U.S. patent application number 09/804801 was filed with the patent office on 2001-08-02 for intrusion alarm and detection system.
Invention is credited to Carney, William P..
Application Number | 20010010492 09/804801 |
Document ID | / |
Family ID | 27005935 |
Filed Date | 2001-08-02 |
United States Patent
Application |
20010010492 |
Kind Code |
A1 |
Carney, William P. |
August 2, 2001 |
Intrusion alarm and detection system
Abstract
An intrusion detection system includes a remote controller
activated by a user transmitting a particular RF carrier signal to
a self-contained monitor. The self-contained monitor is energized
by a primary power source and comprises an RF receiver circuit for
receiving the particular RF carrier signal, a tuning code circuit
for inputting a tuning code, a nonvolatile memory circuit for
storing the tuning code which makes the RF receiver circuit
responsive to the particular RF carrier signal, a volatile memory
circuit having an armed state and a disarmed state, a motion
detector for detecting an intruder in the predetermined space, a
timing circuit for measuring a preset period of time and a
responder. The user switches the volatile memory circuit from the
disarmed state to the armed state by activating the remote
controller. The volatile memory circuit is switched from the armed
state to the disarmed state by either the volatile memory circuit
sensing an interruption in primary power lasting longer than the
preset period of time or by the motion detector detecting an
intruder. The user tests the state of the volatile memory circuit
by manipulating the remote controller to prompt a response from the
responder indicating whether the volatile memory circuit is in the
armed state or the disarmed state. A response indicating that an
intrusion event has occurred warns the user not to enter the
predetermined space to avoid the possibility of inadvertently
confronting a remaining intruder.
Inventors: |
Carney, William P.; (Oyster
Bay, NY) |
Correspondence
Address: |
Charles E. Temko
22 Marion Road
West Port
CT
06880
US
|
Family ID: |
27005935 |
Appl. No.: |
09/804801 |
Filed: |
March 14, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09804801 |
Mar 14, 2001 |
|
|
|
09624513 |
Jul 24, 2000 |
|
|
|
09624513 |
Jul 24, 2000 |
|
|
|
09372836 |
Aug 12, 1999 |
|
|
|
6137405 |
|
|
|
|
Current U.S.
Class: |
340/541 ;
340/531; 340/539.1 |
Current CPC
Class: |
G08B 25/10 20130101;
B60R 25/24 20130101; G08B 25/008 20130101; B60R 25/1012
20130101 |
Class at
Publication: |
340/541 ;
340/531; 340/539 |
International
Class: |
G08B 001/00 |
Claims
What is claimed is:
1. An intrusion detection system comprising: a self-contained
monitor energized by a primary power source responsive to a remote
controller transmitting a particular RF carrier signal under the
control of a user; said self contained monitor including a
nonvolatile memory circuit storing a tuning code therein, a tuning
code circuit for inputting said tuning code communicating with said
nonvolatile memory circuit, a transfer switch communicating with
said nonvolatile memory circuit and with said tuning code circuit,
an RF receiver circuit communicating with a motion detector, a
volatile memory circuit, a responder, and with said nonvolatile
memory circuit; said motion detector surveiling a predetermined
space for an intruder; said transfer switch being manually
activated by said user transferring said tuning code from said
tuning code circuit to said nonvolatile memory circuit; said RF
receiver circuit being made responsive to said particular RF
carrier signal by said tuning code stored in said nonvolatile
memory circuit; said volatile memory circuit selectively defining
an armed state and a disarmed state; said volatile memory circuit
being selectively disarmed by sensing at least one of an
interruption of primary power and said motion detector detecting an
intruder; and said responder being prompted by said RF receiver
circuit responding to said particular RF carrier signal to generate
a response indicating one of said states of said volatile memory
circuit.
2. An intrusion detection system in accordance with claim 1 wherein
said remote controller further comprises a DIP switch, said user
manually inputting a code setting thereon representing a binary
code defining said tuning code being transmitted as part of said
particular RF carrier signal.
3. An intrusion detection system in accordance with claim 2 wherein
said tuning code circuit further comprises a plurality of switches,
said user manually inputting said code setting thereon and
activating said transfer switch thereby storing said tuning code in
said nonvolatile memory circuit for subsequently qualifying said
particular RF carrier signal transmitted by said remote
controller.
4. An intrusion detection system in accordance with claim 3 wherein
said user may change said binary code after activating said
transfer switch so that said binary code cannot be determined by an
intruder observing said switches.
5. An intrusion detection system in accordance with claim 1 wherein
said self-contained monitor further comprises a code transfer
circuit including a normally open pushbutton switch..
6. An intrusion detection system in accordance with claim 1 wherein
said self-contained monitor further comprises a timing circuit
communicating with said primary power source and with said volatile
memory circuit, said timing circuit providing a preset period of
time during which said volatile memory circuit does not sense an
interruption of primary power.
7. An intrusion detection system in accordance with claim 6 wherein
said timing circuit further comprises a capacitive component.
8. An intrusion detection system in accordance with claim 1 wherein
said volatile memory circuit is switched from said disarmed state
to said armed state by said RF receiver circuit responding to said
particular RF carrier signal.
9. An improved intrusion detection system of the type wherein a
self-contained monitor is energized by a primary power source and
is responsive to a remote controller transmitting a particular RF
carrier signal under the control of a user, said self-contained
monitor including an RF receiver circuit communicating with a
motion detector surveiling a predetermined space for an intruder
and with a responder for reporting the occurrence of an intrusion,
the improvement comprising: a nonvolatile memory circuit storing a
tuning code therein communicating with said RF receiver circuit; a
volatile memory circuit selectively defining an armed state and a
disarmed state communicating with said motion detector; a tuning
code circuit for inputting said tuning code communicating with said
nonvolatile memory circuit; a transfer switch communicating with
said tuning code circuit and said nonvolatile memory circuit being
manually activated by said user transferring said tuning code from
said tuning code circuit to said nonvolatile memory circuit; said
RF receiver circuit being made responsive to said particular RF
carrier signal by said tuning code stored in said nonvolatile
memory circuit; said volatile memory circuit being selectively
disarmed by sensing at least one of an interruption of primary
power and said motion detector detecting an intruder; and said
responder being prompted by said RF receiver circuit responding to
said particular RF carrier signal to generate a response indicating
one of said states of said volatile memory circuit.
10. An intrusion detection system in accordance with claim 9
wherein said remote controller further comprises an encoder chip
encoding said particular RF carrier signal with an identification
code defining said tuning code being transmitted as part of said
particular RF carrier signal.
11. An intrusion detection system in accordance with claim 10
wherein said tuning code circuit further comprises a decoder chip
for decoding said particular RF carrier signal.
