U.S. patent number 3,886,352 [Application Number 05/409,662] was granted by the patent office on 1975-05-27 for light and chime control system.
Invention is credited to Thomas K. Y. Lai.
United States Patent |
3,886,352 |
Lai |
May 27, 1975 |
Light and chime control system
Abstract
A daylight sensor and a headlight sensor are connected in a
variable voltage divider. When darkness turns the daylight sensor
off and headlights turn a sensor on, a potential is provided to a
voltage gate which is sufficient to break down a zener diode and
gate current to a timer circuit. A diode in the voltage gate
prevents reverse flow of current from a timer. A timer circuit
contains a capacitor and resistor which discharges the capacitor.
When the voltage is gated to the timer circuit and during the time
that capacitor maintains a sufficient potential, a light switch is
held on. A triac in the light switch control the lights.
Approximately 3 seconds after the capacitor in the timer is charged
to its potential, a transistor is switched on, placing a ground
potential to the midpoint of the voltage divider to cut off the
gate voltage. A chime operator is activated by sampling the
potential from the variable voltage divider to slowly ring a door
chime as an automobile is sensed. House and garage lights are
lighted automatically a short time after a doorbell is rung at
night to suggest a human response to the doorbell.
Inventors: |
Lai; Thomas K. Y. (Honolulu,
HI) |
Family
ID: |
26935025 |
Appl.
No.: |
05/409,662 |
Filed: |
October 25, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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242351 |
Apr 10, 1972 |
3790848 |
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Current U.S.
Class: |
250/215; 315/360;
340/326; 340/600; 340/942; 340/815.7; 340/393.3 |
Current CPC
Class: |
H03K
17/292 (20130101); H05B 47/10 (20200101) |
Current International
Class: |
H03K
17/292 (20060101); H03K 17/28 (20060101); H05B
37/02 (20060101); G08g 001/14 (); G10k 003/00 ();
H05b 041/36 () |
Field of
Search: |
;250/215,206
;340/31R,51,392 ;315/360,136 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawrence; James W.
Assistant Examiner: Grigsby; T. N.
Attorney, Agent or Firm: Wray; James C.
Parent Case Text
This application is a continuation-in-part of patent application
Ser. No. 242,351 now U.S. Pat. No. 3,790,848 filed Apr. 10, 1972 by
Thomas K. Y. Lai for Automatic Light Control System.
Claims
I claim:
1. A system for responding to intentionally indicated presence of
persons comprising a power source,
a response means connected to the power source for receiving power
from the source and performing a discernible response,
a controller connected to the source and to the response means for
selectively completing a circuit from the source to the response
means, whereby the response means operates,
a time delay means connected to the controller for delaying
complete operation of the response means,
intentionally activated indicator means connected to the controller
for setting the controller and time delay means in operation upon
actuation of the indicator means wherein the intentionally
activated indicator means comprises an automobile presence sensing
indicator means and a doorbell pushbutton switch mounted along side
of a door, wherein the response means comprises door chime means,
and wherein the controller comprises a circuit connected between
the indicator and the chime for ringing a first tone of a chime and
wherein the time delay means comprises an electronic time delay for
delaying a ringing of a second tone of a chime thereby to
differentiate between indicator means activated by a doorbell
pushbutton switch and by the automobile presence sensing
indicator.
