U.S. patent application number 09/911881 was filed with the patent office on 2001-11-29 for method and apparatus to read different types of data carriers, such as rfid tags and machine-readable symbols, and a user interface for the same.
Invention is credited to Bodnar, Daniel B., Reynolds, Andrew E., Wiklof, Christopher A..
Application Number | 20010045460 09/911881 |
Document ID | / |
Family ID | 23587440 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045460 |
Kind Code |
A1 |
Reynolds, Andrew E. ; et
al. |
November 29, 2001 |
Method and apparatus to read different types of data carriers, such
as RFID tags and machine-readable symbols, and a user interface for
the same
Abstract
A data carrier reader includes an RFID tag reading section and a
machine-readable symbol reading section, which can contain some
common components. The reader is operable in an RFID tag reading
mode and/or a symbol reading mode. The reader provides a consistent
and intuitive user interface within, and between, the operating
modes. The user interface can include visual, aural and tactile
indicators. The visual indicators can include a pattern displayed
by indicators on the reader, or projected onto or near the data
carrier.
Inventors: |
Reynolds, Andrew E.;
(Bothell, WA) ; Wiklof, Christopher A.; (Everett,
WA) ; Bodnar, Daniel B.; (Duvall, WA) |
Correspondence
Address: |
SEED INTELLECTUAL PROPERTY LAW GROUP PLLC
701 FIFTH AVE
SUITE 6300
SEATTLE
WA
98104-7092
US
|
Family ID: |
23587440 |
Appl. No.: |
09/911881 |
Filed: |
July 23, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09911881 |
Jul 23, 2001 |
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09401362 |
Sep 21, 1999 |
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Current U.S.
Class: |
235/385 |
Current CPC
Class: |
G06K 7/10881 20130101;
G06K 7/0004 20130101 |
Class at
Publication: |
235/385 |
International
Class: |
G06F 017/60 |
Claims
We claim:
1. A multi-purpose data carrier reader, comprising: a symbol
reading section including an image sensor to image machine-readable
symbols; an RFID tag reading section including a radio to
interrogate RFID tags; a first set of human-perceptible indicators
coupled to the symbol reading section for control thereby to
produce human-perceptible indications in response to at least one
symbol reading activity; and a second set of human-perceptible
indicators, different from the first set of human-perceptible
indicators and coupled to the RFID tag reading section for control
thereby to produce human-perceptible indications in response to at
least one RFID tag reading activity.
2. The reader of claim 1 wherein each of the first and second sets
of human-perceptible indicators include a respective light emitting
diode of a first color, the first color light emitting diode in the
first set of human-perceptible indicators being activated when a
machine readable symbol is successfully read and the first color
light emitting diode in the second set of human-perceptible
indicators being activated when an RFID tag is successfully
read.
3. The reader of claim 1 wherein the first set of human-perceptible
indicators produces a first human-perceptible signal when a machine
readable symbol is successfully read; and the second set of
human-perceptible indicators produces the first human-perceptible
signal when an RFID tag is successfully read.
4. The reader of claim 1 wherein the first set of human-perceptible
indicators produces a first human-perceptible signal when a first
symbol reading activity occurs; and the second set of
human-perceptible indicators produces the first human-perceptible
signal when a corresponding RFID reading activity occurs.
5. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are visual indicators.
6. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are light emitting diodes.
7. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are visual indicators are icons
displayed on a display.
8. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are visual indicators are
alpha-numeric characters displayed on a display.
9. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are sounds emitted from an audio
source.
10. The reader of claim 1 wherein the first and second set of
human-perceptible indicators are vibrations emitted by a tactile
source.
11. A multi-purpose data carrier reader, comprising: a symbol
reading section including an image sensor to image machine-readable
symbols; an RFID tag reading section including a radio to
interrogate RFID) tags; and a mode switch configured to switch
operation between the symbology reader section and the RFID tag
reader section.
12. The reader of claim 11 wherein the mode switch is a user
selectable switch.
13. The reader of claim 11 wherein the mode switch is a user
selectable membrane switch.
14. The reader of claim 11 wherein the mode switch is responsive to
a command signal from an external host device.
15. The reader of claim 11 wherein the mode switch provides a
command signal to an external host device.
16. The reader of claim 11 wherein the mode switch is responsive to
at least a portion of data in a previously read data carrier.
17. The reader of claim 11 wherein the mode switch is a trigger
responsive to select a mode based on a number of successive trigger
activations.
18. The reader of claim 11 wherein the mode switch is a trigger
responsive to select a mode based on a duration of trigger
activation.
19. The reader of claim 11, further comprising a first number of
visual indications corresponding to a symbol mode and a second
number of visual indicators corresponding to an RFID mode, wherein
the mode switch has at least a first and a second positions, the
first and second positions oriented to provide a visual indication
consistent with the positions of the visual indicators.
20. A method of operating a data carrier reader, comprising:
selecting one of at least two human-recognizable temporal
indication patterns based on a current operation of the data
carrier reader, where the human-recognizable temporal indication
patterns each correspond to a respective temporal user indication;
and projecting light substantially outward of the data carrier
reader to form the selected human-recognizable temporal indication
pattern.
21. The method of claim 20 wherein projecting the light includes
successively flashing the light to produce the selected
human-recognizable temporal indication pattern.
22. The method of claim 20 wherein projecting the light includes
selectively flashing a first color light and a second color light
to produce the selected human-recognizable temporal indication
pattern.
23. The method of claim 20 wherein projecting the light includes
modulating a laser to produce the selected human-recognizable
temporal indication pattern.
24. The method of claim 20, further comprising: modulating a laser
while in an RFID reading mode to produce the selected
human-recognizable temporal indication pattern; and illuminating a
symbol with the laser in a symbol reading mode to scan the
symbol.
25. A data carrier reader, comprising: a first light source
substantially alignable with a data carrier; a processor coupled to
control the first light source to produce a selected one of at
least two human-recognizable temporal indication patterns based on
a reader operation, where each of the human-recognizable temporal
indication patterns correspond to a respective temporal user
indication.
26. The data carrier reader of claim 25 wherein the processor is
coupled to control the first light source to produce a scanning
beam across the data carrier in a symbol reading mode, and to
produce the selected human-recognizable indication pattern in an
RFID reading mode.
27. The data carrier reader of claim 25 wherein the selected
human-recognizable indication pattern includes a number of
successively timed flashes of light.
28. The data carrier reader of claim 25 wherein the selected
human-recognizable indication pattern includes a number of
different color flashes of light, successively timed.
29. A method of operating a data carrier reader having a laser,
comprising: producing a first scanning laser beam with the laser in
a symbol reading mode; and producing a human-recognizable temporal
indication pattern based on a reader operation in an RFID reading
mode.
30. The method of claim 29, further comprising: selecting the
human-recognizable temporal indication pattern from a number of
human-recognizable temporal indication patterns, the
human-recognizable temporal indication patterns corresponding to
respective temporal user indications.
Description
TECHNICAL FIELD
[0001] This application relates to methods and apparatus for
reading data carriers such as machine-readable symbols (e.g.,
barcode symbols, area and/or matrix code symbols) and wireless
memory devices (e.g., RFID tags).
BACKGROUND OF THE INVENTION
[0002] A variety of methods exist for tracking and providing
information about items. For example, inventory items typically
carry printed labels providing information such as serial numbers,
price, weight, and size. Some labels include data carriers in the
form of machine-readable symbols that can be selected from a
variety of machine-readable symbologies, such as bar code, and/or
area or matrix code symbologies. The amount of information that the
symbols can contain is limited by the space constraints of the
label. Updating the information in these machine-readable symbols
typically requires the printing of a new label to replace the old
label.
