Overhead detector and light assembly with remote control

The detector assembly is connectable to a power line which includes a switch which, when operated, causes power transitions at a power terminal for the detector assembly. The detector assembly includes a code responsive controller which operates in response to a plurality of power transitions occurring within a predetermined time period to deactivate a detector alarm for a determined delay period. The code responsive controller may also operate in response to different numbers of sensed power transitions to control the activation and deactivation of a light forming part of the detector assembly. A code transmitter responsive to the activation and deactivation of the detector alarm transmits an activation code and subsequently a deactivation code over the power line to activate and deactivate other detector assemblies, and a code receiver receives activation and deactivation codes from the power line and controls the activation and deactivation of the detector alarm in accordance therewith.

TECHNICAL FIELD 
The present invention relates generally to alarm detectors for sensing the 
occurrence of a dangerous condition and providing an alarm in response 
thereto, and more particularly to an alarm detector which is connected to 
the conventional electrical wiring circuit of a building, such as by 
threaded reception in an overhead light socket, and which is remotely 
controlled by means of such electrical wiring circuit. 
BACKGROUND OF THE INVENTION 
Property loss, personal injury and loss of life due to fire can often be 
minimized or avoided when smoke or heat detectors are employed to provide 
an alarm during the initial stages of a fire. Consequently, local law in 
many jurisdictions requires that smoke and heat detectors with alarms be 
provided in public and commercial buildings and private homes. This has 
led to the development of a wide variety of commercially available smoke 
and heat detectors which are battery operated or are connected to the 
electrical wiring circuit of a building by a permanent wiring connection 
or by reception in a light socket or other female electrical receptacle. 
In general, fire safety experts recommend that smoke alarm detectors be 
placed near the ceiling of a room and preferably near the center. In older 
homes, this recommended position is usually occupied by an existing light 
fixture, and in such cases, removable detector-light combinations of the 
type shown by U.S. Pat. Nos. 4,694,285 and 4,812,827 to Scripps, 4,717,910 
to Scripps et al., and 4,980,672 to Murphy can be threaded into the 
fixture. In newer homes, there may be no central ceiling fixture in a 
room, and in such cases, detector alarm devices which incorporate a light 
fixture have been hard wired into the house circuit and provide a 
permanently mounted fixture on the ceiling of a room. Since both the 
permanent and removable detector units incorporate lights, which may be 
switched on and off by conventional wall switches, such detectors are 
powered by rechargeable batteries which are charged when the detector 
light is switched on by a wall switch. 
A problem with ceiling mounted detectors powered by rechargeable batteries 
is that they are difficult to reach and deactivate in the event the alarm 
is inadvertently triggered by a condition which is not dangerous. For 
example, cigarette and cooking smoke have the capability to trigger a 
smoke alarm, as does steam from cooking or a shower, and normally the 
alarm will remain operative until the alarm triggering condition 
dissipates. However, it is difficult or impossible, particularly for 
elderly or infirm persons, to reach ceiling mounted detectors to 
deactivate an alarm resulting from a false alarm condition. 
In the past, attempts have been made to temporarily disable detector alarms 
in the event that a false alarm condition occurs. U.S. Pat. No. 4,313,110 
to Subulak et al. discloses a manually actuated control circuit for 
temporarily deactivating a smoke alarm and then automatically reactivating 
the same after a predetermined time delay. However, this device is 
controlled by a switch activating pull chain which hangs from the detector 
and which would prove to be unsightly and often difficult to locate at 
night when attached to a ceiling mounted unit. 
U.S. Pat. No. 5,093,651 shows a smoke detector unit having a switch for 
temporary deactivation of the detector connected on the unit between the 
battery and the detector component. This switch would be difficult to 
reach in the case of a ceiling mounted unit. 
Finally, U.S. Pat. No. 4,788,530 to Bernier discloses a remote switching 
device for deactivating a ceiling mounted smoke detector which is affixed 
to a wall below the detector. This switching device includes a holding 
relay, a dry cell battery and a time delay circuit, and is connected to 
the smoke detector by special wiring installed in the wall and ceiling. 
Large multistory homes and buildings often have one or more alarm detectors 
installed on each level, and it is often difficult when an alarm condition 
occurs on a remote level, for it to be promptly recognized and action 
taken by persons on other levels. In an attempt to alleviate this problem, 
U.S. Pat. No. 4,812,827 to Scripps illustrates a detector unit combined 
with a small radio transmitter which communicates with a second remote 
detector having a small radio receiver. This system is effective only if 
the initial alarm condition occurs in the vicinity of the detector with 
the transmitter. To be even more effective, each detector would have to 
incorporate both a radio transmitter and a radio receiver, which could 
prove expensive and result in a bulky and unsightly unit. 