2. A system for responding to intentionally indicated presence of
persons comprising a power source,
a door chime means connected to the power source for receiving
power from the source and performing a discernible response,
a controller circuit connected to the source and to the chime means
for selectively completing a circuit from the source to the chime
means, whereby the chime means operates,
a time delay means connected to the controller circuit for delaying
complete operation of the controller circuit and
an automobile presence sensing indicator means connected to the
controller for setting the controller circuit and time delay means
in operation upon actuation of the indicator means, wherein the
controller comprises a circuit connected between the indicator and
the chime means for ringing a first tone of a chime means and for
delaying a ringing of a second tone of a chime means thereby to
differentiate between indicator means activated by a doorbell
pushbutton switch and by the automobile presence sensing
indicator,
wherein the controller circuit further comprises a relay having
normally open contacts and having a drive, wherein the door chime
means is electrically connected to the normally open contacts of a
relay in the controller circuit, wherein the automobile presence
sensing indicator means comprises electrical pulse generating
means, and wherein the controller circuit further comprises gate
means connected to the pulse generating means and transistor means
controllably connected to the gate means, the transistor having a
control terminal connected to the gate means and having power
terminals completing a connection between the relay drive and the
power source, and wherein the time delay means comprises charge
storing means connected between the gate and the transistor control
terminal and discharging means connected to the charge storing
means for slowly discharging the charge storing means, whereby the
indicator pulse generating means turns the transistor on,
completing power to the relay and closing the contacts, supplying
power to the chime for a first tone, and whereby the generating
means concurrently charges the storage means, which maintains power
transmission through the transistor, holding the contacts closed,
and whereby the discharging means causes the charge storing means
to be discharged and the transistor to be turned off after a delay,
stopping power to the relay, permitting the relay contacts to open,
and permitting the chime to ring a second tone.
3. For the system of claim 2, wherein the controller means further
comprises a circuit for lighting lights upon sensing presence of an
automobile, and wherein the intentionally activated indicator means
further comprises push-to-light switch means for activating the
light controlling circuit, and wherein the chime controlling
circuit comprises means for isolating the push-to-light switch
means from operation of the chime, wherein the isolating means
comprises a second transistor having power terminals connected
between a base of the first relay power controlling transistor and
ground, the second transistor having a base connected to the
push-to-light switch means for biasing the second transistor on and
grounding the base of the first transistor preventing on biasing of
the first transistor upon pushing of the push-to-light switch
means.
4. A system for responding to intentionally indicated presence of
persons comprising a power source,
a response means connected to the power source for receiving power
from the source and performing a discernible response,
a controller connected to the source and to the response means for
selectively completing a circuit from the source to the response
means, whereby the response means operates,
a time delay means connected to the controller for delaying
complete operation of the controller, and
intentionally activated indicator means connected to the controller
for setting the controller and time delay means in operation upon
actuation of the indicator means,
wherein the controller includes a voltage divider circuit connected
between a power supply and a gate, wherein the intentionally
activated indicator means is connected on one side of the voltage
divider for raising voltage level of a midpoint in the divider
circuit sufficiently high to flow current through the gate, and
wherein the voltage divider further comprises deactivating means
connected between the midpoint and ground and receiving power from
the gate for reducing voltage level of the midpoint subsequent to
gating of current and thereby deactivating the indicator.
5. The apparatus of claim 4, wherein the deactivating means
comprises first and second resistances serially connected from the
gate to ground, and a storage device connected from a point between
the resistances to ground, whereby the storage device is charged by
gated current, and further comprising a transistor having a base
connected to the storage device for on biasing the transistor when
the storage device is sufficiently charged and wherein the
transistor has power terminals connected between the midpoint and
ground for lowering voltage level of the midpoint upon on biasing
of the transistor, and whereby the transistor discharges through a
resistance to reactivate the indicator.
6. The system for responding to intentionally indicated presence of
persons comprising a power source, an intentionally activated
indicator means comprising a doorbell pushbutton switch mounted
near a door of a house and a response means comprising lights
associated with the house, and a controller means comprising an
electronic circuit connected to the power source, to the pushbutton
and to the lights and including a time delay means for supplying
power from the power source to lights associated with the house
after a time delay which is consistent with a normal human response
to a doorbell, whereby a person pressing a doorbell is aware of a
normal human response to the ringing of the doorbell.
