Real-time measurement and monitoring system for the fruit ripening process with a wireless, low-power and long-distance communication

Establishing a proper harvesting schedule based on the fruit ripening process is the key issue for guaranteeing high-quality fruits to consumers. Previously, several non-destructive evaluation methods have been used to monitor and quantify the fruit ripeness. However, conventional equipment entails bulkiness, costliness, and huge power consumption. The authors propose a capacitive sensing-based real-time measurement system for the fruit ripening process. As a communication method between the device and its users, LoRa was adopted for long-distance and secured data communication with lower power consumption while conductive gel pads were utilized to realize capacitive sensing. The measurement system installed on plum tomatoes was regularly under observation for 2 weeks. The increasing ratios of the capacitance were calculated with its initial values and compared to the 5 ripening stages of the plum tomato represented by different colors. Our measurement system for the fruit ripening process showed a relevant and reliable relationship between the fruit ripening stages and the capacitance changes, which would be able to elucidate the understanding of plant physiology and to promote the production of high-quality fruits in a sophisticated manner.