Patent Document

CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/269,688 filed May 5, 2014, and entitled “USE OF OPTICAL REFLECTANCE PROXIMITY DETECTOR FOR NUISANCE MITIGATION IN SMOKE ALARMS,” which is a continuation of U.S. application Ser. No. 12/727,983 filed Mar. 19, 2010, and entitled “USE OF OPTICAL REFLECTANCE PROXIMITY DETECTOR FOR NUISANCE MITIGATION IN SMOKE ALARMS,” which claims the benefit of U.S. Provisional application for patent Ser. No. 61/162,193, filed on Mar. 20, 2009, and entitled “USE OF OPTICAL REFLECTANCE PROXIMITY DETECTOR FOR NUISANCE MITIGATION IN SMOKE ALARMS,” the entire disclosures of which are hereby incorporated by reference for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to smoke alarms, and more particularly to smoke alarms including proximity detectors for controlling operation of the smoke alarm. 
       BACKGROUND 
       [0003]    Smoke alarms are utilized for detecting and warning the inhabitants of a home or other occupied location of the existence of smoke which may indicate a fire. Upon detection of the smoke by the smoke alarm, the device emits a shrill, loud alarm that notifies all individuals within the area that smoke has been detected and departure from the premises may be necessary. 
         [0004]    While the smoke alarms are very effective at notifying individuals of the possible existence of fire that is generating the smoke, certain types of false alarm indications may often be very annoying to a user. These false alarms may be triggered, for example, by smoke generation within the kitchen during preparation of a meal. This may cause the creation of enough smoke that will set off the smoke alarm causing the loud, shrill alarm. In this case, a fire that is dangerous and out of control is not of concern to the residents so the loud, shrill smoke alarm will provide more of an annoyance than a benefit. Presently, there exists no method for easily discontinuing the loud, shrill alarm other than fanning the atmosphere in the area of the smoke alarm in an attempt to remove the smoke from the area that is causing the smoke alarm to activate or removing the battery or house power from the smoke alarm in order to turn it off Removal of the power source may be difficult as smoke alarms are usually mounted upon the ceiling or other high area of the house or building to provide maximum smoke detection capabilities. 
         [0005]    An additional problem with existing smoke alarms is the battery check or low battery condition. In smoke alarms that are powered by batteries, it is often necessary to periodically check the battery within the smoke alarm in order to confirm that the battery has sufficient charge. This often requires obtaining a ladder or chair for the user to reach the smoke alarm which has been placed in a substantially high location within the home or building to maximize smoke detection capabilities. The user is required to push a button that is located on the smoke alarm to perform a battery check. An audible signal is provided for an indication of whether or not the battery is in need of replacement. 
         [0006]    An additional related problem relates to the low battery condition within a smoke alarm. When the battery reaches a low power condition, the smoke alarm will commonly beep at a low duty cycle of around once per minute. Unfortunately, this beep often occurs in early morning hours when the house temperature is at a minimum and these conditions maximize the low battery condition and increase the likelihood of an alarm. This is of course a most irritating time for this to occur. Additionally, the beep is very difficult to locate since the beep is short and a single high frequency tone. The beep is short to enable up to a week or more of low power battery alert on a mostly depleted battery. The alert transducer uses a single high frequency, typically around 3 kilohertz due to the need to produce a very high output from a small transducer which necessitates the use of a high frequency resonate transducer. Due to the reflections and use of half wavelengths shorter than the distance between the human ears, it is very difficult to localize the source which may present a problem since most homes normally include a number of smoke alarms. 
         [0007]    Thus, there is a need to provide an improved method for temporarily mitigating an undesired activation of a smoke alarm and to provide battery check capabilities within the smoke alarm. 
       SUMMARY 
       [0008]    The present invention, as disclosed and described herein, in one aspect thereof, comprises smoke detection circuitry for detecting smoke and generating a detection signal responsive thereto. Proximity detection circuitry generates a proximity detection signal responsive to the detection of an object within in a selected distance of the smoke alarm. Alarm generation circuitry generates an audible alarm responsive to the detection signal. The audible alarm may be deactivated for a predetermined period of time responsive to at least one proximity detection signal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a block diagram of a ionization type smoke alarm; 
           [0010]      FIG. 2  is a block diagram of an optical type smoke alarm; 
           [0011]      FIG. 3  is a more detailed circuit diagram of an optical type smoke alarm; 
           [0012]      FIG. 4  illustrates a block diagram of a smoke alarm including proximity sensor operation capabilities according to the present disclosure; 
           [0013]      FIG. 5  illustrates the various functionalities associated with the smoke alarm including proximity sensor modes of operation; and 
           [0014]      FIG. 6  is a flow diagram describing the operation of the smoke alarm including proximity sensor modes of operation. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring now to the drawings, wherein like reference numbers are used herein to designate like elements throughout, the various views and embodiments of a smoke alarm having proximity detection operation mode are illustrated and described, and other possible embodiments are described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations based on the following examples of possible embodiments. 
