U.S. patent application number 11/778390 was filed with the patent office on 2008-01-17 for moisture vapor exhaust system.
Invention is credited to Dale Mark Anderson, Clifford Roux, Glenn C. Skelton.
Application Number | 20080011863 11/778390 |
Document ID | / |
Family ID | 37571065 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080011863 |
Kind Code |
A1 |
Roux; Clifford ; et
al. |
January 17, 2008 |
MOISTURE VAPOR EXHAUST SYSTEM
Abstract
An exhaust system for evacuation of vapor and gases from an
area, the system including a fan mounted on a motor, an activation
circuit coupled to the motor and adapted to couple the motor to a
first voltage source, a detection circuit adapted to sense the
presence of moisture on a sensor surface and to generate a
detection signal when moisture is sensed and to not generate a
detection signal when moisture is not sensed, and a control
circuit. In one embodiment the control circuit is coupled to the
detection circuit and the activation circuit and adapted to
generate a control signal in response to the detection signal, the
control signal received at the activation circuit to cause coupling
of the motor to the first voltage source after a delay programmed
in to a programmable logic chip in the control circuit.
Inventors: |
Roux; Clifford; (Gig Harbor,
WA) ; Skelton; Glenn C.; (Port Orchard, WA) ;
Anderson; Dale Mark; (Gig Harbor, WA) |
Correspondence
Address: |
SEED INTELLECTUAL PROPERTY LAW GROUP PLLC
701 FIFTH AVE
SUITE 5400
SEATTLE
WA
98104
US
|
Family ID: |
37571065 |
Appl. No.: |
11/778390 |
Filed: |
July 16, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11153528 |
Jun 14, 2005 |
|
|
|
11778390 |
Jul 16, 2007 |
|
|
|
Current U.S.
Class: |
236/44E |
Current CPC
Class: |
F24F 2110/20 20180101;
F24F 11/30 20180101; F24F 2013/221 20130101; H05K 7/20209
20130101 |
Class at
Publication: |
236/044.00E |
International
Class: |
F24F 3/14 20060101
F24F003/14 |
Claims
1. A controller for a fan, comprising: a sensor adapted to detect
the presence of condensed water; and a circuit coupled to the
sensor and adapted to control operation of the fan in response to
the sensing of condensed water by the sensor.
2. The controller of claim 1 wherein the circuit is adapted to
activate the fan for a fixed period of time.
3. The controller of claim 1 wherein the sensor comprises exposed
leads that conduct current when the leads are coupled together by
condensed water.
4. The controller of claim 3 wherein the circuit is configured to
compare current conducted by the sensor in the presence of
condensed water to a reference current and to activate the fan when
the current from the sensor reaches a level of the reference
current.
5. A fan for exhausting air, the fan comprising: a motor for
rotating the fan; and a controller for the motor, the controller
comprising: a sensor adapted to detect the presence of condensed
water; and a circuit coupled to the sensor and adapted to control
operation of the motor in response to the sensing of condensed
water by the sensor.
6. The fan of claim 5 wherein the circuit is adapted to activate
the fan for a fixed period of time.
7. The controller of claim 5 wherein the sensor comprises exposed
leads that conduct current when coupled together by condensed
water.
8. The controller of claim 7 wherein the circuit is configured to
compare current conducted by the sensor to a reference current and
to activate the fan when the current from the sensor reaches a
level of the reference current.
9. A fan controller, comprising: a sensor configured to detect
moisture condensed from water vapor; and a circuit coupled to the
sensor and configured to operate the fan when the sensor detects
the moisture.
10. The fan controller of claim 9 wherein the circuit coupled to
the sensor is configured to operate the fan for a fixed duration of
time when the sensor detects the moisture condensed from water
vapor.
11. The fan controller of claim 9 wherein the circuit coupled to
the sensor is configured to alert a user when the sensor detects
moisture condensed from water vapor.
