Abstract:
An elliptically housed solar powered intrusion detection/notification device having a flashing LED light source and audible human voice alarm activated by a passive infrared (PIR) sensor motion detector in conjunction with a battery recharged via surface mounted photovoltaic cells, and a control circuit coupled to the light source/alarm, the PIR motion detector and the battery.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to security devices. More specifically, the present invention is directed to a solar powered security system providing localized illumination and audible detection notification utilizing infrared intrusion detection. 
         [0003]    2. Description of the Background 
         [0004]    Residential security systems are commonplace in modern homes and typically incorporate a series of sensors to detect the presence of an intruder, plus an indicator for alerting both the intruder and the homeowner or neighbors that a threat has been detected. Home intruders such as burglars typically rely on stealth to complete their crime rather than risk confrontation and apprehension. Consequently, as seen in  FIG. 1 , when intruders are notified that they have detected they are usually deterred from continuing their crime. 
         [0005]    Where a new home is being constructed it is relatively easy to provide 120VAC electrical power to locations where an intrusion detection/notification device may be desirable. However, in existing homes it may be costly or impossible, especially when needed to extend a power to remote locations like sheds, barns, mailboxes and driveways or to other exterior location such as gardens (where animal intruders destroy crops or decorative plantings). Moreover, 120VAC security lights have been known to be tripped, power cut, damage, stolen, etc. With a solar-powered security light, the light can be placed anywhere away from where intruders. Thus a solar-powered light is 100% maintenance free with no energy costs. 
         [0006]    There are known solar powered lighting devices including U.S. Pat. No. 4,782,432; U.S. Pat. No. 4,823,241; U.S. Pat. No. 5,211,470; U.S. Pat. No. 5,217,296, and the present inventor&#39;s own U.S. Pat. No. 20080218088 which describes an easily deployable miniature, LED light unit specifically for home security yard signs. 
         [0007]    While the foregoing devices fulfill their particular objectives none disclose a solar-powered lighting solution with intrusion detection/notification capabilities, that is miniaturized and housed in a suspension-type housing for unobtrusive mounting under the eaves or awnings of residential houses. Such a device should be inexpensive, durable, lightweight, compact, portable and efficient. Moreover, since the device must brightly illuminate a wide area a particular solar-charging miniature LED array is most appropriate that remains off while charging during the day, and illuminates at night, all night. 
         [0008]    The present system provides a self contained intrusion detection/notification device with unique sensor, optical, and electronic systems capable of responding only to radiation from an intruder to announce them using audio and/or visual indicators. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The objects, features, and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which like numbers represent like items throughout and in which: 
           [0010]      FIG. 1  is a perspective view of a preferred embodiment of the security system  2  attached below the eaves of a house. 
           [0011]      FIG. 2  is a front perspective view of a system  2  according to the present invention. 
           [0012]      FIG. 3  is a front perspective view of a system  2  according to the present invention. 
           [0013]      FIG. 4  is a back-view of the system  2 . 
           [0014]      FIG. 5  is a diagram of the arcuate sensor sweep area of a system according to the present invention. 
           [0015]      FIG. 6  is an electrical block diagram of the components of a system according to the present invention. 
           [0016]      FIG. 7  is an electrical circuit diagram of the components of an infrared sensing component of a system according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the exemplary embodiment illustrated in the drawings and described below. The embodiment disclosed is not intended to be exhaustive or limit the invention to the precise form disclosed in the following detailed description. Rather, the embodiment is chosen and described so that others skilled in the art may utilize its teachings. It will be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and modifications in the illustrated device, the methods of operation, and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates. 
         [0018]    The invention is a self-contained intrusion detection and enunciation device that utilizes an optical platform employing low power infrared sensing technologies to identify intrusion threats and automatically announce them by illuminating the monitored area, and by providing an audible, verbal announcement to the intruder that his presence has been noticed. 