         [0016]    Referring now to the drawings, and more particularly to  FIG. 1 , there is illustrated a functional block diagram of a first type of smoke alarm. The smoke alarm of  FIG. 1  utilizes ionization detection to detect smoke. The alarm generation circuitry  102  is associated with an ionization sensor  104 . The ionization sensor  104  detects particles of smoke using a small amount of radioactive americium  241 . The radiation generated by the americium  241  passes through an ionization chamber within the ionization sensor  104 . The ionization chamber comprises an air-filled space between two electrodes that permit a small constant current between the electrodes. Any smoke that enters the chamber absorbs the alpha particles emitted by the americium  241  which reduces the ionization and interrupts the current between the electrodes. When this condition is detected, the ionization sensor  104  generates an alarm signal to the alarm circuitry  102  that generates an audible alarm signal that is provided to the speaker  106 . Associated with the ionization type smoke alarm is test circuitry  108  that enables testing of the present charge level associated with the battery  110 . The battery  110  provides power to the ionization sensor  104 , alarm generation circuitry  102 , speaker  106  and test circuit  108  to power the smoke alarm. 
         [0017]    Referring now also to  FIG. 2 , there is illustrated an alternative type of smoke alarm circuitry comprising an optical smoke alarm. The optical smoke alarm also includes alarm generation circuitry  202  that is responsive to smoke detection signals provided by an optical sensor  204 . The optical sensor  204  includes a light sensor that includes a light source which may comprise an incandescent bulb or infrared LED, a lens to collimate the light into a beam and a photo diode or other photoelectric sensor for detecting light from the light source. In the absence of smoke, the light passes in front of the detector in a straight line. When smoke enters the optical chamber of the optical sensor  204  across the path of the light beam, some light is scattered by the smoke particles redirecting them at the photo diode or photo sensor, and thus triggering generation of an alarm signal to the alarm circuitry  202 . The alarm generation circuitry  202  will generate the audible alarm signal to the speaker  206  associated with the alarm circuitry  202 . As with the ionization circuit, the optical smoke alarm utilizes a test circuit  208  to test the charge on the battery  210 . The battery  210  is responsible for powering all of the components of the optical smoke alarm including the alarm circuitry  202 , optical sensor  204 , speaker  206  and test circuit  208 . 
         [0018]    As described previously, some issues arising with existing smoke alarms, be they ionization or optical type smoke alarms, arise from the creation of false alarm situations such as, for example, when a small amount of smoke is created within the kitchen due to burning toast, food falling on the heating element of the oven, etc., or the ability to quickly and easily check the battery charge using the test circuitry. Presently, mitigation of an alarm requires disconnection of the power source to the smoke alarm in order to discontinue an undesired alarm. Additionally, any type of test of the battery charge requires pushing of a button on the external surface of the smoke alarm that requires the user to be able to physically touch the smoke alarm. This often presents a great challenge since either removing power sources to discontinue an undesired alarm or pressing a button to perform battery test operations require the user to get out a ladder or stand on a chair to access the smoke alarm placed in a high location to ensure its optimal performance. 
         [0019]      FIG. 3  illustrates a schematic diagram of an optical smoke detection alarm based upon an LDR (light detecting resistor)  302  and lamp  304  pair for sensing smoke. The alarm works by sensing the smoke produced during a fire. The circuit produces an audible alarm from speaker  306  when smoke is detected. When there is no smoke, the light from the lamp  304  falls directly upon the LDR  302 . The LDR resistance will be low, and the voltage across the LDR will be below 0.6 volts. Transistor  308  will be turned off in this state and the circuit is inactive. When there is sufficient smoke to mask the light from the lamp  304  falling on the LDR  302 , the LDR  302  resistance increases and so does the voltage across the LDR. This will cause the voltage at the gate of transistor  308  to increase and turn on transistor  308 . This provides a voltage to power circuit  310  which generates a 5 volt signal to a tone generator  312 . The tone signal from tone generator  312  is amplified by an amplifier  314  which is used to drive the speaker  306 . Diodes  316  and  318  are used to drop the voltage input to the tone generator  312  from the power circuit  310 . 