12. A method for reducing moisture in an enclosed area, the method
comprising: detecting water condensed from water vapor; and
activating a fan for a fixed duration of time in response to
detecting water condensed from water vapor.
13. The method for reducing humidity of claim 12 further comprising
checking repeatedly for the presence of water condensed from water
vapor after the fixed duration of time and activating the fan for
the fixed duration of time in response to detecting water condensed
from water vapor.
14. The method of reducing humidity of claim 12 further comprising
illuminating a light source in response to detecting water
condensed from water vapor.
15. A method for reducing humidity in an enclosed area, the method
comprising: detecting condensation using a sensor; processing an
output signal from the sensor; and activating a fan for a fixed
duration of time in response to the output signal from the
sensor.
16. The method of reducing humidity of claim 15 further comprising
operating the fan manually.
17. A device for eliminating water vapor from an enclosed area, the
device comprising: a condensed water detector; a first circuit
having an automatic switch to activate a fan assembly when
condensation is detected by the detector; and a second circuit
coupled to the first circuit, the second circuit having a manual
switch for controlling the fan assembly.
18. The device of claim 17 wherein the first circuit coupled to the
sensor is configured to illuminate a light when condensation is
detected by the detector.
19. A fan assembly, the assembly comprising: means for sensing
condensed water vapor; and means for activating a fan when the
sensing means detects the condensed water vapor.
20. The fan assembly of claim 19 wherein the means for activating
the fan is configured to alert a user to the sensing of condensed
water vapor.
21. An exhaust system for evacuation of vapor and gases from an
area, the system comprising: a fan mounted on a motor; an
activation circuit coupled to the motor and adapted to couple the
motor to a first voltage source; a detection circuit adapted to
sense the presence of moisture on a sensor surface and to generate
a detection signal when moisture is sensed and to not generate a
detection signal when moisture is not sensed; and a control circuit
coupled to the detection circuit and the activation circuit and
adapted to generate a control signal in response to the detection
signal, the control signal received at the activation circuit to
cause coupling of the motor to the first voltage source after a
delay programmed in to a programmable logic chip in the control
circuit.
22. The system of claim 21 further comprising a low voltage circuit
adapted to receive the first voltage and generate a second voltage
that is at a lower voltage level than the first voltage to provide
operating power for the activation circuit, detection circuit, and
control circuit.
23. The system of claim 22, wherein the sensor comprises interlaced
exposed gold lines on a printed circuit board in which each line
has a width in the range of 0.4 to 0.6 mm, and the gap between the
exposed gold lines is in the range of 0.2 mm to 0.4 mm in
width.
24. The system of claim 23, wherein the gold lines have a preferred
width of 0.5 mm and a preferred gap between them of 0.3 mm.
25. A controller for an exhaust fan motor that utilizes an existing
voltage source for power, the control circuit comprising: an
activation circuit adapted to couple the motor to the existing
voltage source; a detection circuit adapted to sense the presence
of moisture on a sensor surface and to generate a detection signal
when moisture is sensed and to not generate a detection signal when
moisture is not sensed; and a control circuit coupled to the
detection circuit and the activation circuit and adapted to
generate a control signal in response to the detection signal, the
control signal received at the activation circuit to cause coupling
of the motor to the first voltage source after a delay programmed
in to a programmable logic chip in the control circuit.
26. The controller of claim 25 further comprising a low voltage
circuit adapted to receive the existing voltage and generate a
second voltage that is at a lower voltage level than the existing
voltage to provide operating power for the activation circuit,
detection circuit, and control circuit.
27. The controller of claim 25, wherein the sensor comprises
interlaced exposed gold lines on a printed circuit board in which
each line has a width in the range of 0.4 to 0.6 mm, and the gap
between the exposed gold lines is in the range of 0.2 mm to 0.4 mm
in width.
