a bed 10 as shown in fig1 - 2 can include a frame 12 and a mattress 14 . the frame 12 can be a standard sized bed frame , such as a frame for holding a twin , full , queen , or king mattress . the frame 12 can hold the mattress 14 off the ground , such as at a level allowing a user to easily mount and dismount the mattress 14 . while shown as a standard bed frame , the frame 12 can alternatively be a crib , hospital bed , or another support structure for the mattress 14 . also , the mattress 14 can be set directly on the ground or a floor , in which case no frame 12 is necessary . the mattress 14 can have a standard size ( e . g ., a twin , full , queen or king size ) or be sized for use in a crib , on a hospital bed , or in another environment . the mattress 14 can include a bottom padding layer 16 , the sensing layer 18 , and a top padding layer 20 , with the sensing layer 18 sandwiched between the padding layers 16 and 20 as shown in fig1 and 2 . the mattress 14 can be an integral , inseparable unit , or the mattress 14 can be formed by stacking separate layers 16 , 18 and 20 . the bottom padding layer 14 can be a firm layer for providing support . for example , the bottom layer 14 can include firm high density foam ( e . g ., visco - elastic polyurethane foam sometimes referred to as memory foam ), another type of foam , a conventional mattress , a box spring , a fluid bladder , a straw - filled pad , a feather - filled pad , a sawdust - filled pad , a spring - based pad , and / or another material that offers flexibility and / or softness . a top side 22 of the bottom layer 14 can partially define a recess 24 sized to receive the sensing layer 18 . the recess 24 can have a depth less than a height of the sensing layer 18 when inflated to a normal pressure as shown in fig2 . the recess 24 can have one open end 26 at a foot of the mattress 12 as shown in fig1 . the open end 26 can allow a cord , hose , or other structure to easily access the sensing layer 18 , and the open end 26 can be on a different side of the mattress 12 than shown in fig1 and 2 . the top padding layer 20 can be a comfort layer , which can be softer ( i . e ., less firm ) than the bottom padding layer 14 . the top layer 20 can include high density foam ( e . g ., memory foam ), another type of foam , a conventional mattress , a fluid bladder , a straw - filled pad , a feather - filled pad , a sawdust - filled pad , a spring - based pad , and / or another material that is offers flexibility and / or softness . a bottom side 28 can partially define the recess 24 . alternatively , the recess 26 can be entirely defined by just one of the bottom layer 16 and the top layer 20 . also , depending on the thickness of the air bladder 18 and the firmness of the bottom and top layers 16 and 20 , among other considerations , the bladder 18 can fit between layers 16 and 20 without the need for the recess 26 . the sensing layer 18 as shown in fig3 includes a fluid bladder 30 , a pressure sensor 32 configured to sense a fluid pressure within the fluid bladder 30 , and a controller 34 . the sensing layer 18 is also shown coupled to a control unit 38 and a pump 39 . however , instead of using the pump 39 to inflate the bladder 30 , another inflation mechanism can be provided . for example , the bladder 30 can be self - inflating by including a foam or other material within the bladder 30 . as another example , compressed gas ( e . g ., compressed air or co 2 ) can be used to inflate the bladder 30 . also , as is explained below in greater detail , the pressure sensor 32 can detect pressure changes caused by , for example , a pulse and / or breath of a user on the mattress 14 , and the controller 34 can determine the user &# 39 ; s heart rate , respiration rate , and / or other vital signs based on the detected pressure changes . the fluid bladder 30 can hold air or another fluid , such as water , gel , another gas , or a combination thereof . the fluid bladder 30 can be sized to extend over a large portion of the top side 22 of the bottom layer 16 , such as substantially the entire top side 22 of the bottom layer 16 as shown in fig1 . alternatively , the bladder 30 can cover a smaller area of the top side 22 than as shown , such as an area of the top side 22 above which the torso of a user is expected to be positioned . thus , the size of the fluid bladder 30 can allow the fluid bladder 30 to sense pressure changes over a wide range of positions of the user on the mattress 14 . that is , even if the pressure sensor 32 is far from a source of a pressure change ( e . g ., a beating heart or inhaling or exhaling lungs of the user ), the pressure change can create a wave within the bladder 30 propagating the pressure change to the sensor 32 . also , the bladder 30 can be shaped to achieve a balance between allowing air to pass across the bladder 30 and providing the bladder 30 with a large area such that pressure changes are not dampened too greatly before reaching the bladder 30 . allowing air to pass across the bladder 30 can be beneficial for multiple reasons . first , passing air can dissipate heat from the top layer 20 , thereby reducing a feeling of warmth common among foam mattresses . second , passing air can remove moisture , thereby reducing the likelihood of mold growth within the mattress 14 . to achieve this balance , the bladder 30 as shown in fig3 defines a plurality of apertures 36 arranged in a grid pattern . the apertures 36 can allow heat and moisture to pass across the bladder 30 . due to the arrangement of the apertures 36 , the bladder 30 defines transverse and lengthwise paths shown , respectively , by lines 35 a and 35 b in fig3 . waves caused by pressure changes input to the top layer 20 can propagate along the paths 35 a and 35 b to the sensor 32 . thus , the bladder 30 as shown in fig3 can both allow moisture to pass between the layers 16 and 20 and can prevent pressure input to the top layer 20 from being dampened before reaching the sensor 32 . however , the bladder 30 can have a different shape from illustrated while still achieving similar functionality . for example , fig4 shows a bladder 40 including longitudinal slots 42 for allowing moisture to pass the bladder 40 . the bladder 40 also includes longitudinal connectors 44 for allowing waves to propagate to the sensor 32 in the bladder 40 . the sizes of the slots 42 and connectors 44 can be a trade off between providing a large area for the passage of moisture and providing the bladder 40 with a large area to prevent pressure changes from being dampened before reaching the bladder 40 . as another example in which the shape of the bladder 30 can different from as shown in fig3 , the fluid bladder 30 can include multiple discrete compartments , in which case each compartment can include one of the pressure sensors 32 . for example , if the mattress 14 is large enough for two users , the mattress 14 can include two discrete compartments , each including its own sensor 32 , for separately detecting the vital signs of the two users . however , the pressure detected by a single sensor 32 can indicate vital signs of multiple users , and the controller 34 can perform a pattern recognition algorithm or other calculation to determine the users &# 39 ; respective vital signs as explained in more detail below . as shown in fig6 , the sensing layer 18 can be subject to a shearing force is a lateral force applied to the top padding layer 20 . as a result , the sensing layer 18 can be deformed to the shape shown in phantom at 18 ′. the height 31 of the fluid bladder 30 can be great enough such that when the sensing layer 18 undergoes an expected amount of deformation , the top of the sensing layer 18 does not contact the bottom of the sensing layer 18 . contact between the top and bottom of the sensing layer 18 can allow force to be transmitted directly from the top padding layer 20 to the bottom padding layer 16 , in which case the pressure sensor 32 may not accurately detect pressure changes in the fluid bladder 30 . the height 31 can also be based on the expected weight of the top padding layer 20 and any users that rest thereon , as well as the expected pressure within the fluid bladder 30 . under normal conditions ( e . g ., a normal user weight and a normal top layer 20 weight ), the fluid bladder 30 portion of the sensing layer 18 can have an approximately 1 . 0 ″ height . as mentioned above , the pressure sensor 32 can be configured to sense a fluid pressure within the fluid bladder 30 . for example , the pressure sensor 32 can be inside the bladder 30 . as another example , the pressure sensor can be in a portion of the pump 39 in fluid communication with the bladder 30 , and thus in a portion of the pump 39 having a pressure corresponding to a pressure in the bladder 30 . the sensor 32 can include a semiconductor pressure sensor or another type of pressure sensor . additionally , other types of sensors , such as a temperature sensor , can also be included . the sensor 22 can output a pressure signal α to the controller 34 . further , the pressure signal a can indicate the whether or not a person is lying on the bladder 30 , the heart rate of a person lying on the bladder 30 , the respiration rate of a person lying on the bladder 30 , other movement ( e . g ., rolling or limb movement ) of a person lying on the bladder 30 , the temperature of the fluid in the bladder 30 , and vital signs because all these can be factors of the pressure within the fluid bladder 30 . the controller 34 , which can include a memory and a cpu for executing a program stored on the memory , can control the pump 39 to produce pressurized air . for example , the controller 34 can control the pump 39 in response to the pressure signal a such as by instructing the pump 39 to inflate the bladder 30 when the controller 34 determines the pressure in the bladder 30 is below a set amount . while the controller 34 is shown as inside the bladder 30 , the controller 34 can alternatively be part of the control unit 38 or otherwise located outside the bladder 30 . the controller 34 can be hard - wired to the sensor 32 and / or pump 39 , in wireless communication with the sensor 32 and / or pump 39 using , e . g ., a standard wireless protocol ( ieee 802 . 