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This invention relates to an electronic access card with visual display.
BACKGROUND OF THE INVENTION
In co-pending application Ser. No. 899,533, filed Aug. 22, 1986 there is
disclosed an electronic access card which can be utilized in connection
with a lock box of the type described in U.S. Pat. No. 4,609,780. However,
the electronic access card disclosed in said U.S. Pat. No. 4,609,780 does
not have a visual display and has other limitations. There is therefore a
need for a new and improved electronic access card.
OBJECTS OF THE INVENTION
In general, it is an object of the present invention to provide an
electronic access card which has a visual display.
Another object of the invention is to provide a card of the above character
in which information can be scrolled in the visual display.
Another object of the invention is to provide a card of the above character
which can be utilized in connection with lock boxes.
Another object of the invention is to provide a card of the above character
which eliminates the need for telephone transmissions from a lock box.
Another object of the invention is to provide a card of the above character
which utilizes active telemetry.
Another object of the invention is to provide a card of the above character
in which a visual display can be given of the entries which have been made
in the lock box.
Another object of the invention is to provide a card of the above character
which produces an audible signal for telephonic transmission.
Another object of the invention is to provide a card of the above character
which has a long life.
Another object of the invention is to provide a card of the above character
which gives a low battery indication of the LCD display.
Another object of the invention is to provide a card of the above character
in which information can be transmitted to a computer terminal.
Another object of the invention is to provide a card of the above character
which can have the information contained therein read by a reader (via RF
telemetry).
Another object of the invention is to provide a card of the above character
which is capable of two way high speed transmission.
Additional objects and features of the invention will appear from the
following description in which the preferred embodiments are set forth in
detail in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of an electronic access card with visual
display incorporating the present invention.
FIG. 2 is a circuit diagram of the circuitry utilized in the electronic
access card shown in FIG. 1.
FIG. 3 is a circuit diagram of another embodiment of the electronic
circuitry which can be utilized in the electronic access card shown in
FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In general, the present electronic access card consists of a printed
circuit board. A microprocessor is carried by the printed circuit board.
Key pad means is carried by the board and is connected to the
microprocessor for inserting information into the microprocessor. Coil
means is carried by the printed circuit board and is connected to the
microprocessor for receiving and transmitting information with respect to
the microprocessor. Visual display means is carried by the printed circuit
board and is coupled to the microprocessor for displaying information in
the microprocessor.
More in particular, the electronic access card 11 having a visual display
in many respects is very similar to the electronic access card disclosed
in co-pending application Ser. No. 899,533, filed Aug. 22, 1986. As
disclosed therein such an electronic access card includes a printed
circuit board 12 which has a key pad or keyboard assembly 13 mounted on
the front side thereof. The key pad assembly includes a plurality of keys
14 in which 10 of the keys carry the arabic numerals 0-9 and in which
other keys carry other suitable indicia. These indicia have been indicated
as the letters A-G for convenience of illustration. However, if it is
preferable that the exact purpose or function of the key be provided
thereon. These functions can be as follows:
A: Obtain Key
B: Remove Shackle
C: Update Card
D: 24 Hour Use
E: Daytime Use
F: Interrogate Box
G: Printer Enable
In addition, other keys 14 serve as scroll keys in which one of the keys
has an arrow facing to the left and the other key has an arrow facing to
the right as shown in FIG. 1. The remaining key can be identified as the
"Clear" and "On" key.
A 10-character alphanumeric liquid crystal display 16 is carried by the
upper extremity of the printed circuit board 12 and is connected to
circuitry 21 carried by the printed circuit board 12 and shown
schematically in FIG. 2. As shown in FIG. 2, the circuitry 21 includes a
microprocessor 22 of a conventional type which is controlled by a crystal
clock 23. Several peripherals are connected to the microprocessor 22 and
take the form of a memory 24 which is connected to the micrprocessor by
data lines 26 and address lines 27. The memory 23 can be of any suitable
size ranging from 1 k up to 64 k. A key pad or keyboard assembly 13 is
connected to the microprocessor which is capable of ascertaining key
depressions in the keyboard assembly 13. The microprocessor 22 is also
connected to the LCD display 16 by a conventional LCD driver 31 which is
connected to the microprocessor 22.
A battery 36 such as a lithium battery is mounted on the printed circuit
board and supplies a suitable voltage such as three volts. The battery is
connected to passive telecommunication circuitry 37 also carried by the
printed circuit board. The circuitry 37 is used for communicating with an
external device 38 such as a lock box of the type described in U.S. Pat.
No. 4,609,780. The passive telecommunication circuitry 13 includes a coil
L1 which is adapted to communicate with a coil L2 forming a part of the
external device 38. The coil L1 is connected across a full wave diode
bridge rectifier 41. The output of the rectifier 41 is supplied through a
protective network 42 consisting of a resistor R1, a diode D1 and a zener
diode D2 to an input I of the microprocessor 22. The protective network 42
serves to protect the microprocessor 22 from inductive spikes which might
be picked up by the communication coil L1. The diode D2 has an appropriate
breakdown voltage which is less than the breakdown voltage of the
transistor Q1. A capacitor C1 in conjunction with a resistor R2 provides
appropriate filtering. With the electronic access card 11 shown in FIG. 1
and which includes the circuitry shown in FIG. 2, power consumption from
the battery is minimal during transmission and reception. The same coil L1
is utilized for both transmission and reception. During the reception, the
voltage induced in the coil L1 within the electronic access card is
rectified by the bridge rectifier 41 and supplied to the microprocessor
input I through the protective network.
