Energy harvesting (EH) is the capture of ambient energy as an unlimited energy source for powering electronic devices. Energy harvesting in sensor networks is deployed as part of an overall Power Management System to create the most efficient use of the total energy available to the network.

One challenge in deploying a sensor network is providing consistent energy to remotely located wireless sensor nodes; hence, the addition of EH as a power source can greatly expand the potential applications, as well as greatly decrease the costs associated with replacing conventional batteries.

EH Components in Sensor Networks:

Energy Harvesting Module: This module captures, stores and manages harvested energy. It includes a transduction device, microprocessor, energy storage device, buffers and additional circuitry for adjusting the harvested power such as a low voltage booster. Examples of such modules include:

EH transduction devices convert ambient energy into usable electrical signals. Specialized materials are used to manufacture these devices, including photovoltaic cells; piezoelectric, electromagnetic, thermoelectric and biochemical materials; and micro-electro mechanical systems (MEMS) materials.

EH storage devices include rechargeable batteries and capacitors.to store the harvested energy so that a constant amount of current can be supplied during times the ambient energy source is not present, like solar energy at night.

Rechargable batteries: Thin Film batteries are often used for their ultra-thin profile and low leakage characteristics. Solid State rechargeable are another good EH option.

Distributed or centralized: Depending on the sensor network type (wired, wireless, combination) EH devices can be centralized or distributed throughout the entire system. Distributed EH modules are integrated with each individual sensor node to create an “energy harvesting sensor.” This type of EH tends to be employed with wireless systems. Centralized EH modules are not integrated with each node and tend to be deployed in wired and fiber-optic based sensor networks.

Power management software module to manage and optimize the efficient use of the power. Specialized power budgeting protocols and algorithms are used to maximize power generated and minimize power use. Since the most energy intensive function is transmitting data, our specialized algorithms focus on precisely controlling the sleep/wake/transmit and receive cycles of the sensor node transceiver, while Multi Sensor Data Fusion (MSDF) algorithms minimize redundancy in the data to reduce the data transmission size.