US Patent 8467981 Non-invasive liquid level sensing system and method

A non-invasive liquid level sensing system for monitoring the amount of liquid in at least one container includes a platform for supporting the at least one container, at least one holder associated with the at least one container supported by the platform, a source for generating a radio frequency signal, circuitry in communication with the at least one holder for transmitting the radio frequency signal through the at least one holder into the at least one container and receiving a portion of the radio frequency signal reflected at a liquid-air interface in the at least one container, and circuitry for processing the reflected radio frequency signal and determining the amount of liquid in the at least one container.