By way of example, the transmission typically received by the coil L1 is
pulse width modulated, which information is supplied to the microprocessor
22. The microprocessor converts the information into digital 1's and 0's
for storage in the memory 23. The output of the microprocessor is supplied
on the terminal 0 to the gate of a N-channel MOSFET transistor Q1. The
drain of the transistor Q1 is connected to the bridge rectifier 41.
With the electronic access card 11 shown in FIG. 1 and which includes the
circuitry shown in FIG. 2, power consumption from the battery is minimal
during transmission and reception. The same coil L1 is utilized for both
transmission and reception. During the reception, the voltage induced in
the coil L1 within the electronic access card is rectified by the bridge
rectifier 41 and supplied to the microprocessor input I through the
protective network.
The resistor R2 and the capacitor C1 provide a filter with a RC time
constant which is less than 1/10th the shortest pulse width in the pulse
wave transmission being received by the electronic access card. The
voltage induced in the coil L1 is equal to or greater than 3 volts so that
no amplification is required within the access card.
During transmission from the electronic access card, the microprocessor 22
reads the contents from the memory 23 and serially transmits a pulse width
modulated stream of data through the output 0.sub.1. The transistor Q1 is
turned on for the appropriate duration, depending on whether it is an 0 or
a 1. When the transistor Q1 turns on, a low impedance load is placed
across the coil L1 and when the transistor Q1 is turned off, the loading
on the coil L1 is removed.
During transmission by the electronic access card, the external device 38
supplies and maintains an unmodulated radio frequency field surrounding
the access card coil L1. The loading and unloading of the coil L1 by the
turning on and off of the transistor Q1 modulates the loading effect of
the coil L1 on the coil L2 of the external device 38 and thus essentially
creates an amplitude modulated pulse width modulated signal cross the coil
L2. The external device 38 demodulates this information so that it can be
utilized for further processing if desired in the external device.
A type of telemetry which is utilized in the electronic access card is
particularly useful since it requires the use of very little power, thus
prolonging the useful life of the access card battery 36.
It can be seen that the microprocessor 22 does not expend any energy in
transmission except for turning the transistor Q1 on and off which is
quite small. Thus no energy is used from the internal battery to power the
inductor L1. This helps to prolong the life of the battery 36 and thereby
the life of the card before battery replacement is required. Radio
frequency communication can be utilized for the communication link between
L1 and L2. The coil L1 merely loads and unloads an externally present RF
field generated by the coil L2.
The card has an additional advantage since it does not transmit radio
frequency energy it will not disturb devices in close proximity to it, or
accidentally erase magnetic strips on credit cards.
Means is provided for ascertaining when a low battery condition occurs and
takes the form of a battery voltage measuring device 46 which is comprised
of a comparator 47 that is provided with a suitable reference 48 such as
one having 1.2 volts. A voltage divider network 49 having resistors R3 and
R4 reduces the voltage from the battery so that it can be compared with
the 1.2 volt reference.
Operation and use of the electronic access card 11 may now be briefly
described as follows. The electronic access card 11 can be programmed so
that it contains additional information other than the identification
number described in co-pending application Ser. No. 899,533, filed Aug.
22, 1986. For example, the user's name (real estate broker), his phone
number and his address can be programmed into the card using ASCII
characters. Thus, when a real estate agent opens the key container of a
lock box, in addition to his identification number being transferred into
the lock box, listing information including his name, address and the like
also would be transferred. This informaton is stored in the lock box. When
the owner of the lock box arrives to poll the lock box to ascertain the
number of visits and who visited the listed property, the information
which is carried in the lock box can be read by the electronic access card
11 of the present invention when it is inserted into the lock box. The
scroll keys provided on the electronic access card can be actuated to
cause information which has been passed into the electronic access card 11
from the lock box to scroll across the liquid crystal display 16. In this
way it is possible for a listing agent to rapidly ascertain the activity
which has occurred to a listed property. If necessary, the real estate
agent can rescroll the information by depressing the appropriate keys on
the keyboard 13. If desired, the listing real estate agent can make notes
with respect to information appearing on the liquid crystal display 16.
Thus it can be seen with such an electronic access card 11, the need for a
telephone transmission to a central computer is eliminated. Utilizing the
electronic access card 11 gives an immediate alphanumeric display making
it possible to access all the entries in the lock box.