12. An intrusion detection system in accordance with claim 11
wherein said decoder chip is prompted to extract said
identification code from said particular RF carrier signal during a
time period wherein said particular RF carrier signal is being
transmitted and simultaneously said transfer switch is being
activated to transfer said identification code into said
nonvolatile memory circuit for subsequently qualifying said
particular RF carrier signal transmitted by said remote
controller.
13. An intrusion detection system in accordance with claim 9
wherein said self-contained monitor further comprises a code
transfer circuit including a normally open pushbutton switch.
14. An intrusion detection system in accordance with claim 9
wherein said self-contained monitor further comprises a timing
circuit communicating with said primary power source and with said
volatile memory circuit, said timing circuit providing a preset
period of time during which said volatile memory circuit does not
sense said interruption of primary power.
15. An intrusion detection system in accordance with claim 14
wherein said timing circuit further comprises a capacitive
component.
16. An intrusion detection system in accordance with claim 9
wherein said volatile memory circuit is switched from said disarmed
state to said armed state by said RF receiver circuit responding to
said particular RF carrier signal.
17. An intrusion detection system comprising: a self-contained
monitor energized by a primary power source responsive to a remote
controller transmitting a particular RF carrier signal under the
control of a user; said self-contained monitor including a
microcontroller, a motion detector, a tuning code circuit for
inputting a tuning code communicating with said microcontroller; a
transfer switch communicating with said microcontroller and said
tuning code circuit, an RF receiver circuit communicating with said
motion detector and said microcontroller; said motion detector
surveiling a predetermined space for an intruder; said transfer
switch being manually activated by said user transferring said
tuning code from said tuning code circuit to said microcontroller;
said microcontroller being programmed to define an emulated
volatile memory circuit having an armed state and a disarmed state
and being programmed to define an emulated nonvolatile memory
circuit for storing said tuning code therein; said RF receiver
circuit being made responsive to said particular RF carrier signal
by said tuning code stored in said emulated nonvolatile memory
circuit; said tuning code including at least one of a binary code
and an identification code; and said emulated volatile memory
circuit being disarmed by selectively sensing at least one of an
interruption of primary power and said motion detector detecting an
intruder.
18. An intrusion detection system in accordance with claim 17
wherein said microcontroller further comprises a clock circuit
communicating with said emulated volatile memory circuit such that
said emulated volatile memory circuit is not switched to said
disarmed state by an interruption in primary power lasting less
than a preset period of time as measured by said clock circuit.
19. An intrusion detection system in accordance with claim 17
wherein said emulated volatile memory circuit is switched from said
disarmed state to said armed state by said RF receiver circuit
responding to said particular RF carrier signal.
20. In combination, an intrusion detection system energized by a
primary power source surveiling a predetermined space comprising: a
nonvolatile memory circuit storing a tuning code therein; a
volatile memory circuit defining an armed state and a disarmed
state; a timing circuit measuring a preset period of time coupled
to said volatile memory circuit; an RF transmitter circuit
transmitting an RF carrier signal; an RF receiver circuit
communicating with said volatile memory circuit and with said
nonvolatile memory circuit, said RF receiver circuit being made
responsive to said RF carrier signal by said tuning code; and said
volatile memory circuit being switched from said armed state to
said disarmed state by sensing an interruption in said primary
power source lasting longer than said preset period of time.
21. The combination as claimed in claim 20 wherein said intrusion
detection system further comprises a tuning code circuit
communicating with said nonvolatile memory circuit for inputting
said tuning code therein.
22. The combination as claimed in claim 20 wherein said timing
circuit further comprises a short term energy storage circuit
supplying secondary power to said volatile memory circuit for said
preset period of time so that said volatile memory circuit does not
sense said interruption in primary power during said preset period
of time.
23. The combination as claimed in claim 20 wherein said timing
circuit further comprises a clock circuit which prompts said
volatile memory circuit to switch to said disarmed state after said
preset period of time has elapsed as measured by said clock
circuit.
24. The combination as claimed in claim 20 wherein said volatile
memory circuit is switched from said disarmed state to said armed
state by said RF receiver circuit responding to said particular RF
carrier signal.
25. A method for operating an alarm system including a remote
controller controlling a self-contained monitor surveiling a
predetermined space, said self-contained monitor having a primary
power source energizing a volatile memory circuit selectively
defining an armed state and a disarmed state, a tuning code
circuit, a nonvolatile memory circuit for storing a tuning code, an
intrusion detector and a responder, including the steps of: a)
setting a tuning code in said tuning code circuit; b) transferring
said tuning code to said nonvolatile memory circuit; c) disposing
said self-contained monitor to surveil a predetermined space; d)
switching said self-contained monitor to said armed state; e)
surveiling said predetermined space to detect an intruder; f)
monitoring said primary power source for an interruption of primary
power having a duration longer than a predetermined period of time;
and g) switching said self-contained monitor from said armed state
to said disarmed state as a result of said self-contained monitor
alternatively sensing said interruption of primary power and
detecting said intruder.
26. The method set forth in claim 25 including the additional step
of testing said state of said volatile memory circuit generating a
response from said responder indicating one of said states of said
volatile memory circuit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a CIP of U.S. Pat. application Ser. No.
09/624,513, filed Jul. 24, 2000 which is a CIP of U.S. Pat.
application Ser. No. 09/372,836 filed Aug. 12, 1999 now U.S. Pat.
No. 6,137,405, issued Oct. 24, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to burglar alarm systems
and more particularly to a self-contained monitor surveiling a
predetermined space for an occurrence of an intrusion. The
self-contained monitor may be remotely tested by a returning
occupant to determine if an intrusion event has occurred in the
predetermined space.
[0004] 2. Description of Related Art
[0005] Burglar alarm systems comprising a self-contained monitor
used to surveil a predetermined space having a remote controller
transmitting an RF signal to control the self-contained monitor are
well known in the prior art. In such systems, the monitor typically
includes a primary power source, a motion sensor, a responder and a
memory circuit. The motion sensor detects an unauthorized entry
into the predetermined space causing the responder to sound an
alarm and, at the same time, causing the memory circuit to record
the occurrence of the intrusion. In certain prior art systems, the
memory also records any interruption of primary power as an
intrusion event. Before reentering the premises, a returning
occupant activates the remote controller prompting a response from
the self-contained monitor to determine if an intrusion event has
occurred in order to determine whether it is safe to enter the
premises.
[0006] Since the personal wellbeing of the returning occupant is at
risk, it is essential that the self-contained monitor provides not
only a reliable means by which to record an intrusion event but
also a reliable means by which to remotely test whether an
intrusion has, or has not, occurred. On one hand, it is extremely
dangerous for a returning occupant to unwittingly confront an
intruder. On the other, it is stressful, inconvenient and time
consuming for the returning occupant to seek help mistakenly
believing that an intrusion has occurred as a result of a false
test report.
