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Claims  |
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What is claimed is:
1. A bi-directional wireless portable communication device comprising:
a portable housing;
a plurality of user operable switches mounted in said portable housing,
said plurality of user operable switches including a record switch, a
transmit switch and a play switch;
a sound input transducer mounted in said portable housing;
an integrated circuit comprising memory, mounted in said portable housing,
coupled to said sound input transducer and coupled to said record switch,
wherein, in response to activation of said record switch, said integrated
circuit stores electrical signals from said sound input transducer in
direct analog form in said memory, said electrical signals being
representative of audio signals;
a wireless transmitter, mounted in said housing, coupled to said memory and
coupled to said transmit switch,
wherein, in response to activation of said transmit switch, said wireless
transmitter transmits electromagnetic signals representative of said
electrical signals stored in said memory;
a wireless receiver, mounted in said housing and coupled to said memory,
wherein, said wireless receiver receives electromagnetic signals, said
electromagnetic signals being representative of audio signals; and
further wherein said integrated circuit stores electrical signals from said
wireless receiver in said memory while said record switch is deactivated;
and
a sound output transducer, mounted in said housing, coupled to said memory
and to said play switch,
wherein, in response to activation of said play switch, said sound output
transducer generates sound waves representative of said electrical signals
stored in said memory.
2. The bi-directional wireless portable communication device of claim 1
wherein said memory is capable of storing a plurality of selected
pre-recorded sounds; said bi-directional wireless portable communication
device further comprising a plurality of sound effect switches coupled to
said memory, wherein on activation of a sound effect switch, said
bi-directional wireless communication device adds to a message at least
one of said selected pre-recorded sounds.
3. The bi-directional wireless portable communication device of claim 1
further comprising a message indicator for indicating the receipt of a
message by said wireless receiver.
4. The communication device of claim 1 further comprising a housing, said
housing having a grille for said sound input transducer, and said housing
having an opening for said sound output transducer.
5. The bi-directional wireless portable communication device of claim 1
wherein said portable housing has the shape of a pen.
6. A communication system comprising a plurality of bi-directional wireless
portable communication devices of claim 1,
wherein at least one bi-directional wireless portable communication device
of said plurality is capable of receiving an infrared signal transmitted
by another bi-directional wireless portable communication device of said
plurality.
7. A bi-directional wireless portable communication device comprising:
an audio recorder circuit comprising a first input terminal, a second input
terminal, and an output terminal,
wherein, in response to an active signal on said second input terminal,
said audio recorder circuit stores an electrical signal received on said
first input terminal; and
further wherein said audio recorder circuit supplies said stored electrical
signal on said output terminal;
a wireless infrared receiver circuit comprising an input terminal, a first
output terminal coupled to said first input terminal of said audio
recorder circuit, a second output terminal coupled to said second input
terminal of said audio recorder circuit, and a third output terminal,
wherein, in response to an infrared signal at a predetermined frequency,
and an inactive signal on said input terminal, said wireless infrared
receiver circuit supplies an electrical signal representative of said
infrared signal on said first output terminal and simultaneously drives a
control signal active on said second output terminal, and
further wherein, when said infrared signal goes inactive, said wireless
receiver drives a signal active on said third output terminal;
a wireless infrared transmitter circuit comprising a first input terminal
coupled to said third output terminal of said wireless infrared receiver,
a second input terminal coupled to said output terminal of said audio
recorder circuit, an output terminal coupled to said input terminal of
said wireless infrared receiver, and a transmit switch,
wherein, in response to closure of said transmit switch, and an inactive
signal on said wireless infrared transmitter input terminal, said wireless
infrared transmitter drives a signal on said wireless infrared transmitter
first output terminal active and transmits an infrared signal at said
predetermined frequency, said infrared signal being representative of an
electrical signal received on said wireless infrared transmitter second
input terminal.
8. A communication system comprising a plurality of bi-directional wireless
portable communication devices of claim 7,
wherein at least one bi-directional wireless portable communication device
of said plurality is capable of receiving an infrared signal transmitted
by another bi-directional wireless portable communication device of said
plurality. |
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Claims  |
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Description  |
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FIELD OF THE INVENTION
This invention relates to a compact solid state interactive communication
device that allows the user to record, transmit, receive and play sounds.