It should be appreciated that if desired a small speaker could be mounted
on the printed circuit board of the card 12 which could be utilized for
transmitting information telephonically to a computer terminal. The card
can use FM, FSK, AM, or DTMF transmission. Synthetic speech can be added
to speak the content of the memory in addition to the display on the LCD
display. Alternatively, a special computer or reader could be utilized to
read the information carried by the card. In other words, a real estate
broker could take his card and read out all of the boxes in which he is
the listing agent and thereby store the information contained in the
different lock boxes. After he has made his rounds and collected the
information he could come back to his office and obtain a printout of the
information contained in the lock boxes. It should be appreciated that a
printout is not needed since the information is readily available on the
display 16 merely by operating the scroll keys on the keyboard 13.
Another embodiment of the circuitry which can be provided on the electronic
access card 11 is shown in FIG. 3 and as hereinafter described includes
active telemetry or telecommunication circuitry which permits
communication between a master card and a slave card. The circuitry 51
which is shown in FIG. 3 includes a microprocessor 52 of a conventional
type controlled by a crystal clock 53 as well as a memory 54 connected by
data and address lines 56 and 57.
A keyboard 58 is provided similar to the keyboard 13 but is different in
that it is a full alphanumeric keyboard having all the alphabet characters
from a to z, the numerals from 0 to 9 and various function keys.
The circuitry shown in FIG. 3 as the circuitry in FIG. 2 includes a display
61 of the same type as the display 16 in FIG. 2 which is connected through
a driver 62 to the microprocessor 52. A speaker 63 is coupled to the
microprocessor 52 through a speech synthesizer 64 providing an audio
output from the information supplied by the microprocessor to the LCD
display 61. The speech synthesizer 64 can be programmed to provide a male
or female voice.
The active telemetry circuitry 65 of the circuitry shown in FIG. 3 consists
of the coil L1 which functions in a manner similar to the coil L1 in FIG.
2. It is coupled through a filter network 66 consisting of a diode D1, a
capacitor C1 and a resistor R1 to the input I of the microprocessor 52.
The output O of the microprocessor 52 is coupled to the gate of a high
frequency gatable oscillator 67 having a frequency range from
approximately 10 khz to 1 megahertz. The output of the oscillator 67 is
connected to a transistor Q1 which can be a P N P transistor or a P
channel MOSFET transistor. The transistor Q1 is connected to the coil L1
and supplies energy to the coil L1 to cause it to radiate radio frequency
energy which can be picked up by the pick-up coil of an external device of
the type described in conjunction with FIG. 2. The output from the
micrprocessor 52 typically is in the form of pulse width modulation.
Operation and use of the circuitry shown in FIG. 3 in conjunction with
electronic access card with visible display is very similar to that
hereinbefore described in conjunction with FIG. 2. The principal
difference is that active telemetry is utilized in the circuitry shown in
FIG. 3 whereas passive telemetry is utilized in the circuitry shown in
FIG. 2. As hereinbefore explained, the electronic access cards are
particularly adapted for use with external devices such as lock boxes. The
electronic access cards with active telemetry can be utilized in place of
a central station and can be programmed for receiving a program for
generating cyclic codes that are needed for electronic access cards and
for reading and displaying the information contained in the lock boxes. In
such an application, the master card would have a complete alphanumeric
keyboard 58 of the type hereinbefore described. Slave cards for
utilization with such a master card would only need a limited keyboard
such as the type shown in FIG. 2. The master card with the complete
alphanumeric keyboard makes it possible to enter user names and other
information when programming the slave cards. The master card is capable
of generating cyclic codes to validate the slave cards. If desired, it
should be appreciated that the slave cards can also be of the type
described in co-pending application Ser. No. 899,533, filed Aug. 22, 1986.
With the use of the active telemetry shown in FIG. 3, it can be seen that
battery power is utilized during transmission of information to create
electromagnetic or radio frequency radiation to convey the information to
an external device. As pointed out previously, battery power is not
required for this function with the circuitry shown in FIG. 2.
From the foregoing it can be seen that in connection with the present
invention it has been possible to provide an electronic access card which
has a visual display to provide an immediate readout when desired, as for
example, from a lock box to ascertain the activity with respect to that
lock box. Card to card communication is possible. Trans-telephonic
communication is possible utilizing the audio output, thereby making it
possible to transmit information from a card to a central computer. The
card 11 is capable of performing several central computer functions, such
as generating cyclic codes, programming slave access cards and
interrogating slave access cards and lock boxes.
The electronic access cards of the present invention are very small and
generally have the size of a credit card and thus can be carried in a
billfold. They can have a thickness ranging from 0.035 to 0.04 inches.
Within such parameters an ultrathin speaker/microphone can be provided for
interfacing with telephonic communication devices. High speed
communication is possible with the electronic access cards making it
possible to transmit substantial amounts of information, as for example,
the user's true identity, by supplying the full name and the telephone
number of the user upon each opening of the lock box. High speed two-way
communication is provided between the electronic access cards and external
devices such as lock boxes. The alphanumeric display provided by the
liquid crystal display provides an immediate readout from lock boxes to
give the activity with respect to that lock box. The electronic access
cards, even though having these capabilities, can have a life ranging from
3 to 5 years. A low battery indication is provided on the liquid crystal
display. Large internal memory can be provided. The circuitry provided
permits the use of low cost CMOS microprocessors.
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