7. The system of claim 6 wherein the doorbell pushbutton switch has
terminals connected to a chime and chime power source, and wherein
the terminals are connected through a diode and resistance to
ground, wherein the resistance is connected between ground and a
base of a first transistor and wherein power terminals of the first
transistor are connected to a control terminal of a SCR switch,
wherein the circuit further comprises a storage means connected to
the power source for charging the storage means and connected to
control terminals of electronic switches for reversely biasing the
switches off, and wherein the SCR is connected to the storage
device for slowly discharging the storage device when the SCR is
on, whereby the electronic switches are turned on as the reverse
bias charge drains from the storage means, and wherein the
electronic switches further comprise power terminals connected to a
light system for turning on the light system after the storage
means has been discharged sufficiently to permit turning on of the
electronic switches.
8. The apparatus of claim 7 wherein the electronic switch means
comprises a second transistor with power terminals connected for
supplying a pulse to a third transistor for momentarily switching
the third transistor on, and wherein the third transistor has power
terminals connected to a sensor input in an automatic light control
system for starting the automatic light control system after a time
delay during discharge of the storage means.
9. The apparatus of claim 7 further comprising a transistor having
power terminals connected between one power terminal of the SCR and
ground for grounding the SCR, and turning the SCR off, the
transistor having a base connected to the electronic switch for
turning on the transistor and grounding the SCR when the electronic
switch is turned on.
Description
BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION
The automatic light control system is designed to provide home
owner with safety, convenient and security within a garage or
passageways or residences with minimum investment lasting a
lifetime.
This solid state device is used for controlling and providing
temporary lighting in darkened areas usually outside a house or
apartment. Lights controlled by this system are usually those
lights within a garage, those within a passageway, or those between
a parking space and residence, or those placed exteriorly near the
front door or inside lights.
The system is designed to operate in any house, garage or carport.
Pneumatic switches are provided for homes with driveways, to turn
on lights to ring door chimes when vehicles enter the area.
The operation of this system is automatically turned off during the
daylight hours.
Parameters of system operation are described as follows:
Power Requirement: 117 volts AC, 60 Hertz, Fuse for half amps.
Circuit Power Supply: Regulated 11.8 volts DC.
Circuit DC Current Drain:
Daylight Hours -- approximately 30 MA.
Night Hours -- STAND BY less than 5 MA., OPERATING -- approximately
60 MA.
Load: 450 watts maximum, incondescent lamps.
Time Delay: 4 minutes and 9 minutes.
Condition Held System Inoperative: Daylight hours -- hazy,
overcast, dawn to dusk.
Light Starting Requirement:
1. 470 ohms control element at voltage divider circuit between
midpoint and positive line.
2. three second of exposure of 100 foot-candle illumination on
interior photocell.
Self Adjust Sensor Circuit:
Interior photocell PCl becomes de-sensitized to 60 foot-candle
illumination in three seconds after the light is started. The
interior photocell automatically restores to maximum sensitivity
when the area is darkened.
The embodiments of this device take two forms, permanent
installation or plug-in types. The system comprises electronic
circuitry which is enclosed in the main chassis box with two
terminal blocks. One terminal block is a low voltage block to which
the remote switching or starting elements are connected, for
example, a push-to-light switch near a doorway for starting a
system as one leaves the house. A headlight receiving photocell is
employed to switch on lights as the automobile approachs the area.
A pneumatic switch may be substituted for the photocell sensor in
some cases, such as in drive-through carports where no wall is
available for mounting of an interior photocell. A daylight sensor
photocell is mounted on an exterior of a building to prevention
operation of the system during the daylight hours. A chime operator
is connected to the system to ring the door chime.
A daylight sensor and a headlight sensor are connected in a
variable voltage divider. When darkness turns the daylight sensor
off and headlights turn a sensor on, a potential is provided to a
voltage gate which is sufficient to break down a zener diode and
gate current to a timer circuit. A diode in the voltage gate
prevents reverse flow of current from a timer.
A timer circuit contains a capacitor and resistor which discharges
the capacitor. When the voltage is gated to the timer circuit and
during the time that capacitor maintains a sufficient potential, a
light switch is held on. A triac in the light switch controls the
lights.
