Abstract:
A non-rigid electrical component includes a first layer of a compressible material. The first layer has at least one aperture therethrough. A second layer of an electrically conductive material is positioned on one side of the first layer across the aperture and a third layer of an electrically conductive material is positioned on an opposite side of the first layer across the aperture. The first layer is compressible such that the second and third layers of material may be brought into contact with each other in the aperture of the first layer to complete an electrical connection between the second and third layers upon application of a compression force. The first layer is also made of a resilient material such that when the compression force is removed, the first material expands to separate the second and third layers, thereby breaking the electrical connection.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a “soft” electrical sensor. More particularly, this invention relates to a flexible and compressible sensor that can be incorporated into compressible items where a rigid sensor would be undesirable. The sensor can not only detect compression of the sensor, but can also detect varying degrees of compression, thereby permit responsive actions related to the degree of compression. 
     Numerous types of plush toys (e.g., teddy bears) and items with electronics therein are known in the art. Generally, however, the mechanical and electrical components inside the plush are perceptible by the user of the plush upon squeezing the plush, as they are generally a hard, rigid material, such as plastic and/or metal. This is in contrast to the overall purpose of the plush in the first place, i.e., to be soft. 
     The method and apparatus of the present invention overcomes these and other drawbacks by providing an electrical component which is soft, squeezable, and resilient. In one embodiment a soft sensor is designed for use in a plush toy to identify interaction and even degrees of interaction with the plush toy by a user. As a holder of the plush toy gently squeezes the plush, the sensor initially identifies a first level of compression and thereby identifies it with a gentle hug, at which point the plush may respond with an appropriate audible response. As the holder of the plush squeezes the plush harder, the sensor identifies a greater level of compression associated with a stronger hug and provides for playback of an alternate appropriate audible response. 
     In one embodiment, the sensor may include a pair of conductive foam sheets separated by a non-conductive foam sheet. The non-conductive foam sheet has one or more holes therethrough. As such, the conductive foam sheets are space apart by the non-conductive foam sheet, but the two outer conductive foam sheets may be made to connect in the holes by compressing the two outer sheets together. 
     Further objects, features and advantages of the present invention over the prior art will become apparent from the detailed description of the drawings which follows, when considered with the attached figures. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The features of the invention noted above are explained in more detail with reference to the embodiments illustrated in the attached drawing figures, in which like reference numerals denote like elements, in which  FIGS. 1-16  illustrate several possible embodiments of the present invention, and in which: 
         FIG. 1  is a front side elevation view of a plush toy having a sensor constructed in accordance with an embodiment of the present invention positioned therein in a use environment; 
         FIG. 2  is a front side elevation view of the plush toy of  FIG. 1 ; 
         FIG. 3  is an illustration similar to  FIG. 2 , but with portions of the plush toy cut away to reveal an embodiment of the sensor of the present invention and electrical components therein; 
         FIG. 4  is an illustration similar to  FIG. 3 , but with an alternate arrangement of the electrical component connections; 
         FIG. 5  is a left side elevation view of the plush of  FIG. 2  in a rest position and with a portion thereof cut away to illustrate the sensor in a rest position; 
         FIG. 6  is an illustration similar to  FIG. 5 , but with the plush and the sensor in a compressed position; 
         FIG. 7  is a perspective view of a first embodiment of the sensor of the present invention with a portion of an enclosure cut away for clarity; 
         FIG. 8  is a side elevation view of the sensor of  FIG. 7 ; 
         FIG. 9  is a cross-sectional view taken along the line  9 - 9  of  FIG. 7 ; 
         FIG. 10  is a view similar to  FIG. 9 , but with the sensor in a compressed position; 
         FIG. 11  is an enlarged, fragmentary view of the sensor of  FIG. 10  in the area  11 ; 
         FIG. 12  is an exploded, perspective view of the sensor of  FIG. 7 ; 
         FIG. 13  is a perspective view of a second embodiment of the sensor of the present invention with a portion of an enclosure cut away for clarity; 
         FIG. 14  is side elevation view of the sensor of  FIG. 13 ; 
         FIG. 15  is a cross-sectional view taken along the line  15 - 15  of  FIG. 13 ; and 
         FIG. 16  is an exploded perspective view of the sensor of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in more detail and initially to  FIG. 1 , numeral  10  generally designates a plush item or toy, such as a teddy bear. The plush  10  may be of any configuration or shape, but generally includes a soft fabric outer layer  12  and is generally filled with some type of soft compressible fill material  14 . This well-known combination creates a plush item  10  that children  16  like to hold and/or squeeze, as pictured in  FIG. 1 . 
