Cross-Reference to Related Applications

This application claims the benefit of U.S. Provisional Application 62/532,915 filed July 14, 2017, which is incorporated by reference in its entirety herein for any and all purposes.

Background

Technical Field

The present subject matter relates to motion sensors, and more specifically to housings for passive infrared motion sensors.

Background Art

Motion Sensors utilizing infrared (IR) radiation detectors are well known. Such sensors are often used in security systems or lighting systems to detect movement in a monitored space. A passive infrared detector (PIR) detects changes in IR radiation and can be manifested as one of a variety of types of devices, including, but not limited to, a pyroelectric detector, a bolometer, or a thermopile. Changes in IR radiation detected may be are due to temperature differences between a warm object, such as a warm blooded animal, and its background environment as the warm object moves through that environment. Upon detection of motion, motion sensors typically activate an audible alarm such as a siren, turn on a light, and/or transmit an indication that motion has been detected. An example PIR-based motion sensor is described in US Patent 9,569,953, issued on Feb. 14, 2017 and entitled Motion Sensor, which is incorporated by reference herein.

A typical passive infrared detector utilizes a pyroelectric or piezoelectric substrate with a detector element that consists of conductive areas on opposite sides of the substrate, acting as a capacitor. As the substrate changes temperature, charge is added or subtracted to the capacitor, changing the voltage across the capacitor. The amount of mid-IR radiation that hits the detector element determines the temperature of that area of the substrate, and therefore, the voltage across the capacitor that makes up the detector element. Some motion sensors utilize an infrared detector that includes multiple detector elements. To reduce the chance of false alarms, some infrared detectors include a pair of equally sized detector elements of opposing polarities. Non- focused out-of-band radiation, as well as ambient temperature changes or physical shock, is equally incident on both detector elements, thus causing the signals from the equal and opposite elements to roughly cancel one another.

Many motion sensors incorporate an optical array (comprised of optical elements, such as lenses, focusing mirrors, and so on) to be able to monitor a large space with a single infrared detector. The optical array directs the IR radiation from multiple monitored volumes onto the infrared detector, which sometimes includes filters to minimize the radiation outside of the desired mid-infrared range from reaching the infrared detector. Each of the monitored volumes is typically a pyramidal shaped volume extending into the space to be monitored with the apex of the pyramid at the motion sensor. Concentrations of radiation from each of the pyramids are projected by the optical arrays on to the infrared detector where they are superimposed, and different regions of the infrared detector are heated based on the amount of IR radiation received from the superimposed images. The detector elements on the infrared detector react to the localized heating by changing their voltage. The resultant change in voltage across the detector elements is monitored and used to detect motion in the space being monitored.

Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate various embodiments. Together with the general description, the drawings serve to explain various principles. In the drawings:

FIG. 1 A and IB show different embodiments of motion sensors;

FIG. 2A and 2B show different views of an embodiment of a motion sensor cover;

FIG. 3 A and 3B show cross-sectional views of two embodiments of motion sensors;

FIG. 4A and 4B show cross-sectional views of two embodiments of motion sensors with different optical elements;

FIG. 5 shows the monitored volumes of an embodiment of a motion sensor;

FIG. 6 shows yet another embodiment of a motion sensor; and

FIG. 7 shows a block diagram of an embodiment of an electronics subassembly for a motion sensor.

Detailed Description

In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures and components have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present concepts. A number of descriptive terms and phrases are used in describing the various embodiments of this disclosure. These descriptive terms and phrases are used to convey a generally agreed upon meaning to those skilled in the art unless a different definition is given in this specification. Some descriptive terms and phrases are presented in the following paragraphs for clarity.

A pyroelectric material is a material that temporarily generates a voltage as it is heated or cooled. If the temperature remains constant, the voltage may gradually disappear due to leakage current, depending on the pyroelectric material used. Examples of pyroelectric materials include the mineral tourmaline and the compounds gallium nitride, cesium nitrate, cobalt phthalocyanine, and lithium tantalite. A piezoelectric material is a material that generates a voltage in response to mechanical stress. Examples of piezoelectric materials include tourmaline, quartz, topaz, cane sugar, and sodium potassium tartrate tetrahydrate. Some materials exhibit both pyroelectric and piezoelectric properties and localized heating of a piezoelectric material can cause mechanical stress which then generates a voltage. Therefore, while the detailed physical properties of pyroelectric materials and piezoelectric materials are different, the two terms are used as synonyms herein and in the claims. Thus, a reference to a pyroelectric material includes both pyroelectric materials and piezoelectric materials.

