Abstract:
The present invention is a battery powered, portable microprocessor based early warning alarming smoke detector. It provides the user two different time limited unattended alarms, as well an alarm for a tipped smoke detector; an alarm for a bumped smoke detector; an alarm based on nearby or lower elevation smoke by either of the two smoke detection devices; and a low power alarm. It offers “full protection” for most of the likely scenarios encountered by residential users that could result in a fire. Since the device is microprocessor controlled, the timing intervals and magnitude of the different alarm notifications can be preprogramed as well as the sensitivity of the smoke detector devices.

Description:
[0001]     This application is a continuation-in-part of application claiming benefit under 35 U.S.C. § 121 U.S. non-provisional application No. 11/131,094 May 16, 2005. The benefit of which is claimed, is considered to be a part of the disclosure of the accompanying application and is hereby incorporated herein its entirety by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a device capable of both preventing and detecting residential fires and more particularly, to a microprocessor based battery powered, portable early fire detection and prevention device.  
         [0003]     Cooking fires are one of the leading causes of residential fires and related injuries. Often, to avoid false alarms, most smoke detectors are not recommended for use in the kitchen. The lack of smoke detectors in such close proximity to the oven or range is one of the leading factors in the rapid spread and destruction of kitchen fires. Additionally, cigarette related fires are commonplace and rank as the leading cause of fire deaths for senior citizens and children under eight years old in the United States. It is well documented that many of the cigarette related fires stem from a lit cigarette that is knocked from an ashtray, a lit cigarette that burns unattended and shortens until it tips from the ashtray, or a person who falls asleep while smoking. Although early warning smoke detectors are commonplace in most residences, their proximity to the source of the smoke is directly related to the amount of time available to rectify the situation before it gets out of hand. Furthermore, many smokers prefer to disable their ceiling mounted smoke detectors if they smoke indoors as the hot rising smoke particles continually set off the alarms, and ceiling mounted smoke detectors are difficult to disarm.  
         [0004]     The present invention offers true “full protection” for a variety of scenarios, and since it is portable, is easy to disarm. Its portability allows it to be moved to locations of temporary interest, ie a smoking room at a party, a BBQ, an ironing room, a crafts room etc. This is something not likely to be one if one has to get out a ladder to remove the existing smoke detector from a ceiling or stairwell location. Bumping or tilting the device beyond a pre-set angle initiates a continual, audible notification until the situation is remedied. The device also warns the user of a low battery condition. Since the device is microprocessor controlled, the timing intervals and magnitude of the different alarm notifications can be preprogramed as well as the sensitivity of the smoke detectors.  
         [0005]     Henceforth, a “full protection” alarming portable early fire detection and prevention device would fulfill a long felt need in the industry. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems and accomplish this.  
       SUMMARY OF THE INVENTION  
       [0006]     The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved early warning microprocessor operated, portable early fire detection and prevention device (smoke detector) that will alert the user of potential fire causing scenarios as well as to actual smoke generating situations.  
         [0007]     It has many of the advantages mentioned heretofore and many novel features that result in a new microprocessor operated, portable early fire detection and prevention device which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof.  
         [0008]     It is a object of this invention to provide an improved microprocessor operated, portable early fire detection and prevention device that automatically gives the user a twp level audible notification if the device has been tipped over or bumped.  
         [0009]     It is still a further object of this invention to provide for an improved smoke detector that automatically alarms the user if there is a smoke emitting source near or below the microprocessor operated, portable early fire detection and prevention device.  
         [0010]     It is yet a further object of this invention to provide an improved microprocessor operated, portable early fire detection and prevention device that automatically provides the user with a notification of the battery status.  
         [0011]     The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. Other objects, features and aspects of the present invention are discussed in greater detail below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a top view of the smoke detector showing the general arrangement of some of the components;  
         [0013]      FIG. 2  is a side view of the smoke detector showing it&#39;s general configuration;  
         [0014]      FIG. 3  is a bottom view of the smoke detector showing it&#39;s general configuration;  
         [0015]      FIG. 4  is a cross sectional view of the angle alarm device.  