         [0019]    As seen in  FIG. 1 , a preferred embodiment of the system  2  is shown which may be readily attached in a suspended configuration below the eaves or awnings of a house, or may be attached to walls, fences, etc. The system  2  employs a passive infrared (PIR) sensing device to detect intruders and illuminate a high-intensity LED array and audio-enunciator circuit to deter them, a self-sustaining solar charging battery circuit for powering the foregoing, all of which enclosed in a low-profile elliptical housing with wide-angle Fresnel lens. The foregoing components are herein described in detail. 
         [0020]    As seen in  FIGS. 2 and 3 , the low-profile elliptical housing  10  contains and protects all the system components. Housing  10  is a unitary composite-polymer enclosure preferably formed in a one-shot open-molding process to define a substantially elliptical form factor with a flattened back surface area (obscured, see  FIG. 4 ), elliptical side walls  14  and elliptical frontal aperture  15 . The housing  10  is preferably formed from a tough, weather resistant and impact resistance polymer such as acrylonitrile butadiene styrene (ABS) plastic or a similar polymer that may color modified to a preferred color to match (or contrast) residential architectural elements and may be modified to enhance resistance to UV light degradation. 
         [0021]    The housing  10  has a generally semi-circular cross-section around the horizontal axis and an elliptical cross section about the vertical axis providing a semi-spherical enclosure which permits a 120° arc of monitored space without obstruction from the housing  10 . The upper quadrant of the hemispherical shape of the housing  10  presents a natural forward incline for positioning of a photovoltaic solar cell  16  at an upward/forward incline directly toward the sun. The integrally-molded square receptacle for the photovoltaic solar cell  16  is slightly offset forwardly from center for maximum exposure. Opposing through holes  12 A,  12 B are formed from front to back of the housing  10  to provide the option of permanent mounting by the provision of one or (preferably) at least two screws through the housing  10 . Semi-permanent mounting may alternately be accomplished with mastic or adhesive films attached to the flattened back surface area (see  FIG. 4 ) which is preferably defined by a removable battery cover  17  that conforms to a battery receptacle formed in the rear of housing  10 . 
         [0022]    With renewed reference to  FIG. 2 , a speaker grill  17  is formed in the lower quadrant of the hemispherical housing  10  by a plurality of evenly-spaced perforations through the ABS shell. In addition, an aperture is co-located at one side of the lower hemisphere for seating a protruding on/off detent switch  13  by which a user can deactivate the voice enunciator circuit. An elliptical-shaped convex transparent lens  20  is seated flush in the elliptical frontal aperture  15 , and the convexity of lens  20  conforms to the semi-spherical contour of the housing  10  to maintain a uniform overall shape. The specific elliptical shape of housing  10 , the seamless integrally-molded form factor, and flush seating of conformal lens  20  in housing  10  greatly enhances the moisture-resistance of the system  2  and weatherability thereof by sealing the housing and protect the internal components including the IR sensor  18  and LED light sources  22  (described below) from the elements. 
         [0023]    The lens  20  is made from an infrared transparent plastic material and is positioned within the housing aperture to direct and focus thermal radiation to the infrared sensor  18  from a wider field of view than would be possible with a non-refracting cover in the aperture  15 . The lens  20  is preferably made from polyethylene (HDPE) which is largely transparent to IR radiation in the range of 5 to 15 micrometers typically emitted by humans, and highly translucent to visible light. The lens  20  is a Fresnel type lens which is a plano-convex lens defined by inclined surfaces or “grooves” which allow the bulk of the lens to be collapsed into shallower profile while retaining its optical characteristics. Such a lens is lighter and less prone to absorption losses than a full depth lens and, when constructed of polyethylene, is relatively flexible and durable so as to readily seal the aperture  15 . 