An infrared radiation detector, or simply infrared detector or IR detector, is a component having one or more outputs to provide information related to warm objects in a field of view of the infrared detector. An infrared detector has one or more detector elements on a pyroelectric substrate. The detector elements receive electromagnetic radiation, such as mid-infrared radiation, and receive a pyroelectric charge from the substrate which is then exhibited at the outputs of the infrared detector. Mid-infrared radiation has a wavelength of about 6-14 microns A motion sensor is a system for detecting motion in a monitored space. A motion sensor includes one or more infrared detectors, an optical system to direct electromagnetic radiation from the monitored space onto the infrared detector(s), and circuitry to receive the information related to motion from the infrared detector(s) and take action based on that information. Any type of action can be taken, but various embodiments take actions such as, but not limited to, sounding an audible alarm, turning a light on or off, or sending a message indicating that motion was detected. A monitored space may include monitored volumes which intersect the monitored space. A monitored volume is a volume in space that has electromagnetic radiation from the volume, such as infrared light, directed onto a single detector element of the infrared detector.

Motion sensors often utilize an IR-opaque housing to contain the IR detector and associated electronic circuitry of the motion sensor. An example motion sensor 110 is shown in FIG. 1 A mounted on a wall 101 with a front view 110F and a side view 110S. The motion sensor 110 includes a front housing 111 and a base 113 that are separate pieces and join at mating line 123 after the motion sensor 110 is assembled. Because most housing materials are opaque to mid-IR radiation, in order for the detector of the motion sensor 110 to receive radiation from monitored volumes, an opening may be included in the housing 111 to accommodate mounting an IR-transmissive window 115. In some embodiments, the window 115 may simply allow the IR radiation to pass through to optical elements inside of the motion sensor 110 but other embodiments may integrate optical elements into the window 115 such as a molded-polymer multi-Fresnel-lens array. At the places where the opening of the housing 111 meets the window 115 a visible mating line 121 may be created. The mating lines 121, 123 can be minimized, but are nearly impossible to make completely invisible on motion sensors of such construction.

One technique to eliminate visible mating lines is to construct the housing of the motion sensor from a material that is substantially transparent to infrared radiation and to construct housing of the motion sensor from a single molded piece, which may be referred to as a unitary housing. FIG. IB shows a front view 150F and a side view 150S of an embodiment of a motion sensor 150 which has a unitary housing 151. The housing 151 consists of a single piece formed from a material substantially transparent to mid-infrared radiation. This allows the IR radiation to pass through the housing 151 to an IR-detector inside of the housing 151. Although some embodiments may use a base as shown in FIG. 1 A that mates with the housing 151 and leaves visible mating lines, the motion sensor 150 includes a base 153 with a substantially flat mounting surface on its exterior. The base 153 is located entirely within an opening of the housing 151 and includes holes, a mounting bracket, or some other mechanism which allows that motion sensor 150 to be mounted with its mounting surface against the wall 103. This completely eliminates visible mating lines as a substantially flat surface of the housing 151 abuts the wall 103. While the motion sensor 150 is shown mounted on a wall 103, in some embodiments, the motion sensor 150 may be placed with its mounting surface on a table, the ground, or other horizontal surface. Note that if the motion sensor 150 is placed with its substantially flat mounting surface on a horizontal surface, no physical attachment between the motion sensor 150 and the mounting surface may be necessary, as gravity may be sufficient to keep the motion sensor 150 in place. As used hereinafter and in the claims, the term "horizontal" mean "parallel to the mounting surface, and "vertical" means "perpendicular to the mounting surface."

It is common for the cover 151 to be molded using a plastic-injection molding processes. Molds using in an injection molding process must have a positive draft angle. Without a positive draft angle, the part might not be able to be removed from the mold. As such, the shape of the cover 151 is limited to shapes whose horizontal-cross-sectional profile size decreases with distance from the base, so that lines tangent to the base's exterior side walls lie at an obtuse angle 161 with respect to the nominal base-to-mounting-surface plane.