[0007] A self-contained monitor, employed by a returning occupant
to remotely test for a remaining intruder, presents certain
problems relating to its reporting accuracy and reliability because
such monitors are often located in either apartments or homes where
an intruder has the privacy and the time to gain control of the
alarm system. In the privacy of an isolated premises, it is
possible for the intruder to manipulate the self-contained monitor
to purposely produce a false test report which causes the returning
occupant to enter his or her premises unaware that the intruder
remains therein. Further, in some instances, self-contained
monitors are subject to primary power interruptions which may cause
false test reports which result in the returning occupant
needlessly seeking help. Finally, if the remote controller
transmits a fixed frequency RF signal to control the self-contained
monitor, the intruder can surreptitiously intercept the signal and
easily determine its frequency by using what is known in the
industry as a "code grabber". Subsequently, the intruder can gain
control of the system by transmitting a duplicate signal causing
the self-contained monitor to produce a false test report.
[0008] U.S. Pat. No. 6,137,405 which issued to the applicant of the
present invention, William P. Carney, on Oct. 24, 2000 teaches an
intrusion detection system including a self-contained monitor
disposed to surveil a predetermined space for an intrusion event.
Should an intrusion event occur during an occupant's absence, the
self-contained monitor not only sounds an alarm to frighten away
the intruder but also records the occurrence of the event. Upon
returning and before reentering the predetermined space, the
occupant employs a remote controller to test the self-contained
monitor prompting a response therefrom to determine if an intrusion
event has occurred and whether or not it is safe to reenter. The
self-contained monitor comprises a primary power source, an RF
receiver circuit, a PIR motion detector, a memory circuit and a
responder. The self-contained monitor is tuned to the remote
controller by a tuning code set on a DIP switch in the monitor
which matches a tuning code set on a DIP switch in the remote
controller. The memory circuit taught by Carney includes a volatile
memory circuit defining an armed state and a disarmed state and a
nonvolatile memory circuit for storing the tuning code therein. The
volatile memory circuit is armed and tested by a particular RF
carrier signal transmitted by the remote controller to the
self-contained monitor wherein it is qualified by the tuning code.
Further, the self-contained monitor is disarmed by either sensing a
power interruption or by the motion sensor detecting an intruder.
In Carney, the volatile memory circuit can only be rearmed by a
particular RF carrier signal qualified by the tuning code stored in
the nonvolatile memory. Carney teaches that the tuning code set on
the monitor DIP switch may be transferred into the nonvolatile
memory circuit by the user manually operating a code transfer
switch. Because the user can change the setting on the DIP switch
after transferring the tuning code, Carney's disclosure solves the
problem of an intruder gaining control of the self-contained
monitor by simply observing its DIP switch setting and using the
same on an unauthorized remote controller. However, in this
disclosure, Carney does not teach a means by which to control the
system with other than a fixed frequency RF signal and does not
solve the problem of momentary power interruptions causing false
intrusion reports.
[0009] U.S. Pat. application Ser. No. 09/624,513 filed Jul. 24,
2000 by William P. Carney, the applicant of the present invention,
is a CIP of his above referenced U.S. Pat. No. 6,137,405. In
application Ser. No. 09/624,513, Carney discloses an improved
intrusion detection system similar to that disclosed in its parent
case U.S. Pat. No. 6,137,405 summarized above. Further, in
application Ser. No. 09/624,513, Carney teaches a short term energy
storage circuit which provides secondary power to a volatile memory
circuit for a predetermined period of time so that a momentary
interruption of primary power lasting less than the predetermined
period of time is not sensed by the volatile memory circuit. By not
sensing and by not recording momentary interruptions, the improved
intrusion detection system taught by Carney minimizes the number of
false intrusion reports generated as a result of primary power
interruptions. Therefore, Carney's improved system minimizes the
number of times a returning occupant will seek help mistakenly
believing an intrusion has occurred as a result of a false
intrusion report. However, in this disclosure, Carney does not
teach a means by which to control an intrusion detection system
with an RF signal other than a fixed frequency RF signal in order
to make it difficult for an intruder to intercept the RF signal and
duplicate the same to gain control of the system and possibly cause
harm to an unsuspecting returning occupant.
[0010] As can be seen from the foregoing, there exists a definite
need in the art for a self-contained monitor which includes a
reliable means by which to record and test for an intrusion event,
which generates a minimum number of false intrusion reports due to
primary power interruptions and, in addition, employs an RF signal
that cannot be easily intercepted and duplicated so that an
intruder can gain control of the system and jeopardize the well
being of a returning occupant.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to a system which includes
a reliable means by which to record and test for an intrusion
event, a system which generates a minimum number of false intrusion
reports due to primary power interruptions and, in addition,
employs an RF signal that cannot be easily intercepted and
duplicated thereby preventing an intruder from gaining control of
the system and jeopardizing the well being of a returning
occupant.
[0012] A first embodiment of the present invention comprises a
self-contained monitor which is energized by a primary power source
and which is responsive to an authorized remote controller
transmitting a particular RF carrier signal under the control of a
user. The self-contained monitor includes a nonvolatile memory
circuit for storing a tuning code therein, a tuning code circuit
for inputting the tuning code communicating with the nonvolatile
memory circuit, a transfer switch communicating with the
nonvolatile memory circuit and with the tuning code circuit, an RF
receiver circuit communicating with a motion detector, a volatile
memory circuit, a responder, and with the nonvolatile memory
circuit. The motion detector surveils a predetermined space for the
presence of an intruder. The transfer switch is manually activated
by the user transferring the tuning code from the tuning code
circuit to the nonvolatile memory circuit. The RF receiver circuit
is made responsive to the particular RF carrier signal by the
tuning code stored in the nonvolatile memory circuit. The volatile
memory circuit selectively defines an armed state and a disarmed
state. The volatile memory circuit is selectively disarmed by
either sensing an interruption of primary power or by the motion
detector detecting the intruder. The responder is prompted by the
RF receiver circuit responding to the particular RF carrier signal
to generate a response or absence thereof indicating one of the
states of the volatile memory circuit. The remote controller
further comprises a DIP switch and the user manually inputs a code
setting thereon representing a binary code defining the tuning code
which is transmitted as part of the particular RF carrier signal.
The tuning code circuit further comprises a plurality of switches.
The user manually inputs the code setting thereon and activates the
transfer switch thereby storing the tuning code in the nonvolatile
memory circuit for subsequently qualifying the particular RF
carrier signal transmitted by the remote controller.
