Hybrid energy harvester using optimised piezoelectric and solar power for self-powered global positioning tracking system

Abstract

The rapid advancement of Wireless Sensor Nodes (WSNs) in conjunction with the Global Positioning System (GPS) tracker has resulted in various applications, including health monitoring, industrial process monitoring, and security system monitoring. However, a significant problem of the GPS device is short tracking and positioning due to high power consumption. This study develops a Self-Power Global Positioning System (SP-GPS) for tracking objects powered by hybrid energy harvesting sources, piezoelectric and solar. First, the Taguchi Design of Experiment (DOE) method is used to optimise the design of the piezoelectric energy harvester based on ruler and cylinder designs. Then, the piezoelectric is combined with solar to create the hybrid Power Management Unit (PMU) for the sustainability of the SP-GPS Tracker device. Finally, to develop the SP-GPS tracking system, the SP-GPS tracker is integrated with SP-GPS Base Station. The results demonstrated that the optimum design for a ruler-based piezoelectric generator is five centimetres and a mass of two grams. Meanwhile, the optimum design for a cylindrical shape of piezoelectric is the glass ball-bearing material with a mass of five grams, and the height between the ballbearing and casing surfaces is five millimetres. Based on the field experiments around the Universiti Teknologi Malaysia campus by motorcycle and a car with a distance of 1.74 km and average speed from 11.8 to 24.1 kmh, the total energy generated by hybrid energy harvester of piezoelectric design is a cylinder (glass), 6.07 kWh and ruler, 2.85 kWh, respectively. On the other hand, the piezoelectric cylinder design achieved higher total energy of 6.26 kWh and 2.96 kWh. The reason is that the latter design can induce considerable vibration with the impact of the heavy mass glass ball-bearing on the cylinder surface. The estimated life span of SP-GPS Tracker is computed and found can be up to approximately two years and three months for a motorcycle and one year and five months for a car. Therefore, the current study benefits long-term tracking and monitoring, such as wild animals or vehicles, in observing their pattern movement.