Some applications of a motion sensor may want to minimize the visibility of the motion sensor so that people are not aware that their motion is being monitored. It was determined by the inventors that building a motion sensor cover that masquerades as another object, or emulates another object, would make the motion sensor much less noticeable. As one example, a motion sensor that looks like a stone or a candle sitting on a shelf would not arouse suspicion that motion was being monitored. Removing or obscuring mating lines between parts, and having the ability to form the parts with arbitrary shapes allows such motion sensor covers to be created.

In some embodiments, it may be useful to create a motion sensor that has a cover that is wider than the base and has no visible mating lines. The cover may be created using a blow- molding process using a material, such as high-density polyetheline (HDPE), which is substantially transparent to mid-infrared radiation. Even though blow molding may use a multi- part mold that is separated to remove the part which may leave mold lines, those lines can be minimized by careful construction of the mold and/or even eliminated by a secondary process such as sanding/polishing or painting the cover after it is molded. The cover may have a body that is wider than the opening in the cover, similar to a bottle. The opening can be is used to insert an electronics subassembly into an interior cavity of the cover. A base, which may be matched in size and shape to the opening in the cover, can provide a mounting surface for the motion sensor once the base is mated to the opening of the cover. The base may be completely inserted into the cover in some embodiments, or it may extend from the cover somewhat. The overhang of the larger cover over the edges of the base make the base harder to see and the lack of mating lines between parts can add to an Organic' feel for the motion sensor if created in a non-traditional shape, which may also be asymmetric. The motion sensor may be mounted on a wall or set on a flat surface, such as a table or shelf or placed in any other appropriate location, which may include being on the floor or ground. In some cases visible-light reflecting IR- transparent pigments may be added to the cover material before (or painted on after) the cover is molded to produce a visibly-colored IR-transparent cover. The combination of visual de- emphasis of the base, the lack of straight mating lines between parts, and pigment in the cover allows the PIR motion sensor to not resemble a typical motion sensor, but rather look like a more natural object, such as a river rock.

Reference now is made in detail to the examples illustrated in the accompanying drawings and discussed below.

FIG. 2A shows a bottom view 200B and a side view 200S of an embodiment of a motion sensor cover 210 and FIG. 2B shows a cross-sectional view 200C of the motion sensor cover 210 as taken through line B:B of view 200B of FIG. 2 A. The different figures show different aspects of the same motion sensor cover 210 so not every element of the motion sensor cover 210 is shown in all views. The cover 210, which may also be referred to as a housing, consists of a single piece formed from a material substantially transparent to mid-infrared radiation and having an opening 212 to an interior cavity 214. A single molded piece may also be referred to as a unitary piece. Mid-infrared (TR) radiation has a wavelength of about 6-14 microns and the material used may be substantially transparent to any sub-range of those wavelengths or to the entire range. Substantially transparent for a wavelength of electromagnetic radiation may be interpreted to mean that over 25% of the radiation at that wavelength is transmitted through the material, although in some embodiments, a material with transmissivity for mid-infrared radiation of over 33%, over 50%, over 66%, over 75%, or over 80% may be used. In at least one embodiment, the cover 210 may be made with high-density polyethelene (HDPE) and may be molded using a blow-molding process. In some embodiments, the cover 210 may be made with a material that includes both a moldable polymer (e.g. HDPE) and a pigment that is substantially transparent to mid-infrared radiation and may also reflect visible light to change the appearance of the cover 210. In other embodiments, the cover may be painted with a paint containing pigments that are substantially transparent to mid-infrared radiation and may also reflect visible light to change the appearance of the cover 210.