[0013] A second embodiment of the present invention comprises a
second self-contained monitor which is energized by a primary power
source and which is responsive to a second authorized remote
controller transmitting a second particular RF carrier signal under
the control of a user. The second self-contained monitor includes a
nonvolatile memory circuit for storing a second tuning code
therein, a second tuning code circuit for inputting the second
tuning code communicating with the nonvolatile memory circuit, a
transfer switch communicating with the nonvolatile memory circuit
and with the second tuning code circuit, an RF receiver circuit
communicating with a motion detector, a volatile memory circuit, a
responder, and with the nonvolatile memory circuit. The motion
detector surveils a predetermined space for the presence of an
intruder. The transfer switch is manually activated by the user
transferring the second tuning code from the second tuning code
circuit to the nonvolatile memory circuit. The RF receiver circuit
is made responsive to the second particular RF carrier signal by
the second tuning code stored in the nonvolatile memory circuit.
The volatile memory circuit selectively defines an armed state and
a disarmed state. The volatile memory circuit is selectively
disarmed by sensing either an interruption of primary power or the
motion detector detecting the intruder. The responder is prompted
by the RF receiver circuit responding to the second particular RF
carrier signal to generate a response or absence thereof indicating
one of the states of the volatile memory circuit. The second remote
controller further comprises an encoder chip encoding the second
particular RF carrier signal with an identification code defining
the second tuning code which is transmitted as part of the second
particular RF carrier signal. The second tuning code circuit
further comprises a decoder chip for decoding the second particular
RF carrier signal. The decoder chip is prompted to extract the
identification code from the second particular RF carrier signal
during a time period wherein the second particular RF carrier
signal is being transmitted and simultaneously the transfer switch
is being activated to transfer the identification code into the
nonvolatile memory circuit for subsequently qualifying the second
particular RF carrier signal transmitted by the second remote
controller.
[0014] A third embodiment of the present invention comprises a
third self-contained monitor energized by a primary power source
responsive to a third remote controller transmitting a third
particular RF carrier signal under the control of a user. The third
self-contained monitor includes a microcontroller communicating
with a third tuning code circuit for inputting a third tuning code,
a transfer switch communicating with the microcontroller and the
third tuning code circuit, an RF receiver circuit communicating
with a motion detector and with the microcontroller. The motion
detector surveils a predetermined space for the presence of an
intruder. The transfer switch is manually activated by the user
transferring the third tuning code from the third tuning code
circuit to the microcontroller. The microcontroller is programmed
to define an emulated volatile memory circuit having an armed state
and a disarmed state and is programmed to define an emulated
nonvolatile memory circuit for storing the tuning code therein. The
RF receiver circuit is made responsive to the third particular RF
carrier signal by the third tuning code stored in the emulated
nonvolatile memory circuit. The third tuning code includes either a
binary code or an identification code. The emulated volatile memory
circuit is selectively disarmed by either sensing an interruption
of primary power or by the motion detector detecting the intruder.
The third self-contained monitor further comprises a clock circuit
communicating with the emulated volatile memory circuit such that
the emulated volatile memory circuit is not switched to the
disarmed state by an interruption in primary power lasting less
than a preset period of time as measured by the clock circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a plan view of a prior art self-contained
intrusion monitor disposed to surveil a predetermined space. Also
included in this figure is a prior art remote controller.
[0016] FIG. 2 is a front elevation view of the self-contained
monitor embodying the present invention.
[0017] FIG. 3 is a sectional view taken along the line 3-3 in FIG.
2.
[0018] FIG. 4 is a block diagram of a first embodiment of the
present invention.
[0019] FIG. 5 is a block diagram of a second embodiment of the
present invention.
[0020] FIG. 6 is a block diagram of a third embodiment of the
present invention.
[0021] FIG. 6A is a block diagram of an alternative aspect of the
third embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Before describing the details of the embodiment of the
present invention, a discussion of a prior art remotely controlled
self-contained intrusion alarm monitor is considered apposite.
[0023] Turning now to the Figures, there is shown in FIG. 1, by way
of explanation, a prior art intrusion detection system used to
monitor a predetermined space 10 for an intruder. The space 10
includes a door 12 and may or may not include additional openings
such as a front window 14 and a rear window 16 depending on a
particular premises 18 in which the system is deployed. The system
comprises an authorized remote controller generally referred to by
reference number 20 and a Passive Infrared (PIR) intrusion monitor
22 having a detection pattern 38. The remote controller 20 may be
hand held and includes a button switch 24 and a transmitter circuit
28 and remotely controls the intrusion monitor 22 by transmitting a
Radio Frequency (RF) carrier signal to a receiver circuit 30. The
intrusion monitor 22 is disposed within the predetermined space 10
and can be armed, disarmed, and tested by the carrier signal
initiated by an authorized user manipulating the button switch 24.
When armed, the intrusion monitor 22 produces an alarm response if
the detection pattern 38 is entered by the intruder. In addition,
the intrusion monitor 22 records and may be tested from outside of
the premises 18 by the remote controller 20 for the intrusion so
that a returning occupant is warned not to reenter the
predetermined space 10, thus avoiding the risk of confronting the
intruder. The transmitter circuit 28 and the receiver circuit 30
noted in FIG. I operate in a manner similar to the manner in which
transmitter and receiver circuits operate in remotely controlled
garage door systems having a typical button switch remote which
causes a particular RF carrier signal to be transmitted to a
receiver to either open or close a garage door. So that
interference with other systems in the vicinity does not occur,
garage door transmitters are generally tuned to associated
receivers by any one of a number of well known methods such as by
tuning one to the other in the factory, by matching the settings on
a plurality of two position switches 36 in the transmitter 20 to
the settings on a similar plurality of two position switches 36 in
the self-contained monitor 22 or by the use of a known code
learning technique wherein receivers are taught by authorized
transmitters to be responsive thereto. The plurality of two
position switches 36 is often referred to in the art as a Dual
In-Line Package (DIP) switch.
[0024] FIGS. 2 and 3 illustrate the improved self-contained monitor
of a first embodiment of the present invention generally referred
to by reference number 60 which includes a housing 62 having a
front section 64, pictured partially fragmented, and a rear section
66, each molded from plastic resin and shaped to accommodate the
components of the self-contained monitor 60. A printed circuit
board (PCB) 72 mounts certain of the electrical components thereon,
including a primary power source 76 comprising a battery pack 78
and/or a power jack 80 for an AC adaptor cord 82, a short length of
which is shown in FIG. 2. The AC adaptor cord 82 which supplies a
DC potential to the electrical components is connected to a well
known AC wall outlet adaptor (not shown) that transforms and
rectifies an AC line voltage to the DC potential. As will be
explained in more detail below, it has been found that because of
the power consumed by the electrical components comprising the
self-contained monitor 60, it is advantageous to use only the AC
wall outlet adaptor as the primary power source providing energy to
the components.
