초록 ▼

A method and apparatus for detecting a level of a content in a vessel using an RFID tag. In one embodiment, an RFID tag located on one side of the vessel opposite a side on which the reader is, is interrogated. A reply signal, if any, received from the RFID tag is interpreted to determine the inform

A method and apparatus for detecting a level of a content in a vessel using an RFID tag. In one embodiment, an RFID tag located on one side of the vessel opposite a side on which the reader is, is interrogated. A reply signal, if any, received from the RFID tag is interpreted to determine the information returned from the RFID tag. The level of the content in the vessel is determined based on the information received from the RFID tag.

대표청구항 ▼

The invention claimed is: 1. A method of detecting a level of a content in a vessel using an RFID tag: interrogating an RFID tag in close proximity to one side of the vessel using a reader in close proximity to an opposite side of the vessel; interpreting a presence or absence of a reply signal rec

The invention claimed is: 1. A method of detecting a level of a content in a vessel using an RFID tag: interrogating an RFID tag in close proximity to one side of the vessel using a reader in close proximity to an opposite side of the vessel; interpreting a presence or absence of a reply signal received from the RFID tag to determine information returned from the RFID tag; and determining that the level of the content in the vessel is above or below a predetermined level based on the information received from the RFID tag. 2. The method of claim 1 wherein a lack of the reply signal indicates that the vessel is full. 3. The method of claim 1 wherein a portion of the RFID tag is always exposed and a reply indicates at least an existence of the RFID tag. 4. The method of claim 1 wherein a first reply signal from the RFID tag indicates a first level in the vessel and a second reply signal indicates a second level in the vessel. 5. The method of claim 1 wherein the content is a liquid. 6. The method of claim 1 wherein the content is a solid. 7. The method of claim 1 wherein the RFID tag is mounted on one side of the vessel. 8. The method of claim 1 wherein a change in fluid level is sensed by the RFID tag not responding to interrogation by the reader to responding to the interrogation. 9. A system for monitoring a level of a liquid in a vessel comprising: a RFID tag in close proximity to one side of the vessel; a RFID reader located in close proximity to another side of the vessel, positioned to be able to interrogate the RFID tag; and wherein as the level of the content of the vessel lowers, the RFID tag is exposed and can be interrogated by the reader to determine that the level of the liquid in the vessel is above or below a predetermined level. 10. The system of claim 9, wherein the system is a postage meter and the vessel is an ink container. 11. The system of claim 9 wherein the RFID tag is positioned in relation to the vessel so that at least a portion of the tag remains exposed when the level of the liquid is at a high point. 12. The method of claim 1 further comprising the RFID tag being active and able to be interrogated when a portion of the RFID tag is exposed. 13. The system of claim 9 wherein the RFID tag cannot transmit signals through the liquid. 14. The method of claim 1 wherein the RFID tag is electrically separated from the content of the vessel. 15. The method of claim 14 wherein the RFID tag is on an exterior of the vessel. 16. The method of claim 1 wherein the RFID tag is a passive RFID tag. 17. The system of claim 9 wherein the RFID tag is electrically separated from the liquid in the vessel. 18. The system of claim 9 wherein the RFID tag is mounted on an exterior of the vessel. 19. The system of claim 9 wherein the RFID tag is a passive RFID tag. 20. The method of claim 4, wherein the second level is lower than the first level.