This invention describes a small, low-cost sensor that can measure both humidity and soil moisture using a single device. It is built using a special design called interdigitated electrodes (IDE) on a silicon wafer. These electrodes are coated with graphene oxide (GO), a material that reacts to changes in moisture by changing its electrical capacitance. The sensor can be made using a simple fabrication process and can be used in agriculture to track soil moisture for better irrigation management. It works well in both red and black cotton soils, responds quickly, and can be stacked in multiple layers to monitor different soil depths.
Figure 1. Measurement set-up for the soil moisture measurements
Modern agriculture requires accurate, affordable tools to monitor soil moisture and humidity for effective irrigation. Traditional sensors are either too expensive, bulky, or unstable over time. Some require multiple fabrication steps and separate devices to measure humidity and soil moisture, increasing cost and complexity. There is a need for a compact, stable, and dual-purpose sensor that works reliably in different soil conditions.
- Dual-Purpose Moisture Sensing: This patent presents a single capacitive micro-sensor capable of measuring both humidity and soil moisture using graphene oxide (GO) as the sensing layer.
- Simple and Cost-Effective Design: The sensor uses interdigitated electrodes (IDE) fabricated via a single-step lithographic process, offering a compact, low-cost design with enhanced sensitivity.
- Fast Response and Wide Operating Range: The sensor delivers fast response (100–120 s) and recovery (10–20 s) times and operates effectively across humidity levels of 50%–94% and soil moisture up to 55%.
- Adaptable for Real-World Conditions: It can be used with or without a protective mesh based on the application environment and has been tested successfully in both red soil and black cotton soil.
The sensor is built on a silicon wafer coated with a thin oxide layer, with electrodes formed using Chromium-Gold (Cr/Au) metal layers. A GO layer is drop-casted between the electrode fingers to enable moisture detection. For use in harsh soil conditions, the sensor can be optionally packaged with mesh protection. It exhibits a linear response to changes in moisture, demonstrating sensitivity up to 1240% at 500 Hz. Capacitance measurements ranged from approximately 50 pF to 577 pF, varying with soil type and environmental conditions.
The prototype has been successfully fabricated and tested.
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This sensor can help farmers monitor soil moisture and humidity accurately, leading to better irrigation decisions and reduced water waste. Its low cost and simple design make it ideal for rural use, promoting sustainable farming and improving crop yield through data-driven practices.
- Precision agriculture
- Smart irrigation systems
- Environmental monitoring
- Internet of Things (IoT) in agriculture
- Sensor manufacturing industry
Geography of IP
Type of IP
201621019123
462168