Approximately 3 seconds after the capacitor in the timer is charged
to its potential, a transistor is switched on, placing a ground
potential to the midpoint of the voltage divider to cut off the
gate voltage.
A chime operator is activated by sampling the potential from the
variable voltage divider to slowly ring a door chime as an
automobile is sensed. House and garage lights are lighted
automatically a short time after a doorbell is rung at night to
suggest a human response to the doorbell.
A power supply transmits power to the light switch and also
provides 11.8 volt DC to the circuit.
DETAILED DESCRIPTION OF THE DRAWINGS
Throughout the drawings, like elements are referred to by like
numerals.
FIG. 1 generally indicates the light control system of a preferred
embodiment of the present invention. Electric lights 2 represent a
lighting circuit which is controlled by the automatic device of the
present invention. Plug 4 is representative of a connection for a
power source. Box 6 contains the electronic circuits of the present
invention and terminal boards.
Photocell 8 is mounted on an exterior of a building, for example, a
garage to prevent operation of the system during daylight hours in
one embodiment. Photocells 10 are mounted within a garage to detect
headlights of cars for starting the system when a car is parked in
a garage. In a two-car garage, photocells 10 may be mounted to
detect headlights from either car. Photocells 10 may be used with
adjustable circuits to detect back up lights when automobiles are
backed into a garage.
In some cases, such as in drive-through carports, no wall is
available for mounting of an interior photocell. A pneumatic switch
may be substituted for photocells 10. A closed air hose supplies a
pulse of air to a switch as an automobile crosses the hose. It is
convenient to mount a push button starter adjacent a pedestrian
entry to the garage. Where more than one entry to a garage is
commonly used in darkness hours, two or more push buttons may be
connected in parallel.
As shown schematically in FIG. 2, exterior photocell 8 and interior
photocell 10 are connected in a variable voltage divider 20. When
darkness turns photocell 8 off, and headlights turn photocell 10
on, a potential is provided to voltage gate 22 which is sufficient
to breakdown device 24 and gate current to timer circuit 30.
Unidirectional device 26 in gate 22 prevents reverse flow of
current from timer 30.
Timer circuit 30 contains a capacitor 32 and a resistance 34 which
discharges the capacitor. When the potential is gated to the timer
circuit 30, and during the time that capacitor 32 maintains a
sufficient potential, light switch 36 is held on. Triac 38 is
schematically shown within the light switch 36 for controlling lamp
2.
Power supply 40 receives power from source 4, transmits the power
to the light switch 36, and reduces and rectifies current which it
supplies to the variable voltage divider, the gate and the timer
circuit.
A three seconds cut off 50 with a transistor 52 is connected to
gate 22 and voltage divider 20 to desensitize the interior
photocell 8 to illumination after the system has been on for 3
seconds.
In FIG. 3 a low voltage terminal board generally indicated by TB1
has connections A through G, which are found also in the upper part
of the figure. High voltage terminal board TB2 has connections A, B
and C which also are shown in the upper part of the drawing as, for
example, TB2-A. Terminals A and B on the high voltage board are
connected to lamps 2, and terminals B and C are connected to a
voltage source which is shown as a plug 4. In systems which are
intended for use in new constructions, lamps 2 generally indicate
the basic garage lights, lights within a house and lights near
doors. Source 4 is wired directly to the roughed in electrical
wiring. In add on systems a plug 4 and power lines are supplied.
Lamps 2 may be the existing lamps, or lamps may be provided with a
kit.
On the low voltage terminal board TB1, contacts A and B receive
push button 16. Terminals C and D receive internal photocell 10 or
a roll over switch, or both may be connected in parallel to TB1
terminals C and D. Terminals E and F receive low voltage wiring
from the external photocell 8. Terminal G is connected to
ground.
Referring to the main circuit in FIG. 3, voltage is supplied at
source 4. A fuse 42 protects the circuit against voltage surges,
which may be caused externally or by a short circuit in the system.