         [0016]      FIG. 5  is a side cross sectional view of the smoke detector showing the general arrangement of the smoke detector&#39;s major components;  
         [0017]      FIG. 6  is a top view of the circuit board; and  
         [0018]      FIG. 7  is a bottom view of the circuit board without a battery installed. 
     
    
     DETAILED DESCRIPTION  
       [0019]     Looking at  FIGS. 1, 2 , and  3  it can be seen that the smoke detector body  2  is comprised of two matingly engagable polymer parts. There is an upper housing  16  and a vented lower component housing  18 . The location of the override optical sensor  14  is visible through the upper housing  16  from a top view. Lower component housing  18  has multiple vents  20  disposed about the circumference to allow the movement of local air and smoke into the vicinity of the smoke detector sensors. The preferred embodiment of smoke detector  1  has feet  22  formed on the base of the lower component housing  18 . These may be made of the same material as the rest of the smoke detector body  2  or of a gripable polymer or rubber.  
         [0020]     The material of construction for the preferred embodiment is an infra red translucent, heat resistant polycarbonate, although other infra red translucent compounds will suffice, or other heat resistant substrates having regions of infra red translucent material adjacent to the sensors. The entire body  2  need not be made from the same infra red translucent material, as the infra red translucent property is only critical in the area directly above and adjacent to where override optical sensor  14  are located.  
         [0021]     Referring now to  FIG. 5  and  6 , the circuit board  36  is a circular, double sided, standard phenolic circuit board capable of withstanding temperatures in excess of those generated by a cigarette, for example, alone before distorting or experiencing melting of the conductive circuit pathways  44 . The circuit board  36  rests on flange  5  of the lower component housing  18  and is held in place by the close tolerance between the upper housing and the vented lower component housing flange  5  and adhesive. The preferred embodiment uses a 25 mm separation between the bottom of the upper housing and the top face of the circuit board  40 .  
         [0022]     Looking at  FIG. 7 , a view of the bottom face of the circuit board  38 , the general arrangement of the components can be seen. Smoke detector ionization chamber  24  is mounted above smoke detector integrated circuit microchip  48  and adjacent piezoelectric horn  26 , and angle alarm optical sensor  32  which is centered above hemispherical cup  34 . Microprocessor chip  46  is located approximately centrally on the circuit board  36  and adjacent smoke detector photo sensor  25 .  
         [0023]     Looking at  FIG. 6 , a view of the top face of the circuit board  40  the general arrangement of the remaining components can be seen adjacent to LED  52 . Conductive circuit pathways  44  can be seen traced about the circuit board  36  connecting the various electrical components.  
         [0024]      FIG. 4  shows the ball  30 , hemispherical body  34 , and angle alarm optical sensor  32  of the angle alarm device, as mounted onto circuit board  36 .  
         [0025]     To increase the margin of protection afforded to the components and circuit board  36 , in the event the unit is placed in an extremely warm environment (I.E. next to a burner, light, heat source, etc.)the main body  2  is constructed from a heat resistant polycarbonate. It is expected that this unit will find use in commercial and industrial environments where it may be located beside processes utilizing high temperatures and prone to initiating fires. Although it is well known that it may be made from any of a plethora of heat resistant polymer such as that trade named Melamine (an organic base with the chemical formula C3H6N6, with the IUPAC name 1,3,5-triazine-2,4,6-triamine.) As additional protection, there is an air filled void  50  between the upper housing  16  and the circuit board  36  and all the components except for the LED light  52 , and the override optical sensor  14  reside on the bottom face  38  of the circuit board  36 . A thin heat dissipating circular metal foil disk may be optionally placed in the void  50  between the circuit board  36  and the upper housing  16 , although it is not utilized in the preferred embodiment.  