More particularly this invention relates to a compact solid state
interactive device that includes a solid state direct analog storage audio
recorder, an infrared receiver and an infrared transmitter all encased in
a single compact housing.
BACKGROUND OF THE INVENTION
In today's hide and seek games, persons such as children can use toy laser
guns that send and receive infrared signals. Most such toys produce a
laser gun sound effect and send an infrared beam when the gun's trigger is
depressed. If the infrared beam is received by photo-receptors of a remote
toy, lights flash and a beep goes off indicating a hit.
However, it is not known for toy laser guns to record messages of voice
and/or sound effects and to send or receive voice and/or sound effects. To
record messages, a person can use conventional audio recorders typically
sized to be held in a human hand. The smallest size achievable by such
recorders is limited by the physical dimensions of an audio-cassette tape
traditionally included in such recorders. To send messages, a person can
use two way wireless sets, typically strapped over the person's back or
held in the person's hand. Although wireless microphone transmitters are
known in the prior art, such transmitters merely transmit radio signals
representive of sound waves and cannot be used to receive signals. Also
known in the art are wireless receiver headphones that a person can use to
listen to sounds derived from radio broadcasts or compact discs or tapes.
However, such headphones merely receive infrared signals representative of
sound waves and cannot be used to transmit signals.
SUMMARY OF THE INVENTION
In accordance with this invention, a compact solid state interactive
communication device allows the user to record, play and erase messages or
sounds. The communication device also permits the person to wirelessly
transmit and receive previously recorded messages and sounds to/from
another such device.
In one embodiment the communication device includes a record switch for
recording messages to be sent, a transmit switch for sending messages, a
play switch for playing recorded and received messages, a microphone for
converting sound waves into analog electrical signals representative of
sound waves, a direct analog storage audio recorder, preferably but not
necessarily solid state, for recording and playing back electrical signals
representative of sound waves, a transmitter, preferably but not
necessarily, of infrared signals for transmitting signals representative
of sound waves, a receiver, preferably but not necessarily of infrared
signals, for receiving signals representative of sound waves and a speaker
for converting analog electrical signals into sound waves, all encased in
a single compact housing. The communication device is small enough and
light enough to be worn on the clothing of a person. In one embodiment the
communication device includes one or more sound effects switches that can
record, play and add to a message being recorded already pre-recorded
sound effects selected by the person.
In the preferred embodiment, the communication device is clipped onto the
user's lapel, belt or pocket or worn by the user on a chain around the
user's neck. Messages can be transmitted to and received by a
communication device without the user of that device being aware of such
receipt until receipt of the message is completed and further without the
user being aware of the source of the message. The communication device
has several modes of operation; namely record, transmit a recorded message
to another communication device, play a recorded message and receive and
record a message transmitted from another communication device. The
received and/or recorded message can be listened to by the user at any
convenient time.
This invention will be more fully understood in view of the detailed
description taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a person wearing one embodiment of a
communication device in accordance with this invention.
FIGS. 2A and 2B are the front elevation and back elevation views of a
communication device in accordance with this invention.
FIGS. 2C and 2D are the plan and front elevation views of another
embodiment of a communication device in accordance with this invention.
FIGS. 2E and 2F are the rear and front elevation views of another
embodiment of a communication device in accordance with this invention.
FIG. 3A is a high level block diagram of two communication devices being
used in accordance with the present invention.
FIG. 3B is a low level block diagram of a communication device in
accordance with this invention.
FIG. 4 is a circuit diagram of the infrared transmitter of FIG. 3B.
FIG. 5 is a circuit diagram of the infrared receiver of FIG. 3B.
FIG. 6 is a circuit diagram of the audio recorder of FIG. 3B.
DETAILED DESCRIPTION
FIG. 1 is a perspective view of a person 1 wearing a communication device 3
in a shirt pocket. In accordance with this invention, communication device
3 can be stored or carried on any part of a person's body.
FIGS. 2A and 2B show the front elevation and back elevation views of one
embodiment of a communication device 3A in accordance with this invention.