         [0020]    Referring now to  FIG. 4 , there is illustrated a block diagram of a circuit which enables a user to utilize proximity detection circuitry for temporarily abating an undesired alarm or performing battery test operations rather than using previously described processes. While the implementation with respect to  FIG. 4  describes the use of proximity sensor circuitry  402  within an optical type smoke alarm, the proximity sensor circuitry  402  could also be implemented within the ionization type circuitry described hereinabove. The smoke alarm detection capabilities of the smoke alarm of  FIG. 4  operate in a similar manner to the optical alarm described previously. Alarm generation circuitry  404  generates alarm signals to a speaker  406  responsive to smoke detection signals received from optical sensor  408 . The optical sensor  408  generates the smoke detection signal to the alarm generation circuitry  404  in the same manner as that described previously with respect to the optical smoke alarm of  FIG. 2 . 
         [0021]    The optical sensor  408  in addition to detecting smoke is used for detecting the proximity of a user&#39;s hand or other item in conjunction with the proximity sensor circuitry  402 . The proximity sensor circuitry  402  detects when a hand or for example, a broom or other item are being waved in close proximity to the smoke alarm. The optical sensor  408  comprises a short-range (approximately 6 inches) optical proximity sensor that in conjunction with the proximity sensor circuitry  402  may be used to control operations of the smoke alarm with either the wave of a hand or some other readily available object such as a broom. The test circuitry  410  enables testing of the charge within a battery  412 . The battery  412  provides power to each of the components within the smoke alarm circuit. 
         [0022]    Utilizing a combination of the proximity sensor circuitry  402 , optical sensor  408  and alarm generation circuitry  404 , the smoke alarm may provide a number of proximity controller functionalities. These are generally illustrated in  FIG. 5 . A number of proximity controlled functions  502  may be provided using the proximity sensor  402 . The proximity controlled functions include the alarm mitigation function  504  and the battery test function  506 . The alarm mitigation function  504  enables a temporary discontinuation of the audible alarm in situations when an undesired activation of the alarm has occurred. This would occur for example, when a small amount of smoke created within a kitchen that does not indicate a fire or emergency condition has been created. The proximity sensor of the smoke alarm is activated when an object such as a hand or a broom is brought close to the optical sensor  408 . If the smoke alarm has been activated due to kitchen smoke or other situations that have been resolved by human intervention, proximity detection would enable the user to disable the smoke alarm for a short period of time, such as 3 minutes, to allow the area around the smoke alarm to air out. A double wave or other more complex detection by the proximity sensor circuitry  402  and optical sensor  408  may be accomplished in a short period of time, such as less than 10 seconds in order to enable assurances that the detection was for a desired mitigation of the alarm and not some type of random event occurring during actual smoke detection. 
         [0023]    In order to assist a user in temporarily mitigating the alarm, a momentary change in the audible alarm would be desirable for each proximity event that has been detected by the optical sensor  408  and proximity sensor circuit  402 . This would assist the user in knowing whether they had accurately or inaccurately waved their hand or broom in the area of the smoke alarm and provide for an audible indication of aiming feedback with respect to the proximity detection. After the appropriate combination of proximity detection events have been detected by the optical sensor  408  and proximity sensor circuit  402 , the audible alarm would be temporarily discontinued. 
         [0024]    The smoke alarm commonly beeps at a low duty cycle of around once per minute when the battery  412  has its charge fall below a predetermined level. These beeps can often be very difficult to locate since the beep is short and comprises a single high frequency tone. The beep is short to enable up to a week or more of low battery alerts to be created on an almost depleted battery. The alert transducer uses a single high frequency chirp typically around 3 kilohertz due to the need to produce a very high output from a small transducer. This necessitates the use of a high frequency resonate transducer. Due to the reflections and the use of a half wavelength shorter than the distance between the human ear, it is often very difficult to locate the source requiring the user to check each smoke alarm within the house requiring a great deal of time. 
         [0025]    The battery test functionality  506  enables a battery test operation to be performed on the battery  412  within the smoke alarm without having to manually press a button on the smoke alarm. The battery test functionality  506  can be utilized in two situations. When a low battery charge chirp is being emitted by the smoke alarm, the low battery test functionality  506  may be used to determine whether a particular smoke alarm has a low battery charge or whether the battery presently has sufficient charge. The battery test functionality  506  would similarly be useful for performing the periodic battery charge tests that are required to ensure the smoke alarm is in working operation. 
