Power scavenging enables maintenance-free wireless sensor nodes
Fred M. Discenzo
Last modified: June 7, 2006
Pumps, fans, and compressors are critical elements in many industrial, commercial, and shipboard systems. Effective failure prevention may be performed by continuously monitoring critical machines and identifying incipient failures in time to permit orderly repair or other corrective action. Considerable development work is underway to implement wireless sensor nodes employing “motes” or other low-power processors, sensors, memory, and communications. The remaining maintenance burden of periodically replacing batteries may be eliminated by scavenging energy from the environment. Energy scavenged from the environment may be converted and stored as needed to power remote sensors, processors, and RF communications. Furthermore, there is an information content in the scavenged energy that may augment or replace conventional machinery diagnostic sensors.
This paper describes the development of several prototype wireless self-powered sensor nodes. Power is extracted from the vibration of an oil pump using tuned piezo-electric elements. Self-powered sensor nodes each perform local processing and transmit analytic results or raw data to a central node for database storage and more extensive analysis. Power efficiencies are reported along with opportunities for adaptive power scavenging and dynamically optimizing power consumption. The system design problem is formulated and design and operation rules are established to optimize the amount of power available to perform useful work. Examples are presented from a laboratory pump systems and from a recent at-sea trial.