[0003] Data carriers such as memory devices provide an alternative
method for tracking and providing information about items. Memory
devices permit the linking of large amounts of data with an object
or item. Memory devices typically include a memory and logic in the
form of an integrated circuit ("IC") and means for transmitting
data to and/or from the device. For example, a radio frequency
identification ("RFID") tag typically includes a memory for storing
data, an antenna, an RF transmitter, and/or an RF receiver to
transmit data, and logic for controlling the various components of
the memory device. RFID tags are generally formed on a substrate
and can include, for example, analog RF circuits and digital logic
and memory circuits. The RFID tags can also include a number of
discrete components, such as capacitors, transistors, and
diodes.
[0004] RFID tags can be passive, active or hybrid devices. Active
devices are self-powered, by a battery for example. Passive devices
do not contain a discrete power source, but derive their energy
from an RF signal used to interrogate the RFID tag. Passive RFID
tags usually include an analog circuit that detects and decodes the
interrogating RF signal and that provides power from the RF field
to a digital circuit in the tag. The digital circuit generally
executes all of the data functions of the RFID tag, such as
retrieving stored data from memory and causing the analog circuit
to modulate the RF signal to transmit the retrieved data. In
addition to retrieving and transmitting data previously stored in
the memory, the RFID tag can permit new or additional information
to be stored in the RFID tag's memory, or can permit the RFID tag
to manipulate data or perform some additional functions. RFID tags
are available from a number of manufacturers, including Texas
Instruments, Dallas, Tex., and Omron of Japan.
[0005] Another form of memory device is an optical tag. Optical
tags are similar in many respects to RFID tags, but rely on an
optical signal to transmit data to and/or from the tag.
[0006] Additionally, touch memory data carriers are available, for
example touch memory devices from Dallas Semiconductor of Dallas,
Tex. Touch memory devices are similar to RFID tags but require
physical contact with to store and retrieve data.
[0007] A user typically secures a data carrier to an item, such as
a good, product, or container by way of a pressure sensitive
adhesive. The data carrier often encodes information specifically
relating to the item such as identifying or destination
information. An individual, such as a checkout or inventory clerk,
can retrieve data about any given item, for example, by scanning
the machine-readable symbol or interrogating the RF tag, optical
tag, or touch memory device. Access to the data can be useful at
the point of sale, during inventory, during transportation, or at
other points in the manufacture, distribution, sale, or use of the
tagged item.
[0008] Relatively high cost is one of the drawbacks of memory
devices, thus, many applications rely on the less expensive printed
machine-readable symbols. Another significant drawback is the
difficulty of identifying a particular memory device from a group
of memory devices. It is particularly difficult to associate the
information read from the RFID tag with a physical item or
container. The ability to read data from different types of data
carriers, for example machine-readable symbols and RFID tags,
and/or to associate and manipulate such data can provide numerous
benefits in the automatic data collection ("ADC") industry.
SUMMARY OF THE INVENTION
[0009] In one aspect a data carrier reader includes an RFID tag
reading section and a machine-readable symbol reading section,
which can contain some common components. The reader is operable in
an RFID tag reading mode and/or a symbol reading mode. The reader
provides a consistent and intuitive user interface within, and
between, the operating modes. The user interface can include
visual, aural and tactile indicators. The visual indicators can
include a pattern displayed by indicators on the reader, or
projected onto or near the data carrier.
[0010] In another aspect, a data carrier reader is capable of
executing a number of different reading methods. A method for
reading single RFID tags can store read data to a buffer for
eventual transmission to a host, and can suppress redundant data.
Another method identifies all RFID tags having a characteristic
data string that appears on a list. In contrast, another method
identifies any RFID tags having a characteristic data string that
does not appear on the list. Still another method associates data
read from an RFID tag with a particular object or item using a data
coded in a machine-readable symbol. In a further method, the
machine-readable symbol is automatically read when the RFID tag is
within a predetermined proximity of the reader. In each method, a
consistent and intuitive output can be provided to the user to
identify the successful and unsuccessful operations such as reading
an RFID tag or machine-readable symbol.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the drawings, identical reference numbers identify
similar elements or acts. The sizes and relative positions of
elements in the drawings are not necessarily drawn to scale. For
example, various elements may be arbitrarily enlarged and
positioned to improve drawing legibility.
[0012] FIG. 1 is a partial block diagram, partial front elevational
view of a facility including a data carrier reader reading data
carriers carried by a number of items, the reader communicate with
a host through an interface.
[0013] FIG. 2 is a functional block diagram of the reader according
to one embodiment of the invention.
[0014] FIG. 3 is a top plan view of the reader of FIG. 2.
[0015] FIG. 4 is a partial top plan view of an alternative set of
visual indicators for the reader of FIG. 2.
[0016] FIGS. 5A-5C together form a chart of selected input and
output signals for operating the reader of FIG. 2 and the visual
indicators of FIG. 4.
[0017] FIG. 6 is a top plan view of a graphic display of the reader
of FIG. 3.
[0018] FIG. 7 is a top plan view of an alpha-numeric display of the
reader of FIG. 3.
[0019] FIG. 8 is a flowchart showing a method of reading single
RFID tags.
[0020] FIG. 9 is a flowchart showing a method of determining when a
reader is finished reading RFID tags.
[0021] FIG. 10 is a flowchart showing a method of reading multiple
RFID tags.
[0022] FIG. 11 is a flowchart showing a method of performing an
inclusive search of RFID tags.
[0023] FIG. 12 is a flowchart showing a method of performing an
exclusive search of RFID tags.
[0024] FIG. 13 is a flowchart showing a method of associating data
from an RFID tag with an item using a machine-readable symbol.
[0025] FIG. 14 is a flowchart showing a method of automatically
imaging a machine-readable symbol based on proximity to an RFID tag
to associate data from an RFID tag with an item using the
machine-readable symbol.
DETAILED DESCRIPTION OF THE INVENTION
[0026] In the following description, certain specific details are
set forth in order to provide a thorough understanding of various
embodiments of the invention. However, one skilled in the art will
understand that the invention may be practiced without these
details. In other instances, well-known structures associated with
RFID tags, RFID tag readers, one- and two-dimensional symbologies,
symbol readers, microprocessors and communication networks have not
been shown or described in detail to avoid unnecessarily obscuring
descriptions of the embodiments of the invention.
[0027] The headings provided herein are for convenience only and do
not interpret the scope or meaning of the claimed invention.
[0028] Data Carrier Reader
[0029] FIG. 1 shows a data carrier reader 10 reading one or more of
a number of data carriers, such as the RFID tags 12 on the
containers or items 14. The reader 10 includes a head 16, a handle
18 and a trigger 20. An interface 22 can couple the reader 10 to a
host 23, such as a centralized computer, as described in detail
below.
[0030] The tags 12 can take the form of an RFID tag 12A that
carries a machine-readable symbol 24A on a visible surface of the
tag. Alternatively, the tags 12 can take the form of a separate
RFID tag 12B and machine-readable symbol 24B. The separate RFID tag
12B and machine-readable symbol 24B can be physically associated,
for example, securing each to the same physical object, such as the
item 14. The RFID tag 12A, 12B and machine-readable symbol 24A, 24B
can contain logically associated information, for example
information related to the item 14 to which the tags 12 are
secured, such as identifying and/or shipping information.