         [0026]    By utilizing the proximity sensor circuitry  402 , if the smoke alarm has not been activated to indicate detection of smoke, the detection of a single proximity event from a hand or broom by the optical sensor  408  and proximity sensor circuitry  402  initiates a battery check test. If the battery  412  is weak, the test circuitry  410  will cause the production of a distinctive series of beeps or a distinctive tone to indicate a dying battery. If the battery  412  is sufficiently charged, a single short beep of a different tone may be created. Thus, if a user hears a low battery beep, they can use their broom or hand to quickly and easily check all of the smoke alarms within their home without having to climb up on a chair or ladder or remove the devices in order to press a detection button upon the smoke alarm. 
         [0027]    As described previously, smoke alarms generally use either an ionization chamber or optical smoke detection circuitry or a combination of both to detect smoke. These differing techniques have distinct advantages and disadvantages. However, a high performance optical reflective detector implemented within the circuit of  FIG. 4  including proximity sensor circuitry  402  can readily be adapted to detect reflectance from smoke and to provide proximity detection data since both detections are equivalent low reflectance functions. The proximity detector is more sophisticated since it must deal with ambient light while the conventional optical smoke detector does not have to cancel ambient light since it looks for reflections from smoke in an optically baffled compartment which blocks out ambient light but allows the entry of smoke. A reflectance proximity detector can drive two different LEDs, one for proximity detection and the other for smoke detection within the optical sensor  408 . A light pipe can provide a signal from the baffled smoke detector and also from the outside proximity view. Depending on which LED is driven, the proximity detector is either for reflectance above a threshold for either the proximity detection or for smoke and of course giving a different alarm response. Optionally, an auxiliary photo diode can be used for the smoke detector portion to avoid artifacts or issues arising from ambient light. Because the proximity detection technology uses a low duty cycle controller to make proximity detection measurements every second or so, this low duty cycle controller can also be used for the low duty cycle smoke controller which is beneficial for reducing battery charge consumption. 
         [0028]    Referring now to  FIG. 6 , there is illustrated a flow diagram describing the operation of the proximity detection controlled smoke alarm. Initially, at step  602 , the optical sensor  408  and proximity sensor circuitry  402  monitor for a proximity actuation. Inquiry step  604  determines whether there has been a detection of a proximity actuation. If not, control passes back to step  602  to continue monitoring for a proximity actuation. Once a proximity actuation is detected, inquiry step  606  determines if the smoke alarm is presently activated. If so, control passes to inquiry step  608  which determines if a predetermined number of proximity activations have been detected. If not, the alarm tone provided by the smoke alarm may be altered at step  610  and control returns back to step  602  to continue monitoring for additional proximity activations. If inquiry step  608  determines that a predetermined number of proximity actuations have been detected, the smoke alarm is disabled at step  612 . Inquiry step  614  monitors for the expiration of a selected period of time. If the period of time has not yet expired, the process remains at inquiry step  614 . Once the predetermined period of time has expired, control passes to step  616 , wherein the smoke alarm is re-enabled and control passes back to step  602  to continue monitoring for proximity actuation. Once the alarm is re-enabled, the smoke detector can monitor for smoke and react accordingly. 
         [0029]    If inquiry step  606  determines that the smoke alarm is not presently activated, control passes to inquiry step  618  to make a determination if the battery low alarm is presently active for the smoke alarm. If so, a battery low indication is audibly provided from the smoke alarm at step  620 . If the battery low alarm has not been activated, a battery charge check is performed at step  622 . Inquiry step  624  determines whether the battery is in a low charge condition. If not, a battery OK audible indication is provided at step  626  to indicate a sufficient charge and control passes back to step  602 . If inquiry step  624  determines that the battery is in a low charge condition, the battery low indication is provided at step  620  before control passes back to step  602  to monitor for additional proximity actuations. 
         [0030]    The above-described solution provides a low cost intuitive battery alarm control system to limit nuisance alarms within the smoke alarm and enables ease of battery charge checking using a proximity detection control process. The system also improves safety since users often remove batteries or take down smoke alarms that are producing spurious alarms or low battery beeping alarms. Users will also take down unaffected smoke alarms since the user cannot localize the beep associated with the alarm and then do not replace the alarm. Consumers do not check battery levels if the smoke alarm is out of reach. Additionally, use of an optical reflection proximity control system is better than a capacitive proximity system since convenient hand extension devices such as brooms would not work to activate a capacitive sensor which senses a conductive object such as the human hand or body. 
         [0031]    It will be appreciated by those skilled in the art having the benefit of this disclosure that this smoke alarm having proximity detection operation mode provides an improved method for controlling operation of a smoke alarm. It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. On the contrary, included are any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments apparent to those of ordinary skill in the art, without departing from the spirit and scope hereof, as defined by the following claims. Thus, it is intended that the following claims be interpreted to embrace all such further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments.

Technology Category: g