         [0024]      FIG. 5  is a plan view illustrating the field of coverage for a preferred embodiment in which the Fresnel lens  20  collects infrared light from a monitored arc of included angle α which, in the preferred embodiment spans 120°. The IR sensor has a maximum sensing distance ranging from approximately 15-20 feet at the midpoint of the monitored arc to approximately 10-13 feet at the periphery, depending on the selected lens and varying with environmental conditions. Alternate lenses  20  can be utilized to expand the monitored arc α to substantially 180° but with a diminished sensing distance. 
         [0025]    The Fresnel grooves are interrupted by integrally-molded lenses/windows  19  in lens  20  to ensure that light from the LED&#39;s  22  (described below) is not obscured or overly dispersed. The lens  20  is preferably formed as an integrally-molded component including both the Fresnel grooves and windows  19  such that the IR sensors  18  and LED light sources  22  can share the aperture  15  with the lens  20  further serving to seal the housing and protect the sensors and light sources from the elements. Window  19  may be optically refractive (i.e. a lens) so as to shape the wave front emitted from the LED light sources or maybe simply transparent. Where window  19  is a refractive lens the LED light source is preferably positioned within the housing  10  at the focal point of the lens. 
         [0026]    The infrared (IR) sensor  18  is positioned behind the lens  20  and is preferably a passive infrared (PIR) sensing device capable of detecting within its field of view the approach or movement of objects (such as a person, animal or vehicle) emitting thermal energy in the form of infrared radiation. The PIR motion sensor  18  is preferably a pyroelectric device that detects motion by measuring changes in the thermal energy levels emitted by surrounding objects but requiring very little power (600 mAh/60 hours). One or more pyroelectric sensor elements within IR sensors  18  are made of a crystalline material that generates an electric charge when exposed to infrared radiation. A change in the amount of infrared radiation striking the crystalline element(s) due to the appearance or movement of a thermally emitting object changes the voltage generated by the crystal or the difference between the voltages generated between crystals where more than one crystal is used. 
         [0027]    The change in absolute or differential voltage is amplified and measured to identify motion and generate an indicative detection signal. Differential IR motion detectors utilizing more than one pyroelectric sensor elements are less prone to false alerts due to changes in ambient IR conditions affecting all elements equally (such as a flash of lightening). Thus, motion can be detected by identifying changes in electrical properties that result from sudden change in the surrounding IR patterns. When motion is detected the PIR sensors  18  output a signal to an internal logic controller (described below). 
         [0028]    An LED array comprising a plurality of LED light sources  22  commonly-mounted on a circuit board is positioned directly behind the lens  20 . Two LED light sources are provided in the preferred embodiment with one each position behind the two windows  19  within the lens  20 . An LED array packaged on a circuit board and operable from 3 VDC is preferred, and is commercially available from a variety of companies including Lumex, Inc.™ Although the LED light sources  22  may preferably provide blue light, they may alternatively provide light at one or more colored wavelengths or white light. A specular mirror reflector may preferably be positioned behind the LED light sources  22  within the housing aperture to maximize the emissive efficiency of the light sources and provide the maximum possible ambient light in the protected area in response to intrusion detection. 
         [0029]    Speaker grill  17  is characterized by a series of holes or apertures in the housing  10  order to permit audibalization of an alarm signal by a piezoelectric speaker or horn  26  situated within the housing  10 , and as described below. Additionally, the pushbutton switch  13  provided on the downward facing horizontal portion of the housing  10  is a push-button detent switch encased in a rubber helmet protruding from the housing  10  to enable the user to easily toggle between a sound mode (in which an audible/voice alarm is sounded) and a silent mode (no audible alarm) when the housing  10  is mounted overhead. 
