An Orientation-Independent Multi-Input Energy Harvesting Wireless Sensor Node

Deploying energy harvesting-based wireless sensor nodes (WSNs) in challenging environments often means we do not have precise control over the placement and orientation of the nodes. This article introduces a novel smart WSN whose operation does not depend on its placement and orientation. The proposed WSN unit is a cube-shaped device, each side of which is a complete wireless sensor module, sharing a common energy storage and a common communication bus with the other faces. In this article, an energy-efficient algorithm is designed based on the concepts of "strongest energy face" and "strongest radio face." The proposed algorithm facilitates energy and information sharing among the faces of the cube with the common goal of harvesting the maximum possible energy from all sides, aggregating the energy on the shared energy bus, and then, using the strongest radio face to transmit the sensed signal to the base station. The concept is verified in a 50-cm(3) laboratory prototype built with off-the-shelf components. The experimental results show that the device successfully transmits the sensed data even in the worst case where only one face, which may not be the transmitting face, is harvesting energy.