         [0026]     It is to be noted that the lower component housing  18  is configured with an angular face and a plethora of equally spaced vents  20  thereon as well as orifices on the base  23 . The vents  20  extend axially along the housing  18  and onto the outer periphery of the base  23 . Experimentation has shown that this is the best physical configuration to draw in warm, smoke laden air into the internal cavity and toward the two smoke sensors. This physical configuration utilizes the principles of the venturi effect (from the angled slots), warm air rising and thermal siphoning or thermal cycling to draw the smokey air into the unit. When smoke is present there will be a temperature gradient across the unit which initiates the drawing action. Since the vents  20  reside below lip  3  of the main body  2 , the lip serves to constrain and accumulate warm, smoke laden air momentarily until the full action as described above can occur. The design of the slots  18  extending onto the base  23  also enhances the ventilation draw again utilizing the “warm air rising” principle. There was an unexpected result discovered with this angled slotted configuration, not found with any diameter of similarly situated round or oval orifices—that of an increased draw of smokey air into the unit. Additionally, the base&#39;s orifices  21  allow smoke below the unit to be drawn in since the unit&#39;s feet  22  allow the orifices to remain open to the atmosphere. In combination these design features enable an enhanced ventilation flow making the unit extremely sensitive in all locations and renders a very fast response time.  
         [0027]     Note, the override optical sensor  14  and the angle alarm optical sensor  32  are all identical optical sensors. (These are also commonly referred to as photo sensors.) The smoke detector&#39;s responses to single or multiple sensor signals are defined by the logic programed into the microprocessor  26 .  
         [0028]     Referring to  FIG. 5  again, it can be seen that the angle alarm device is made of a angle alarm optical sensor  32 , and a hollow hemispherical body  34  with a ball  30  that is free to move within the body  34 . This sensor is also a standard discrete infra red matched LED and infra red receiver unit.  
         [0029]     The angle alarm optical sensor  32  is mounted directly above the hemispherical body  34  and at the proximate centerline of the body  34  and ball  30  when the smoke detector  1  and angle alarm device is horizontally orientated position. In this manner the ball  30  reflects emitted light back to the angle alarm optical sensor  32  when the smoke detector  1  remains within a specific range of angles. Thereafter, the ball  30  will not be in the path of the emitted infra red light and there will be no back reflection to the sensor  32 . Following this logic, severe bumping or rapid movement of the smoke detector  1  will also cause the ball  30  to move away from the path of the emitted infra red light, momentarily eliminating any back reflection to the sensor  32 . This presents the user with audible notification if the unit has been knocked from its temporary location and perhaps landed at an elevation or location where the smoke sensing capability is diminished.  
         [0030]     The override optical sensor  14  is located below an area on the flange  4  of the upper housing  16 . When this override optical sensor  14  is covered, it senses any back reflection of infra red light and sends a signal to the microprocessor  46  which stops generating all audible and visual alarm signals, (including all alarms soon to be initiated by the angle alarm optical sensor  32  if the smoke detector is being tipped), and resets the alarm timers. The override optical sensor  14  thus overrides all audible and visual alarm signals sent by the microprocessor  46 . This useful when moving or relocating the unit so as to eliminate an unwanted audible alarm.  
         [0031]     Note, that the angle alarm optical sensor  32  elicits responses upon an absence of reflected light within the sensor, while the override optical sensor  14  and the smoke detector photosensor  25  elicit responses based on the detection of infra red light within the sensor. All of these optical/photo sensors are standard discrete infra red matched LED and infra red receiver combination units as are well known in the industry.  
         [0032]     A visual alarm light  52  is located adjacent the override optical sensor  14 . It is a colored light emitting diode (LED) that is clearly visible through the upper housing  16 . It is activated simultaneously by the microprocessor  46  with either the first or second level audible alarm signal.  
