Measurement of Granary Moisture Content Using Wireless Sensor Network

The book characterized a sensor node and developed a measuring system consisting of network of calibrated sensor nodes. It also evaluated the system developed against test values from the established oven-drying method. This was with a view to developing a system for measuring moisture content of bulk grains in silos. The distributed sensor network consisting of sensor nodes and a sink node or access point (AP) was connected to a Personal Computer (PC) through a USB port. Sensor nodes consisting of programmable Temperature/Humidity sensors SHT21 connected to microcontroller unit (MCU) MSP430F2274 were developed. Each of the sensor nodes was characterized using standard temperature - humidity environments provided by different saturated salt solutions. The salts used include: Sodium Chloride (NaCl), Potassium Chloride (KCl) and Sodium Nitrate (NaNO3) at different temperatures. Each of the calibrated sensor nodes was connected through radio frequency (RF) link to the AP which acted as a central hub, using a Texas Instrument low-power RF network protocol known as SimpliciTI. Data collection and analysis were achieved with Graphical User Interface (GUI) developed using LABVIEW.