[0025] In addition, there is shown in FIGS. 2 and 3 a known Passive
Infrared (PIR) detector 86 or an equivalent motion sensing device
mounted on the PCB 72 adjacent an arcuate fresnel lens 88 affixed
to the front section 64 which communicates with a responder 104.
The fresnel lens 88 is well known in the art as a means by which to
focus infrared energy on the PIR detector 86 in order to sense an
intruder entering the detection pattern 38 of the self-contained
monitor 60 which is aimed to surveil the predetermined space 10 as
shown in FIG. 1. The sensing of the intruder by the PIR detector 86
prompts the responder 104 to sound an alarm in order to frighten
away the intruder.
[0026] Also mounted on the PCB 72, electrically coupled to the PIR
detector 86 and the primary power source 76, are an RF receiver
circuit 96, a volatile memory circuit 98, a nonvolatile memory
circuit 100, and a logic circuit 102. For the sake of clarity,
certain of the aforementioned components are shown diagrammatically
in FIG. 2 as defining areas on the PCB 72 bounded by dashed lines
pictured thereon. As previously mentioned, the RF receiver circuit
96 is of the type commonly used with garage door openers and is
employed in the self-contained monitor 60 to receive the particular
RF carrier signal transmitted by the remote controller 20 (FIG. 1).
When activated, the remote controller 20 transmits a particular RF
carrier signal having encoded therein a binary tuning code in
accordance with a binary number set by the user on the DIP switch
36 in (FIG. 1). In the instant invention, the user manipulates the
button switch 24 (FIG. 1) in order to selectively transmit coded RF
carrier signals such as either a coded RF arm signal or a coded RF
test signal. The RF arm signal is coded as such by the user
activating the remote controller 20 for about five seconds, thus
transmitting the particular RF arm signal for an interval of about
five seconds. The RF test signal is coded as such by activating the
remote controller 20 for about one second, thus transmitting the
particular RF test signal for an interval of about one second. In a
method detailed in the disclosure which follows, the RF receiver
circuit 96 is made responsive to the particular RF carrier signal
by a tuning code stored in the nonvolatile memory circuit 100. The
logic circuit 102, prompted by the RF receiver circuit 96
responding to the particular RF carrier signal, directs the
self-contained monitor 60 to selectively react to either the longer
RF arm signal or the shorter RF test signal. The volatile memory
circuit 98 has an armed state and a disarmed state employed to
provide the user with a means by which to remotely test for the
occurrence of at least one intrusion by transmitting the coded RF
test signal.
[0027] While leaving the predetermined space 10 (FIG. 1), the user
arms the monitor 60 by transmitting the coded RF arm signal. Should
an intruder enter the predetermined space during the user's
absence, the monitor 60 senses the intrusion and switches the
volatile memory circuit 98 from the armed state to the disarmed
state thereby activating the responder 104. The sounding of the
alarm may prompt a startled intruder to try to mute the responder
104. When the alarm is triggered, the intruder most probably will
be able to determine the location of the self-contained monitor 60
and disconnect its power source to silence the alarm. Therefore, it
is advantageous to alternatively switch the volatile memory circuit
98 from the armed state to the disarmed state as a result of at
least one sustained primary power interruption, as would occur if
the intruder disconnects the self-contained monitor 60 from its
primary power source 76, recording the same as having been caused
by the intruder. Upon returning, the user manipulates the remote
controller 20 (FIG. 1) causing it to transmit the coded RF test
signal in order to remotely test the state of the volatile memory
circuit 98. If the self-contained monitor 60 produces a response,
the returning occupant can be reasonably assured that an intrusion
has not occurred. If the self-contained monitor 60 does not
respond, the returning occupant can be reasonably suspect that an
intrusion has occurred and it may not be safe to enter the premises
18 (FIG. 1).
[0028] As will be explained in more detail below, the
self-contained monitor 60 is made responsive to the remote
controller 20 (FIG. 1) via the tuning code installed by the
authorized user in the nonvolatile memory circuit 100 which tunes
the receiver circuit 96 to the particular RF carrier signal
transmitted by the remote controller 20. Further, as presented in
this disclosure and as is generally understood in the art, a
volatile memory is defined as a device which loses the data stored
therein when the primary power source energizing the device is
interrupted and, conversely, a nonvolatile memory arrangement does
not. For example, the data stored in the volatile memory circuit 98
is lost when the AC adaptor cord 82 is unplugged and, if the
self-contained monitor 60 includes the battery pack 78, when the
batteries in the battery pack 78 are removed. It is important to
note that reconnecting primary power to the self-contained monitor
60 does not restore the volatile memory circuit 98 of the present
invention to the armed state. If such were the case, the intruder
could simply interrupt and restore power to the self-contained
monitor 60 in order to rearm the volatile memory circuit 98, avoid
the detection pattern 38 (FIG. 1) of the rearmed self-contained
monitor 60, and remain in the premises 18 (FIG. 1) to accost an
unsuspecting returning occupant. In the present invention, after
the volatile memory circuit 98 is disarmed by either the sensing of
the intrusion or the aforementioned sustained power interruption,
it can only be restored to the armed state by the coded RF arm
signal described above, which matches and is qualified by the
tuning code installed by the authorized user in the nonvolatile
memory circuit 100 in a manner described below. Since the data
stored in the nonvolatile memory circuit 100 is not erased when
primary power is interrupted, it is advantageous to store the
tuning code therein so that the user does not have to reprogram the
system after each time primary power is removed therefrom.
[0029] Various types of nonvolatile memory circuit arrangements are
known in the industry which, once programmed, do not lose the data
stored therein unless reprogrammed by the user. Commercially
available long term energy storage capacitors are designed to hold
an electrical charge for at least several months and are adapted
specifically to provide a back-up voltage for a solid state memory
making it nonvolatile by providing an uninterrupted voltage thereto
should the primary power be interrupted for a sustained period of
time. In their idle state, backup capacitors are kept charged by
the primary power. In FIGS. 2 and 3 there is shown a backup
capacitor 106 which is electrically coupled to the nonvolatile
memory circuit 100 and which may be obtained as a model SG
capacitor from Panasonic.
[0030] As previously noted, it has been found that when the
self-contained monitor 60 is employed to surveil the predetermined
space 10 (FIG. 1) and report the occurrence of an intrusion
therein, it is advantageous and less costly to supply primary power
thereto through the AC adaptor cord 82 rather than via batteries.