As shown in FIG. 2A, communication device 3A has: a record switch 8A for
recording messages to be sent, an erase switch 4A for erasing recorded
messages, a play switch 9A for playing recorded and received messages and
a transmit switch 5A for sending recorded messages. Messages stored,
transmitted, received and played by one embodiment of a communication
device include sounds of any type (such as, for example, voice sounds,
artificial sounds and natural sounds). Also provided in communication
device 3A are a transmit indicator light emitting diode (henceforth "LED")
5A1, a transmit window 6A and a receive window 10A. All the above
components of communication device 3A are encased in a compact housing
11A. Housing 11A is typically plastic and includes a speaker grille 11A1
for a speaker (not shown in FIGS. 2A and 2B), a microphone opening 11A2
for a microphone (not shown in FIGS. 2A and 2B) and a clip 7A for wearing
device 3A on the clothing (for example, on a lapel or pocket) of a person.
FIGS. 2C and 2D are the plan and front elevation views of another
embodiment of a communication device 3B in accordance with this invention.
Communication device 3B is similar to communication device 3A of FIGS. 2A
and 2B. Communication device 3B also has a record switch 8B, a play switch
9B, a transmit switch 4B, a transmit indicator LED 5B1, a transmit window
6B (that also serves as a receive window), a housing 11B with a speaker
grille 11B1, a microphone opening 11B2 and a clip 7B.
Furthermore, communication device 3B has a record/message indicator LED 5B2
to indicate receipt of a message or to indicate recording in progress.
Communication device 3B also has sound effect switches 12A, 12B, 12C and
12D to record, to playback and to add to a message, sounds selected by a
person. Sound effects can include, for example, sounds of "Oink Oink Oink"
recorded from a real pig, "Quack Quack Quack" recorded from a real duck,
other sounds recorded from a radio or television show or even sound
effects created by the user (including special personalized messages).
FIGS. 2E and 2F are the rear and front elevation views of another
embodiment of a communication device 3C in accordance with this invention.
Communication device 3C is similar in function to communication device 3A
of FIGS. 2A and 2B but has a substantially different more slender
appearance similar to a pen. Communication device 3C also has a record
switch 8C1, a play switch 9C, a transmit switch 4C, a transmit indicator
LED 5C1, a transmit window 6C (that also serves as a receive window), a
housing 11C with a speaker grille 11C1, a microphone opening 11C2 and a
clip 7C.
Furthermore, communication device 3C has a record/message indicator LED 5C2
to indicate receipt of a message or to indicate recording in progress.
Communication device 3C also has an erase switch 8C2 for erasing a message
stored in device 3C. The housing 11C of device 3C is shaped and sized in
the form of a typical pen. As shown in FIG. 2F, a battery compartment 13C
is provided for holding two AAA type batteries required to power device
3C.
Although three embodiments of a communication device are shown in FIGS. 2A
to 2F, a communication device in accordance with this invention can be of
any desired and appropriate shape or size. Although in the embodiments
shown in FIGS. 2A to 2F, push activated switches are shown, other suitable
types of electrical switches such as sliding switches may be used in
accordance with this invention. Although in the above embodiments, certain
configurations of the transmit and receive windows are shown, other
configurations can be used. For example, multiple receive windows can be
provided to receive signals from the front and sides of a communication
device.
The interactive communication device of this invention has many novel
features and advantages. The representative communication device provides
fun in a personal way by allowing a user to transmit messages in the
user's own voice (with optionally interspersed sound effects in some
embodiments). Also, the communication device is light enough and small
enough to be worn on the clothing or around the neck of a person.
Furthermore, the communication device is "idiot proof" due to its basic
repertoire of only a few controls: record, play and transmit (with
optional erase in some embodiments).
FIG. 3A is an illustrative high level block diagram of two identical
communication devices 3D and 3D' being used in accordance with this
invention. Communication devices 3D and 3D' are identical in structure and
can be any of the above-described embodiments 3A, 3B and 3C or any other
embodiment. Although communications devices 3D and 3D' are identical in
structure, device 3D' is shown in FIG. 3A in an inverted orientation with
respect to device 3D for convenience. As shown in FIG. 3A, communication
devices 3D and 3D' include transmitters 15D and 15D' for transmitting
electromagnetic signals (preferably but not necessarily IR signals)
indicative of sound waves through transmit windows 6D and 6D', receivers
14D and 14D' for receiving electromagnetic signals indicative of sound
waves through receive windows 10D and 10D', audio recorders 16D and 16D'
for recording and playing back electrical signals (typically analog but
also capable of being digital with appropriate A/D and D/A circuitry)
indicative of sound waves, sound output transducers 18D and 18D' (such as,
for example, loudspeakers) for converting analog electrical signals
indicative of sound into corresponding sound waves and sound input
transducers 20D and 20D' (such as, for example, microphones) for
converting sound waves into analog electrical signals indicative of
incident sound waves. Also, communications devices 3D and 3E have switches
13D and 13E that include record switches, play switches, transmit switches
and optional erase switches (not shown in FIG. 3A).
