Highly sensitive screen-printed soil moisture sensor array as green solutions for sustainable precision agriculture

• Published in: Sensors and actuators. A. Physical. Vol. 371; p. 115297
• Main Authors: Ullah, Asad, Zubair, Muhammad, Zulfiqar, Muhammad Hamza, Kamsong, Wichayaporn, Karuwan, Chanpen, Massoud, Yehia, Mehmood, Muhammad Qasim
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2024
• Subjects: Capacitive sensing; Flexible sensors; Green electronics; Interdigital electrode; Precision agriculture; Relative humidity; Screen printing; Soil monitoring; Screen printing; Relative humidity; Precision agriculture; Soil monitoring; Green electronics; Flexible sensors; Interdigital electrode; Capacitive sensing
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2024.115297

Monitoring soil moisture in real-time is an important parameter that helps farmers decide to enhance agriculture productivity and reduce resource wastage for better production and plant growth. In this work, we presented an easy-to-use and highly sensitive screen-printed flexible soil moisture sensor array to monitor soil moisture remotely for precision agriculture. The proposed sensor is based on a unique interdigitated electrode (IDE)-based capacitive structure with conductive carbon ink printed on a flexible polyethylene terephthalate (PET) substrate using the screen printing technique. Before soil moisture monitoring, the sensor is tested for humidity monitoring in an environmental chamber. A response of ∼144–1760 pF for 20–100%RH with 10%RH variation is observed for a single sensor, while an array configuration ranges from ∼127–1802 pF. The sensor response is observed for a temperature range from 20 to 50 ‘C. The sensor's sensitivity for relative humidity sensing is 19.123%pF/RH, and the response and recovery time are ∼3.3 s and ∼4.2 s. Further, the sensor is tested for soil moisture sensing, as moisture content is gradually added to the completely dry soil. A highly sensitive response for soil moisture content (MC) with a ∼40.7%pF/MC sensitivity is obtained. The sensor data is transmitted wirelessly using a Bluetooth module. The sensor is supported by a wooden stick, which illustrates the capabilities of biodegradability, the sensor is cost-effective and provides a real-time measurement for soil moisture. The sensors have the potential to provide maintenance-free monitoring, facilitating precise control of irrigation practices in precision agriculture. With their affordability and ability to operate on a large scale, the sensor offers promising opportunities for enhancing irrigation systems. [Display omitted] •A highly sensitive, printed, and flexible sensor’s array is presented to monitor soil moisture content and humidity.•A unique IDE based design is proposed to enhance the sensor sensitivity which is important parameter for agriTech monitoring.•Response of the soil sensor array for given humidity is ∼144-1760pF, with sensitivity of 19.123%pF/RH.•The sensor illustrates cost-effectiveness and real-time soil moisture measurement capabilities for precision agriculture.•The soil moisture sensor enables maintenance-free monitoring, aiding precise irrigation control in precision agriculture.