         [0033]     There are two types of smoke detecting means utilized in the smoke detector  1 , a photo sensor smoke detector  25  and an ionization chamber smoke detector  24 . Both means sense smoke particles that pass into the vented lower component housing  18  through the vents  20 . Since hot smoke rises, the only smoke to enter the lower component housing  18  would be from a smoke source that below the smoke detector  1 .  
         [0034]     The ionization chamber smoke detector  24  generates a signal which it sends to the smoke detector microchip  48 . (The industry standard is used in the preferred embodiment which is a low voltage CMOS integrated circuit Motorola model MC 14467 microchip, although there are other microchips which perform adequately.) This signal increases with the increasing level of smoke detected by the ionization chamber. Once the signal strength increases beyond a certain threshold level as set in the microchip  48 , the microchip  48  sends a signal to the microprocessor  46 . The microprocessor  46  will then send an alarm signal back to the driver circuit of the microchip  48  to sound the second level (loudest sounding) alarm via the horn  26  and activate the LED  52 . (Provided that the override optical sensor  14  is not activated.) The driver circuit of the microchip  48  is used to drive the horn  26  since the microchip  48  has a higher voltage capability than does the microprocessor  46 . Thus, the driver circuit on the smoke detector microchip  48  powers the horn  26  but based on a signal input from the microprocessor  46 . The microprocessor  46  can send two different signals to be generated by the microchip  48  depending on the desired horn frequency which then determines the corresponding horn sound and volume.  
         [0035]     The smoke detector photo sensor  25  is a standard discrete infra red matched LED and infra red receiver positioned in a spaced configuration (approximately ⅜″ apart) at right angles to each other on the bottom side of the circuit board  36 . Smoke particles moving in the beam path of emitted infra red light from the LED, reflect infra red light onto the receiver. A signal is generated by and sent from the photo sensor  25  directly to the microprocessor  46  (bypassing the smoke detector microchip  48 ). The signal strength increases with an increasing amount of smoke particles as seen and detected by the photo sensor  25 . The microprocessor  46  compares the magnitude of the signal strength through an algorithm to a preset preprogrammed threshold value (that corresponds to a predetermined positive indication of smoke detection). Once this threshold value is exceeded, the microprocessor  46  sends a second level alarm signal to the smoke detector microchip&#39;s driver circuit to drive the horn  26  as discussed above, and activates the LED  52 . (Provided that the override optical sensor  14  is not activated.) On the detection of smoke from either of the smoke detecting means, the loudest audible alarm or second level alarm, is sounded.  
         [0036]     Referring now to the operation of the smoke detector  1 , the microprocessor  46  receives information from the following four sources: the battery  42 , the override optical sensor  14 , the angle alarm optical sensor  32 , the smoke detector photo sensor  25 , and the smoke detector integrated circuit microchip  48 . Based on algorithms programed onto the microprocessor  46 , in response to signals from the abovementioned sources, the microprocessor  46  sends one of two different frequency signals to the piezoelectric horn  26  via the smoke detector microchip&#39;s driver circuit, resets the internally programed algorithmic countdown timer on the microprocessor, activates a LED light  52 , or initiates a rhythmic “chipping” alarm from the horn  26 .  
         [0037]     The microprocessor  46  used in the preferred embodiment is a Silicon Labs Model 8051 microprocessor, flash programable device, although a plethora of others could be substituted. It has been programed to initiate a first level, second level or battery low alarm signal; to control the tone of the horn  26 ; to filter and analyze the various sensor inputs; to run the countdown timer; to activate a LED alarm light  52  and it can also vary the threshold smoke detection limit from the smoke detector photo sensor  25  or the threshold smoke detection limit of the smoke detector microchip  48 . A power converter is utilized to switch the 9 volt dc power down to approximately 3.3 volts and 25 μ amperes to operate the microprocessor  46 .  