The cover 210 can have any shape and size, including asymmetric shapes, depending on the embodiment, but the opening 212 and the internal cavity 214 may be sized to allow at least a portion of an electronic subassembly to be positioned in the internal cavity 214. The cover 210 may be shaped to emulate another object in some embodiments, and the cover 210 may be shaped to emulate a stone as shown in FIG. 2A/B. In some embodiments, the cover may also include a base having a substantially flat mounting surface and adapted to fit the opening 212. The cover 210 may be placed on a flat surface 201 and a maximal external perimeter 222 of the cover 210 may be thought of as projecting to a plane of the flat surface 201, which may be a mounting surface. The maximal external perimeter 222 has the shape of a shadow cast by the cover 210 on the flat surface 201 from a point light source at an infinite distance directly above the cover 210. The cover 210 may be in contact with the flat surface 201 in an area 216 (shown with vertical cross-hatching) between an opening external perimeter 224 of the housing 210 and the opening 212. In embodiments, the a maximal external perimeter 222 of the housing, as projected to a plane of a mounting surface of the motion sensor 210, extends beyond an opening external perimeter 224 of the housing 210 at the opening 212, as projected to the plane of the mounting surface. This can be seen in FIG. 2A as the maximal external perimeter 222 completely surrounds the opening external perimeter 224; thus the maximal external perimeter 222 extends beyond the opening external perimeter 224 at all points of the maximal external perimeter 222. Note that in the embodiments shown in FIG. 1 A and IB, the maximal external perimeter does not extend beyond the opening external perimeter; the maximal external perimeter and the opening external perimeter have exactly the same size and shape in those embodiments.

The unitary piece of the cover 210 has an opening 212 and an opening plane 203 can be defined as a plane that intersects an external edge of the opening 212 in at least three places. In some embodiments, such as the embodiment shown in FIG. 2A/B, the external edge of the opening 212 is a planar curve that lies in the opening plane 203, which is coincident with the surface 201. A maximum width 236 of the cover 210 is found. The maximum width is measured as a maximum distance across the maximal external perimeter 222. A cross-sectional plane through the location of maximum width 248 and perpendicular to the opening plane 203 is defined and a minimum width 238 of the unitary piece on the cross-sectional plane between a location 248 of the maximum width 236 and the opening plane 203 is identified. Both the maximum width 236 and the minimum width 238 are measured parallel to the opening plane 203 in the cross-sectional plane. In embodiments, the maximum width 236 is greater than, not merely equal to, the minimum width 238. While in some embodiments, the minimum width 238 is located on the opening plane 203 as shown in FIG. 2B, in other embodiments, the minimum width may be located at any point between the location 248 of the maximum width and the opening plane 203.

In some embodiments, the cover 210 includes a substantially flat side 216 with an opening 212 to the interior cavity 212. An exterior surface of a wall 218 of the cover 210 may form an acute angle 232 with a plane 203 of the substantially flat side 216 at a point where the wall 218 is adjacent to the plane 203. This creates an overhang of the cover 210 at the substantially flat side 216 of the cover 210.

In some embodiments, cover 210 includes a unitary housing molded from a material substantially transparent to mid-infrared radiation and having a substantially flat side 216 with an opening 212 to an interior cavity 214. The unitary housing 210 may be shaped to intersect with a vector 242 normal to a plane 203 coincident with the substantially flat side 216 at a point outside of a closed curve 224 formed by an exterior of a contact area of the substantially flat side 216 on the plane 203.

FIG. 3 A shows a cross-sectional view of an embodiment of a motion sensor 301. The motion sensor 301 includes a housing 310 consisting of a single piece formed from a material substantially transparent to mid-infrared radiation. In some embodiments, the material may be a high-density polyethelene and/or the material may include a pigment that reflects visible light and is substantially transparent to mid-infrared radiation. The housing 310 may be molded using a blow-molding process or any other process suitable to form the housing 310. The housing 310 may be shaped to emulate another object, such as a stone, in some embodiments. The housing 310 also has an opening 312 to an interior cavity 314.

The motion sensor 301 also includes an electronics subassembly 320 positioned at least partially within the interior cavity 314 of the housing 310. The opening 312 may be sized to allow at least a portion of the electronics subassembly 320 to pass into the interior cavity 314. In some embodiments, the electronics subassembly 320 may be fully contained in the interior cavity 314. A structure 318, such as a slot, a peg, fingers, or any other appropriate structure, may be integrally formed in the housing 310 and adapted to position the electronics subassembly 320 in the interior cavity 314.