Security lighting systems have been developed which utilize the utility 
power lines of a building to provide communication between a master 
control transmitting unit and a plurality of remote light receiving units. 
U.S. Pat. Nos. 5,031,082 to Bierend and 5,072,216 to Grange disclose power 
line transmitting and receiving systems of this type. Microprocessor 
transmitters and receivers have also been developed to communicate over 
the utility power lines of a building to control the operation of an 
electrical appliance. U.S. Pat. No. 5,189,412 to Mehta et al. discloses a 
microprocessor control system of this type. Unfortunately, this technology 
has never been adapted for use with detector sensing systems such as fire, 
heat and smoke detector. 
DISCLOSURE OF THE INVENTION 
It is a primary object of the present invention to provide a novel and 
improved overhead detector and light assembly having an alarm which may be 
deactivated for a predetermined delay period by operation of a 
conventional power controlling wall switch for the building electrical 
circuit without the need for special wiring. 
Another object of the present invention is to provide a novel and improved 
overhead detector and light assembly wherein deactivation of an alarm in a 
false alarm situation is controlled by a conventional wall switch for the 
building electrical circuit and the deactivation control circuit is 
incorporated in the detector. 
A further object of the present invention is to provide a novel and 
improved overhead detector and light assembly wherein deactivation of an 
alarm in a false alarm situation is controlled by operating a conventional 
wall switch for the building electrical circuit to provide a deactivation 
code to the detector. Upon receipt of the deactivation code, the detector 
will deactivate an alarm circuit for a short period of time and then will 
reactivate the alarm circuit. 
Yet another object of the present invention is to provide a novel and 
improved overhead detector and light assembly wherein deactivation of an 
alarm in a false alarm situation is controlled by operating a conventional 
wall switch for the building electrical circuit to provide a deactivation 
code to the detector within a predetermined period of time. 
Another object of the present invention is to provide a novel and improved 
overhead detector and light assembly which, when connected to the 
electrical power lines in a building, will respond to a detected alarm 
condition and will send a coded activation signal over the power lines to 
activate the alarms in other detectors sharing the same utility power 
lines. 
A further object of the present invention is to provide a novel and 
improved overhead detector and light assembly which includes a 
transmitter-receiver unit which permits the detector to transmit and 
receive signals over the electrical power lines in a building. The 
detector may be operated from any room of a house or building which has a 
standard utility power receptacle and will communicate with similar 
detectors that share the same utility power lines. 
A still further object of the present invention is to provide a novel and 
improved overhead detector and light assembly which includes a 
transmitter-receiver unit to permit the detector to transmit and receive 
signals over the electrical power lines in a building. When the detector 
senses an alarm condition, it provides an audible and/or visual alarm and 
transmits signals over the building power lines to activate the alarm in 
similar detectors sharing the same utility power line. If another of such 
detectors is activated first in response to an alarm condition, the 
detector will provide an alarm upon receipt of an activation signal over 
the building power lines.

BEST MODE FOR CARRYING OUT THE INVENTION 
A preferred embodiment of the overhead detector and light assembly with 
remote control of the present invention is indicated generally at 10 in 
FIG. 1. It is advantageous for the assembly to be removably received in a 
standard utility power receptacle so that it can be easily installed and 
removed for repositioning. However, although the invention will be 
described with reference to a removable detector assembly of this type, it 
should be understood that the invention may be incorporated in a detector 
connected in any manner to the electrical power system for a building, 
such as by hard wiring. Also, for purposes of description, the overhead 
detector will be referred to as a smoke detector, but it should be 
understood that the detector can constitute any electrically powered 
detector such as for heat, gas, radiation, motion, radon or detection of 
some other condition. 
The overhead detector and light assembly 10 includes a housing 12 having a 
projecting threaded mount and connector assembly 14 which is identical to 
the base portion of a conventional incandescent light bulb. The wall 16 of 
the housing opposite to the mount 14 includes a threaded socket 18 which 
is a unitary part of the threaded mount and connector assembly, and this 
socket receives the threaded base 20 of light bulb 22. The housing is 
provided with openings 24 which permit air to circulate through the 
housing to reach the detector circuitry mounted therein. The condition of 
the detector battery may be tested by a test button 26, and a LED or other 
light indicator 28 indicates when house power is being provided to the 
detector from the building electrical power lines. 