28. The system of claim 27, wherein the gold lines have a preferred
width of 0.5 mm and a preferred gap between them of 0.3 mm.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present disclosed embodiments pertain to the evacuation
of vapor or gas from an enclosed room and, more particularly, to
the detection of moisture or water, particularly condensed water on
a surface, and the control of an exhaust fan in response to the
detection.
[0003] 2. Description of the Related Art
[0004] The present disclosure provides a solution for preventing
fungal and bacterial destruction of materials that are subject to
moist environments. Current devices are both inadequate and
non-functional with respect to providing protection from moisture
and properly maintaining dry conditions. Considerable economic and
physical loss may be experienced by both user and maintenance
personnel either not switching on an exhaust fan or switching it on
for such short times as to be ineffective as a means of preventing
the accumulation of both fungal and bacterial outbreaks that are
health threatening and destructive of the structures or stored
objects themselves. This situation has long been and still is a
large and growing economic and health issue.
[0005] Hence, there is a need for automated control of exhaust
systems used in bathrooms, shower rooms, kitchens, and other
enclosed areas where moisture vapor, condensed moisture, and
various gases must be exhausted. Numerous electro-mechanical
solutions have been proposed. For example, in The IC User's
Casebook, 1988, Howard W. Sams, publisher, it shows at pp. 235-239
various generic circuits using contacts that trigger an output if
liquid shorts the contacts. The liquid level detector shown in FIG.
16-7 of this reference fails to provide sufficient reliability in
the environment to which the present disclosure is directed. This
is due to the great need for sensitivity and reliability in sensing
small amounts of moisture, which is neglected in these proposed
designs. Moreover, the use of gold traces on sensor contacts was
found to be useful only for corrosion control, and no recognition
has been given to the use of gold to control circuit behavior.
BRIEF SUMMARY OF THE INVENTION
[0006] The embodiments disclosed herein are directed to an exhaust
system, including an electronic controller for a fan that is
adapted to be used in environments in which moisture vapor,
moisture in the form of condensation, and gases in various forms is
undesirable. In accordance with one aspect of the disclosure, an
exhaust system is provided that includes a fan mounted on a motor
and in fluid communication with an exhaust duct; a detection
circuit, a control circuit having a programmable circuit for
receiving a detection signal from the detection circuit and
generating an activation control signal in response thereto, and an
activation circuit for coupling and uncoupling a current source to
a fan motor in response to the control circuit.
[0007] In accordance with another aspect of the disclosure, a
low-voltage supply circuit provides a low voltage current for
operation of at least one or more of the control circuit, the
detection circuit, and the activation circuit without using a
transformer.
[0008] In accordance with another aspect of the disclosure, the
system utilizes low-voltage components in the detector circuit,
which includes a sensor and a conditioning circuit, and in the
control circuit, which includes a programmable integrated circuit,
as well as in the activation circuit, which generates a low voltage
control signal to a relay that couples a high voltage line to the
fan motor.
[0009] In accordance with another aspect of the present disclosure,
the sensor utilizes interlaced exposed gold lines on a printed
circuit board in which each line has a width in the range of 0.4 to
0.6 mm and a preferred width of 0.5 mm, and the gap between the
exposed gold lines is in the range of 0.2 mm to 0.4 mm in width
with a preferred gap width of 0.3 mm.
[0010] In accordance with another embodiment of the present
disclosure, a controller for a fan is provided, the controller
having a sensor adapted to detect the presence of condensed water
and a circuit coupled to the sensor that is adapted to control
operation of the fan in response to the sensing of condensed water
by the sensor.
[0011] In accordance with another aspect of the disclosure, a
controller for an exhaust fan is provided that includes a sensor
having electronic leads adapted to be bridged by condensed moisture
to conduct current, and a circuit coupled to the sensor and adapted
to control operation of the fan in response to the flow of current
in the sensor.
[0012] In accordance with another aspect of the present disclosure,
the controller is fully automated in that it automatically
activates the fan when condensed water is detected on the sensor
and maintains activation of the fan for a set period of time.