11 , bluetooth , etc . ), or the controller 34 can communicate with the sensor 32 and / or pump 39 in another way . additionally , the controller 34 can analyze the pressure signal a to determine a heart rate , respiration rate , and / or other vital signs of a user lying or sitting on the mattress 12 . as explained above , when a user lies on the top layer 20 , each of the user &# 39 ; s heart beats and breaths can create a force on the top layer 20 that is transmitted to the bladder 30 . as a result of the force input to the bladder 30 from a heart beat or breath , a wave can propagate through the bladder 30 to the sensor 32 . the sensor 32 can detect the wave , and the pressure signal a output by the sensor 32 can thus indicate a heart rate or respiratory rate of a user . as a result , the bladder 30 can prevent waves from being dampened by foam prior to reaching the sensor 32 . to overcome a dc offset in the pressure signal α , the pressure signal α can pass through a circuit splitting the signal into a dc coupled path and an ac coupled path , and the ac coupled path can be amplified and filtered . the controller 34 can perform a pattern recognition algorithm or other calculation based on the amplified and filtered pressure signal α to determine the user &# 39 ; s heart rate and respiratory rate . for example , the algorithm or calculation can be based on assumptions that a heart rate portion of the signal α has a frequency in the range of 0 . 5 - 4 . 0 hz and that a respiration rate portion of the signal α has a frequency in the range of the range of less than 1 hz . the controller 34 can also be configured to determine other characteristics of a user based on the pressure signal α , such as blood pressure , tossing and turning movements , rolling movements , limb movements , weight , or the identity of the user . further , the controller 34 can receive signals from other sensors ( e . g ., a temperature sensor ). the controller 34 can output a status signal β indicating the characteristics of the user ( e . g ., heart rate and respiratory rate ) to the control unit 38 . the control unit 38 can include a transmitter , a display screen , and controls . the transmitter can relay the status signal β to a database or other source . the transmitter can be a wireless transmitter operating using a standard wireless protocol ( e . g ., ieee 802 . 11 , rf , bluetooth , or 3g ), though the transmitter can alternatively be hardwired to the remote source using a phone line , ethernet line , or other connection . as a result , the database can store sleep information produced as a result of the status signal β , and the user can be alerted to sleep issues based on long - term sleep trends or provided with other communications regarding the user &# 39 ; s sleep ( e . g ., an alarm warning of apnea ), fitness level , cardiovascular condition , or other health information . the display screen can display information relayed in the status signal β , such as a sleep score based on the user &# 39 ; s heart rate , respiratory rate , amount of time spend in rem sleep , total time in bed , and other considerations . the controls can be used to control the operation of the sensor 32 and / or controller 34 . for example , the controls can be used to increase the pressure in the bladder 30 , instruct the sensor 32 and / or controller 34 to operative in a privacy mode in which data is not detected , retained , displayed , transmitted , and / or analyzed , or to communicate with the database to obtain sleep information ( e . g ., sleep trends , sleep scores from previous nights , sleeping tips ). the database can alternatively or additionally be accessible using a computer , e . g ., via the internet . the pump 39 can be a rotary type pump or another type of pump . the pump 39 can be fluidly coupled to the bladder 30 via a hose . however , the pump 39 can alternatively be integral with the mattress 14 such that a hose is not necessary . the mattress 14 can have a different configuration from as shown in fig1 - 2 . as such , while the bottom layer 16 , sensing layer 18 , and top layer 20 are shown as being discrete structures , alternative configurations are possible . for example , fig5 illustrates a foam mattress 60 including a top portion 62 and a bottom portion 64 connected by a linking portion 66 . the mattress 60 defines an envelop 68 for receiving the sensing layer 18 . as additional examples , the sensing layer 18 can be sealed within the mattress 14 during the manufacture of the mattress 14 , or the sensing layer 18 and top layer 20 can be integral . also , in another example , the bladder 30 can be positioned between a foundation ( e . g ., the frame 12 ) and the bottom layer 16 of the mattress 14 . while the invention has been described in connection with what is presently considered to be the most practical example , it is to be understood that the invention is not to be limited to the disclosed example but , on the contrary , is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims , which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law .
a sleeping monitoring system includes a first padding layer . a fluid bladder is beneath the first padding layer . a sensor is in fluid communication with the fluid bladder . the sensor is configured to output a vital sign signal .