of 0.5% for a meter to like-type meter standard. Hence, this confirms the acceptable reading of the device.