The motion sensor 301 also includes a base 330 having a substantially flat mounting surface 332 and adapted to fit to the opening 312 in the housing 310. In some embodiments, the base 330 may be designed to screw into the opening 312, snap into the opening 312, have a friction fit in the opening 312, be held in the opening 312 with a fastener, or be adapted to fit in the opening 312 by any other mechanism or method. In some embodiments, the base 330 is designed to be flush with a flat surface of the housing 310 so that any mating line between the housing 310 and the base 330 is invisible once the motion sensor 301 is placed on a mounting surface. The electronics subassembly 320 includes a passive infrared detector 322 having a plurality of detector elements and positioned on the electronics subassembly 320. The electronics subassembly 320 is located within the interior cavity 314 of the housing 310. The electronic subassembly 320 includes additional electronic componentry 324, which may be coupled to the passive infrared detector 322 to process signals generated by the passive infrared detector 322 and determine whether motion of a warm object has occurred in a space monitored by the motion sensor 301.

The motion sensor 301 also includes a plurality of optical elements 340 positioned to focus mid-infrared radiation from a plurality of monitored volumes in space onto the plurality of detector elements of the infrared detector 322. The optical elements 340 may include, but are not limited to, a convex lens, a concave lens, a Fresnel lens, an array of Fresnel lenses, a reflecting element, a prism, an optical splitter, an optical combiner, or any combination thereof. The optical elements 340 may be held in place by a structure 341, may be integrated into the electronics subassembly 320, may be attached to the housing 310, may be integrated into the housing 310, or may be otherwise included in the motion sensor 301.

The housing 310 has a maximum width that is greater than a minimum width of the housing 310 between the maximum width and the opening 312, wherein the maximum width and the minimum width are measured parallel to the substantially flat mounting surface 332 in a cross-sectional plane that is perpendicular to the substantially flat mounting surface 332, such as the cross-sectional plane used for FIG. 3 A. In some embodiments, an external edge of the opening 312 is a planar curve. The minimum width may be found in some embodiments, such as the embodiment shown in FIG. 3 A, on a plane of the planar curve.

FIG. 3B shows an alternative embodiment of a motion sensor 306. The motion sensor 306 includes a housing 360 formed from a material that is transparent to mid-infrared radiation. In the embodiment, shown, the housing 360 may be formed using an injection molding process. The housing 360 includes an opening 362 to an interior cavity 364 that is sized to accept an electronics module 390. The electronics module 390 may include an infrared detector and other electronics suitable to detect motion by a warm object through a monitored area. The motion sensor 306 also includes an optical subsystem which directs infrared radiation from monitored volumes to the infrared detector. The optical subsystem may be included in the electronics module 390, molded into the housing 360, or included separately in the motion sensor 306, depending on the embodiment. In the embodiment shown in FIG. 3B, the electronics module 390 includes a base with a substantially flat mounting surface. The electronics module 390 extends from the housing 360 so that a portion 392 of the electronics module 390, or base, is visible. Even though the mating line between the housing 360 and the base (i.e. electronics module 390) is visible, it is difficult to see as it is obscured by the overhang 368 of the housing 360 over the base.

FIG. 4A shows a horizontal cross-sectional view of an embodiment of a motion sensor

401 with optical elements (i.e. lenses 442-446) molded into the housing 410 of the motion sensor 401. The motion sensor 401 includes a unitary housing 410, a base 430, and an electronic subassembly 420 in the internal cavity 414 of the housing 410. The electronic subassembly 420 includes an infrared detector 422.

The motion sensor 401 collects infrared radiation from monitored volumes about the motion sensor 401 to use for detecting motion of warm objects near the motion sensor. The infrared radiation from a monitored volume may be focused by an optical element onto a detector element of the infrared detector 422. A first lens 442, a second lens 444, and a third lens 446 are optical elements shown in FIG. 4A. The motions sensor 401 can monitor any number of monitored volumes using any number of optical elements, depending on the embodiment.

