Deep understanding of a field's soil moisture content is the leading indicator for predicting crop yields and making data driven decisions for irrigation and application of topical chemicals for drought resilience. Despite this importance, the cost of adopting and maintaining IoT infrastructure prevents modern farms from employing widespread real time soil moisture sensors. We present an end-to-end platform of buried battery-free sensor nodes and a mobile basestation that leverages the farmer's daily routine for data retrieval. Each node features a self-powered galvanic soil-moisture probe, employing a high impedance analog front end to enable durability. Operating entirely on harvested solar energy for up to 21 days on a single capacitor charge, each node collects soil moisture, temperature, and environment condition data. Using a predictable finite-state machine, handshake-based data exchanges occur with a basestation affixed to standard farming vehicles designed to listen for the nodes while moving through the farm. Our platform organizes all sensor, link-quality, and location data into an easy-to-interpret dashboard to seamlessly integrate with the farmer's everyday routine. Costing less than $35, the platform is a financially accessible, accurate, and easily scalable platform that enables persistent, regular data collection from the most rural plots without adding to or impeding farming operations. Experimental evaluation demonstrates reliable communication over 1 km at 2 dBm transmit power, stable sensor readings over 70 days of indoor operation, and continuous data recovery during multiple periods of intermittent connection.

翻译：对田地土壤含水量的深入理解是预测作物产量、制定数据驱动灌溉决策以及施用抗旱化学药剂的关键指标。尽管土壤湿度监测如此重要，但物联网基础设施的采用和维护成本阻碍了现代农场广泛应用实时土壤水分传感器。我们提出了一种端到端平台，包含埋入式无电池传感器节点和利用农民日常作业进行数据回收的移动基站。每个节点配备自供电原电池式土壤水分探头，采用高阻抗模拟前端以确保耐久性。节点完全依靠收集的太阳能运行，单次电容器充电可持续工作长达21天，收集土壤水分、温度和环境条件数据。通过可预测的有限状态机，节点与安装在标准农业车辆上的基站进行基于握手的数交换，该基站被设计为在农场移动过程中侦听节点信号。我们的平台将所有传感器数据、链路质量数据和位置信息整合到易于理解的仪表盘中，以无缝融入农民的日常农事操作。该平台成本低于35美元，具备高经济性、高精度和易扩展性，能够在不增加或妨碍农业作业的前提下，对最偏远的农田实现持续、定期的数据采集。实验评估表明，在2 dBm发射功率下可实现超过1公里的可靠通信，传感器在70天室内运行中读数稳定，并在多次断连期间实现持续数据恢复。