A study of vibration-based energy harvesting in activities of daily living

Pervasive health applications are usually based on wireless sensors integrated on a personal area network. Human body sensors are intended to be wearable in order to achieve user acceptance and help their integration in patient´s daily living activities. The size reduction of the employed devices, mainly limited by their batteries, is a key factor to achieve such a wearability. As a consequence, different energy harvesting sources are being studied to decrease or remove the dependence on batteries of sensors in personal wireless networks. This paper presents a study of vibration-based energy harvesting aiming to determine the power generation possibilities of human body motion during activities of daily living. A harvesting device is placed on different body parts together with an inertial unit so generated power-body motion patterns are obtained. Same activities showed different generated power depending on the device position. Activities containing high movement frequencies, accelerations and especially impacts, revealed to produce the highest power outputs. Hip and foot instep placing showed better performance and efficiency.