[0031] As shown in FIG. 2, the reader 10 contains an RFID tag
reading section 30, a symbol reading section 32, a user input
section 34, a user output section 36, and a communications section
38 all coupled by a bus 40. The bus 40 provides data, commands
and/or power to the various sections 30-38. The reader 10 can
include an internal power source such as a rechargeable battery
(not shown) or can receive power from an external power source such
as a wall outlet by way of an electrical cord (not shown). Each of
these sections 30-38 will be described individually below, although
in the illustrated embodiment some of these sections share common
components.
[0032] RFID Tag Reading Section
[0033] FIG. 2 shows the RFID tag reading section 30 of the data
carrier reader 10 including an antenna 42 coupled to a radio 44.
The radio 44 is coupled via the bus 40 to a microprocessor 46 and a
random access memory ("RAM") 48. The RAM 48 can include a
characteristic data string buffer 49 to temporarily store
characteristic data strings, as will be explained in detail below.
Alternatively, the reader 10 can include a discrete characteristic
data string buffer (not shown). While FIG. 2 shows a single
microprocessor 46, the data carrier reader 10 may include separate
dedicated processors for each of the RFID tag and symbol reading
sections 30, 32.
[0034] While a dipole antenna 42 is shown, the data carrier reader
10 can employ other antenna designs. Of course, the antenna can be
selected to achieve a particular focus, for example, a highly
directional antenna can enhance the ability of the reader 10 to
select a single RFID tag 12 out of a group of RFID tags. The radio
44 can take the form of a transceiver capable of transmitting and
receiving at one or more of the frequencies commonly associated
with RFID tags 12 (e.g., 350 kilohertz, 400 kilohertz, 900
kilohertz). While these frequencies typically fall within the radio
frequency range of the electromagnetic spectrum, the radio 44 can
successfully employ frequencies in other portions of the spectrum.
Antenna design and radios are generally discussed in The ARRL
Handbook for Radio Amateurs, 76.sup.th Ed., American Radio Relay
League, Newington, Conn., U.S.A. (1999) (ISBN: 0-87259-181-6), and
commonly assigned patent application U.S. Ser. No. 09/280,287,
filed Mar. 29, 1999, entitled ANTENNA STRUCTURES FOR WIRELESS
COMMUNICATIONS DEVICE, SUCH AS RFID TAG (Atty. Docket No.
480062.648).
[0035] A read only memory ("ROM") 50 stores instructions for
execution by the microprocessor 46 to operate the radio 44. As used
in this herein, ROM includes any non-volatile memory, including
erasable memories such as EEPROMs. The programmed microprocessor 46
can control the radio 44 to emit an interrogation signal, including
any required polling codes or encryption, and to receive a return
signal from an RFID tag 12A, 12B. The programmed microprocessor 46,
RAM 48, radio 44 and antenna 42 thus form the RFID reading section
30.
[0036] Symbol Reading Section
[0037] FIG. 2 also shows the symbol reading section 32 of the data
carrier reader 10 including an image sensor 52 and an illumination
source, such as the laser 53. The image sensor 52 can take the form
of a one- or two-dimensional charge coupled device ("CCD") array.
Alternatively, the reader 10 can employ other known imaging
devices, for example laser scanners or Vidicons. In certain
embodiments, the data carrier reader 10 can omit the illumination
source, for example where the image sensor 52 is a two-dimensional
CCD array operable with ambient light. Alternatively, the data
carrier reader 10 can rely on other illumination sources, such as
light emitting diodes ("LEDs") or a strobe light, that can be
positioned to illuminate a desired one of the machine-readable
symbols 24A, 24B. The reader 10 can employ suitable optics such as
lens and mirrors (not shown) for directing light reflected from the
machine-readable symbol 24A, 24B to the image sensor 52.
[0038] The reader 10 includes an analog-to-digital ("A/D")
converter 54, to transform the analog electrical signals from the
image sensor 52 into digital signals for use by the microprocessor
46. The bus 40 couples the image data from the A/D converter 54 to
the microprocessor 46 and the RAM 48. A portion of the RAM 48 can
form an image buffer 56 for temporarily storing data, such as a
captured image data from the image sensor 52. The ROM 50 contains
instructions for the microprocessor 46, that permit the
microprocessor 46 to control the image sensor 52 to capture image
data and to decode and/or manipulate the captured image data. The
programmed microprocessor 46, RAM 48, image sensor 52, and A/D
converter 54, thus form the symbol reading section 32.
[0039] Symbol reading and decoding technology is well-known in the
art and will not be discussed in further detail. Many alternatives
for image sensors, symbol decoders, and optical elements that can
be used in the reader 10 are taught in the book, The Bar Code Book,
Third Edition, by Roger C. Palmer, Helmers Publishing, Inc.,
Peterborough, N.H., U.S.A. (1995) (ISBN 0-911261-09-5).
[0040] Communications Section
[0041] The communications section 38 includes a communications
buffer 47 and a communications port 49. The communications buffer
47 can temporarily store incoming and outgoing data and/or commands
where the communications speed of the reader 10 does not match the
communications speed of some external device, such as the interface
22 (FIG. 1). The communications port 49 provides communications
between the reader and external devices. While shown as a hardwire
connection to the interface 22 (FIG. 1), the communications port
can be a wireless interface, and can even employ the antenna 42 and
radio 44 of the RFID tag reading section 30. Additionally, the
reader 10 can include the interface 22 as an integral part of the
reader 10.
[0042] The interface 22 (FIG. 1) can provide communications over a
communications network 68 to the host 23, allowing transmissions of
data and/or commands between the reader 10 and the host 23. The
communications network 68 can take the form of a wired network, for
example a local area network ("LAN") (e.g., Ethernet, Token Ring),
a wide area network ("WAN"), the Internet, or the World Wide Web
("WWW"). Alternatively or additionally, the communications network
68 can be a wireless network, for example, employing infrared
("IR"), satellite, and/or radio frequency ("RF")
communications.
[0043] The host 23 can receive from each of a number of the readers
10, data collected from the RFID tags 12 and machine-readable
symbols 24. The host 23 can use the data with a database, and can
automatically manipulate the data, for example to automatically
performing inventory or to track shipments.
[0044] The host 23 can provide data and commands to each of a
number of the readers 10. For example, the host can share data
between the readers 10, such as providing a list of either located
or missing identifiers, as will be discussed in more detail below
in reference to inclusive and exclusive searches. The host 23 can
provide a command to toggle the reader 10 between an RFID tag
reading mode and a symbol reading mode, which is described below in
further detail. Thus, the host 23 can command, coordinate and share
data between a number of readers 10. Commonly assigned patent
application U.S. Ser. No. 09/______, filed, 1999, entitled, "SYSTEM
AND METHOD FOR AUTOMATICALLY CONTROLLING OR CONFIGURING A DEVICE,
SUCH AS AN RFID READER" (Atty. Docket No. 480062.672) contains
teachings that can be used to automatically control or configure
the reader 10.
[0045] User Input Section
[0046] The user input section 34 includes the trigger 20, the mode
switch 34, and can include a user input device 58. The bus 40
couples the mode switch 34 to the microprocessor 46. In response to
selection of the mode switch 34, the microprocessor 46 switches
between the symbol reading mode and the RFID tag reading mode, for
example by toggling between the two operating modes. The reader 10
can employ additional operating modes, or switching positions as
desired, for example a switch position that places the reader 10 in
an OFF state or a WAIT state to conserve energy.
