An experimental analysis of pipe inspection using solar panel receiver for visible light communication and energy harvesting

The maintenance of water pipelines is quite essential since the leakage, deformation, and damage can bring fatal problems to the stable supply and safe use of water resource. In our former study, the transmission approach of information (image, sensor data, etc.) from water pipe based on visible light relay communication technology has been proposed since the visible light has less signal attenuation, stronger anti-electromagnetic interference capability, and smaller bit error ratio (BER) than traditional wireless solutions in the water pipe. However, each inspection sensor in the pipe is still powered by the battery, and thus, the operation time of the sensor is severely restricted by the battery consumption. Solar panel has been introduced in the visible light communication (VLC) technology due to its large signal receiving area and higher efficiency than traditional photodiode (PD) receivers. In this study, the performance of the solar panel receiver for VLC and energy harvesting (EH) has been analyzed. Since the LED owns low irradiation energy for energy harvesting, the received power of solar panel is low. To solve these problems, a solution by using sunlight for EH and LED light for VLC was proposed. We performed several experiments to evaluate the energy harvesting based on current and voltage, and VLC quality based on waveform and BER. The results indicated that the hybrid transmission method could increase the receiving current of solar panel with less influence on the VLC quality.