If the self-contained monitor 60 is powered by batteries, because
of the electrical energy consumed performing the aforementioned
testing and reporting functions during an extended period of time,
the batteries have to be replaced too frequently. Further, the
components of the self-contained monitor 60 can be contained in a
much smaller package if the housing 62 does not include space for
the battery pack 78.
[0031] However, when AC power is used as the only primary power
source energizing the self-contained monitor 60 and backup
batteries are not employed, the self-contained monitor 60 is
subject to the momentary and sustained power interruptions
associated with AC power lines feeding electrical energy to
premises located in apartment buildings, housing developments,
commercial buildings and the like. On such AC lines, momentary
power interruptions that can affect electronic equipment connected
to the line occur quite frequently and are generally caused by
environmental conditions such as lightning, high winds and heavy
rains and are sometimes of sufficient duration to cause illuminated
electric light bulbs to flicker, a phenomenon with which we are
familiar. In addition, utility company maintenance of the power
grid and local electrical repair work in apartment and commercial
buildings also create momentary interruptions. Those skilled in the
art recognize AC interruptions which are of short duration as
"sags" and "undervoltages". Such interruptions may or may not be
visibly detected but are easily sensed by electronic devices such
as the volatile memory circuit 100. Industry studies show that
utility company customers can expect a substantial number of such
faults per year occurring on their AC power lines. Sustained
interruptions are typically the result of hurricanes, blizzards,
ice storms and utility company major power failures and occur far
less frequently than momentary interruptions. Such occurrences are
usually publicized and would be known to a returning occupant.
Given that one of the objectives of the present invention is to
warn the returning occupant that there exists the possibility of an
intruder remaining in his or her premises, it is safe for the user
to assume that a sustained power interruption recorded by the
self-contained monitor 60 was most probably caused as the result of
an intrusion.
[0032] To optimize the reporting reliability of the self-contained
monitor 60, it is important that momentary power interruptions on
the AC power line of say less than a second or two do not cause the
volatile memory circuit 98 to switch from the armed to the disarmed
state thereby causing the self-contained monitor 60 to respond as
if an intrusion had occurred. In FIGS. 2 and 3 there is shown a
short term energy storage circuit 108 electrically coupled to the
volatile memory circuit 98 supplying secondary power thereto, which
in the preferred embodiment, may be a standard capacitor or
equivalent thereof, available from any one of a number of sources
such as Cornell Dubilier part no. 203U016AK2B. The capacitance
value and voltage rating of the capacitor are chosen such that the
capacitor acts as a timing circuit supplying a voltage to the
volatile memory circuit 98 for a preset period of time before
discharging during an interruption of primary power. The preset
period of time is selected so that it is longer than most momentary
power interruptions exhibited on a typical AC power line, say about
two to five seconds. If a momentary power interruption occurs on
the AC line, the capacitor in the short term energy storage circuit
108 is a temporary source of electrical energy which prevents the
volatile memory circuit 98 from sensing a loss of power and
switching from the armed to the disarmed state as a result of the
momentary power failure.
[0033] In the prior art, there are intrusion detection systems
energized by AC power backed up by batteries. It is generally the
purpose of the backup batteries to ensure continued surveilance for
intrusions during AC power failures. Such systems do not
differentiate between momentary and sustained AC power
interruptions and the battery backup supplies power to the system
during both momentary and sustained interruptions. Unlike the prior
art, the self-contained monitor 60 does not react to all power
interruptions thereto, rather it records and may be remotely tested
for only those that last more than a preset period of time. Those
skilled in the art recognize that the capacitance value of the
short term energy storage circuit 108 can be selected to coordinate
with the combined capacitance of the electrical components in the
self-contained monitor 60 to produce the aforementioned preset
period of time of up to several seconds. The short term energy
storage circuit 108 may also include a standard resistor having an
ohmic value selected to facilitate coordinating the electrical
characteristics of the short term energy storage circuit 108 with
the combined impedance of the other electrical components
comprising the self-contained monitor 60. Further, the short term
energy storage circuit 108 may be employed in the self-contained
monitor 60 wherein the use of a backup battery is made optional so
that when the user elects to employ only AC power, the system does
not record momentary AC power interruptions. By not recording
momentary power interruptions that occur on the AC power line as
possibly the result of an intrusion, the system of the present
invention minimizes the number of times a returning occupant may
needlessly seek help based on the lack of a monitor response to the
RF test signal.
[0034] FIG. 4 is a block diagram of a first embodiment of the
present invention illustrating the manner in which certain of the
components pictured in FIGS. 2 and 3 are electrically coupled to a
positive terminal 156 and a ground terminal 158 of the primary
power source 76. In the first embodiment, a tuning code circuit
generally referred to by reference number 114 for inputting the
tuning code comprises a digital switch 116 having eight individual
on-off switches 138. Each individual switch 138 may be set manually
in either the on or closed position, representing the binary number
zero, or the off or open position representing the binary number
one. When the user activates a code transfer switch 120, a one shot
122 in a code transfer circuit 124 causes the binary code setting
on the digital switch 116 to be transferred into the nonvolatile
memory circuit 100 thereby making the receiver circuit 96
responsive to the particular RF carrier signal represented by this
binary tuning code. Preferably, the code transfer switch 120 is a
normally open miniature single pole single throw PCB mounted
pushbutton switch which may be purchased from any one of a number
of manufacturers such as Panasonic, part number EVQ-PBCO4M. In the
instant invention, the RF receiver circuit 96 is tuned to the
particular RF carrier signal in order to not only prevent
interference with other RF systems in the vicinity but also prevent
the self-contained monitor 60 from being controlled by an
unauthorized remote controller employed by an intruder.
[0035] The logic circuit 102 is electrically coupled to the RF
receiver circuit 96, the motion detector 86, the volatile memory
circuit 98 and the responder 104. It monitors the status of the
elements to which it is electrically coupled and directs them to
respond according to particular system conditions. For example,
upon receipt of the RF arm signal to which the RF receiver circuit
96 is responsive, if the volatile memory circuit 98 is not armed,
the logic circuit 102 will arm it. Further, if the motion detector
86 senses an intruder and if the volatile memory circuit 98 is
armed, the logic circuit 102 will disarm it. In addition, if the
volatile memory circuit 98 senses a loss of power and if the same
is armed, the logic circuit 102 will disarm it. As a final example,
if the RF receiver circuit 96 receives the RF test signal to which
it is responsive and if the volatile memory circuit 98 is armed,
the logic circuit 102 will direct the responder 104 to generate an
audible or a visible response indicating that an intrusion has not
occurred and it is safe to enter the surveilled space. The
capacitor backup 106 is electrically coupled to the nonvolatile
memory circuit 100 and the positive terminal 156 and the ground
terminal 158 through which the nonvolatile memory circuit 100
receives primary power. The capacitor backup 106 provides a voltage
to the nonvolatile memory circuit 100 during a sustained power
interruption such that the tuning code stored therein is not erased
as a result thereof.