     This particular plush  10  includes electrical components  18  that allow the plush  10  to interact with the child  16 . The electrical components  18  generally include a battery  20 , a micro-processor  22 , a speaker  24 , a plush hug sensor  26  of the present invention, and a plurality of the wires  28  connecting all of the other electrical components  18  to make an electrical circuit  30 . 
     The battery  20  can be any power source known in the art. When the plush hug sensor  20  is positioned inside a plush item  10 , the power source is preferably a self-contained device, such as the battery  20 . The battery  20 , as is known in the art, is preferably contained inside a battery compartment or housing  32 . As the battery housing  32  is generally necessarily a rigid structure, and an item which users occasionally need access to in order to replace the battery  20 , the battery housing is preferably positioned adjacent the outer layer  12 . Additionally, as children  16  generally hug the torso or trunk  34  of the plush item, rigid or non-soft items are preferably positioned above or below the middle  34  of the plush toy  10 . In the embodiments illustrated in  FIGS. 3-6 , the battery compartment  32  is positioned inside a pocket  36  which is accessed through a rear  38  of the plush  10  near a lower most portion  40  of the trunk  34 . It should be noted that the battery compartment  32  can be positioned anywhere within the plush toy  10 . 
     Similarly, the speaker  24  may be positioned within a rigid housing  42  to protect it from damage. In the illustrated embodiments, the speaker housing  42  is positioned in a head  44  of the plush  10  adjacent or directly behind where the animal figure&#39;s mouth would be such that audio emanating from the speaker  24  appears to be spoken by the plush  10  or emanating from its mouth. 
     The microprocessor  22 , to be protected from damage, may be positioned in either the battery compartment  32  or the speaker housing  42 .  FIG. 3  illustrates an embodiment where the microprocessor  22  is positioned in the speaker housing  42  and  FIG. 4  illustrates an embodiment where the microprocessor  22  is positioned in the battery compartment  32 . 
     The sensor  26 , which has been identified as a plush hug sensor for reasons that will become apparent after the benefit of this full disclosure but which is not constrained for use in a plush or for detecting hugs, is preferably constructed as a multi-layer device. In a first embodiment illustrated in  FIGS. 7-12 , the sensor  26  preferably includes a pair of conductive foam sheets  46 ,  48  separated by a non-conductive foam sheet  50 . While the sensor may be made with only the three layers of foam, preferably, adhesive layers  52  and  54  are positioned intermediate the foam layers to secure the foam layers to one another and to maintain the structural integrity of the sensor  26 , as will be discussed in more detail below. 
     The non-conductive foam  50 , which is intermediate the two outer foam layers  46 ,  48 , includes one or more holes or apertures  56  therethrough, as best illustrated in  FIGS. 9 and 12 . While the intermediate, non-conductive foam layer  50  spaces apart the two conductive foam layers  46 ,  48 , the holes  56  through the non-conductive foam  50  provide an opening through the non-conductive layer  50  where inwardly facing surfaces  58  of the conductive layers  46 ,  48  can connect in abutting contact when moved towards one another. In that regard, the sensor  26  has a normal rest or non-compressed position that is illustrated in FIGS.  5  and  7 - 9 . In this position, as best illustrated in  FIG. 9 , the inwardly facing surfaces  58  of the outer conductive layers  46 ,  48  are spaced apart from one another and do not provide an electrical connection from one layer to another or across the sensor  26 . In this regard, the sensor  26 , in this state, essentially acts as an open switch to prevent the flow of current across the sensor  26  and through the circuit  30 . 
