ELECTRONIC MATERIALS Thermo-resistive property of carbon-graphite hybrid based thick film electrode on PET and paper substrates with a smart integrated system for productive soil farming applications Jeya Bharathi Subbiah Pandi 1, * , Hosimin Thilagar Srinivasan 1 , and Kanchana Mani 2 1 Department of Electrical and Electronics Engineering, College of Engineering, Anna University, Chennai, Tamilnadu 600025, India 2 Department of Printing, College of Engineering, Anna University, Chennai, Tamilnadu 600025, India Received: 15 April 2022 Accepted: 28 July 2022 Ó The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022 ABSTRACT This work brings in an eco-friendly, smart integrated miniaturized sensor sys- tem to determine the temperature of aqueous solution and soil in a more affordable way to yield quality farming, small-scale agricultural farming, greenhouse farming, domestic gardening, and hydroponics. Carbon-Graphite hybrid electrode-based planar disposable sensor strip is used for sensing the temperature over a range of 27 to 50°C. The temperature sensor element is compared to four distinct structures, and the meander geometrical structure is deduced as a result. The temperature sensing element is fabricated utilizing a prudent, efficacious, and inexpensive microfabrication methodology of screen printing. The temperature and resistance characteristics are plotted for the carbon-graphite electrode on PET and paper. The temperature coefficient of resistance is determined to be 1%/°C for PET and 0.8%/°C paper substrate in soil. Test experiment was carried out in water, oven and on field to find out the characteristic equation of study. The temperature sensor strip is integrated with a Wi-Fi SoC-assisted nodeMCU processor that is used in IoT platforms. An app is created using MIT app inventor user interface and is launched on an android smartphone. The app gives the suitable temperature range for sowing seed and germination of the plant growth information. The instantaneous temperature of soil or water is measured, and status information for plant cultivation is also provided by the app. Handling Editor: Maude Jimenez. Address correspondence to E-mail: jeyabharathi1608@gmail.com https://doi.org/10.1007/s10853-022-07603-z J Mater Sci Electronic materials