Household current is applied through fuse 42 to primary 44 of
transformer 46. Secondary 48 reduces the voltage to approximately
12 volts AC. A bridge rectifier generally indicated by the numeral
1 and comprising diodes 3, 5, 7 and 9 changes the low AC voltage to
low DC voltage. Capacitor 12 filters AC components and smooths the
output of the rectifier. Current limiting resistor 14 and capacitor
18 bias transistor 17 on to supply current flow through the DC
electronic components. Zener diode 19 breaks down at excessive
voltage effectively shorting capacitor 18, and turning off
transistor 17, insuring that voltage between ground 27 positive
power line 29 does not exceed a predetermined maximum.
In the variable voltage divider 20, photocells 8 and 10 may have
dark resistances of about 5,000 ohms, or more, which are reduced to
about 500 ohms when illuminated. When photocell 8 is at a low
resistance value, the voltage drops across resistances 58,
photocell 8 and resistance 59 cause voltage across resistance 59
sufficient to bias transistor 54 on. Transistor 54 and resistor 53
drop connector 28 to a level sufficiently low to prevent operation
of the voltage gate 22.
15K ohm resistor 55 is connected in parallel to the path including
resistor 53 and transistor 54 in the lower portion of divider 20 so
that the combined resistance of resistor 53 and resistor 55 is
below 500 ohms when external photocell 8 is illuminated during
daylight hours. In daylight conditions, the potential of midpoint
28 is thus reduced toward ground potential.
In the upper portion of the divider 20, light cell 10 is connected
in series with variable resistor 56, which has a capacity of about
25K ohms. Adjustment of resistor 56 is made to bring the mid point
28 to a potential above the breakdown voltage of the breakdown
device 24 in gate 22. When 12 volts are imposed across lines 27 and
29, resistor 56 may be adjusted so that when photocell 10 is
illuminated by headlights during darkness hours, mid point 28 is
brought to a potential slightly above a breakdown voltage of 6.8
volts. Correctly adjusting resistor 56 according to the fixed
position of photocell 10 insures correct operation of the automatic
system and insures against starting of the system by spurious
illumination of photocell 10.
Photocell 10 may be replaced by an impulse switch or other suitable
switch with a series connected resistance.
For convenience, one or more push buttons 16 may be provided at
entrances to a garage. Preferably the push buttons are connected in
series with a resistor 57, which may have a value of about 470
ohms.
During daylight hours, the low resistance of photocell 8 and
resistor 53 and the parallel resistor 55 will always keep mid point
28 below the level of breakdown voltage required by breakdown
device 24. When photocell 8 imposes its high darkness resistance,
the potential of mid point 28 is raised above the breakdown voltage
by reducing resistance in photocell 10 or by completing any of the
switches.
Gate 22 contains breakdown device 24 which is preferably a zener
diode. When voltage at midpoint 28 exceeds breakdown voltage, zener
diode 24 conducts, supplying current to capacitor 32 and to timer
30 and to electronic switch 36. Storage capacitor 32 is charged
immediately upon application of voltage to the timer circuit.
Resistors 33 and 34 discharge voltage from capacitor 32 after the
applied voltage has been discontinued. The rate at which resistors
33 and 34 discharge voltage from capacitor 32 controls the period
of timer 30. Discharge of capacitor 32 through voltage divider 20
is prevented by unidirectional element 26, which is a diode.
Discharge of the timer through the light switch 36 is prevented by
a high input impedence device.
As an example, the capacitor 32 may have a value of 500
microfarads. Resistor 34 may have a value of from about 150 to
about 2 megaohms.
Cutoff 50 includes a transistor 52 which is biased on by capacitor
51 in about three seconds after sufficient voltage is supplied
through resistor 33 from zener diode 24 and from capacitor 32.
