Harvesting energy from the environment is very desirable for many emerging applications that use embedded devices. Energy harvesting also known as energy scavenging enables us to guarantee quasi-perpetual system operation for wireless sensors, medical implants, etc. without requiring human intervention which is normally necessary for recharging batteries in classical battery-operated systems. Nevertheless, energy harvesting calls for solving numerous technological problems in relation with chemistry when batteries are used for temporary energy storage for example, power management of the embedded computing system that consumes the energy, etc. And this latter problem becomes more complex when the embedded system has real-time constraints i.e. deadlines attached to computations. This paper surveys the main issues involved in designing energy harvesting embedded systems that present strict timing requirements. Energy harvesting is a technique that generates electricity from renewable energy sources. Although it has been used for a long time (windmill, solar panel, etc.), the innovation lies in the design of smart embedded systems with efficient energy harvesting capabilities while satisfying reliability, dimensioning and timing requirements that characterize modern embedded computers. Any energy harvesting system is composed of three parts which respectively concern conversion from one form of energy in electricity, storage of the energy once it has been harvested from the source and finally consumption of the energy by the embedded computing system. Many forms of energy can be harvested from the environment and consequently they use different types of generators. They include mechanical, thermal, photovoltaic, electromagnetic, biological, and chemical energy. Solar energy and mechanical energy are certainly the most prevalent ones. For example, the mechanical energy can be drained from ambient vibration. (Task Scheduling In Energy Harvesting Real-time Embedded Systems, Maryline Chetto)
Last date updated on April, 2024