Kinetic-based micro energy-harvesting for wearable sensors

Wearable sensors are considered to be a key component of cognitive infocommunications systems. These sensors, which are basically enabler of inter-cognitive communication, will provide physical interfaces between humans and future information and communication technology (ICT) devices. Due to their small size, such sensors are often powered by small batteries which might necessitate frequent recharge or even sensor replacement. Energy harvesting can reduce the charging frequency of these sensors. Longer operational lifetime can simplify the everyday use of wearable sensors in many of their applications. In this paper, our objective is to estimate the average amount of kinetic energy that can be harvested to power a wearable device. To obtain this estimate, we have measured typical acceleration of the human body through the use of a triaxial accelerometer placed at various locations on the body surface. These locations are assumed to be associated with the typical placement of a wearable sensor. Using the mathematical model of a micro energy-harvester, instantaneous harvested power can be generated, and target statistics such as average power can be calculated. Our preliminary results show that kinetic-based micro harvesters could be a promising technology for prolonging the operational lifetime of wearable sensors.