Transistor 52 has an effect similar to transistor 54 in dropping
the level of midpoint 28 to a value insufficient to break down
zener diode 24 so that lights 2 may not raise the level of midpoint
28 by reducing the resistance of photocell 10. Cutoff 50 in effect
desensitizes interior photocell 10 or renders its effect operative
to raise the level of midpoint 28. Capacitor 51 maintains the on
bias on transistor 52 until it discharges sufficiently through
resistor 34, which is after capacitor 32 has discharged
sufficiently to turn off swithc 36.
The function of the resistors 66, 67 and 69 and of the cascaded
transistors 68 and 68' is to forward bias the light switch 36 while
preventing substantial discharge of capacitor 32.
When transistor 68' is biased on by voltage from the timer section
30, DC power is supplied to reed relay 63 via current limiting
resistor 65. Power terminals 70 and 71 of reed relay 63 close,
completing the AC circuit to diac 60. Capacitor 61 and resistor 62
cooperate as an AC voltage divider so that the appropriate
potential is applied via diac 60 to the biasing terminal of triac
38. Power terminals of triac 38 complete the circuit between power
source 4 and lights. 2.
As shown in FIG. 3, diode 64 protects the transistor 68' from
sudden surges when the field collapses in the coil of relay 63. At
the same time, diode 64 keeps the relay polarized.
In summary, FIG. 3 is a schematic diagram of the main circuit. 117
volts AC is applied across Terminal Block TB2 on Terminal B and C.
Fuse 42 protects the circuit against the damage whenever short
circuit or voltage surge occurs. The AC voltage is then fed to step
down Transformer 46. The secondary of 48 develops a lower AC
voltage, which is rectified by a full wave bridge rectifier 3, 5,
7, and 9. The rectified DC voltage output is filtered by capacitor
12 and is coupled to the collector of transistor 17 and to the base
of 17 through resistance 14. 12 volt zener diode 19 regulates the
base bias voltage, keeping the emitter voltage at constant 11.8
volts.
During daylight hours, both photocells 8 and 10 resistances drop to
approximate 450 ohms. A base bias develops across photocell 8, and
resistor 59 switches on transistor 54, placing a ground potential
on the collector end of resistor 53. Resistor 53 and resistor 55
are electrically connected in parallel, and their total resistances
are low, as compared to 400 ohms of photocell 10 resistance. The
voltage at the midpoint 28 is kept below the break down level of
zener diode 24.
When night falls, the resistance of PC1 and PC2 rise beyond 5,000
ohms. Transistor 54 cuts off the ground path of resistor 53. The
midpoint voltage at 28 still is below the zener diode 24 break down
level, because resistance of photocell 10 is high as compared with
resistor 55.
When an automobile enters the premise, its headlights strike the
sensor photocell 10. The photocell resistance suddenly drops to 500
ohms. Voltage a midpoint 28 rises above 10 volts of which cause
zener diode 24 to break down. A DC current is induced through diode
26, charging capacitor 32. Transistor 68 is turned on by the
voltage which develops across base resistor 67 by capacitor 32. The
emitter voltage across resistor 66 switches on transistor 68',
placing a ground potential to relay 63 and energizing it.
117 volts AC from terminal block TB2 on terminals V and C applies
to resistor 62 and capacitor 61 when closing relay contacts 70 and
71. The diac 60 which receives AC voltage from resistor 62 and
capacitor 61 transmits trigger pulses to the gate of triac 36.
Incondescent lamp 2 is turned on by the triac.
Approximately three seconds following the sudden rise of potential
in capacitor 32, a voltage is developed across resistors 33 and 34,
charging capacitor 51 to a potential that sufficiently forward
biases transistor 52. Once again resistor 53 is electrically
connected in parallel with resistor 55 by the collector-emitter
path of transistor 52 to the ground. The midpoint voltage
immediately drops below the zener gated level. That cuts off the
charging current to capacitor 32. Capacitor 32 begins to discharge
through resistors 33 and 34. The voltage in 32 slowly drops to a
level that turns off transistors 68 and 68' and relay 63 and then
the light switching circuit. The period which takes capacitor 32 to
discharge to a cutoff level is approximately 9 minutes. The time
delay could be reduced to approximately 4 minutes by adding a
discharge path with another resistor connected in parallel to
capacitor 32.
