Influence of Moisture Content in Rice on Radio Signal Strength Indicator Readings at 2.4GHz

Paddy is the main staple crops in Malaysia. The harvested paddy is often processed for selling or stored for later use. Paddy undergoes several processes including cleaning, dehusking, and milling to produce polished rice. Besides that, paddy or rice also stored to ensure ample supply because paddy is a seasonal crop where it is only harvested twice during a year. Due to the tropical weather in Malaysia, maintaining the optimal condition for the storage is quite challenging. From the literature, moisture content is a factor that significantly affects the storage of paddy or rice. There are numerous methods available to measure the moisture content in paddy or rice, however, most of the existing technique requires complex and expensive devices. Hence, this study aims to investigate the feasibility of using free space radio waves transmission using devices operating using 2.4GHz (WiFi) for moisture content detection in rice. The rice was divided into a smaller sample size of 200g each. The samples were set at moisture levels of 10, 15, 20, 25, 30 and 35% using the moistening technique. The transmitter and receiver consist of Arduino Mega2560, Tri-comm Shield (equipped with ESP7S), and a 3dBi directional antenna. The transmitter and receiver were placed 50cm apart. The receiver measured the Received Signal Strength Indicator (RSSI) and a model was developed from the experimental test data. A polynomial equation was obtained as the model with a coefficient of correlation of 0.739.