In the motion sensor 401, at least one of the one or more optical elements 442-446 is integrally formed into the housing 410. All three lenses 442-446 shown are molded, or integrally formed, into the housing 410. In embodiments, any combination of optical elements that are integrally formed into the housing and optical elements separately provided may be used. The first lens 442 focusses the IR radiation 452 from a first monitored volume onto a detector element of the IR detector 422, the second lens 444 focusses the IR radiation 454 from a second monitored volume onto a detector element of the IR detector 422, and the third lens 446 focusses the IR radiation 456 from a third monitored volume onto a detector element of the IR detector 422. Depending on the embodiment, the IR radiation 452-456 from the three monitored volumes may be focused on three different detector elements, or on the same detector element, of the IR detector 422. So a motion sensor 401 may include at least one lens integrally formed in the unitary piece (i.e. the housing 410) and positioned to focus mid-infrared radiation from a monitored volume in space onto predetermined location within the interior cavity 414, which may contain a detector element of an IR detector 422. In some embodiments, IR radiation from outside of a monitored volume may be blocked by the addition of an IR-blocking element which may include a piece of metal, a piece of plastic made from an IR-blocking material, or IR- blocking paint applied to certain areas of the housing 410, such as on the inside surface of the housing 410 between the three lenses 442-446. FIG. 4B shows a vertical cross-sectional view of an embodiment of a motion sensor 406 with optical elements (i.e. reflecting elements 482, 484) molded into the housing 460 of the motion sensor 406. The motion sensor 406 includes a unitary housing 460, a base 474, and an electronic subassembly 470 in the internal cavity 464 of the housing 460. The electronic subassembly 470 includes an infrared detector 472.

The motion sensor 406 includes one or more optical elements integrally formed into the housing, those being a first reflector 482 and a second reflector 484. The motion sensor 406 may include any number of additional optical elements not visible in the cross-sectional view.

Because the material used for the housing 460 is transparent to mid-infrared radiation, an IR- reflecting material must be added to the integral reflectors 482, 484 molded into the housing 460. This IR reflecting material may be an IR-reflective paint, a metallic foil, or any other suitable material. As long as the shape of the reflector is created by the molded feature of the housing 460, a reflector can be considered to be integral to the housing 460 even if another material is applied to actually reflect the IR radiation.

FIG. 4B shows IR radiation 492 from a first monitored volume reflected and focused by first reflector 482 on a detector element of the IR detector 472. IR radiation 494 from a second monitored volume is reflected and focused by second reflector 484 on a detector element of the IR detector 472. Depending on the embodiment, the IR radiation 492, 494 from the two monitored volumes may be focused on a single detector element or separate detector elements of the IR detector 472.

FIG. 5 shows a top view 500T and a side view 500S of monitored volumes of an embodiment of a motion sensor 510. Embodiments of a motion sensor 510 may have any number of monitored volumes 520-551 arranged in any number of tiers. Each monitored volume can have any shape and can subtend any number of degrees of azimuth and elevation from the motion sensor 510. The motion sensor 510 includes a passive infrared detector having a plurality of detector elements. The passive infrared detector may be positioned on an electronics subassembly of the motion sensor 510 and may be located within an interior cavity of the housing of the motion sensor 510.

A plurality of optical elements may be positioned to focus mid-infrared radiation from the plurality of monitored volumes 520-551 in space onto the plurality of detector elements. In the embodiment of FIG. 5, a first tier of monitored volumes 520-531 is shown in solid lines and the second tier of monitored volumes 540-551 is shown in broken lines in view 500T. Other tiers of monitored volumes that may be positioned above or below the first tier and the second tier are not shown in view 500T for clarity. The side view 500S only shows the monitored volumes closest to a center of the monitored space, first tier monitored volumes 520, 526 and second tier monitored volumes 540, 545, with the other monitored volumes omitted for clarity. While the plurality of monitored volumes 520-551 in space are distributed through 360 degrees of azimuth about the motion sensor 510 in the embodiment shown, other embodiments may have different coverage, such as over 180 degrees of azimuth. Some embodiments may distribute the monitored volumes through 90, 180, or 270 degrees of azimuth around the motion sensor 510. Different embodiments may distribute the monitored volumes through different ranges of elevation as well, depending on the application. A motion sensor 510 made to look like a rock to sit on a level surface at waist level may only provide one or two tiers of monitored volumes projecting out from horizontal to slightly above horizontal. A motion sensor designed to sit on the ground may include more than two tiers of monitored volumes to cover a larger elevation range.

