The present invention is a fluid level sensing system for determining fluid levels in a fluid container. The system has a resonant member with an attached magnet. The resonant member is disposed in the fluid container. The system also has a sensing device for sensing motion of the magnet. The movement...http://www.google.com.au/patents/US6312074?utm_source=gb-gplus-sharePatent US6312074 - Method and apparatus for detecting fluid level in a fluid container