Alternatively, the controller can be adapted to permit manual
deactivation of the fan or to permit both manual deactivation and
automatic deactivation of the fan.
[0013] In accordance with another aspect of the present disclosure,
the sensor and the circuit are hardwired together and the circuit
is coupled to the fan via either a hardwire or a wireless
connection.
[0014] In accordance with another aspect of the disclosure, the
sensor is formed from exposed electrically-conductive leads that
are designed to conduct current when the leads are bridged by
condensed moisture.
[0015] In accordance with another aspect of the present disclosure,
the circuit is adapted to compare the amount of current conducted
by the sensor with a reference current and to activate the fan when
the conducted current by the sensor is at an appropriate level.
[0016] In accordance with another aspect of the present disclosure,
the controller utilizes an optical coupler to isolate high voltage
or high current circuit components from low voltage components,
such as sensing and switching components.
[0017] In accordance with another aspect of the disclosure, an
electronic circuit is provided for sensing moisture in any enclosed
space (especially a bathroom with shower/tub) and by the use of
appropriate signal conditioning, amplification, timing and on-site
power switching causing the already installed exhaust fan to be
switched on for a time appropriate to dry the affected space and
then be automatically switched off. In the case of an average
residential bathroom, this is about 20 min.
[0018] In another embodiment of the present disclosure, miniature
electronic components are provided to fit into the space provided
for and replacing an ordinary and standard manual switch used to
switch on a fan in a room or other chosen space. In accordance with
one preferred embodiment, no additional wiring to the building's
electrical system is required, and it is a direct replacement for
the manual exhaust fan switch installed as standard practice in all
toilet or shower facilities.
[0019] In accordance with another aspect of the present disclosure,
the controller automatically turns on the exhaust fan to air out or
dry out the confined space in the event that a factory
predetermined level of moisture or other substance or material has
been exceeded, thereby limiting any destruction or health risks
caused by negligence on the part of users or infrequent
maintenance. Periodic maintenance schedules are often extended so
far as to be ineffective in moisture control. In one embodiment,
the controller of the present disclosure takes out of a user's
control the option to turn off the exhaust fan but not the option
to turn it on.
[0020] In accordance with another embodiment of the disclosure, the
controller is manufactured in such a way that all electronic
components, sensor and pc board mounting fit into any ordinary
switch box in a building electrical system and wire directly into
the already installed wiring for the manual switch which it will
replace.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0021] The foregoing features and advantages of the present
disclosure will be more readily appreciated as the same become
better understood from the following detail description when taken
in conjunction with the accompanying drawings, wherein:
[0022] FIGS. 1A-1C are a schematic of an exhaust fan controller
formed in accordance with the present disclosure;
[0023] FIGS. 2A and 2B are illustrations of alternative
applications for the exhaust fan controller formed in accordance
with the present disclosure;
[0024] FIGS. 3A and 3B are an illustration of an alternative
embodiment of an exhaust fan and accompanying controller formed in
accordance with the present disclosure;
[0025] FIG. 4 is a block diagram illustrating another embodiment of
the present disclosure;
[0026] FIG. 5 is a circuit schematic for circuits in the embodiment
of FIG. 4; and
[0027] FIGS. 6A-6B illustrate replacement of an existing fan switch
with a controller of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring to the embodiment of a vent fan controller shown
in schematic form in FIG. 1, the components with reference labels
SENS 1, R7, R1, R2 & R3, Q1, and U2 form the moisture sensing
and post sensing conditioning circuit. The moisture sensor itself
has in this case been chosen for its cost effect manufacture and
low component requirements to reliably trigger the rest of the
exhaust fan controller circuitry. In one embodiment, it has been
made as a half inch by half inch PC board with gold leads arranged
as two interleaved four pronged forks spaced at about 1/20 an inch
between the tines. (Refer to FIG. 1, SENS1 symbol details on the
schematic).