FIG. 6 shows a front view 600F and a side view 600S of yet another embodiment of a motion sensor 600. The motion sensor 600 includes a housing 610 consisting of a single piece formed from a material substantially transparent to mid-infrared radiation and having an opening to an interior cavity. The motion sensor 600 also includes a base 613 having a substantially flat mounting surface and adapted to fit to the opening in the housing 610. The substantially flat mounting surface of the base 613 is shown against the wall 601. The motion sensor 600 also includes an electronics subassembly positioned at least partially within the interior cavity of the housing 610. The opening, interior cavity, and electronics subassembly cannot be seen in either view of FIG. 6, but are similar to the embodiments shown in FIG. 3A/B and FIG. 4A/B.

The opening of the housing 610 is located in a surface of the housing 610 that mates with the base 613 at mating line 623. A maximum width 636 of the housing 610 is determined to be found at the vector 626 which goes from one tip of the housing 610 to the opposite tip of the housing 610. A cross sectional plane may be defined as the plane that contains the vector 626 and is perpendicular to the substantially flat mounting surface of the base 613 which is shown against the wall 601. Thus the cross-sectional plane would be parallel to the viewing plane of view 600S through the center of the motion sensor 600. A minimum width 638 of the housing 610, as measured in the cross-sectional plane between a location 626 of maximum width and the opening, is then found at location 628. The housing 610 of the embodiment of the motion sensor 600 has a maximum width 636 that is greater than a minimum width 638 of the housing 610 between a location 626 of the maximum width and the opening. Note that the housing 610 of the motion sensor 600 has a location 628 of the minimum width that is not located on the surface of the housing 610 that includes the opening. In other embodiments, such as the housing of FIG. 2A/B, the minimum width of the housing between the location of the maximum width and the opening on a cross-sectional plane perpendicular to the mounting surface is at the surface that includes the opening.

FIG. 7 shows a block diagram of an embodiment of an electronics subassembly 710 for a motion sensor 700. The phrase "electronics subassembly," as used herein and in the claims, denotes electronic circuitry with a physical structure and while the electronics subassembly may include software, the phrase is not used herein to denote a block of code or other non-physical structure. The embodiment of the electronics subassembly 710 of the motion sensor 700 includes an infrared detector 730 that has a first set of detector elements 732, 734 and a second set of detector elements 736, 738. The motion sensor 700 also includes an optical system 704. The optical system 704 includes a plurality of optical elements positioned to focus mid-infrared radiation 706, 708 from a plurality of monitored volumes in space onto the plurality of detector elements 732-738. In some embodiments, the electronics subassembly 710 may include the optical system 704, but in other embodiments, the optical system 704 may be separate from the electronics subassembly 710 and may be integrated into a housing of the motion sensor 700 or included as a separate component or components of the motion sensor 700.

The electronics subassembly 710 includes as a processor 711 coupled to the infrared detector 730. Memory 712, which can store computer code 720, is coupled to the processor 711 in embodiments, and the processor 711 can read the computer code 720 from the memory 712 and execute the computer code 720 to perform one or more of the methods to detect motion based on the output of the infrared detector 730. A wireless network interface 714 is coupled to an antenna 716 as well as to the processor 711 in some embodiments to allow radio frequency messages to be sent and/or received by the motion sensor 700 over a wireless computer network such as, but not limited to, a Wi-Fi ^® network or a Zigbee ^® network. Other embodiments include different types of circuitry 710 that may or may not include a processor 711, but may include hard-wired or specialized circuitry to perform one or more methods of motion detection.

Unless otherwise indicated, all numbers expressing quantities, properties, measurements, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about." The recitation of numerical ranges by endpoints includes all numbers subsumed within that range, including the endpoints (e.g. 1 to 5 includes 1, 2.78, π, 3.33, 4, and 5).

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. Furthermore, as used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. As used herein, the term

"coupled" includes direct and indirect connections. Moreover, where first and second devices are coupled, intervening devices including active devices may be located there between.

The description of the various embodiments provided above is illustrative in nature and is not intended to limit this disclosure, its application, or uses. Thus, different variations beyond those described herein are intended to be within the scope of embodiments. Such variations are not to be regarded as a departure from the intended scope of this disclosure. As such, the breadth and scope of the present disclosure should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and equivalents thereof.