[0047] In the symbol reading mode, the microprocessor 46 operates
the image sensor 52 to image one of the machine-readable symbols
24A, 24B. The microprocessor 46 decodes the imaged symbol to
retrieve the data encoded in the machine-readable symbol 24A, 24B,
such as a respective identifier. In the RFID tag reading mode, the
microprocessor 46 operates the radio 44 to emit an interrogation
signal and to receive a response from one or more of the RFID tags
12A, 12B to the interrogation signal. The microprocessor 46 decodes
the response signal to retrieve the data encoded in the RFID tag
12A, 12B, such as a respective identifier.
[0048] The mode switch 34 can be a membrane switch, mounted to the
exterior of the reader 10 for easy selection by the user. The mode
switch 34 can additionally, or alternatively, be implemented in the
software to supplement or replace the user selectable mode switch
on the exterior of the reader 10. The software implemented switch
is particularly useful where the host 23 (FIG. 1) controls the
operating mode of the reader 10. Alternatively, the mode switch 34
can be implemented as an icon on a touch sensitive display 74. In
further alternatives, the trigger 20 can function as the mode
switch 37. In one instance, the number of successive trigger pulls
or activations can determine the operating mode. For example, two
successive trigger pulls can select the symbol mode, while three
successive trigger pulls selects the RFID mode; or a single trigger
pull can cause the reader 10 to read a symbol while a double
trigger pull toggles between the symbol and RFID modes.
Alternatively, the duration of trigger activation can determine the
operating mode. For example, a trigger pull of under 0.5 seconds
can select the symbol mode, while a trigger pull of longer than 0.5
seconds can select the RFID mode; or a trigger pull of under 0.5
seconds can cause the reader 10 to read a symbol while a trigger
pull of over 0.5 seconds toggles the reader between the symbol and
RFID modes. Additionally, or alternatively, the mode switch can be
context sensitive, switching modes based on data read from a
previously read data carrier 12A, 12B, 24A, 24B. For example, a
previously read RFID tag 12A can indicate the existence of a symbol
24A. In response, the data carrier reader 10 can automatically
switch into symbol mode and read the symbol 24A associated with the
RFID tag 12A.
[0049] The bus 40 also couples the trigger 20 to the microprocessor
46. In response to activation of the trigger 20, the microprocessor
46 can cause the image sensor 52 to image one of the
machine-readable symbols 24A, 24B when the reader 10 is operating
in the symbol reading mode. In at least one embodiment, the
microprocessor 46 can also cause the radio 44 and antenna 42 to
emit an interrogation signal in response to the activation of the
trigger 20 while in the reader 10 is operating in the RFID tag
reading mode.
[0050] The user input device 58 can take the form of a keypad 60
(FIG. 3), mouse, touch screen and/or other user operable device to
input information and/or commands to the reader 10. The bus 40
couples the user input device 58 to the microprocessor 46, to allow
the user to enter data and commands.
[0051] User Output Section
[0052] The user output section 36 includes human-perceptible visual
and audio indicators 62, 64 respectively. The bus 40 couples the
visual and audio indicators 62, 64 to the microprocessor 46 for
control thereby. The visual indicators 62 can take a variety of
forms, for example: light emitting diodes ("LEDs"); a graphic
display such as a liquid crystal display ("LCD"), and/or an
alpha-numeric display such as a 7-segment display. The audio
indicator 64 can take the form of one or more dynamic,
electrostatic or piezo-electric speakers 66. The speaker 66 is
operable to produce a variety of sounds (e.g., Clicks and Beeps),
and/or frequencies (e.g., tones), and to operate at different
volumes. The reader 10 can also include tactile indicators such as
a vibrating member. The specific operation of the user output
section 36 is discussed in more detail below.
[0053] FIG. 3 shows a portion of the user interface located on the
head 16 of the reader 10. The user interface includes the elements
of the user input section 34, such as the trigger 20, the mode
switch 34 and the keypad 60. The user interface also includes the
elements of the user output section 36 including the visual
indicators 63 and the speaker 66. In particular, the visual
indicators 62 in the illustrated embodiment include a set of RFID
related LEDs 70, a set of machine-readable symbol related LEDs 72,
and a display 74.
[0054] The data carrier reader 10 can additionally, or
alternatively, employ the laser 53 as the visual indicator. The
laser can be successively pulsed or flashed according to a set of
predefined human-recognizable temporal patterns to provide
information to the user, such as user indications corresponding to
the various reader operations and/or the responses from the date
carriers 12A, 12B, 24A, 24B. Employing the laser 53 as a portion of
the user interface provides a number of distinct benefits. For
example, operating the laser 53 to provide human-recognizable
patterns can eliminate the need for other visual indicators 62. The
data carrier reader 10 can employ multiple illumination sources
such as lasers 53 or LEDs of different colors, or an illumination
source capable of producing a number of different colors to provide
the appropriate user indications, as set out in FIGS. 5A-5C. As
discussed in detail below, the human-recognizable patterns can Sake
the form of a predefined sequence of laser flashes of one or more
colors, separated by time (i.e., temporal pattern).
[0055] The visual and audio indicators 62, 64 are configured to
provide an intuitive user interface consistent across the RFID tag
and symbol reading modes. For example, the RFID tag related and
symbol related LED sets 70, 72 each contain green 76, 78, yellow
80, 82 and red 84, 86 LEDs, in an order or pattern that is
consistent between the sets. The particular LED 76-86, as well as
the number and/or pattern of flashes, is set such that the same
color LEDs flash the same pattern for analogous RF tag reading and
symbol reading activities. For example, the yellow LED 80 in the
RFID tag related set 70 flashes during the reading of one of the
RFID tags 12A, 12B (FIG. 1), while the yellow LED 82 in the
machine-readable symbol related set 72 flashes during the reading
of one of the machine-readable symbols 24A, 24B (FIG. 1). The
reader 10 responds to a successful read of the RFID tag 12A, 12B or
machine-readable symbol 24A, 24B by illuminating the corresponding
green LED 76, 78, respectively, for a set period of time such as 5
seconds. The red LEDs 84, 86 can indicate unsuccessful or
incomplete operations. The user receives visual feedback, where the
color, position and sequence of the visual indicators 62 is
consistent within, and across the RFID tag and symbol operating
modes. Consistent feedback can reduce training time and costs, and
can lead to more efficient operation of the reader 10.
[0056] Similar to the visual indicators 62, the speaker 66 provides
consistent feedback within and across the operating modes. In the
illustrated embodiment, the speaker 66 emits a "beep" or a "click"
sound, although the speaker 66 can emit different and/or additional
sounds. The speaker 66 can emit, for example, a single beep each
time either an RFID tag 12A, 12B or a machine-readable symbol 24A,
24B is successfully read. When searching a field of RFID tags 12A,
12B for one or more particular tags, the speaker 66 can emit a
click for each non-match and a beep for each match.
[0057] The user interface can also include an ON/OFF indicator 97,
and/or a Low Power indicator 99 to identify the operating condition
of the reader 10.
[0058] FIG. 4 shows an alternative set of visual indicators for the
reader 10. This alternative embodiment, and those alternative
embodiments and other alternatives described herein, are
substantially similar to previously described embodiments, and
common acts and structures are identified by the same reference
numbers. Only significant differences in operation and structure
are described in detail below.
[0059] The reader 10 of FIG. 4 employs only three LEDs to simplify
switching while providing the human-perceptible visual indications.
