3 - Harnessing Ambient Energy for Embedded Systems

Abstract

Over the last decade, researchers and companies have been actively working to develop new methods and techniques for extracting, storing, and efficiently and economically exploiting the energy that surrounds us, often described as green energy. The process of gathering this energy is more commonly known as energy harvesting or energy scavenging. There are a number of physical phenomena that allow us to gather environmental (or ambient) energy and convert it into electrical form. The best-known methods are piezoelectricity and photoelectricity. Energy harvesting technology, still in its infancy for some types of energy, will allow wireless systems to become fully autonomous for the full duration of their lifetime. In this chapter, we will begin by giving an overview of the principal forms of energy present in our surroundings, whether already exploited or on their way to becoming exploitable in the near future. We will focus, in particular, on the types of energy that are particularly suitable for powering small embedded systems, such as wireless sensor nodes and cyber-physical systems. In the next chapter, we will then be able to describe the software technology crucial for implementing autonomous real-time systems characterized by two significant global constraints: time and energy.