A Passive-RFID Wireless Sensor Node for Precision Agriculture

Accurate soil data is crucial for precision agriculture.  While existing optical methods can correlate soil health to the gasses emitted from the field, in-soil electronic sensors enable real-time measurements of soil conditions at the effective root zone of a crop. Unfortunately, modern soil sensor systems are limited in what signals they can measure and are generally too expensive to reasonably distribute the sensors in the density required for spatially accurate feedback.  In this work, we determined the optimal placement of soil sensors in various agricultural fields using a genetic algorithm informed by geostatistical data.  From this, we designed and fabricated low-cost, passive RFID wireless sensor nodes for measuring nitrate content in soil. Finally, we characterized the performance of the wireless sensor nodes in both greenhouse and field experiments.