When the detector and light assembly 10 is threaded into an overhead socket 
30 which is connected to a household electrical power line 32, it will 
receive household power from the power line under the control of a wall 
switch (not shown). When power is provided, the light bulb 22 will light 
and a battery charger in the detector circuit will be powered to charge a 
detector battery. When no power is received from the power line 32, the 
detector circuit will be powered from the detector battery. 
FIG. 2 shows the overhead detector and light assembly with remote control 
10 connected by the power line 32 to the building power supply 34. A wall 
switch 36, when closed, energizes the light bulb 22 and provides power to 
a battery charger 38. The battery charger maintains the charge on a 
rechargeable battery 40, which provides power to a detector 42. Connected 
to the detector through a normally closed switch 44 is a horn or similar 
electrically powered audible alarm unit 46. 
Normally, the detector 42 breaks the circuit from the battery 40 to the 
horn 46, but when the detector detects smoke, heat, gas, movement or some 
other condition for which an alarm is to be given, the detector closes the 
circuit to the horn 46 to cause an audible alarm to occur. When the wall 
switch 36 is open, the light bulb 22 is extinguished, but power to the 
detector 42 is provided by the battery 40. The battery may be tested by 
pushing the test button 26 as shown in FIG. 1 to close a switch 48 which 
completes a short circuit from the battery around the detector to the horn 
46. 
To this point, the circuit of the assembly 10 is conventional, and in such 
conventional circuits, if the horn 46 is activated by a condition which is 
not hazardous, such as cooking smoke, the horn will continue to sound 
until the smoke dissipates or the battery 40 is removed from the housing 
12. In some units, the switch 44 may be manually activated by a pull chain 
hanging from the ceiling or by a switch button on the casing 12. Neither 
of these alternatives is desirable, for the pull chain is both unsightly 
and difficult to find in the dark, while reaching the deactivating switch 
button on the casing 12 is both difficult and dangerous when the casing is 
mounted in a ceiling socket. 
A preferred solution to the false alarm problem is to control the operation 
of the switch 44 with a microprocessor 50. The microprocessor is 
programmed to open the switch 44 for a predetermined delay period upon 
receipt by the microprocessor of a predetermined number of input pulses 
within a defined input time. For example, if the microprocessor receives 
three input pulses within a three second period, it can be programmed to 
open the switch 44 for, as an example, two minutes before reclosing the 
switch. 
The input pulses to the microprocessor 50 are provided by rapidly closing 
and opening the wall switch 36. This pulses the house power on the power 
line 32 to the overhead detector and light assembly with remote control 
10, and it is these power transitions between a power on and power off 
condition which are sensed by the microprocessor 50. For example, the zero 
power pulses when the wall switch is open may be sensed or the power 
pulses when the switch is closed may be sensed. It is also possible to 
sense a combination of zero power pulses and power pulses. When power 
pulses are among those sensed, these pulses are provided to an AC to DC 
converter 52 which causes lower voltage DC pulses to be provided to the 
microprocessor 50. In some cases, the AC to DC converter can be eliminated 
and the microprocessor input pulses can be provided directly from the 
output of the battery charger 38 as indicated by the connection shown in 
broken lines at 54. 
It is desirable to have a microprocessor 50 operate in response to a 
plurality of input pulses created within a short period of time. This will 
preclude the processor from operating in response to a single closing or a 
single closing and opening cycle of the wall switch 36, and it is unlikely 
that momentary disruptions in household power will occur the necessary 
number of times within the time period required to operate the 
microprocessor so as to cause the microprocessor to open the switch 44 for 
the preset delay time. Thus the conventional wall switch can be used 
effectively without special wiring to terminate a false alarm condition 
for a preset delay period. If the false alarm condition persists at the 
end of the delay period, the wall switch can again be manipulated to 
initiate a new delay period. 
The microprocessor 50 can be replaced by a logic circuit or a counter or 
timing circuit which will control the timed deactivation of the horn 46 in 
response to pulses from the wall switch 36. For example, as shown in FIG. 
3, the pulses from the charger 38 or the AC to DC converter 52 are applied 
to a counter 56 having a timed reset circuit 58. If the counter receives 
the preset number of pulses before being reset, it provides an output 
signal which operates both to trigger a timer 60 and to open the switch 
44. In this case, the switch 44 is a latching relay that includes a coil 
62 which, when energized, holds a relay switch against contacts 63 until 
the coil is shunted by conduction of a transistor 64. This conduction of 
the transistor is initiated by the timer 60 at a predetermined time after 
the timer is triggered, and deenergizes the relay coil so that the switch 
moves back to its normal position across contacts 65 to reconnect the horn 
46 to the detector 42. In this circuit, the counter 56 and timed reset 
circuit 58 can be replaced by a one shot multivibrator circuit which 
operates upon receipt of a preset number of input pulses within a 
specified time to provide an output to the timer 60 and switch 44. 