In accordance with this invention, the user of communication device 3D can
create a message to be sent to a remote device by using a record switch
(one of switches 13D) to record sounds. When the record switch is
depressed and continuously held down, any sounds impinging on a microphone
opening (not shown in FIG. 3A) are converted by sound input transducer 20D
into analog electrical signals and are stored in audio recorder 16D.
Recording of the message stops when record switch 8D is released. When
record switch 8D is held down during message recording, a message cannot
be received from a remote communication device.
In some embodiments, a user can start a message with or add to an already
recorded message, a pre-recorded sound effect. The user can push and
release a sound effect switch (such as, for example, one of switches 12A
to 12D of device 3B of FIGS. 2C and 2D) so that a sound effect already
pre-recorded in device 3B corresponding to the sound effect switch hit by
the user is added to a message (to be recorded or already recorded). A
sound effect switch can be pushed and released as often as desired to add
to the message a sound effect of any desired length. A sound effect can be
pre-recorded into a communication device (such as, for example, device 3B
of FIGS. 2C and 2D) by pushing and continuously holding down a selected
sound effect switch so as to record any sounds impinging on a microphone
opening. No sound effect is recorded initially for a short period of time
(for example, one or two seconds) when a sound effect switch is
continuously held down to distinguish the function of sound effect
pre-recording from the function of adding a sound effect to a message.
In some embodiments of a communication device (such as, for example,
communication devices 3B and 3C of FIGS. 2C, 2D, 2E and 2F), a record LED
(such as, for example, LED 5B2 and LED 5C2) glows continuously to indicate
message recording in progress. A record LED stops glowing to indicate no
recording of a message when a record switch (such as, for example, switch
8B of device 3B of FIG. 2D) is released. In embodiments of a communication
device having sound effects switches and a record LED (such as, for
example, device 3B of FIG. 2D), the record LED also glows to indicate a
sound effect being added to a message.
In accordance with this invention, to continue recording a message, a
record switch 8A (of device 3A of FIG. 2A) can be used as often as
desired. In embodiments with sound effects switches (such as, for example,
device 3B of FIG. 2D), the record switch can be used to continue a message
after addition of sound effects. When the user has finished recording, the
user can press a play switch (such as, for example, play switch 9A of
device 3A of FIG. 2A) to hear the recorded message. The play switch can be
repeatedly pushed to hear a recorded message as often as desired. Once a
play switch has been pushed, recording of a message cannot be continued.
Using a record switch after use of the play switch causes an already
recorded message to be erased so that a new message can be recorded
(except in embodiments provided with an erase switch, in which case use of
a record switch continues the recorded message and the message is erased
only on hitting the erase switch).
To transmit a message recorded in a communication device, a user can aim
the transmit window (such as, for example, window 6D of device 3D of FIG.
3A) at the receive window of a remote communication device (for example,
device 3D with window 10D'). If the person with remote device 3D' is not
facing the user, the user can aim the transmit window at a wall in front
of or to the side of the person such that infrared signals emitted by
device 3D "bounce" off the wall to reach device 3D'.
Referring to FIG. 3A, when the user pushes and holds down a transmit switch
(one of switches 13D), a transmit LED (not shown in FIG. 3A) glows and
electrical signals representative of a message stored in audio recorder
16D are transferred to transmitter 15D which transmits electromagnetic
signals 22 representative of the sound message. In some embodiments, the
transmit LED glows for as long as a message is being transmitted and stops
glowing when message transmission is completed. During message
transmission, a user must keep the communication device aimed at the
remote device or in a fashion so that the remote device receives a
reflected signal until message transmission is completed. During message
transmission, a message cannot be received from a remote communication
device. Although in the embodiment described above the message
transmission is done in real times, in other embodiments the message is
compressed and transmitted in a burst.