[0029] The NPN transistor(Q1) receives a "moisture present" signal
from the sensor and shapes it appropriately to be used to drive the
LM311 Comparator (U2), which, when the appropriate level is reached
as determined by comparison to a reference current, will trigger
the LS7213 Timer (U5) to drive the output triac (U4) for the
appropriate time chosen, which is established by the values of R9
and C5. Nominal time is 20 min. Other values chosen for particular
applications are adjustable from 1 second to hours. A signal from
the Timer IC (U5) pin 12 thru resister R11 to D2 will light the LED
whenever the exhaust fan is on. The LED is optional but
recommended.
[0030] IC U1 is a triac driver optical coupler used to isolate the
110V AC being switched on and off by the triac to the exhaust fan
motor. This optoisolation decouples the triac 110V AC switching
current from the low voltage supplied IC and transistors of the
circuits.
[0031] The low voltage power supply shown is known and certain
versions are readily commercially available and will not be
described in detail herein. In FIG. 1 the miniature transformer
(T1), full wave bridge rectifier (D1), electrolytic capacitor (C1),
and the IC 5 volt regulator (U3) supply the necessary regulated 5
vdc to the entire circuit. Capacitors C2, C3, C4, and C6 are bypass
capacitors necessary to short unwanted voltage transients to
ground.
[0032] We have also found by experiment that the power supply can
benefit from slight changes, substituting a 9V DC regulator to
supply the entire circuit, with the exception of the LSI timer,
which requires a 5V DC regulator. This makes a much more sensitive
circuit, both in the lower level of moisture vapor it will detect
and the speed of its response.
[0033] FIG. 1 also shows the single 5V DC regulator option for the
entire controller. While this makes it less sensitive to the amount
of moisture vapor present, taking several minutes to switch on the
exhaust fan motor, in most applications this delay is
insignificant. In others the dual supply (9V DC and 5V DC)
regulators are preferred as being more sensitive and timely.
[0034] The light switch circuit shown at the bottom right of FIG. 1
is another option for sites that may operate both the exhaust fan
and the lights from the same manual switch. The miniature low
voltage switches shown on the Schematic (SW1 and SW2) make the
manual switching functions of turning on the fan motor at will, or
turning the room lights on and off possible from a electrical box
that formerly held only one manual electrical switch. Again, the
optocoupler (U6) isolates the AC being switched at the triac (U7)
from the low voltage portions of the circuits. The detailed parts
list is shown below: TABLE-US-00001 Vent Fan Controller Description
Qty Location CAP 220 UF 25 V ELECT WT SMD 1 C1 CAP CERM. 1 UF 10%
25 V X7R 0603 2 C3, 4 CAP CER 2000 PF 50 V 5% C0G 0603 1 C5 FUSE 4
A 125 V SLO BLO NANO 2 SMF 1 F2 LED BLUE CLEAR 0805 SMD 1 D2 IC REG
LDO MICROPOWER SOT23-5 1 U3 IC DIFF COMP STROBE 8-SOIC 1 U2 IC,
LS7213-S, DELAY TIMER, 14-SOIC 1 U5 PHOTOCOUPLER TRIAC OUT 4-MSOP 1
U1 RECT BRIDGE SMD 100 V 1 A 4P DF-S 1 D1 RES 1.00K OHM 1/4 W 1%
1206 SMD 1 R6 RES 100 OHM 1/10 W 1% 0603 SMD 1 R4 RES 100K OHM 1/10
W 1% 0603 SMD 2 R1, 3 SWITCH TACT SPST-NO 300GF G-WING 1 SW1 TRANS
SS GP NPN 25 V LN SOT23 1 Q1 TRANSFORMER 9 V, 167 mA SECONDARY, 1
T1 115 V PRIMARY TRIAC, 600 V 4 A, DPAK, SMD 1 U4 CAP CERAMIC .01
UF 100 V X7R 0603 1 C6 CAP CER 2.2 UF 10 V 10% X5R 0603 1 C2 RES
1.00K OHM 1/10 W 1% 0603 SMD 1 R11 RES 56.2K OHM 1/10 W 1% 0603 SMD
1 R9 RES 10K OHM 1/10 W 5% 0603 SMD 1 R5 RES 200 OHM 1/10 W 5% 0603
SMD 1 R7 RES 30K OHM 1/10 W 5% 0603 SMD 1 R2 PCB, VENT FAN
CONTROLLER rev 04 1 0 CONN RECEPT 4POS 2 MM GOLD SMD 1 0 ASSEMBLY