A two state LED serves as the machine-readable symbol related
indicator 87. The machine-readable symbol indicator 87 produces no
light in an OFF state and a Green light in an ON state. A three
state LED serves as the RFID related indicator 89. The RFID related
indicator 89 produces a Green light in first ON state, a Yellow
light in second ON state, and NO light in an OFF state. A two state
LED serves as the ON/OFF indicator 97. The ON/OFF indicator
produces a Yellow light, or No light. The ON/OFF indicator is
proximate the machine-readable symbol related and RFID related
indicators 87, 89. In FIG. 4, the mode switch 34 takes the form of
a toggle or slider switch, having a neutral position (center), a
symbol mode position (left of center) and an RFID mode position
(right of center). The positions are consistent with the
corresponding visual indicators 87, 89, respectively.
[0060] FIGS. 5A-C describe a variety of input and outputs signals
for the reader 10, and particularly for the audio indicator 64 and
laser 53 of FIG. 2, and for the visual indicators 87, 89, 97 of
FIG. 4. While the table is self-explanatory, a brief description of
the columns follows. Column 31 defines a reader status or error
conditions corresponding to reader activities. Column 33 describes
the operation of the visual indicators 87, 89, 97 of FIG. 4, in
response to the various reader status or errors conditions.
Similarly, column 35 describes the operation of the audio indicator
64 in response to the various reader status or error conditions 33.
Column 37 describes the operation of the laser to produce the
desired human-recognizable patterns corresponding to the various
reader status or errors conditions 31. Column 39 describes messages
for display on the display 74 corresponding to the various reader
status or errors conditions 31. Column 41 describes PDT/Host
messages corresponding to the various reader status or errors
conditions 31. Column 43 describes data and/or error codes sent to
the host 33, corresponding the various reader status or errors
conditions 31. As discussed above, these user indications provide a
consistent interface for the user within and across the operating
modes, permitting the user to efficiently operate the reader
10.
[0061] The display 74 can additionally, or alternatively, provide
the user other visual indications. For example, a graphical display
88 (FIG. 6), can employ a first set of icons 90 to indicate RFID
tag activities and a second set of icons 92 to indicate symbol
reading activities. (Note, typically only a single icon will be
displayed at a time, although multiple icons are shown in FIG. 6
for the convenience of this description.) For example, screen icons
81, 83 and 85 can represent RFID reading, successful reading of the
RFID tag 12A, 12B, and unsuccessful reading of RFID tag 12A, 12B,
respectively. Similarly, screen icons 91, 93 and 95 can represent
machine-readable symbol reading, successful reading of the
machine-readable symbol 24A, 24B, and unsuccessful reading of the
machine-readable symbol 24A, 24B, respectively.
[0062] Similarly, an alpha-numeric display 94 (FIG. 7) can employ a
first set of words 96 to indicate RFID tag activities and a second
set of words 98 to indicate symbol reading activities. (Again,
typically only a single word will be displayed at a time, although
multiple are shown in FIG. 7 for the convenience of this
description.) The display 94 is self-explanatory and in the
interest of brevity will not be further described. Other visual
indications, as well as audio and tactile indications are of course
possible.
[0063] Selected Methods of Operation
[0064] Different methods of operating the reader 10 or a reader
having similar capabilities are disclosed below. As set out in the
below methods, the intuitive and consistent operation of the user
interface within and across operating modes can provide numerous
benefits. While several methods are set out for illustration, other
methods employing similar techniques are within the scope of the
invention. Also, the following descriptions employ certain
descriptions of user outputs (e.g., Beep, Click, Red LED, Yellow
LED, and Green LED) for convenience of description. Those skilled
in the art will appreciate that other sounds, colors, visual,
tactile indications, and/or other human-perceptible indications
could be used.
[0065] Single Tag Read Mode
[0066] FIG. 8 shows a method 100 of reading RFID tags 12A-12B (FIG.
1) employing the reader 10 (FIGS. 1-3). Turning on the reader 10,
or switching into the RFID tag reading mode, can automatically
cause the microprocessor 46 to start the method 100 in step 102.
Alternatively, or additionally, the user can cause the
microprocessor 46 to start the RFID tag reading method 100 by
selecting an appropriate key from the keypad 60 or icon from the
display 74. Upon starting in step 102, the microprocessor 46 can
perform an initialization process, for example loading appropriate
operating instructions from the ROM 50 to the RAM 48, initializing
the characteristic data string buffer 49 and/or performing a series
of systems checks on the various component and subsystems of the
reader 10, as set out in step 104.
[0067] Under the instructions loaded in the RAM 48, the
microprocessor 46 activates the radio 44 in step 106. In step 108,
the radio 44 receives data from the RFID tags 12A, 12B. The radio
44 can emit an interrogation signal to cause the RFID tags 12A, 12B
to respond, or, the radio 44 can simply receive signals from RFID
tags 12A, 12B that emit signals without interrogating the RFID
tags. A variety of passive, active and hybrid RFID tags 12A, 12B
are known in the art and will not be discussed in further detail. A
discussion of RFID tags can be found in commonly assigned patent
applications: U.S. Ser. No. 09/173,539, filed Oct. 15, 1998,
entitled WIRELESS MEMORY DEVICE AND METHOD OF MANUFACTURE (Atty.
Docket No. 480062.630); U.S. Ser. No. 09/164,203, filed Sep. 30,
1998, entitled MEMORY TAG AND METHOD OF MANUFACTURE (Atty. Docket
No. 480062.632); U.S. Ser. No. 09/173,137, filed Oct. 15, 1998,
entitled RF TAG HAVING STRAIN RELIEVED STIFF SUBSTRATE AND
HYDROSTATIC PROTECTION FOR A CHIP MOUNTED THERETO (Atty. Docket No.
480062.635); and U.S. Ser. No. 09/164,200, filed Sep. 30, 1998,
entitled CHIP PLACEMENT ON SMART LABELS (Atty. Docket No.
480062.642).
[0068] In step 110, the microprocessor 46 determines whether
duplicate tag data should be suppressed. If suppressed, previously
read or acquired data will not be stored or reported a second time.
Suppression can be a user selection, or can be a selection
transferred from the host 23, or can be preset, for example by the
reader manufacturer or owner. If suppression is not active, the
reader 10, in step 112, automatically transmits the read data, for
example to the host 23, and provides an indication to the user that
the data has been received and transmitted. To provide the
indication, the reader 10 activates the speaker 66 to emit a single
"beep" and activates the Green RFID related LED 76 for a short
time, in steps 114, 116, respectively. Control passes to an end of
the routine 100, in step 118.
[0069] If suppression is active, the microprocessor 46, compares a
characteristic data string from the received data to other
characteristic data strings stored in the characteristic data
string buffer 49, in step 120. The characteristic data string can
be any string of characters stored in the RFID tags 12A, 12B that
permit the reader 10 to determine whether a particular RFID tag
12A, 12B has been read more than once. For example, the
characteristic data string can be a unique identifier programmed
into each of the RFID tags 12A, 12B. Alternatively, the
characteristic data string can be the entire set of data stored in
the RFID tag 12A, 12B, or can be any subset or field of data
recognizable by position, offset, delimiter or other such field
identifier. The microprocessor 46 branches at step 122 based on the
determination of whether the received characteristic data string
corresponds, or matches, any of the stored data strings.
[0070] If the received characteristic data string corresponds to,
or matches, any of the stored characteristic data strings, the
reader 10 provides an indication that the RFID tag 12A, 12B has
been read again, activating the speaker 66 to emit a single "click"
and activating or "flashing" the Red RFID related LED 84 in steps
124, 126, respectively. The microprocessor 46 determines in step
128, if the reader 10 is finished reading RFID tags 12A, 12B, as
described in detail below.