Electromagnetic signals 22 can be received by receiver 14D' of
communication device 3D' if the receive window 10D' is properly oriented
to receive the electromagnetic signals. On receipt of signals 22, receiver
14D' converts the received signals into electrical signals indicative of
the sound message. These electrical signals are stored by audio recorder
16D' and one or two "beep" sounds are emitted by speaker 18D' to indicate
receipt of a message. In some embodiments, an LED (such as, for example,
LED 5B2 of device 3B of FIG. 2C also used for indicating recording of a
message) will flash periodically (for example, once a second) to provide
additional or alternate indication of receipt of a message. When the user
presses play switch 9D', audio recorder 16D' transfers the analog
electrical signals to sound output transducer 18D' which converts the
electrical signals into sound waves. A user can press a play switch (one
of switches 13D') to hear the received message as often as desired. Using
a record switch (one of switches 13D') after receipt of a message causes
the received message to be erased so that a new message can be recorded.
Thus a received message can be erased even without playback of the message
by using the record switch.
FIG. 3B illustrates in block diagram form the internal circuitry of a
communication device such as, for example, 3D or 3D' shown in FIG. 3A. In
FIG. 3B element 314 is an infrared (henceforth "IR") receiver, element 312
is an IR transmitter and element 316 is an audio recorder. While IR is
used for transmitting signals in the preferred embodiment, other
electromagnetic energy could also be used if desired. For example,
collimated light could be used (of course the secrecy of transmission is
then potentially lost) as well as other frequencies of electromagnetic
radiation including radio frequencies.
In FIG. 3B, IR receiver 314 receives an IR signal 322 and converts this
signal into an electrical signal which is transmitted by the RX audio
output pin 320 on wire 370 to audio recorder 316. This electrical signal
is received on RX audio input 352 of audio recorder 316 and recorded
within audio recorder 316 in a manner well known in the art. For example,
see the ISD chip specification describing the ISD 1000 Series to the ISD
2500 Series of products (including ISD addressable memory chips, such as,
for example, ISD 1420) available from Information Storage Devices, 2841
Junction Avenue, San Jose, Calif. 95134.
To initiate recording in audio recorder 316, IR receiver 314 produces a
control signal which is transmitted from receiver 314 to recorder 316 on
lead 372. Shown in FIG. 3B are two wires 372 and 374 for transmitting
control signals from receiver 314 to recorder 316. A start control signal
is transmitted from RECORD 1 pin on receiver 314 to RECORD 1 pin on audio
recorder 316 by a lead 372 while a second control signal is provided from
receiver 314 RECORD 2 pin on lead 374 to RECORD 2 pin on audio recorder
316. The second control signal is provided because recorder 316 in one
embodiment may require a second level control signal not available on lead
372. However, in general only one control lead is required between
receiver 314 and recorder 316.
Lead 366 entitled RECEIVER DISABLE to receiver 314 from transmitter 312
disables the receiver during the transmission of signals from the device
on IR transmitter 314. The signal labelled END OF INCOMING MESSAGE
provides a pulse to the transmitter 312 upon the termination of an
incoming message to allow the transmitter 312 to again transmit the signal
and to activate a beep to inform the wearer of the device that a message
has been received. The beep typically is an 800-cycle pulse with a
duration of about one second. Of course, other appropriate frequencies and
durations could be used as desired. In addition, the end of incoming
message signal received by transmitter 312 causes an LED to start
blinking. The LED will blink for about 1/4 to 1/2 second, every 2 seconds,
until the message is played back. Naturally, the light could have a
different duration and a different frequency as desired.
Further, in FIG. 3B, VBAT+ is a direct connection from battery to the
transmitter 312 to avoid stressing a regulator circuit during the
transmission of messages by the device. The SP+ signal is the positive
signal wire to the speaker. The SP+ wire goes through transmitter 312
which has a switch which opens the SP+ circuit during the transmission of
signals to prevent the speaker from reproducing the message during the
transmission of the message. This saves power and prevents disruption of
meetings while a person using the device is transmitting a message. In
fact, this particular switch prevents what is intended to be a covert
message from becoming overt.
