Method and apparatus to perform a predefined search on data carriers, such as RFID tags

• US 6,286,762 B1
• Filed: 09/21/1999
• Issued: 09/11/2001
• Est. Priority Date: 09/21/1999
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.), Siemens Corporate Research Incorporated (Siemens AG)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Wiklof, Christopher A., Bodnar, Daniel B., Reynolds, Andrew E.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US09/401,363
• Time in Patent Office: 721 Days
• Field of Search: 235/472.01, 235/472.02
• US Class Current: 235/472.01
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader

Abstract

A data carrier reader is capable of executing a number of different reading methods. One method performs an inclusive search, identifying all RFID tags having a characteristic data string that appears on a list of characteristic data strings, for example, stored in a buffer. Another method performs and exclusive search, identifying any RFID tags having a characteristic data string that does not appear on the list. In each method, the data carrier reader provides a consistent and intuitive output the user to identify the successful and unsuccessful operations such as locating a desired RFID tag on the list or missing from the list.

Claims

1. A method of automatically searching RFID tags, comprising:

storing a number of characteristic data strings in a buffer;

reading a respective characteristic data string from each of a number of RFID tags; and

identifying any of the RFID tags that have the respective characteristic data strings that correspond to the characteristic data strings stored in the buffer after reading the respective characteristic data strings from at least two of the number of RFID tags.

2. The method of claim 1 wherein identifying the RFID tags includes comparing at least a portion of each of the read characteristic data strings to at least one of the characteristic data strings stored in the buffer.

3. The method of claim 1, further comprising:

producing a human-perceptible indication corresponding to the number of identified RFID tags.

4. The method of claim 1, further comprising:

producing a human-perceptible indication for each of the identified RFID tags.

5. The method of claim 1, further comprising:

producing a human-perceptible indication having a characteristic that varies corresponding to the number of identified RFID tags.

6. The method of claim 1, further comprising:

producing a second human-perceptible indication each time one of the read characteristic data strings matches at least one of the characteristic data strings stored in the memory.

7. The method of claim 1, further comprising:

producing a second human-perceptible indication if all of the characteristic data strings stored in the memory match at least a respective one the read characteristic data strings.

8. The method of claim 1, further comprising:

relaying data from the identified RFID tags to a host computer.

9. The method of claim 1, further comprising:

transmitting an enable signal to a first one of the RFID tags that has a respective characteristic data string that matches one of characteristic data strings stored in the memory, the enable signal comprising a command to activate a human-perceptible indicator on the first one of the RFID tags.