Terminal block TB1 is used for interconnecting low voltage switch
elements to the main circuit.
Terminal block TB2 provide connections between the light switch
triac 36 and its load. TB2 also supplies AC power to the main
circuit.
When the push to light switch 16 is depressed, it applies 11.8
volts DC to 470 ohms resistor 51. The midpoint voltage at 28 rises
above the gated level of zener diode 24.
A door chime operator generally referred to by the numeral 90 is
shown in FIG. 4.
Two conditions activate the door chime; when vehicle head lights
are detected by PC1 photocell, and when automobile rolls over the
pneumatic switch hose.
This system utilizes the same two or more tone door chime as in a
house. The vehicle entering a garage immediately activates the door
chime to produce a ding tone first and then three seconds later a
dong tone. The reason for the dragging tone is to enable homeowner
to distinguish the ringing sound of an incoming car and that of a
person at the door.
The contacts 93 and 94 of the chime relay 92 are normally open.
Referring to FIG. 4, they are connected in parallel to the door
chime button switch 79 by a pair of wires from TB3 terminal board
terminals M and L.
When vehicle head lights are detected by photocell 10 in the main
chassis circuit in FIG. 3 the resistance of the photocell suddenly
drops, causing a positive 11.8 volts DC to appear at TB1 terminal A
through resistor 56. This voltage is transferred from terminal
block TB1 to chime operator box TB3 terminal 4, the voltage causes
the 5.6 volt zener diode 88 to break down. Capacitor 102 picks up
this positive pulse and couples it to the base of the transistor
91. This pulse energizes the relay 92. Relay contacts 93 and 94
complete the current path of the door chime, which rings its first
tone ding. At approximately three seconds later, the positive
voltage in terminal J of TB3 drops below the zener diode 88 break
down level by the action of transistor 52 in the main chassis.
Transistor 91, losing its base bias voltage then subsequently
switches off the relay 92. The relay's contacts 93 and 94 are again
opened to release the door chime solenoid holding current. Its
action rings the second tone, dong. Diode 97 is used to short out
any negative pulse at the base of transistor 91 during the
capacitor 102 discharge period. Resistor 103 discharges the voltage
of capacitor 102.
When the light switch 16 is depressed momentarily, a positive 11.8
volts DC from terminal B of TB1 to terminal K of TB3 is transferred
to terminal J by way of diode 87. The zener diode 88 breaks down
and induces a positive pulse to the base of transistor 91, but the
pulse is grounded by collector to emitter of transistor 98, which
is turned on by the base bias that is developed across resistors 99
and 100. This positive Dc voltage is made possible from TB3
terminal I. The results is no chime operation when the light button
switch 16 is pushed.
Diode 87 is used to prevent the circuit of transistor 91 from
operating whenever a positive DC voltage appears at terminal J of
TB3.
A Light Ringer circuit is generally referred to by the numeral 110
in FIG. 5.
After a guest or burglar rings the door bell, the exterior lights
automatically turn on approximately 40 seconds later.
As the door bell 79 is pushed, the 10 or 16 volts AC from the
secondary coil of the chime transformer is applied to terminals P
and Q of terminal board TB4 75 through the chime solenoid, door
bell switch 79 and wires 80 and 81. The diode 111 converts this AC
voltage to DC voltage across resistors 114 and 113. This DC voltage
causes transistor 117 to conduct. The emitter current that flows
through emitter resistor 118 develops a voltage across it. The AC
ripple in this voltage is filtered by capacitor 123.
When the circuit stands idle, the silicon control rectifier 116 is
in an off state. The transistors 146, 143, 137 and 138 are also in
off state. The positive voltage from terminal N through resistors
131, 132 and 133 charges capacitor 135 to a positive 11.5
volts.