[0071] If the received characteristic data string does not
correspond to, or match any of the stored data strings, the
microprocessor 46 updates the characteristic data string buffer 49
containing the read characteristic data strings, for example
storing the newly received characteristic data string to the buffer
49 in step 130. The reader 10 can automatically transmit the read
data in step 132, for example to the host 23 (FIG. 1). The reader
10 also provides an indication that a new RFID tag 12A, 12B has
been read (e.g., read for the first time since the buffer 49 was
initialized), activating the speaker 66 to emit a "beep" in step
134 and activating the Green RFID related LED 76 in step 136.
Control passes to the end of the routine 100 in step 118.
[0072] FIG. 9 is a flowchart of a method 200 of determining when a
reader 10 is finished reading. The microprocessor 46 can execute
this method 200 in place of each step labeled "DONE" in the various
other methods, such as at step 128 of FIG. 8 (discussed above), or
in the other Figures (discussed below). As set out in the Figures,
the method 200, starting at step 202, acts as a function or
subroutine, returning a Boolean value (e.g., TRUE/FALSE, YES/NO, or
DONE/NOT DONE conditions). While the method 200 could be
implemented as an integral part of the other methods discussed
herein, it is set out separately for ease of discussion.
[0073] At step 240, the microprocessor 46 determines whether the
trigger 20 has been released. A trigger release indicates that the
user is finished reading. If the trigger 20 has been released, the
microprocessor 46 sets the Boolean value to "DONE" at step 242, and
passes control to an end of the routine 200 at step 218, returning
the appropriate Boolean value. For example, when returning to the
method 100 (FIG. 8), the condition "DONE" can cause the reader 10
to stop interrogating RFID tags 12A, 12B.
[0074] If the trigger 20 has not been released, the microprocessor
46 in step 244 determines whether a timeout condition has been
exceeded. For example, the reader 10 can assume that all RFID tags
12A, 12B have been read if a new (e.g., not previously read) tag is
not found after some length of time or some number of consecutive
repeatedly read RFID tags 12A, 12B. While the length of time or
number of repeated reads can be preset, the length or number of
repeats can also be determined during the reading, for example as a
function of RFID tag density (e.g., number of RFID tags per unit
time). The microprocessor 46 can rely on an internal clock or a
separate clock circuit (not shown) in measuring the timeout period.
Employing RFID tag density to calculate the stopping condition "on
the fly" reduces the likelihood of ending a search prematurely.
[0075] If the timeout condition is exceeded, the reader 10
considers reading to be finished, sets the Boolean value to "DONE"
at step 242, and passes control to the end of the method 200 at
step 218, producing the appropriate Boolean value for determining
the next operation, such as turning the radio OFF. If the timeout
condition is not exceeded, the microprocessor 46 determines whether
a stop command has been received from the host 23 in step 246. If a
stop command has been received, the Boolean value is again set to
"DONE" at step 242, and control passes to the end of the method 200
at step 218. If a stop command has not been received from the host
23, the microprocessor 46 at step 248, determines whether all RFID
tags 12A, 12B have been read. If all RFID tags 12A, 12B have been
read, the Boolean value is set to "DONE" at step 242 and control
passes to the end of the method 200 at step 218, returning the
appropriate response. If all RFID tags 12A, 12B have not been read,
the Boolean value is set to "NOT DONE" at step 250 and control
passes to the end 218, thereby returning the appropriate Boolean
value.
[0076] Multi Tag Read/Write Modes
[0077] FIG. 10, shows an additional, or alternative embodiment of
operating under the present invention. Similar steps in the methods
are assigned reference numerals that have the two least significant
digits in common (e.g., the "Start" step is respectively numbered:
102, 202, 302, . . . , 702 in FIGS. 6-12, respectively).
[0078] FIG. 10 shows a method 300 of reading multiple RFID tags
12A, 12B (FIG. 1) employing the reader 10 (FIGS. 1-3). In a similar
fashion to the method 100, the microprocessor 46 starts executing
the method 300 at step 302, initializing the reader 10 at step 304,
turning ON the radio 44 in step 306, and receiving responses from
the RFID tags 12A, 12B in step 308. In step 320, the microprocessor
46 compares a characteristic data string from the received data to
other characteristic data strings stored in the characteristic data
string buffer 49 to determine whether the reader 10 has read the
particular RFID tag 12A, 12B before. The microprocessor 46 branches
at step 322 based on the determination of whether the received
characteristic data string corresponds, or matches, any of the
stored data strings.
[0079] If the received characteristic data string corresponds to,
or matches, any of the stored characteristic data strings, the
microprocessor 46 adds the read characteristic data string to the
characteristic data string buffer 49, at step 330. The reader 10
provides an indication that the read RFID tag 12A, 12B has been
previously read, activating the speaker 66 to emit a single "click"
and activating or "flashing" the Red RFID related LED 84 at steps
352 and 354, respectively. In step 356, the microprocessor 46
examines a counter ("Retry") to determine whether a maximum number
of iterations has been exceeded without finding a "new" (e.g., not
previously read) RFID tag 12A, 12B. If the number of iterations
without encountering a new RFID tag 12A, 12B has been exceeded,
control passes to an end of the method 300 at step 318. If the
number of iterations without encounter a new RFID tag 12A, 12B has
not been exceeded, the microprocessor 46 increments the Retry
counter in step 358, and determines in step 328 whether the reader
10 is finished reading RFID tags 12A, 12B, as described in detail
above with respect to method 200 (FIG. 9). The microprocessor 46
returns to receiving RFID tag responses in step 308, or passes
control to the end of the method 300 at step 318 based on the
Boolean value returned by the method 200 (FIG. 9).
[0080] If the received characteristic data string does not
correspond to, or match any of the stored data strings, the
microprocessor 46 resets the Retry counter in step 360, and adds
the read characteristic data string to the characteristic data
string buffer 49 in step 362. The reader 10 in step 364,
automatically transmits the read data, for example to the host 23.
The reader 10 also provides an indication that a new RFID tag 12A,
12B has been read (e.g., read for the first time since the buffer
49 was initialized), activating the speaker 66 to emit a "beep" in
step 314 and activating the Green RFID related LED 76 in step 316.
The microprocessor 46 determines in step 328 whether the reader 10
is finished reading RFID tags 12A, 12B, as described in detail
above with respect to method 200 (FIG. 9). The microprocessor 46
returns to receiving RFID tag responses in step 308 or passes
control to the end of the method 300 in step 318 based on the
condition returned by the method 200.
[0081] Inclusive Search
[0082] The reader 10 can perform an "inclusive" search, such as
finding all RFID tags 12A, 12B on a list of RFID tags 12A, 12B.
FIG. 11 shows a method 400 for performing an inclusive search. The
user can start the inclusive search 400 by, for example, selecting
an appropriate key or icon as in step 402. The microprocessor 46
performs an initialization at step 404, for example loading a list
of characteristic data strings for the RFID tags 12A, 12B to be
located or identified into the characteristic data string buffer
49. The list of characteristic data strings can, for example, be
downloaded from the host 23 via interface 22. The microprocessor 46
turns ON the radio 44 at step 406.
[0083] In step 408, the radio 44 interrogates the RFID tags 12A,
12B to receive response signals containing the respective
characteristic data strings. Alternatively, the radio 44 can
receive the response signals without interrogating if the RFID tags
12A, 12B are active and periodically transmit data without
requiring initiation by an interrogation signal. In step 420, the
microprocessor 46 compares the received characteristic data string
with the characteristic data strings stored in the characteristic
data string buffer 49. The microprocessor 46 branches at step 422,
based on the determination of whether the received characteristic
data string corresponds, or matches, any of the stored data
strings.