FIG. 4 illustrates a transmitter used in one embodiment of this invention.
In FIG. 4, when it is desired to transmit a signal to some other like
device, the person wearing the device presses the transmit switch SW1
thereby grounding the RECEIVER DISABLE terminal and providing a low
voltage on the collector of PNP transistor Q2. In addition, the gate of N
channel MOS transistor Q4 (whose substrate is held at the source voltage)
is turned off thereby disconnecting the SPEAKER output terminal from the
SP+ terminal, which is the terminal on which an incoming message is
received. The message to be transmitted is received on terminal SP+ from
the audio recorder (shown in FIG. 6) and is transmitted through blocking
capacitor C18 to control lead 5 of timer and modulator chip 405.
Typically, timer and modulator chip 405 is the well known LM555 timer chip
available from, for example, National Semiconductor. The output signal
from chip 405 is provided on output pin 3 and is sent to the base of PNP
transistor Q2. The input signal to timer chip 405 is the recorded signal
SP+ provided on input lead 5. Timer chip 405 produces on output lead 3 a
high frequency signal (typically, about 175 KHz) the frequency of which is
modulated by the amplitude of the incoming signal on terminal SP+. Thus
the output frequency on lead 3 is a stream of pulses which have a
substantially constant pulse width but the pulse frequency of which is
modulated by the amplitude of the incoming signal on SP+. This output
signal turns on and off PNP transistor Q2 thereby turning on and off
infrared emitting diodes D8 and D9 at the frequency of the output pulses.
Thus diodes D8 and D9 (which in one embodiment are diodes AN305 provided
by Stanley Electric) generate an IR signal which represents the output
signal on lead 3 from chip 405. This IR signal is transmitted in a
directional manner to another like device at which the transmit window of
the transmitting device is being pointed. The collector of PNP transistor
Q2 is grounded thereby disabling the receiver (shown in FIG. 5). Moreover,
the speaker in the device is also disabled by the turning off of NMOS
switch Q4 thereby preventing the transmitted signal from being audible to
the sender.
The transmitter circuit in FIG. 4 also includes LED D10 which turns on in
response to a message being sent to tell the user that the message is
being sent. This particular diode turns on in response to the recorded
message being transmitted to the base of NPN transistor Q5 through base
resistor R27. Transistor Q5 is turned on and off in respond to the audio
signal being received by the transmitter on terminal SP+ and causes LED
D10 to emit light in response to NPN transistor Q5 turning on and off in
response to the received audio signal. Resistor R28 prevents a substantial
flow of current through diode D10 and NPN transistor Q5. In reality
transistor Q5 is on most of the time during the receipt of the signal on
terminal SP+ causing LED D10 to transmit modulated light continuously
telling the sender that, in fact, the sender must keep pointing the device
because the message is still being transmitted.
The transmitter also is capable of indicating the receipt of an incoming
message at the device from another device. An end of incoming message
signal received on END OF INCOMING MESSAGE terminal is passed through
blocking capacitor C20 to an oscillator including NAND gate 401 feedback
resistor R20 and capacitor C21.
When an incoming message is received, initially, the signal on END OF
INCOMING MESSAGE terminal goes low thereby driving the voltage on node A
(which has been at ground level) beneath ground. Gradually, the voltage on
node A comes back up to ground and sits at ground as long as the signal on
the terminal END OF INCOMING MESSAGE is low. Then at the end of the
incoming message, the signal on terminal END OF INCOMING MESSAGE goes high
thereby driving the voltage on node A high for a short period of time
until this voltage again is pulled back to ground through resistor R19.
The voltage on node A is applied to NAND gate 401 on input lead 1 thereby
enabling NAND gate 401. NAND gate 401 then functions as an oscillator at a
frequency of about 800 Hz for the period of time that the voltage on node
A remains high to enable NAND gate 401. This time is about 1 second.
Naturally, this time can be varied by varying the value of resistor R19.
Also the frequency of oscillation of the oscillator comprising NAND gate
401, resistor R20 and capacitor C21 can be varied by varying the value of
resistor R20 and capacitor C21. The output oscillations from NAND gate 401
are driven on output lead 3 through blocking capacitor C22 to the speaker
terminal thereby to activate the speaker and provide an audio signal or
buzz for about 1 second.
