Development and Evaluation of Mobile-App Controlled Self-Propelled Sensor-Integrated Rover for Site Specific Fertility Monitoring

The study was directed to programme and calibrate soil fertility (nitrogen, phosphorus and potassium) sensor, integrate the sensor with self-propelled solar-powered rover and evaluate the performance of the setup at different field conditions. Using KOTLIN programming in AndriodStudio software, a mobile App was also developed to control the movement of rover, sensor and record the data. The optimization of working parameters and economic assessment was also carried out to assess the technical feasibility and economic viability of the technology. The results revealed that calibrated sensor possessed 90.47% efficiency and 9.52% error percentage at depth of 7 cm with 30–50% moisture content. The self-propelled solar-powered sensor integrated rover comprised of main frame, power unit, electronic circuit, microcontroller and sensor unit. The sensor integrated rover was tested in terms of soil condition (untilled, disc plough tilled and rotavator tilled), depth (3 cm, 5 cm and 7 cm) and response time (5, 10 and 15 s) and responses were nitrogen content (mg kg−1), phosphorus content (mg kg−1) and potassium content (mg kg−1). The optimum working conditions occurred at 3 cm depth for untilled condition with 216.69 mg kg−1 nitrogen, 31.0 mg kg−1 phosphorus and 125.75 mg kg−1 potassium content. The cost of the sensor integrated self-propelled rover was estimated as Rs. 30,000. The cost parameters were observed as Rs. 110.0 per hour operating cost, 1.38 benefit–cost ratio, 28.51 ha break-even point and 769.23 h payback period, respectively. The sensor integrated rover can be useful for remote monitoring of soil fertility in vegetable crops, cereal crops and orchards, besides a potent tool to generate employment through custom hiring centers. © The Institution of Engineers (India) 2025.