     Because the sensor  26  is compressible (or at least because the two conductive layers  46 ,  48  are moveable towards one another), external forces on the sensor  26 , preferably from opposite sides of the sensor  26  in the form of compression forces, will act to compress the non-conductive foam layer  50  and move the inwardly facing surfaces  58  of the two conductive layers  46 ,  48  towards one another until they are in abutting contact in the areas where the non-conductive foam layer  50  has apertures  56 , as best illustrated in  FIGS. 10 and 11 . Accordingly, the sensor  26  has a second or compressed state where at least a portion of one of the conductive foam layers  46 ,  48  is in abutting contact with a portion of the other conductive foam layer  46 ,  48 . This abutting contact, identified in  FIG. 11  by numeral  60 , makes an electrical connection which permits current to flow through the sensor  26  and from one of the foam layers  46 ,  48  to the other. As such, in the compressed state, the sensor  26  acts as a closed switch to complete the electrical circuit  30 . 
     The conductive foam used in the outer layers  46 ,  48 , has a known resistance per length or distance between connection points. Accordingly, if a piece of the conductive foam were to be placed in a circuit with a contact going in one end of the foam and another out the other end, if the distance between the contacts through the foam was known, a known resistance level could be calculated. The resistance level could be changed slightly by compression of the foam thereby decreasing the resistivity of the foam piece. While the connections to the conductive layers  46 ,  48  of the sensor  26  can be made by inserting wires  28  therein, as illustrated in  FIGS. 3 ,  4  and  8 , the wires  28  can also be connected to the conductive layer by way of a piece of conductive copper tape  62  with a conductive adhesive, as best illustrated in  FIGS. 7 and 12 . 
     With a known resistivity for the conductive foam, the location at which the wires  28  are connected to the outer layers  46 ,  48  will have an effect on the voltage across the sensor  26 . For example, in  FIG. 8 , the leads are wires  28  are connected to the sensor on opposite sides and at opposite ends. Consequently, a single connection point between the outer layers  46 ,  48  towards the upper portion of the sensor in  FIG. 8  will result in a resistance that is similar to a single connection by compression at the lower end of the sensor  26 . Alternatively, if both leads were placed in the sensor on opposite sides at about the same location, the resistance would appear differently if the connection occurred farther away from the leads than if the connection occurred closer to the leads. These differences can be used and incorporated into the responses that are given, depending on the desired purpose of the sensor. 
     In addition to the compressing of the conductive foam changing the resistance through the foam, the amount of surface area connection between the inwardly facing surfaces  58  of the two outer conductive foam layers  46 ,  48  also changes the resistance across the sensor  26  and can be measured as a change in voltage by the micro-processor  22 . In that regard, if contact is only made between the two layers  46 ,  48  through one hole  56  in the non-conductive or insulated foam layer  50 , a first resistivity value occurs that is associated with a first voltage level through the circuit  30 . If, however, more of the sensor  26  is compressed such that contact is made between the two layers  46 ,  48  through multiple holes  56 , as illustrated in  FIGS. 10 and 11 , an alternate and decreased resistance level is provided across the sensor  26  resulting in a second resistance and, in turn, a second voltage through the circuit that can be measured again by the micro-processor  22 . These detected changes correlate with a level of interaction with the sensor  26  and, in turn, changes in a level of interaction with the item, such as the plush toy  10  into which the sensor  26  is inserted. These detected changes can be used to create responses to the changes in interaction such as, for example, varying audio messages that are played back to the user or child  16  by the micro-processor  22  through the speaker  24 . For instance, in one example, a child may gently squeeze the plush toy  10  just enough to compress the sensor  26  sufficiently such that the outer layers  46  and  48  connect with each other through one hole  56 . The micro-processor can notice the change in the circuit  30  from an open circuit to a closed circuit and can associate the resulting voltage through the circuit  30  with an appropriate response message. An exemplary response message would be “Thanks for the gentle hug. Can you give a bear hug too?” Should the child  16  squeeze harder, such that a greater amount of surface area of the two foam layers  46 ,  48  abut one another through multiple holes  56  in the insulation layer  50 , the micro-processor  22  can recognize the resulting voltage change, associated with an increased compression or squeeze of the sensor  26  and output an appropriate response, such as “You did it! Are you a bear too?” It should be noted that other responses, apart from audio responses, may be made based on detected changes by the sensor. Other responses may include for example, but are not limited to, activation or modification of light output, motion or data output based on the sensor readings, as well as changes in volume of audio outputs. 