The output signal on lead 3 from NAND gate 401 in oscillator 406 is also
driven to input lead 4 on NAND gate 402. NAND gate 402 is cross-coupled in
a well known manner with NAND gate 403 to form a latch circuit. The
instant the output signal on lead 3 from NAND gate 401 goes low, the latch
made up of cross-coupled NAND gates 402 and 403 produces a high output
signal on lead 6 of NAND gate 402. This high output signal drives the
output signal on lead 8 from NAND gate 403 low thereby disabling NAND gate
402 and preventing the oscillations on output lead 3 from NAND gate 401
from having any further effect on the latch circuit. The high level output
signal on lead 6 from NAND gate 402 thus is provided on input lead 12 to
NAND gate 404 thereby providing a low level output signal on output lead
11 to turn on PNP transistor Q3. LED D11 thus produces a visible output
signal to the wearer of the device, telling the wearer that a message has
been received. The low level output signal on lead 11 from NAND gate 404
is fed back through resistor R17 to discharge capacitor C19 thereby
driving the input signal on input lead 13 to NAND gate 404 low. The time
necessary for this to occur is typically about 1/4 to 1/2 second. When the
input signal on lead 13 goes low, the output signal of NAND gate 404 on
output 11 goes high thereby shutting off transistor Q3. This high signal
then charges capacitor C19 through resistor R17 and series connected
resistor R18 and diode D6 in parallel with resistor R17. When the charge
on capacitor C19 produces a high level signal on input lead 13, NAND gate
404 then produces a low output signal thus again turning on transistor Q3.
A typical duty cycle for transistor Q3 is to be on for approximately 1/4
to 1/2 second and off for about 11/2 to 13/4 second. Thus, this particular
oscillator 407 continues to oscillate until the wearer of the device
presses the play button (see FIG. 6). When the play button is pressed,
input lead 10 of NAND gate 403 goes low thereby switching the state of
flip-flops 402 and 403 to provide a low signal on output lead 6 from NAND
gate 402 thereby stopping oscillator 407 from oscillating.
The ratings of the components for a transmitter in one embodiment of this
invention are listed in Table 1.
FIG. 5 illustrates a receiver used in one embodiment of this invention. In
FIG. 5, light sensitive diodes D5 and D6 (which in one embodiment are
photodiodes PD638B provided by Everlight) receive the transmitted IR
signal from another like device. Diodes D5 and D6 are back biased to lower
their capacitances thereby to provide a faster response time to incident
infrared radiation. The anodes of these diodes are connected to one
terminal of resistor R1 the other terminal of which is connected to the
voltage supply VCC. The anodes of diodes D5 and D6 are also connected
through blocking capacitor C1 to inverting input lead 2 on transimpedience
amplifier 501. Amplifier 501 converts an input current to an output
voltage. Input lead 3 is biased to be at approximately half of VCC by
means of a voltage-divider made up of resistors R3 and R4. An off switch
(not shown) can be provided in the circuit to shut off all current to all
components in the device when the device is not in use to prevent unwanted
battery drain. Capacitor C3 in connection with resistors R3 and R4
functions as a filter preventing noise from impacting the circuit. The
output of inverting transimpedience amplifier 501 is provided through
blocking capacitor C2 and resistor R2 to input lead 6 on inverting
amplifier 502 (a voltage-to-voltage amplifier) and then from output lead 7
of inverting amplifier 502 through blocking capacitor C5 and resistor R7
to inverting input lead 2 of inverting amplifier 503. The signal on output
lead 1 from inverting amplifier 503 is passed through blocking capacitor
C8 and resistor R10 to inverting lead 6 on inverting amplifier 504. The
output signal on output lead 7 from inverting amplifier 504 is passed
through blocking capacitor C9 and C10 in parallel on output leads FM1 and
FM2 which go respectively to the FM1 input lead 14 on phase locked loop
block 505 and to the input terminal FM2 on a signal detection circuit 506.
Phase locked loop 505 is basically a demodulator which demodulates the
pulse frequency modulated signal received by diodes D5 and D6 into an
audio signal which is then transmitted from phase locked loop 505 on
demodulator output pin 10. This signal is then transmitted on RX AUDIO
terminal to the recording structure which will be described later in FIG.
