Printed Sensor Technologies for Monitoring Applications in Smart Farming: A Review

Smart farming is the integration of advanced technologies such as sensors, wireless communication, Internet of Things (IoT), artificial intelligence (AI), and robots, with traditional farming practices. The goal is to increase the yield and quality of the crops or other agricultural products, as well as to reduce the cost and improve efficiency. Sensors play a critical role in smart farming as they provide the most important information related to varied aspects of agriculture, namely soil conditions, plant growth, and environmental conditions. With the emergence of printed electronics technologies, printed sensors have gained much attention in recent years. Printed sensors are fabricated through the additive manufacturing and are extremely versatile. They can be made on any solid substrate and be conformable, flexible, stretchable, low-cost, and/or bio-degradable. These unique features have made the printed sensors attractive for a variety of applications. This article aims to review the potential applications of printed sensors in smart farming. First, the state of the art of printed sensor fabrication is presented with a discussion on their advantages and disadvantages. Then, the measurement and monitoring applications of printed sensors in the key aspects of smart farming, are reviewed, including measurement of chemicals, soil monitoring, and microclimate monitoring in greenhouses. The article also pinpoints the limitations and potentials of printed sensors for farming applications. This article will benefit the researchers and practitioners in the field to advance the printed sensor technologies to mitigate the current issues in smart farming.