CHARGES FAN CONTROLLER 1 0 BOARD REV04
[0035] TABLE-US-00002 Sensor Board Description Qty Location PCB,
SENSOR rev 01 1 0 CONN HEADER 4POS 2 MM GOLD SMD 1 0 ASSEMBLY
CHARGES SENSOR BOARD REV01 1 0
[0036] The present disclosure provides an economical and practical
means to detect and exhaust moisture vapor from indoor spaces. In
checking patents published on the USPTO website, none were found to
address or to be aimed at detecting and exhausting moisture
automatically from indoor spaces, as this disclosure provides.
There are proposed manually adjustable humidity sensors, requiring
or allowing the user to determine if or when the exhaust fan motor
will be switched on. The present disclosure is wholly dissimilar in
several ways. First, the present disclosure is not based on sensing
humidity, but the more direct moisture or condensation sensing.
Second, the disclosure in one embodiment is truly automatic and
does not allow users the option of turning the fan motor off, but
only to turn it on. The third major difference is the adaptability
of the various means the circuits offer to different room and
electrical installations to accomplish condensation sensing and fan
control.
[0037] In the detail show in FIG. 2A the vent fan controller is
configured to be installed as a direct replacement of an ordinary
fan motor control switch. The configuration in FIG. 2B takes
advantage of the flexibility allowed in new installations, as this
allows the exhaust fan and the controller to be mounted on the
ceiling of the subject room and permanently wired there before the
room walls are installed.
[0038] FIG. 3A depicts a configuration that would mount on the
ceiling of larger rooms, possibly in multiples, and using only the
sensor, signal conditioning circuit, and a miniature radio
frequency transmitter, would become the monitor of moisture events
from the more ideal location on the ceiling. Upon triggering, this
unit would send a radio frequency "moisture present" signal to a
wall mounted receiver, timer, and triac controller, which would
turn on the vent fan motor or motors in the case of multiple
installations. The wall-mounted unit can also include a sensor.
[0039] Each of these different adaptations of the basic design of
the present disclosure are necessary in certain indoor situations;
however, it should be noted that all of them could utilize either
the small gold tined fork sensor of FIG. 1 or the sensor found in
any generic smoke detector interchangeably if each sensor is given
its suitable signal conditioning circuit.
[0040] Turning next to FIG. 4, shown therein is a block diagram of
a exhaust fan controller circuit 50 formed in accordance with the
present disclosure. The circuit 50 includes a detector circuit 52
coupled to a processor or control circuit 54, which in turn is
coupled to an activation circuit 56. Not shown in this figure is a
low voltage circuit that provides a low voltage, (e.g., 0.5, 1.0,
1.5, 3.0, or 5.0 volts) to these three circuits. While a
transformer can be used to provide power from conventional house
current, such has the disadvantages of inefficient use of energy,
increased temperature at the circuit board, consumption of space,
and increased costs to manufacture the circuit and hence the
exhaust system. A more efficient source of low voltage is described
herein below.
[0041] The conditioning circuit 52 shown in FIG. 4 includes a
sensor 58 having an output 60 coupled to an input 62 of a
transistor 64 in which the output 66 "Signal Out" is conditioned by
the transistor 60 and a resistor 68. The Signal Out is generated in
response to the sensor 58 completing an open circuit between the
interleaved leads 70, such as with condensed moisture.
