Design and performance analysis of a low cost light energy harvester for Wireless Sensors

Developments over the past decade in wireless and sensor technology have resulted in the growth of new applications for Wireless Sensor Networks (WSNs). One of the most popular areas for WSNs is the Built Environment Network (BEN), which comprises a wide variety of applications such as energy monitoring/smart homes, surveillance and healthcare applications. Such WSNs normally consist of a large number of devices with sensing, communications, and limited processing capabilities. These devices are very power constrained, as they typically depend on a small battery. Developments in recent years have led to an improvement in the energy efficiency of both hardware and software, which has resulted in increased lifetime of wireless sensors, but with limited battery capacity and size, real world lifetime is typically limited to 5 - 10 years. This paper presents a simple low cost, light energy harvester, that can easily be implemented with existing wireless sensor technology, to dramatically increase lifetime and remove the need for batteries. A WSN with nodes powered only by the presented harvester is deployed in an office, and results show that it can fully function in an environment where light is available for only 23.8% of the time.