[0084] If the read characteristic data string corresponds to, or
matches any of the stored characteristic data strings, then one of
the RFID tags 12A, 12B has been found and the reader 10 reports
such to the user and/or host 23. The reader 10 provides the user
indication by activating the speaker 66 to "beep" in step 414 and
activating or "flashing" the Green RFID related LED 76 in step 416.
If the read characteristic data string does not correspond to, or
match any of the stored characteristic data strings, then one of
the RFID tags 12A, 12B has not been found, and the reader 10
reports such to the user, and/or host 23. The reader 10 provides
the user indication by activating the speaker 66 to "click" in step
424 and activating or "flashing" the Red RFID related LED 84 in
step 426.
[0085] After providing the user indications, the microprocessor
determines whether the reader is finished reading, in step 428. If
the reading is finished, the returned Boolean value (i.e., DONE)
causes control to pass to an end of the inclusive search routine
400 in step 418. If the reading is not finished, the returned
Boolean value (i.e., NOT DONE) causes the radio 22 to continue
receiving response signals, passing control to step 418.
[0086] Exclusive Search
[0087] The reader 10 can perform an "exclusive" search, such as
finding any RFID tags 12A, 12B not on a list of RFID tags 12A, 12B.
FIG. 12 shows a method 500 for performing an exclusive search. The
user can start the exclusive search 500 at step 502 by, for
example, selecting an appropriate key or icon. The microprocessor
46 performs an initialization at step 504, for example loading a
list of characteristic data strings for the RFID tags 12A, 12B to
be located. At step 506, the microprocessor turns ON the radio
44.
[0088] In step 508, the radio interrogates the RFID tags 12A, 12B
to receive response signals containing the respective
characteristic data strings. Alternatively, the radio can receive
the response signals without interrogating if the RFID tags 12A,
12B are active and periodically transmit without requiring an
interrogation signal. In step 520, the microprocessor 46 compares
the received characteristic data string with the characteristic
data strings stored in the characteristic data string buffer 49.
The microprocessor 46 branches at step 566, based on the
determination of whether the received characteristic data string
does not correspond, or match, any of the stored data strings.
[0089] If the read characteristic data string does not correspond
to, or match any of the stored characteristic data strings, then
one of the RFID tags 12A, 12B missing from the list has been found,
and the reader 10 reports such to the user and/or host 23. The
reader 10 provides the user indication by activating the speaker 66
to "beep" in step 514, and activating or "flashing" the Green RFID
related LED 76 in step 516. If the read characteristic data string
corresponds to, or matches any of the stored characteristic data
strings, then one of the RFID tags 12A, 12B missing from the list
has not been found, and the reader 10 reports such to the user,
and/or host 23. The reader 10 provides the user indication by
activating the speaker 66 to "click" in step 524, and activating or
"flashing" the Red RFID related LED 84 in step 526.
[0090] After providing the user indications, the microprocessor 46
determines whether the reader 10 is finished reading, in step 528.
If the reading is finished, the returned Boolean value (i.e., DONE)
causes control to pass to an end of the exclusive search routine
500 in step 518. If the reading is not finished, the returned
Boolean value (i.e., NOT DONE) causes the radio to continue
receiving response signals, passing control to step 508.
[0091] Association of RFID Tag Data With Item Using
Machine-Readable Symbol
[0092] Often a user desires to make a physical association between
the data read from one of the RFID tags 12A, 12B and a particular
object or item 14 (FIG. 1). While the RFID tag 12A, 12B may be
attached to, or contained with the item, it can be difficult to
identify the particular RFID tag 12A, 12B that is being read. For
example, trying to identify one or more bags in a cargo hold, or
cargo container on an airliner is difficult and time consuming
using only RFID tags 12A, 12B. Each bag would have to be isolated
and the RFID tag 12A, 12B read to ensure that the read data came
from the RFID tag 12A, 12B associated with the particular bag. At
least one proposed solution involves placing human-perceptible
indicators on each of the RFID tags, as disclosed in the commonly
assigned U.S. Ser. No. 09/______, filed, 1999, and entitled "METHOD
AND APPARATUS FOR HUMAN-PERCEPTIBLE IDENTIFICAITON OF MEMORY
DEVICES, SUCH AS RFID TAGS" (Atty. Docket No. 480062.663). This
solution can be relatively expensive since each RFID tag 12A, 12B
requires its own human-perceptible indicator which complicates RFID
tag manufacture.
[0093] FIG. 13 shows a method 600 of associating the read data from
the RFID tag 12A, 12B with a particular one of the items 14. The
association method 600 assumes that an RFID tag 12A, 12B has
already been read, a characteristic data string retrieved and
stored, for example, in the characteristic data string buffer 49.
The user can start the association method 600 in step 602, as
discussed generally above. Alternatively, the reader 10 can be
configured to automatically start the association method 600 at
step 602. In step 668, the microprocessor 46 enters the symbol
reading mode. The user activates the trigger 20 in step 670,
causing the microprocessor 46 to activate the image sensor 52 to
read the machine-readable symbol 24A, 24B at which the reader 10 is
directed. In step 672, the image sensor 52 acquires data from the
machine-readable symbol 24A, 24B by scanning, digitizing, or by any
commonly known methods in the relevant art. As part of acquiring
the data, the microprocessor 46, or a dedicated processor (not
shown), decodes the image to acquire a characteristic data string
encoded in the machine-readable symbol 24A, 24B. Methods and
apparatus for acquiring data from machine-readable symbols are
commonly known in the art, and are specifically taught in The Bar
Code Handbook 3.sup.rd Ed(, by Palmer, Roger C, Helmers Publishing,
Inc. (ISBN 0-911261-09-5), and, in the interest of brevity, will
not be described in further detail.
[0094] To determine whether the machine-readable symbol 24A, 24B
that the reader 10 is pointing at is associated with the RFID tag
data read by the reader 10, the microprocessor 46 compares a
characteristic data string read from the RFID tag 12A, 12B with the
characteristic data string read from the machine-readable symbol
24A, 24B, in step 620. The user can visually associate the RFID tag
12A, 12B with the machine-readable symbol 24A, 24B since the RFID
tag 12A includes the machine-readable symbol 24A, or the RFID tag
12B and machine-readable symbol 24B are carried by the same item
14, or can be visually associated is some other manner. The user
can therefore determine that the data is from a particular RFID tag
12A, 12B when a match is indicated by the reader 10.
[0095] If the characteristic data string from the machine-readable
symbol 24A, 24B corresponds to, or matches, the characteristic data
string from the RFID tag 12A,12B, the reader 10 provides an
indication that an association exists. To provide the indication,
the microprocessor 46 activates the speaker 66 to emit a single
"beep" in step 614 and activates or "flashes" the Green RFID
related LED 76 and the Green symbol related LED 78 in step 674. The
RFID related and the symbol related LEDs 76, 78 are each activated,
indicating that both an RFID tag 12A, 12B and a machine-readable
symbol 24A, 24B have been located, providing a consistency across
the user interface.
[0096] In step 676, the microprocessor 46 can turn OFF the image
sensor 52 after having found an association. In step 612, the
reader 10 can report the data, for example transmitting the RFID
data to the host 23 via the communications port 38 and interface
22. In step 676, the reader 10 can receive a direction or command
from the host 23 via the interface 22 and the communications port
38. In step 678, the microprocessor 46 determines whether the
buffer should be modified based on the command from the host 23. If
the buffer is to be modified, the microprocessor 46 modifies the
buffer at step 680, and passes control to an end of the association
method 600 in step 618. Otherwise, the microprocessor 46 passes
control directly to the end of the association method, in step 600,
without modifying the buffer.
