Flexible wearable optical wireless sensing system for fruit monitoring

Conventional rigid optical-electronic systems need to be improved to adapt to the current food quality monitoring. This paper aims to propose and develop a flexible wearable optical wireless sensing system (FWOS) by laser ablation of polyethylene terephthalate/polyimide/copper (PET/PI/Cu) film. The FWOS can consist of different sensor arrays to suit different fruit sizes. FWOS can acquire the spectral data of the fruit and transmit it by Bluetooth (BT) to smartphones or personal computers (PCs). Simulations are used to determine the most suitable ablation power and speed and to measure the surface characteristics of the flexible Cu circuit using a stereomicroscope. FWOS has the characteristics of a simple process, simple operation, low cost, low power consumption, real-time monitoring, and small physical size. The soluble solids content (SSC) of apples, grapes, peaches, and cherries was evaluated. The results show the potential application of FWOS for quality monitoring of a wide range of fruits. It can significantly reduce fruit waste rates and ensure food quality and safety.