         [0038]     The smoke detector integrated circuit microchip  48  is a low voltage, CMOS, integrated circuit, analogue microchip. The preferred embodiment uses the industry standard Motorola MC 14467 microchip, although substitution of other microchips would render the equivalent performance. The microchip  48  receives a variable signal from the smoke detector ionizing chamber  24  that increases with increasing smoke particle density within the chamber  24 . The microchip  48  has a driver circuit on it that powers and sounds the horn  26  in response to the first level alarm signal, the second level alarm signal or the low battery “chirping” signal sent by the microprocessor  46 .  
         [0039]     The microprocessor  46  generates different audible alarm signals depending upon the algorithmic determination of which level of alarm is to be sounded. There is only one audible alarming device  26  but three distinct audible alarms are emitted. The first level alarm will initiate an intermittent “chirping” alarm a will occur with a low voltage level battery  42  and continue until such time as the battery  42  dies or is replaced. The second level alarm (optional) is a continual audible alarm, initiated in response to an extremely low voltage battery level or an override optical sensor that has been activated for more than a preselected period generally 30 seconds (thus disabling all audible alarms.) The third level alarm is initiated by, a tipped smoke detector  1 , or a positive indication of smoke from either of the smoke detector means.  
         [0040]     The horn  26  is modulated to control the volume level and the tone. This will affect the resonance of the horn. For the first level alarm a quiet, low frequency signal (one that is not a harmonic of the resonant frequency) is generated. For the second level alarm a high decibel, high frequency signal is emitted. The second level alarm is designed to attract more attention than the first level.  
         [0041]     All alarms can be temporarily over ridden by the alarm override sensor  14 , logically since it indicates the presence of an awake person until the preselected period (commonly 180 seconds) has been reached. The preselected period time is to prevent the cancellation of the unit&#39;s alarm features in the event that an object inadvertently blocks the alarm override sensor  14 .  
         [0042]     One of the features offered by this unit is the ability for easy testing. All one needs to do to test its function is to tilt it with the alarm override sensor unactivated. (I.E. with no finger covering the sensor area.)  
         [0043]     While the unit is primarily intended for use with DC power to enable the portability feature, it is known that it may be connected to AC power through the use of an AC/DC adapter where longer term use is intended.  
         [0044]     The actions of the user and/or smoke detector and the responses triggered by the microprocessor are best illustrated by the following chart:  
                                       Microprocessor Activated       Action   Response                   cover alarm override sensor   initiate override timer       (system alarm override)   mute alarms           turn off light       tip smoke detector   sound 2 nd  level alarm activate           light       bump smoke detector   sound 2 nd  level alarm           activate light       stabilize or put smoke detector   mute alarm       horizontal   turn off light       smoke enters through vents &amp;   sound 3 rd  level alarm activate       triggers ionization chamber   light       smoke clears in ionization   mute alarm       chamber   turn off light       smoke enters through vents &amp;   sound 3 rd  level alarm activate       triggers photo cell   light       smoke clears in photo cell   mute alarm           turn off light       smoke enters through vents &amp;   sound 3 rd  level alarm activate       triggers ionization chamber and   light       photo cell       smoke clears in ionization   3 rd  level alarm remains on       chamber or photo cell while   light remains on       other smoke detector still       activated       smoke clears in ionization   mute alarm       chamber and photo cell   turn off light       battery voltage level drops   intermittent “chipping” alarm       below first preset level   sounds           and light is activated       battery voltage level drops   1 st  level alarm remains on       below second preset level   light remains on       battery replaced with new one   mute alarm           turn off light       battery voltage drops below   alarm cannot sound       level to operate unit   light cannot come on           microprocessors cannot function                  
 
         [0045]     The above description will enable any person skilled in the art to make and use this invention. It also sets forth the best modes for carrying out this invention. There are numerous variations and modifications thereof that will also remain readily apparent to others skilled in the art, now that the general principles of the present invention have been disclosed.