Referring now to FIG. 4, it will be noted that a plurality of overhead 
detector and light assembly with remote control units 10 may be connected 
to a common utility power line 66. When one of these units detects a 
dangerous condition and initiates an audible alarm, it would be beneficial 
to have the remaining units also initiate an alarm before the dangerous 
condition is actually sensed by them. This can be accomplished with the 
circuit of FIG. 5 wherein a transmitter microprocessor 68 replaces the 
microprocessor 50. The transmitter microprocessor operates in the same 
manner as the microprocessor 50 to respond to a DC coded signal from the 
charger 38 triggered by the switch 36 to open the switch 44 for a 
predetermined delay period. 
The transmitter microprocessor 68 is also programmed in a known manner to 
send coded signals over the common utility power line 66 to other overhead 
detector and light assembly with remote control units connected to the 
same power line. Upon receipt of an input signal on an input line 70 which 
lasts for more than a predetermined time period, i.e., thirty seconds, the 
transmitter microprocessor will send a coded horn actuation signal 
modulated over the 60 Hz AC power signal on the power lines 32 and 66 to 
other overhead detector and light assembly with remote control units 
connected to the power line. This coded horn actuation signal is delayed 
after the initial activation of the horn 46 so that the signal will not be 
sent in response to a momentary closure of the switch 48. Also, the delay 
provides a short period during which the wall switch 36 can be actuated to 
shut off the horn in a false alarm situation. 
The delay period is preferably programmed into the transmitter 
microprocessor 68, but obviously a signal delay circuit could be connected 
to the input line 70 to delay the input signal from the horn power circuit 
to the transmitter microprocessor. 
Once the delay period expires and the signal from the horn power circuit is 
still present on the input line 70, the transmitter microprocessor will 
send a horn activation code to other units on the common utility power 
line 66. This code is received by an AC decoder 72 along with the 60 Hz AC 
power signal, and the decoder decodes the code modulated on the power 
signal and transmits the decoded signals to a receiver microprocessor 74. 
In response to the decoded horn activation signals, the receiver 
microprocessor closes a normally open switch 76 to shunt the detector 42 
and actuate the horn 46. The horn 46 will remain activated in response to 
receipt by the receiver microprocessor of a horn activation signal until a 
horn terminate coded signal is sent over the power line 66 by the 
transmitter microprocessor 68. Of course, the horn can be temporarily 
deactivated by operation of the wall switch 36, but after the delay 
period, the horn will be reactivated if the horn terminate coded signal 
has not been received by the receiver microprocessor 74. 
It is important to require units having horns which have been activated by 
a coded horn activation signal to receive a coded horn termination signal 
before they can be permanently turned off without removal of the battery 
40. This requires someone to find and check the conditions in the area of 
the original transmitting unit before turning it off, or for the condition 
which triggered the horn in the original transmitting unit to dissipate. 
Only then will the horn terminate code be sent by the transmitting 
microprocessor 68 in response to the absence of an input signal on the 
input line 70. This prevents someone from easily turning off the remote 
units will, out checking for the alarm condition which triggered the 
original transmitting unit. 
When the overhead detector units 10 of FIG. 4 include a light 22, it is 
preferable to be able to switch the lights off while maintaining the wall 
switches closed so that the units can communicate over the power line 66. 
For this purpose, each unit is provided with a light switch 78 which may 
constitute a manually activated switch connected to open the circuit to 
the light 22. When the wall switch 36 is closed and the light switch 78 is 
open, the light switch completes a circuit to the LED 28 to indicate that 
the wall switch has connected the unit 10 to the power line 66. 
Ideally, the light switch 78 can be activated by the microprocessor 68 in 
the same manner as the horn switch 44. For example, the wall switch might 
be opened and closed three times to open the horn switch for a delay 
period, four times to open the light switch 78 and five times to close the 
light switch. When this code is used, the horn switch will be opened each 
time the light switch 78 is operated by the transmitter microprocessor 68, 
but only for the short preset delay period and then the horn switch will 
automatically reclose. To prevent this, the microprocessor 68 may operate 
the horn switch in response to zero power pulses and the light switch in 
response to power pulses or vice versa. 
In FIG. 5, the overhead detector and light assembly 10 is shown with both a 
transmitter microprocessor 68 and a receiver microprocessor 74, and 
ideally, each assembly will have this capability to transmit and receive. 