If the door bell button is depressed momentarily, its action
creates a temporary short circuit across terminals P and Q. This
action switches the transistor 117 from conduction to off and back
on again. A positive pulse is generated across resistor 118 and the
pulse is coupled to the gate of the SCR 116 by way of resistor 126
and capacitor 125. This positive pulse turns on SCR 116 which
places a ground potential at the junction of resistors 132 and 133.
The positive voltage stored in capacitor 135 slowly discharges
through resistor 133 and SCR 116 to ground. Approximately forty
seconds later, the voltage of capacitor 135 drops to a level where
transistors 138 and 137 begin to switch on through a base bias path
from resistors 134 and 133 and SCR 116.
As transistor 138 turns on, its collector current starts to flow
through resistor 136, causing a positive voltage to develop across
it. Simultaneously the same voltage feeds through resistors 129 and
127 and capacitor 128 to the base of transistor 130 to turn it on.
The collector and emitter provide a momentary ground path at the
junction of 131 and 132. This short circuit condition removes the
current path which holds SCR in the on state. SCR 116 switches off
and subsequently turns off transistors 138 and 137.
When transistor 137 is in an on state as described previously, its
collector current flows through resistors 139 and 141. A positive
pulse is coupled by capacitor 140 and resistor 142 to the base of
transistor 143 to switch it on momentarily. The collector current
of transistor 143 flows through resistors 144 and 145 and develops
a voltage across them. This voltage turns on transistor 146.
As transistor 146 is momentary in conduction, the collector-emitter
transfers the positive voltage on terminal N to terminal O in form
of a positive pulse that is applied to the main chassis of the
system or to the chime operator, which subsequently activates all
lights within the system.
Diode 124 is employed in the circuit to prevent a negative spike of
the transit pulse that might be destructive to the gate of SCR 116.
Diode 119 is used in the circuit to isolate the power supply source
from terminal N to the unfiltered DC voltage of the diode 111.
The system installation is generally shown in FIG. 6. The system is
provided with two photocells. One photocell is mounted on the
exterior of a building such as a garage to prevent the operation of
the system during daylight hours. It is recommended to mount the
exterior photocell on a shaded area to avoid direct sun and rain.
The interior photocell is mounted within a garage at the same level
as headlights, or 20 7/8 inches from the ground to detect
headlights of cars for triggering system when a car is parked in
garage. In a two-car garage, the interior photocell may be
centrally mounted between the two cars to detect either or both car
headlights.
In some cases, such as in drive through carports, no wall is
available for mounting of an interior photocell, a pneumatic switch
may be substituted for the interior photocell. A closed air hose
supplies a pulse of air to switch on the system as an automobile
crosses the hose. A pair of wires connected between the pheumatic
switch and TB1 terminals C and D of the main chassis are polarized
so the switch won't operate if wire is hooked up in wrong
polarity.
The pneumatic switch is also useful for homes with driveways. Place
the hose switch on driveway to alert the homeowner of approaching
vehicles by means of the door chime and lights.
Manual pushbutton switch for convenience should be installed near
the entrance to garage and home. The chime operator box should be
mounted next to the main chassis.
The wiring is indicated by the chime operator diagram in FIG. 6 as
follows. The push-to-light switch 16, normally connected to TB1
terminals A and B of the main chassis, is connected to K and J
terminals of TB3 in the chime operator box. Jumper wires are
connected between terminals H, J and K of TB3 to terminals G, A and
B of TB1. It is important to check for correct wiring because K-B
terminals of both blocks are positive line and H-G terminals are
grounded. A pair of wires from terminal M and L is connected in
parallel with the door chime button switch to provide chime
operation.
The basic garage lights may be wired by licensed electrician to
house power lines using existing lamps in garage or passageway.
This system can be wired into any garage light system without
disturbing its normal electrical function. Door lights and interior
lights may replace or augment garage lights.
Lights may be wired into the main chassis. An installer may mount
the main box at a suitable place in the garage, run the 117 volts
AC line to the nearest AC outlet, and connect all switch elements
as described.
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