[0042] Ideally, the leads 70 are deposited gold traces on a printed
circuit board in which each trace is in the range of 0.4 to 0.6 mm
in width, and having a preferred width of 0.5 mm, and the gap 72
between the exposed gold lines or traces 70 is in the range of 0.2
mm to 0.4 mm in width, with a preferred width of 0.3 mm. These size
ranges and preferred dimensions in combination with the gold traces
70 provide a workable sensor circuit. While other materials can be
used, they suffer from low resistance to corrosion, and they are
not compatible with the trace width and gap width listed above due
to conductivity properties. The use of gold traces 70 having the
noted gaps 72 has been found to be reliable in moisture detection
and exhaustion.
[0043] However, the output signal of the detector 50 described
above requires processing through the control circuit 54 in order
to generate a reliable and usable control signal for the activation
circuit 56. More particularly, the control circuit 54 includes a
memory 74 having software 76 stored therein, a user interface 78
for storing and modifying the software 76, and a signal monitor 80
to receive as input the Signal Out from the detector circuit
52.
[0044] In one embodiment, the software 76 is in the form of BASIC
or Assembly language code, such as the code shown below, that
processes the output of the detector 52 to include a timing delay
for the operation of the fan motor. TABLE-US-00003 list p=10F200
#include <p10F200.inc> _CONFIG _MCLRE_OFF & _CP_OFF &
_WDT_OFF cblock 0x010 delayl delaym delayh delayhh delaylL delaymL
delayhL endc
;************************************************************ ORG
0xFF ORG 0x000 movwf OSCCAL GOTO start
;.sub.---------------------------------------------------------------------
-------- ;INITIALIZE MICROCONTROLLER SETUP movlw b`00000111` option
movlw B`00001001` tris GPIO clrf GPIO retlw 0x000 ; - - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - start call SETUP MAIN CLRF GPIO BTFSS GPIO,3 GOTO
FANON BTFSS GPIO,0 GOTO FANON GOTO MAIN
;.sub.---------------------------------------------------------------------
-------- FANON HO BSF GPIO,2 BTFSS GPIO,0 GOTO HO BSF GPIO,2 BSF
GPIO,1 CALL DELAY GOTO FANOFF GOTO MAIN ; - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - FANOFF A BTFSS GPIO,0 GOTO A BCF GPIO,2 BCF GPIO,1 GOTO MAIN ;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - DELAY clrf delayl CLRF delaym
movlw.000 movwfdelayh movlw .14 movwf delayhh wait decfsz delayl,f
goto wait BTFSS GPIO,0 GOTO FANOFF decfszdelaym,f goto wait
decfszdelayh,f goto wait decfsz delayhh,f goto wait RETLW 0X000 ; -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - GOTO MAIN END
[0045] The control circuit 54 can utilize a low voltage
programmable integrated chip, such as the MIC 10F200T-I/OT, which
is readily commercially available and will not be described in
further detail herein. Included in the control circuit 54 is a
on-reset switch 82 that enables a user to turn the fan on or to
reset the timing of the operation of the fan motor. The
low-voltage/low current output 84 of the control circuit 54 carries
the control signal to the activation circuit 56, which includes a
relay 86 coupled to conventional house current/voltage as described
above. Energizing of the relay 86 with the control signal closes
the contacts 88. In the illustrated embodiment of FIG. 4, the
contacts 88 are shown in a position in which the fan motor is not
energized.
[0046] Preferably, the delay time is 20 minutes, meaning the
circuit energizes the fan for 20 minutes. the fan can be turned off
via the manual switch, but the sensor can override the manual
switch if moisture is detected or is still present on the
sensor.