However, for some applications, the most remote unit 10 could be provided 
with only a transmitting capability, thus eliminating the decoder 72 and 
the receiver microprocessor 74, while the remaining units might include 
only the decoder 72 and receiver microprocessor 74. For these 
applications, if microprocessor control of the horn switch 44 and/or the 
light switch 78 is required, these functions would be performed by the 
receiver microprocessor. 
The transmitter and receiver microprocessors may be any one of a number of 
microprocessors known to the art. In some cases, both the transmitting and 
receiving function can be performed by a single microprocessor which may 
also be programmed to control the horn switch 44 and the light switch 78. 
To aid in identifying the overhead detector and light assembly 10 which is 
the transmitting unit originally activated by an alarm condition, the 
transmitting microprocessor 68 is programmed to provide an output 
indication, such as the illumination of a red LED 80, when the activation 
code is transmitted over the power lines 32 and 66. This LED would be 
extinguished when the input signal no longer appears on the input line 70. 
A number of known circuits can be incorporated into the detector portion of 
the overhead detector and light assembly with remote control 10 to cause a 
code to be transmitted over the power line 66 when one assembly is 
activated to activate the alarm horns for other assemblies on the power 
line. FIG. 6 illustrates one of these known circuits which can be 
substituted for the transmitter microprocessor 68, the decoder 72 and the 
receiver microprocessor 74. This circuit can be used in an assembly where 
microprocessor control of the light switch 78 is not required and the horn 
switch 44 is either controlled by a circuit such as that in FIG. 3 or is 
eliminated. 
The transmitter microprocessor 68 is replaced by a transmitting unit 82 
having an input line 70 connected to sense the horn activating signal from 
the detector 42. A delay circuit 84 is provided to delay the signal on the 
line 70 so that momentary operation of the switch 48 will not provide an 
input signal to the transmitting unit. 
The transmitting unit 82 includes an encoder 86 which operates in response 
to an input on the line 70 to provide a horn activation code in the form 
encoded digital signals to a universal asynchronous receiver/transmitter 
88. A horn deactivation code is provided in a similar manner once the 
input on the line 70 is removed. The receiver/transmitter 88 converts the 
signal from the encoder into a digital serial format and applies it to a 
power line modem 90, which in turn converts the digital serial signal into 
a modulated signal for transmission over the power line 66 by means of a 
power line interface circuit 92. The modulated signal consists of an 
amplified shift key carrier on/off modulated signal where for a one bit, 
the modem outputs the carrier frequency while for a zero bit the modem 
sends no signal. A frequency selector switch 94 connected to the power 
line modem selects one of a plurality of operational frequencies for the 
transmitting unit, and a power supply 96 connected to the power lines 
32-66 converts the power line AC voltage to a DC voltage suitable for 
powering the components of the transmitting unit 82. 
The decoder 72 and receiver microprocessor 74 may be replaced by the 
receiving unit 98 of FIG. 6 which includes a power line interface 100 to 
receive and process the modulated signal from the power line 66. The power 
line interface 100 couples the received signal to a power line modem 102 
while preventing any relatively high voltage on the power line 66 from 
entering the receiving unit. The power line modem 102 converts the 
received modulated signal back to a digital serial data format and 
provides this digital serial data to a universal asynchronous 
receiver/transmitter 104. The output from the receiver/transmitter 104 is 
applied to a decoder 106 which converts the digital code to a control 
signal for a switch driver 108. This switch driver in turn operates the 
switch 76 to complete a shunt circuit around the detector 42 to energize 
the horn 44 until a horn terminate signal is received by the receiving 
unit 98. 
A receiver frequency selector switch 110 sets the same operational 
frequency for the receiving unit 98 as that set by the frequency selector 
switch 94 for the transmitting unit 82, and a receiver power supply 112 
operates in the same manner as the power supply 96 to supply DC power to 
the components of the receiving unit. 
As in the case of the transmitter and receiver microprocessors 68 and 74 of 
FIG. 5, each overhead detector and light assembly with remote control unit 
10 may include both a transmitting unit 82 and a receiving unit 98, or 
alternatively, the transmitting unit may be located in the most remote 
unit 10 with the remaining units 10 connected to the power line 66 having 
only a receiving unit. 
INDUSTRIAL APPLICABILITY 
The overhead detector and light assembly with remote control 10 may be 
connected to the common utility power line of a building by hard wiring or 
by installation in an electrical socket connected to the utility power 
line. The unit will activate similar units connected to the same power 
line by sending an activation code over the power line, and includes an 
alarm circuit which can be deactivated for a predetermined delay time by 
the operation of a conventional wall switch connected to the power line.