[0097] If the characteristic data string from the machine-readable
symbol 24A, 24B does not correspond to, or match the characteristic
data string from the RFID tag 12A,12B, the reader 10 provides an
indication that an association does not exist. To provide the
indication, the microprocessor 46 activates the speaker 66 to emit
a three "Beeps" in step 682, and activates or "flashes" the Red
RFID related LED 84 and the Green symbol related LED 78 in steps
626, 684, respectively. The Green symbol related LED 78 is flashed
to indicate that a symbol has been successfully read, while the Red
RFID related 84 is flashed to indicate that the data is not
associated with the machine-readable symbol 24A, 24B, further
providing consistency across the user interface. The microprocessor
46 proceeds to the end of the method 600, in step 618.
[0098] Automatically Reading a Symbol Based on Proximity to RFID
Tag, or Frequency of RFID Tag's Responses
[0099] FIG. 14 shows a method 700, in which the reader 10
automatically reads the machine-readable symbol when the reader 10
is within a defined proximity of the RFID tag 12A, and hence within
the defined proximity of the machine-readable symbol 24A. The
automated symbol reading feature provides numerous benefits, for
example the automated symbol reading feature can simplify operation
of the reader, and/or reduce the probability of user error. The
automated symbol reading feature can also reduce the amount of
labor required to operate the reader 10, and can even eliminate the
need for a human operator. The method 700 of FIG. 14 can be used as
part of, or with, many of the previously described methods.
[0100] The antenna 42 in the reader 10 can be directionally
sensitive. The directionally sensitive antenna 42 has a directional
range, in other words, the antenna is more sensitive in certain
directions than other directions. As the reader 10 approaches a
particular RFID tag 12A, 12B, that RFID tag 12A, 12B spends a
higher percentage of time within the range of the reader 10. In
contrast, other RFID tags 12A, 12B are in the range a lower
percentage of time. Thus, as the reader 10 comes within a
predefined proximity of the RFID tag 12A, 12B, the number of "hits"
(i.e., reading an RFID tag having a desired characteristic data
string) will increase, and the number of "misses" (i.e., reading
RFID tags not having the desired characteristic data string) will
decrease. The user may recognize this from an increase in the
number of "Beeps" and a decrease in the number of "Clicks" emitted
by the reader 10. The microprocessor 46 in the reader 10, can keep
track of the number of hits and the number of misses for some unit
length of time, steps 786, 788, respectively. The microprocessor 46
can determine a ratio of the number of hits per unit of time and
the number of misses per unit of time. Alternatively, the host 23
can process the same information.
[0101] In step 790, the microprocessor 46 determines whether the
ratio of hits to misses exceeds a symbol reading threshold. If the
ratio does not exceed the symbol reading threshold, the
microprocessor 46 returns to step 786 and the reader 10 continues
to read the RFID tags 12A, 12B, continually revising and checking
the ratio against the threshold.
[0102] If the ratio exceeds the symbol reading threshold, the
microprocessor 46 turns the image sensor 52 ON, for example,
switching from the RFID reading mode to the symbol reading mode in
step 768. The microprocessor 46 controls the image sensor 52 to
image and decode the machine-readable symbol 24A, 24B in 772. In
step 774, the microprocessor 46 turns the image sensor 52 OFF,
thereby conserving power. In step 720, the microprocessor 46
compares the characteristic data string from the machine-readable
symbol 24A, 24B to the characteristic data string from the RFID tag
12A, 12B.
[0103] If the characteristic data string from the machine-readable
symbol 24A, 24B corresponds to, or matches, the characteristic data
string from the RFID tag 12A,12B, the reader 10 provides an
indication that an association exists. To provide the indication,
the microprocessor 46 activates the speaker 66 to emit a single
"Beep" in step 714 and activates or "flashes" the Green RFID
related LED 76 and the Green symbol related LED 78 in step 774. The
RFID related and the symbol related LEDs 76, 78 are each activated,
indicating that both an RFID tag 12A, 12B and a machine-readable
symbol 24A, 24B have been located, providing a consistency across
the user interface.
[0104] In 712, the reader 10 can report the data, for example
automatically transmitting the RFID data to the host 23 via the
communications port 38 and interface 22. In step 776, the reader 10
can receive a direction or command from the host 23 via the
interface 22 and the communications port 38. In step 778, the
microprocessor 46 determines whether the characteristic data string
buffer 49 should be modified based on the command from the host 23.
If the buffer 49 is to be modified, the microprocessor 46 modifies
the buffer at step 780, and passes control to an end of the
association method 700 at step 718. Otherwise, the microprocessor
46 passes control directly to the end of the association method 700
at step 718 without modifying the characteristic data string buffer
49.
[0105] If the characteristic data string from the machine-readable
symbol 24A, 24B does not correspond to, or match the characteristic
data string from the RFID tag 12A,12B, the reader 10 provides an
indication that the association does not exist. The microprocessor
46 activates the speaker 66 to emit three "Beeps" in step 782, and
activates or "flashes" the Green symbol related LED 78 and the Red
RFID related LED 84 in steps 784 and 726, respectively. The Green
symbol related LED 78 is flashed to indicate that a symbol has been
successfully read, while the Red RFID related 84 is flashed to
indicate that the data is not associated with the machine-readable
symbol 24A, 24B, further providing consistency across the user
interface.
[0106] Summary
[0107] The various embodiments described above can be combined to
provide further embodiments. All of the above U.S. patents, patent
applications and publications referred to in this specification are
incorporated by reference. Aspects of the invention can be
modified, if necessary, to employ systems, circuits and concepts of
the various patents, applications and publications to provide yet
further embodiments of the invention.
[0108] Although specific embodiments of and examples data carrier
readers and reading are described herein for illustrative purposes,
various equivalent modifications can be made without departing from
the spirit and scope of the invention, as will be recognized by
those skilled in the relevant art. The teachings provided herein of
the invention can be applied to any data carrier reader, not
necessarily the exemplary combination RFID tag and symbol reader
generally described above.
[0109] For example, some of the structures and methods can be used
with readers capable of reading only RFID tags. Some of the
structures and methods can be used with readers capable of reading
only machine-readable symbols. Some of the structures and methods
can be suitable with readers for other data carriers, such as
optical tags and touch memory devices. The methods and structures
are generally applicable with other wireless memory devices, not
just radio frequency, and the term RFID as used herein is meant
encompass wireless memory devices operating in all ranges of the
electromagnetic spectrum, not only the radio frequency portion.
Similarly, the structures and methods disclosed can work with any
variety of modulation techniques, including, but not limited to,
amplitude modulation, frequency modulation, phase modulation and/or
pulse width modulation. The structures and methods can also be
applied to various machine-readable symbologies, including, but not
limited to, bar codes, stacked codes, area and/or matrix codes. The
image sensor 52 can be any type of image capture device, including
laser scanners, one- and two-dimensional charged coupled devices,
Vidicons, and the like.
[0110] These and other changes can be made to the invention in
light of the above-detailed description. In general, in the
following claims, the terms used should not be construed to limit
the invention to the specific embodiments disclosed in the
specification and the claims, but should be construed to include
all apparatus and methods that operate in accordance with the
claims. Accordingly, the invention is not limited by the
disclosure, but instead its scope is to be determined entirely by
the following claims.
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