Wireless liquid level sensing system and method
AssigneeMitsubishi Electric Research Laboratories, Inc.
InventorPaul H. Dietz
Life of this patent
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Abstract
A wireless liquid sensing system includes a beverage container and a table top for holding the container. Embedded in the walls and bottom of the container are two electrically conductive plates coupled to a transponder wire coil. A reader radiates an RF signal at a predetermined frequency through a reader antenna. A microprocessor, also coupled to the transponder coil and the two plates, is powered by a rectifier circuit that gains power from then radiated RF signal. The microprocessor amplitude modulates the RF signal in accordance with the amount of liquid in the container. The reader can then detect this modulation with a peak detector to sense the amount of the substance in the container when the transponder antenna is inductively coupled to the reader antenna at the predetermined frequency.
Claims17
A system for sensing an amount of a substance, comprising:
- a container;
- two plates mounted thereon, the plates being electrically conductive;
- a transponder antenna coupled to the two plates;
- and
- a reader having a reader antenna resonating at a predetermined frequency, the reader sensing an amount of a substance in the container when the transponder antenna is inductively coupled to the reader antenna at the predetermined frequency depending on the amount of the substance in the container.
A method for sensing an amount of a substance, comprising:
- resonating a reader antenna at a predetermined frequency;
- and
- modulating the predetermined frequency in a transponder antenna coupled to two electrically conductive plates mounted in a container according to an amount of substance in the container;
- and
- sensing the modulated predetermined frequency in a reader coupled to the reader antenna to determine the amount of substance in the container when the reader and transponder antennas are inductively coupled.
A system for sensing an amount of a substance in a container, comprising:
- two capacitive plates mounted on the container;
- a first coil having ends directly coupled to the two plates;
- and
- a reader having a second coil resonating at a predetermined frequency, the reader sensing an amount of a substance in the container when the first coil is inductively coupled to the second coil by capacitively coupling of the two plates at the predetermined frequency depending on the amount of the substance in the container.
Dependencies are inferred from the claim text.