Towards Low-Cost Low-Power Activity-Aware Soil Moisture Sensing Platform for Large-scale Farming

Researchers from Northwestern University (Jack Thoene, Omar Kamil, Thekra Alkadee, Nivedita Arora) have developed an end-to-end platform for low-cost, low-power soil moisture sensing tailored to large-scale farming. The system features buried, battery-free sensor nodes that each cost under $35, making them financially accessible for widespread deployment. Each node uses a self-powered galvanic soil-moisture probe with a high-impedance analog front end for durability, and operates entirely on harvested solar energy for up to 21 days on a single capacitor charge. The nodes collect soil moisture, temperature, and environmental condition data.

The platform employs a mobile basestation affixed to standard farming vehicles, which listens for nodes while moving through the farm. Data exchanges occur via a predictable finite-state machine and handshake protocol, enabling reliable communication over 1 km at just 2 dBm transmit power. Experimental evaluation showed stable sensor readings over 70 days of indoor operation and continuous data recovery during multiple periods of intermittent connection. The system organizes all sensor, link-quality, and location data into an easy-to-interpret dashboard, integrating seamlessly with the farmer's daily routine without impeding operations.