6. Phase locked loop 505 is a standard commercial component such as
Signetics Part No. 74HC4046. This part is also made, or has been made by a
number of manufacturers including RCA and Motorola. The various resistors
such as R11, R12, R13, R14 and R15 and capacitors such as C11 and C14
shown associated with this part serve functions as described in the data
sheet for this part. These functions are well known and thus will not be
described in detail.
The signal on lead FM2 is input to disable/enable circuit 506. Circuit 506
includes diodes D10, D2, D3 and D4, resistor R30, NPN transistor Q1 and
capacitor C15. When an AC signal is present on lead FM2, diode D2 will
clip the negative portions of the signal and allow the positive portions
of the signal to turn on transistor Q1. Transistor Q1 when turned on pulls
the voltage on capacitor C15 to approximately zero thereby producing a low
level signal on terminals RECORD 1 and RECORD 2 and INCOMING MESSAGE.
Thus, the disable/enable circuit 506 enables the recording of the incoming
message and, as described above in conjunction with FIG. 4, provides, at
the end of the incoming message, a signal indicating that a message has
been received. When the incoming message ends, FM2 no longer is present as
an AC signal. If however, the transmitter associated with the device at
which the receiver is present, is transmitting, the receiver disable
signal will be low pulling FM2 low through diode D10. Pulling FM2 low
through diode D10 shuts off transistor Q1 and prevents RECORD 1, RECORD 2
and INCOMING MESSAGE terminals from going low thereby disabling the
recording functions during the transmission of a signal as well as
inhibiting phase locked loop circuit 505 by providing a high signal on
input pin 5 labelled "INH".
The ratings of components for a receiver in one embodiment of this
invention are listed in Table 1.
FIG. 6 illustrates an audio recorder associated with one embodiment of a
communication device in accordance with this invention. The heart of FIG.
6 is the integrated circuit 605 which in one embodiment is the analog
recorder chip ISD 1400 as described above. The ISD 1400 will store and
record up to 20 seconds of analog signal. Other recording devices can, of
course, be used with this invention if desired and the appropriate
circuitry for use with these devices will be well within the skill of one
skilled in the art given this disclosure. Such other recording devices
could include, for example, a small wire recorder.
When a message is to be recorded, switch S2 is pressed thereby pulling the
voltage on the RECORD 1 terminal to ground. This pulls low the input lead
6 to NAND gate 602 (cross-coupled in a well known manner with NAND gate
601 to form a latch), thus driving the output signal on output lead 4 from
NAND gate 602 high. The input signal on the PLAY terminal which is
connected to input terminal 1 of NAND gate 601 is already held high by VCC
applied to this terminal through series connected resistors R13 and R6.
Thus, the high output signal on output lead 4 of NAND gate 602 drives the
output signal on output lead 3 from NAND gate 601 low thereby applying a
low input signal on input lead 5 to NAND gate 602 and disabling NAND gate
602. The high output signal on output lead 4 from NAND gate 602 is
provided on input pin 2 to recording chip 605 and also on input pin 5 to
chip 605.
In addition, the low record signal resulting from pushing switch S2 is
passed through diode D3 and resistor R7 to record input lead 27 of chip
605 thereby to initiate the recording process. The input signal to be
recorded when the signal is being generated by the user of the device will
come from the microphone 607 into terminals 17 and 18 through blocking
capacitors C4 and C5.
When a signal is being received by the receiver (FIG. 5) as described
above, the signals on terminals RECORD 1 and RECORD 2 will also go low.
These signals will likewise activate the recording in audio recorder chip
605 so that the received demodulated signal on terminal RX AUDIO from FIG.
5 will be received on terminal RX AUDIO of FIG. 6 and recorded by audio
recorder chip 605 as a result of signals transmitted into this device
mainly on pin 20 through blocking capacitor C3. In addition, a small
signal is transmitted into chip 605 through resistor R2 on pin 21.
During the playback of a signal, the PLAY switch S1 is pressed thereby
dropping the input lead 1 of NAND gate 601 low and driving output lead 3
of NAND gate 601 high. This high output signal is applied to | | |