[0036] Also, shown in FIG. 4 is the short term energy storage
circuit 108 connected across the positive terminal 156 and the
ground terminal 158 through which the volatile memory circuit 98
receives primary power. The short term energy storage circuit 108,
or the electrical equivalent thereof, provides a voltage to the
volatile memory circuit 98 during momentary interruptions of
primary power. Thus, the volatile memory circuit 98 is not switched
from the armed to the disarmed state as a result thereof thereby
eliminating the possibility of the self-contained monitor 60
producing an erroneous intrusion report because of momentary
interruptions.
[0037] The first embodiment minimizes false intrusion reports which
are a significant problem and inconvenience for a returning
occupant who would otherwise needlessly seek help based on an
erroneous remote test because a momentary power failure on the AC
line switched the volatile memory circuit 98 to the disarmed state.
Sustained power interruptions are more likely to be caused by an
intruder and, as previously noted, cause the volatile memory
circuit 98 to be switched to the disarmed state.
[0038] Turning now to FIG. 5, in the drawing there is illustrated a
second embodiment of the present invention offering certain
variations over the first embodiment. In the first embodiment, a
self-contained monitor is tuned to its associated remote controller
by a DIP switch in the monitor and a DIP switch in the remote
controller, each DIP switch having a binary code set thereon by the
user. In the second embodiment, a second remote controller,
generally referred to by reference number 220, transmits a second
particular RF carrier signal encoded by an encoder chip 200. A
second self-contained monitor, generally referred to by reference
number 260, is tuned to the second remote controller 220 by a
decoder chip 202 included in a second tuning code circuit generally
referred to by reference number 204. The decoder chip 202 decodes
the second particular RF carrier signal and extracts therefrom a
unique identification code which, in a manner defined below,
comprises a second tuning code. As is well known in the industry,
it is extremely difficult for an intruder to gain control of an
alarm system by surreptitiously intercepting and duplicating an RF
signal encoded by a complex algorithm contained in an encoder chip.
It is less difficult for an intruder to intercept and duplicate an
RF signal encoded by a binary code set on a DIP switch. A user may
elect to deploy an alarm system wherein an RF carrier signal is
encoded by a complex algorithm because this type of system provides
a higher level of security than a system which utilizes DIP
switches. Typically, the user tunes the second self-contained
monitor 260 employing the decoder chip 202 to its associated second
remote controller 220 employing the encoder chip 200 by a method
known in the industry as code learning. In the code learning
method, described below, the user employs the second remote
controller 220 to teach the second self-contained monitor 260 to be
responsive thereto. Certain of the components shown in FIG. 5 are
similar to and perform substantially the same function as
components illustrated and described in the previous figures. To
avoid needless repetition, these components are not described again
in the disclosure of the second embodiment.
[0039] In FIG. 5, the elements of the second self-contained monitor
260 are shown in a block diagram. The physical appearance and
structure of the second self-contained monitor 260 are
substantially the same as those of the self-contained monitor 60
illustrated in FIG. 2. Also, the second remote controller 220 has
substantially the same physical appearance and structure as the
remote controller 20 shown in FIG. 1. Because of the aforementioned
similarities in appearance and structure, and for the sake of
brevity, drawings illustrating the appearance of the second
self-contained monitor 260 and the second remote controller 220 are
not included in the disclosure of the second embodiment. Referring
again to FIG. 5, the encoder chip 200 is commercially available
from any one of a number of sources such as Microchip Technologies
Inc., Chandler, Ariz., their model HCS 200. The encoder chip 200
encodes the second particular RF carrier signal transmitted by the
second remote controller 220 in accordance with the unique
identification code programmed into the encoder chip 200 by its
manufacturer. When the second remote controller 220 is activated by
the user, the aforementioned identification code is transmitted as
a portion of the second particular RF carrier signal. The decoder
chip 202 is also available from Microchip Technologies, model HCS
500, and is factory programmed to decode the second particular RF
carrier signal encoded by the encoder chip 200. However, in order
to make the second self-contained monitor 260 responsive to the
second remote controller 220, the decoder chip 202 has to be tuned
to the second particular RF carrier signal by the user.
[0040] As mentioned above, the second self-contained monitor 260 is
tuned to the second remote controller 220 by what is known in the
industry as the code learning method. In this method, the user
initiates the tuning program by activating the second RF remote
controller 220 thereby transmitting the second particular RF
carrier signal to the second self-contained monitor 260.
Simultaneously, the user manually closes the normally open switch
120 contained in a second code transfer circuit 224 included in the
second self-contained monitor 260. While the button switch 120 is
held closed by the user, the second particular RF carrier signal
received by the RF receiver circuit 96 is processed by the
nonvolatile memory circuit 100 and decoder chip 202 in the tuning
code circuit 204. The decoder chip 202 extracts the identification
code transmitted as part of the second particular RF carrier signal
from the second particular RF carrier signal and transfers the
identification code to the nonvolatile memory circuit 100 for
storing therein. Once stored, the identification code comprises the
second tuning code which is subsequently used to qualify the second
particular RF carrier signal transmitted by the second remote
controller 220 during normal use of the system when the button
switch 120 is not being held closed by the user. The second
self-contained monitor 260 may be programmed to be responsive to
several additional remote controllers using the same code learning
procedure for each additional remote controller as outlined
above.
[0041] As shown in FIG. 5, the RF receiver circuit 96 is
electrically coupled to the logic circuit 102, the motion detector
86, the volatile memory circuit 98 and the responder 104. The RF
receiver circuit 96, responding to the second particular RF carrier
signal, switches the volatile memory circuit 98 from the disarmed
state to the armed state. Either the sensing of an intruder by the
motion detector 86 or the sensing of an interruption of primary
power switches the volatile memory circuit 98 from the armed state
to the disarmed state. It is important to note that in the second
embodiment the short term energy storage circuit 108, or the
electrical equivalent thereof, functions as a timing circuit
providing a preset period of time during which the volatile memory
circuit 98 does not sense the power interruption as previously
described in the disclosure of the first embodiment. Thus, the
volatile memory circuit 98 is not switched to the disarmed state
during momentary power interruptions lasting less than the preset
period of time. It is also important to note that after the
volatile memory circuit 98 is switched to the disarmed state, it
can only be rearmed by the receiver circuit 96 responding to a
qualified RF carrier signal. Further, in the second embodiment, the
state of the volatile memory circuit 98 is tested by the second
particular RF carrier signal causing the responder 104 to generate
a response or nonresponse indicating the state of the volatile
memory circuit 98 in a manner similar to that taught in the first
embodiment.
