A system has been designed that will allow a network of sensor nodes to request power from a base node and receive it wirelessly. The system consists of a central transmitting node which can be powered from an indefinite power source or from a reliable source of energy harvesting such as solar. This energy is converted into UHF radio waves and transmitted to individual stationary or mobile nodes making up the remainder of the network. When a sensor node detects that its onboard power supply is at a critical level it will request a top up from the base station. The base station will scan through 360° for the sensor node and once located begins charging. The charging station will remain in this position until the sensor batteries are fully charged. At this point the base station will seek out another sensor node if required, or go into a standby mode. If a mobile node is moved out of the charging position or interference of the beam occurs this is indicated to the charging station and the transmitting node will scan again until another node is relocated. Results indicate that charging can be obtained within a radius of up to 1.5 meters or greater for a higher transmission power. The sensor positioning and power monitoring aspects of the system could be retained for a laser based system, which would increase the transmission range. The system has the advantage that if sufficient solar energy can be captured during the day, charging of the sensor nodes can be maintained over night allowing the battery size of each sensor node to be reduced significantly.

Date Published: 26 April 2011
PDF: 10 pages
Proc. SPIE 7977, Active and Passive Smart Structures and Integrated Systems 2011, 797705 (26 April 2011); doi: 10.1117/12.880367

Published in SPIE Proceedings Vol. 7977:
Active and Passive Smart Structures and Integrated Systems 2011
Mehrdad N. Ghasemi-Nejhad, Editor(s)