     The sensor  26  may be placed inside a fabric pouch  64 , similar to a pillow case, with the wire leads exiting the pouch. This assists with assembly of the plush toy  10  and allows for positioning of the sensor  26  in a desired location in the plush by securing, such as by sewing, a portion of the pouch  64  to the outer layer  12 , as illustrated in  FIGS. 5 and 6 . While the sensor  26  has been described as having a use for incorporation into a plush toy for detecting squeezes or hugs thereof, the sensor  26  can be used in a number of environments and should not be limited to one particular use. 
     The adhesive layers  52 ,  54 , as discussed above, work to not only hold the sensor  26  together but to prevent distortion or shrinking/closing of the apertures  56  in the non-conductive layer  50 , thereby keeping them open to permit the opposing layers  46 ,  48  to abut therein. The adhesive layers  52 ,  54  can take the form of a two-sided non-conductive adhesive tape, as illustrated in  FIG. 12 , or may be a liquid, such as a glue, applied via conventional solution coaters. One possible manufacturing method for the embodiment of the sensor  26  illustrated in  FIG. 12  includes using sheets of double-sided tape having a non-adhesive backer applied to both sides of the tape. A sheet of the tape may then have the backer layer removed from one of the sides of the tape to reveal the adhesive surface and placing the tape on one side of a sheet of non-conductive foam. A similar step may be taken by placing a second sheet of adhesive tape on the other side of the non-conductive foam sheet. The three layered resulting assembly may be then passed to a machine where it is die cut to not only form the apertures  56  but to also size the middle layer  50  of the sensor  26 . In this manufacturing method, holes  66  are cut through the double-sided tape that forms the adhesive layers  52  and  54  at the same time as the holes  56  are cut through the insulation layer  50 . As such, the holes  56 ,  66  align. The three layer assembly may then be passed on to have the outer conductive foam layers  46 ,  48  applied thereto by removal of the backing sheets on the outer surfaces of the double sided tape, thereby revealing the adhesive layer on the outer surfaces of the three layered assembly and creating the sensor  26  illustrated in  FIGS. 7 through 12 . 
       FIGS. 13 through 16  illustrate an alternate embodiment of the sensor  26 . In this embodiment, an additional outermost layer of nonconductive foam  68  is secured to an outer surface  70  of the conductive foam layer  46 . The outer layer of nonconductive foam material  68  provides the sensor  26  with increased resiliency and firmness without compromising its soft nature. 
     Many variations can be made to the illustrated embodiments of the present invention without departing from the scope of the present invention. Such modifications are within the scope of the present invention. For example, the circumference, shape, and number of holes  56  may be modified depending on the characteristics desired in the sensor  26 . In that regard, the holes may be round, square, triangular, etc. There may be a single hole or a plurality of holes. Also, the holes may be small or large and the thickness of the insulating layer may be modified. Additionally, while the sensor has been shown as a generally plainer item, the sensor could be constructed as a cylinder or other shapes depending on the desired properties and configuration. Further, while the wires  28  are shown connected to the sensor in one embodiment by way of a coppered tape  62 , other methods, such as two sided conductive tape (carbon infused, conductive polymers, and the like), conductive adhesives including “super glues”, epoxies and other conductive adhesives or other methods known in the art for holding electrical leads in low electrically resistive contact with the conductive foam are acceptable. Similarly, the electrically conductive lead or wire  28  could simply be inserted into an area of the conductive foam and secured therein by applying a conductive adhesive to the lead prior to inserting it into the foam or by applying adhesive to the lead where it exits the foam. Further still, while the conductive and non-conductive layers have been identified as a foam, any compressive or stretchable material with the same conductivity properties will suffice. Other modifications would be within the scope of the present invention. 
     From the foregoing it will be seen that this invention is one well adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the method and apparatus. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the invention. 
     Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative of applications of the principles of this invention, and not in a limiting sense.