[0042] Turning now to FIG. 6, in the drawing there is illustrated a
third embodiment of the present invention offering certain
variations over the previous embodiments. The self-contained
monitors disclosed in the first two aspects of the present
invention comprise discrete electronic components which perform
various functions. In the third embodiment, a solid state
microcontroller chip is employed in place of a number of the
aforementioned discrete electronic components and is programmed to
emulate and perform certain of their functions. A number of the
circuit elements shown in FIG. 6 are similar to and perform
substantially the same function as circuit elements illustrated and
described in previous figures. To avoid needless repetition, such
components and their functions are not described again.
[0043] In FIG. 6, the elements of a third self-contained monitor,
generally referred to by reference number 360, are shown in a block
diagram. The physical appearance and structure of the third
self-contained monitor 360 are substantially the same as those of
the self-contained monitor 60 illustrated in FIG. 2. Also, shown in
the block diagram is a third remote controller, generally referred
to by reference number 320, which transmits a third particular RF
carrier signal. The third remote controller 320 has substantially
the same physical appearance and structure as the remote controller
20 shown in FIG. 1. Because of the aforementioned similarities in
appearance and structure, and for the sake of brevity, drawings
illustrating the appearance of the third self-contained monitor 360
and the third remote controller 320 are not included in the
disclosure of the third embodiment. Referring again to FIG. 6, the
third self-contained monitor 360 includes a microcontroller 300
which is commercially available as a solid state chip for mounting
on a PCB from any one of a number of sources such as Phillips
Electronics, their part number 87C750. Microcontroller chips are
used in electronic systems because such chips are programmable
computers which perform the combined functions of a substantial
number of discrete electronic components and typically reduce not
only the cost of the system but also its size. The operating
characteristics of a system in which a microcontroller chip is
employed are programmed into the microcontroller chip by the
manufacturer of the system and are usually changed by the system
manufacturer modifying the program rather than by changing discrete
system components. In FIG. 6, the microcontroller 300 replaces and
emulates the functions of certain elements shown in FIG. 4
including: the volatile memory circuit 98; the nonvolatile memory
circuit 100; the logic circuit 102; the short term energy storage
circuit 108; and the one shot 122 which may comprise a
multivibrator one shot. The third self-contained monitor 360 also
includes a third tuning code circuit generally referred to by
reference number 304 for inputting a third tuning code therein as
explained below.
[0044] As shown diagrammatically in FIG. 6, the microcontroller 300
is programmed to define an emulated volatile memory circuit 310, an
emulated nonvolatile memory circuit 312, an emulated logic circuit
314 and an emulated one shot 316. Further, the microcontroller 300
includes a built-in quartz clock circuit 318 which acts as a timing
circuit emulating the function of the short term energy storage
circuit 108 (FIG. 4) by measuring elapsed time and preventing the
emulated volatile memory circuit 310 from switching to the disarmed
state as the result of sensing an interruption in primary power
lasting less than a preset period of time. In the third embodiment,
the preset period of time is programmed into the microcontroller
chip 300 by the manufacturer of the third self-contained monitor
360 who also installs the program to generate the above mentioned
emulated circuit functions.
[0045] In the third embodiment, illustrated in FIG. 6, the third
remote controller 320 includes the DIP switch 36 and the third
self-contained monitor 360 includes the third tuning code circuit
304 having the digital switch 116 therein. Accordingly, the third
embodiment employs a third tuning code which comprises the binary
code, as disclosed in the first embodiment, making the third
self-contained monitor 360 responsive to the third remote
controller 320. Turning now to FIG. 6A, there is illustrated an
alternative aspect of the third embodiment offering certain
variations over the third embodiment. Principally, in the
alternative aspect, the third remote controller 320 includes the
encoder chip 200 rather than the DIP switch 36 and the third tuning
code circuit 304 includes the decoder chip 202 rather than the
digital switch 116. Accordingly, the alternative aspect of the
third embodiment employs an alternative third tuning code which
comprises the identification code, as disclosed in the second
embodiment, making the third self-contained monitor 360 responsive
to the third remote controller 320. In both the third embodiment
and the alternative aspect thereof, either the binary code or the
identification code is transferred from the third tuning code
circuit 304 to the emulated nonvolatile memory circuit 312 by
closing the normally open switch 120 in a third transfer circuit
324 using the procedure disclosed in the first embodiment to
transfer the binary code and the procedure disclosed in the second
embodiment to transfer the identification code.
[0046] Further, in the third embodiment, the microcontroller 300
monitors the primary power source voltage supplied thereto and
senses any voltage interruption. At a preset period of time after a
power interruption starts, the microcontroller 300 is programmed to
switch the emulated volatile memory circuit 310 to the disarmed
state. The preset period of time is measured by the clock circuit
318 contained in the microcontroller 300 and its duration is
determined by the computer program installed therein by the
manufacturer of the self-contained monitor 360. The third
self-contained monitor 360 may be provided with a preset period of
time ranging from a fraction of a second to several seconds. The
particular time being selected by the system manufacturer adjusting
the program rather than by changing system components. In order to
provide optimum intrusion protection, alarm systems such as the
alarm system disclosed in the third embodiment should respond to
intrusion events as quickly as possible and yet not cause false
intrusion reports by responding too quickly. For example, in rural
areas where typical power interruptions may last for several
seconds, it is advantageous to provide the third self-contained
monitor 360 with a preset period of time of say five seconds. In
urban areas where typical power outages may last for relatively
short time intervals, it is advantageous to supply the third
self-contained monitor 360 with a preset period of time of say one
second. Accordingly, the third self-contained monitor 360 can be
provided with different operating characteristics, as required by
various environments, by the manufacturer changing the computer
program in order to minimize the number of false intrusion reports
caused by primary power interruptions while providing optimum
intrusion protection.
[0047] Finally, it is important to note that once the emulated
volatile memory circuit 310 has been switched to the disarmed state
by either sensing a sustained power interruption or by the motion
detector 86 sensing an intruder, it can only be rearmed by the RF
receiver circuit 96 responding to the third particular RF carrier
signal, including either the binary code or the identification
code, in a manner as disclosed in either the first embodiment or
the second embodiment, respectively. In like manner, the state of
the emulated volatile memory circuit 310 is tested by the third
particular RF carrier signal causing the responder 104 to generate
a response or nonresponse indicating the state thereof.
[0048] It is to be understood that the present invention is not
limited to the precise details of structure shown and set forth in
this specification, for obvious modifications will occur to those
skilled in the art to which the invention pertains.
* * * * *