Portable device for dual impedance and mass measurement in fruit ripening assessment

Quality assessment of fruit ripeness is essential for reducing postharvest losses and ensuring consumer satisfaction. Conventional methods for evaluating fruit maturity are often destructive, labour-intensive, and unsuitable for continuous monitoring. This study presents a portable, low-cost dual-sensor device capable of simultaneously measuring electrical impedance and mass to enable non-destructive tracking of fruit ripening. The system integrates an AD5933-based impedance spectroscopy module and a strain-gauge load cell (HX711 amplifier) with an Arduino UNO for real-time data acquisition and storage. Impedance spectroscopy was performed across 4–30 kHz with a 400-mV excitation voltage, while the load cell provided high-resolution weight measurements. Electrical validation using a 1 kΩ–1 µF parallel RC circuit demonstrated good agreement between measured and theoretical impedance and phase responses, and load cell calibration exhibited relative error below approximately 2%. A seven-day proof-of-concept experiment on Musa acuminata bananas demonstrated measurable changes associated with ripening; impedance magnitude at 12 kHz decreased from roughly 6.5 kΩ on Day 0 to 5.5 kΩ by Day 7, accompanied by a progressive phase shift toward more resistive behaviour and a steady reduction in fruit mass due to moisture loss. The combined trends show that the dual-parameter measurements captured ripening-related physiological changes under the tested conditions. These results indicate that the proposed device offers a practical platform for non-destructive fruit quality monitoring and provides a foundation for further development toward broader agricultural applications.