A Soil Moisture Sensing System Powered by Self-Harvesting Soil Energy

To address the growing demand for self-sustaining sensing systems powered by renewable energy for environmental monitoring, this article proposes a double-helical structure soil energy harvesting device and an integrated system for soil energy harvesting and moisture content sensing detection. The integrated system includes dc-dc converters, microcontrollers, and energy storage. The prepared double-helix soil battery (zinc-copper electrode) can provide a maximum output power of 0.2 mW under a 1-k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> load. This device increases power generation by reducing the distance between electrodes and increasing the contact area between electrodes. While harvesting direct current from the soil, the system can simultaneously monitor soil moisture content, using the relationship between electrical energy and soil moisture content to achieve integrated energy and information management. The system can achieve a measurement error of less than 2% for soil moisture content in the range of 5%–35%. This technology enables self-powered soil moisture monitoring and has promising applications in smart agriculture for soil condition monitoring and in landslide soil environment monitoring. Additionally, it can provide auxiliary power for field environmental monitoring equipment and sensors in areas with limited power supply.