[0047] This is shown more clearly in the detailed circuit schematic
of FIG. 5 in which like components are identified with the same
reference numbers. Additional components are also shown, and these
are identified on the parts list below: TABLE-US-00004 PARTS LIST
TO SCH REV.9.B BBI Description Location CAP CER 4.7 uF 10 V Y5V
0603 C1 CAP CER.01 uF 100 V X7R 0603 C2 CAP 470 uF 25 V ELECT VZ
RADIAL C3 CAP 1.5 uF 305VAC EMI SUPPRESSION C4 DIODE ZENER 5 W 6.8
V DO41 D1 IC RECT BRIDGE 0.5 A 200 V MBS-1 D2 DIODE SMD STANDARD
BLOCKING D3 LED BLUE CLEAR 0805 SMD D4 FUSE FAST-ACT 10. A 250 V UL
TR5 F1 DIODE TVS 150 V 600 W BIDIR 5% SMB D5 TRANS SS GP NPN 25 V
LN SOT23 Q1 TRANS SS GP NPN 25 V LN SOT23 Q2 RELAY PCB HI-CAPACITY
10 A 5VDC RLY1 RES 1.0 M OHM 1/4 W 5% 1206 SMD R1 RES 47 OHM 1/2 W
5% 2010 SMD R2 RES 1K OHM 1/10 W 1% 0603 R3 RES 1M OHM 1/10 W 1%
0603 R4 RES 1K OHM 1/10 W 1% 0603 R5 RES 1K OHM 1/10 W 1% 0603 R6
SWITCH-TACT SPST-NO MOM SMT J TYPE S1 IC REG LDO MICROPOWER SOT23-5
U1 IC PIC PROCESSOR 10F200T-I/OT U2 PCB CIRCUIT TO MOUNT PARTS PCB1
PCB SENSOR IMMERSION GOLD PCB2 BLACK 18AWG STRANDED 105deg C. W1
WHITE 18AWG STRANDED 105deg C. W2 BLUE 18AWG STRANDED 105deg C. W3
WIRE 26AWG STRANDED 50 mm W4 WIRE 26AWG STRANDED 50 mm W5
[0048] Improvements in this embodiment include additional tines in
the sensor. The tines are wider and spaced closer together. In one
embodiment, the tines are formed of copper that is coated with gold
material, 24 ct. gold using standard PCB emersion coating. It was
found that these changes make the sensor very sensitive to dew
point, and it provides a heretofore unexpected improvement over
existing similar sensors.
[0049] In a wall-mount version the sensor is readily accessible
through a window formed in the housing for inspection and cleaning.
The sensor can easily be cleaned because of the gold deposition on
a fiberglass PCB, and it is corrosion resistant because it is not
made of a porous material that absorbs moisture. The non-porous
material of the present embodiment is easily cleaned and maintained
by wiping the sensor face with a mild degreaser, such as household
window cleaner. The sensor can be manufactured at most PCB
manufacturers, resulting in a lower cost to produce.
[0050] The reaction time has been improved by using the PIC
processor, which controls the reaction time, deletes parts, and
results in a simpler controller that is more reliable and less
costly to manufacture.
[0051] The controller is no longer powered by a transformer, which
is replaced by a transformerless circuit that saves energy, drops
temperature to the circuit board, gives the PCB more room for
future add-ons, and it is also less costly to manufacture.
[0052] The signal conditioning circuit has utility with sensors
other than those that sense moisture, making for a much approved
approach to other types of sensors.
[0053] FIGS. 6A-6B illustrate the steps of replacing a conventional
fan wall switch 90 with the controller 92 of the present
disclosure. FIG. 6A shows the existing switch 90 removed from the
wall box after power to the switch 90 has been shut off. Once the
wires 94, 96 are removed from the existing switch 90, the new
controller 92 is hooked up as shown, i.e., blue controller wire to
the existing black wire, the white controller wire to the existing
white wire, and the black controller wire to the remaining wire in
the wall box.
* * * * *