         [0030]    With reference to  FIG. 6 , a schematic block diagram of the system  2  components within the housing  10  is depicted. Solar cell  16  is a commercially-available 1″×1″ photovoltaic cell externally seated and adhered to the housing  10  and electrically connected via power distribution module  30  to a rechargeable battery  35  (preferably two 1.5V AAA nickel metal-hydride batteries providing a combined 600 milliamp-hours). Rechargeable battery  35  is connected to photovoltaic cell  16  through an inline diode and is recharged directly by the photovoltaic cell  16  during periods in which the cell  16  is exposed to direct sunlight (40,000-100,000 lux). The solar cell  16  is capable of fully recharging the rechargeable battery in 8 hours of direct sun exposure, and the diode prevents overcharging as is well-known. A blocking diode may also be utilized as is known to prevent battery discharge. 
         [0031]    The rechargeable battery  35  is capable of powering the IR sensor  18  for 60 hours of monitoring time between charges. Thus, a fully charged system  2  is capable of monitoring an area for five consecutive twelve hour nights with little or no available direct sunlight for charging during the intervening days. Monitoring time is reduced by power expended to illuminate/alarm the monitored area after a motion detection event. A power switch  36  is provided to disconnect the battery from the system when operation is not desired, and switch  36  may be mounted inside the battery compartment shown in  FIG. 2 . Also provided is a photocell  27  which indicates ambient light conditions to the circuit controller  21  and prevents the controller  21  from activating the light source/alarm during daylight hours in order to minimize the battery charging time and maximize the area monitoring time. Photocell  27  is preferably mounted behind lens  20  where it is exposed to ambient visible light and may be comprised of a photosensitive resistor (R 3  in  FIG. 7 ) that has low resistance in strong ambient light. 
         [0032]    The PIR sensors  18  described above are connected to an infrared processor  19  which identifies the change in electrical charge from sensor  18  and signals the circuit controller  21  that motion has been sensed. An exemplary circuit diagram for the infrared processor  19  is provided in  FIG. 7 . 
         [0033]    Circuit controller  21  is also electrically connected via the power distribution module  30  to the battery  35  and energizes the LED light sources  22  in response to a motion detection signal from the IR processor  19  thereby illuminating the monitored area and calling attention to the fact of the intrusion and detection. Circuit controller  21  preferably flashes the LED light sources  22  in an on-off-on pattern for maximum notoriety to both the intruder and homeowner or passers by. Circuit controller  21  further energizes the speaker  26  circuit when motion is detected. The speaker  26  audiblizes a warning that motion has been be detected. Circuit controller  21  includes on-board memory  29  storing a digital sound clip file (way, mp3 or otherwise) comprising a combination of an alarm sound interspersed with a voice-enunciated warning such, for example, “WARNING . . . THIS AREA IS MONITORED.” In response to a motion detection signal from the IR processor  19  the circuit controller  21  broadcasts a combination of an audible alarm in the form of a siren or horn type noise, interspersed with a human voice emulation or recording stating authoritatively that intrusion has been detected and/or the area is monitored, in attempt to scare off the intruder. 
         [0034]    The circuit controller  21  maintains power to the light source and audible alarm for a fixed time, preferably approximately 15 seconds, before disconnecting the power source until the next motion detected signal. Additionally, when the system  2  is turned on the circuit controller  21  introduces a short (3 second) delay before a motion detection signal is emitted, thereby giving the homeowner time to vacate the monitored area. 
         [0035]    It should now be apparent that, once armed, the system  2  will detect any person entering a monitored area during the nighttime when the infrared energy emitted from the intruder&#39;s body is focused onto the PIR sensors  18 . As the intruder moves, so does their heat signature, and this moving hot spot causes the PIR sensors  18  to signal an intrusion to the circuit controller  21 , which then emits the combination light/siren/voice alarm to effectively deter and scare them away. The particular combination of a siren/horn-type alarm with periodic voice warnings, plus flashing high-intensity LED lights is a far more effective warning and deterrent than prior art devices. With no maintenance whatsoever, the system  2  keeps intruders away, protects home and family, and protects property. 
         [0036]    Having now fully set forth the preferred embodiment and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims and may be used with a variety of materials and components. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.