Patent Description:
<CIT> discloses an ear cup with a microphone apparatus which comprises an inner cup portion, for forming a noise damping space, and an outer cup portion for forming a space for accommodating electronics and/or a current source. The inner cup portion and the outer cup portion are separated by a partition. The inner cup portion has a pocket and two opposingly located recesses in which a bracket for a microphone is disposed. Over the microphone, a windshield is provided, this protecting the microphone from being damaged and also damping wind noise. The windshield has an outer configuration that may be seen as a continuation of the outer cup portion, in order to prevent turbulence in the region of the windshield. The windshield is produced from a porous material, which is surrounded by a mounting frame having nap catches for engagement in snap catches; <CIT> discloses a hearing protection system with talk-through having a pair of rigid earcups enclosing a microphone, amplifier and speaker. A concha simulator, having a volume simulating that of the concha of a human ear, is acoustically coupled to the microphone, and also to the outside through an opening in the earcup. By coupling the microphone to the concha simulator, instead of directly to the outside, the acoustic response of the talk-through more accurately represents the hearing of a user.

The invention is directed to a hearing protection device according to claim <NUM>. Further aspects of the invention are defined in the dependent claims.

In some embodiments, a hearing protection device comprising a noise sensor assembly includes a noise sensor comprising a microphone electrically coupled to a printed circuit board (PCB). In some embodiments, the noise sensor assembly comprises a housing dimensioned and configured to be fixably disposed at or proximate an aperture defined in an outer surface of an external casing of the hearing protection device. In some embodiments, the housing comprises an inner surface defining an axial bore. In some embodiments, a distal end of the axial bore is configured to acoustically communicate with an external environment via the aperture. In some embodiments, the housing defines a noise sensor receiving portion comprising a slot configured to engage the PCB of the noise sensor. In some embodiments, the slot of the housing is configured to retain the noise sensor, such that the microphone faces the axial bore. In some embodiments, in an instance in which the noise sensor is engaged with the housing, the noise sensor is sealed against the housing. In some embodiments, the axial bore of the housing is dimensioned and configured to slidably receive a calibration tool to form an airtight seal with the inner surface of the housing. In some embodiments, the housing further defines a securing portion at a distal end, the securing portion adapted to contact and secure the housing with respect to a portion of the outer surface of the hearing protection device. In some embodiments, the noise sensor assembly can further comprise an internal dust protector disposed between the noise sensor receiving portion of the housing and the noise sensor, and wherein the internal dust protector is disposed between the microphone and the axial bore. In some embodiments, the housing comprises at least one of a vibration attenuation material and a noise dampening material. In some embodiments, in an instance in which the noise sensor is engaged with the housing, the noise sensor is retained within the noise senor receiving portion and abuts the slot.

In an example useful for understanding the present invention, an ear cup for a hearing protection device is disclosed. The hearing protection device can comprise an external casing defining an aperture. The ear cup can comprise a noise sensor comprising a microphone electrically coupled to a printed circuit board (PCB) and a housing fixably disposed at or proximate the aperture defined by the external casing. The housing can comprises an inner surface defining an axial bore. A distal end of the axial bore is configured to acoustically communicate with an external environment via the aperture. The housing defines a noise sensor receiving portion comprising a slot configured to engage the PCB of the noise sensor. The slot of the housing is configured to retain the noise sensor, such that the microphone faces the axial bore. In an instance in which the noise sensor is engaged with the housing, the noise sensor is sealed against the housing, and the noise sensor and the housing seal the aperture defined by the external casing. The ear cup can further comprise a removable securing collar. The external casing comprises a first portion and a second portion, the second portion defining the aperture configured to sealably retain the removable securing collar, the second portion configured to sealably engage the first portion such that the first portion, the second portion, and the removable securing collar seal the aperture in the external casing. The noise sensor receiving portion of the axial bore has a first inner diameter and the distal end portion of the axial bore has a second inner diameter less than the first inner diameter. The ear cup can further comprise a removable sealing collar configured to sealably retain the housing at or proximate the aperture defined by the external casing, the removable securing collar comprising an opening such that the distal end of the axial bore of the housing is configured to acoustically communicate with the external environment via the aperture of the external casing and the opening of the removable sealing collar. The ear cup can further comprise a removable sealing collar configured to be retained by the aperture, wherein the axial bore of the housing is configured such that when the removable securing collar is removed and the calibration tool is slidably inserted into the axial bore of the housing, the calibration tool forms an airtight seal with an inner surface of the axial bore of the housing. The ear cup can further comprise an external dust protector disposed between the housing and the removable securing collar. The housing further comprises a securing portion disposed about the axial bore, the securing portion comprising a first securing portion at a distal end of the housing having a first outer diameter and a second securing portion proximal of the first securing portion, the second securing portion have a second outer diameter less than the first outer diameter, the first securing portion and the second securing portion defining a flange and recess configured to secure the housing relative to the external casing. In an instance in which the noise sensor is engaged with the housing and the housing is sealably disposed directly or indirectly at or proximate the aperture of the external casing of the ear cup, and the ear cup is sealably engaged to a wearer's head about the wearer's ear, an internal volume of the ear cup is substantially airtight.

In an example useful for understanding the present invention, a method for calibrating a noise sensor of a hearing protection device is described. The hearing protection device can comprise an external casing defining an aperture, a noise sensor comprising a microphone electrically coupled to a printed circuit board (PCB) and a housing fixably disposed at or proximate the aperture defined by the external casing. The housing of the hearing protection device can comprises an inner surface defining an axial bore. A distal end of the axial bore of the housing of the hearing protection device can be configured to acoustically communicate with an external environment via the aperture. The housing of the hearing protection device can define a noise sensor receiving portion comprising a slot configured to engage the PCB of the noise sensor. The slot of the housing of the hearing protection device can be configured to retain the noise sensor, such that the microphone faces the axial bore. In an instance in which the noise sensor is engaged with the housing of the hearing protection device, the noise sensor can be sealed against the housing and the noise sensor and the housing can seal the aperture defined by the external casing of the ear cup. The ear cup can further comprise a removable securing collar configured to retain the noise sensor and/or the housing in place in or proximate the aperture. The method can comprise at least disposing a calibration tool through the aperture via the axial bore of the housing such that an interior of the calibration tool and the microphone are part of a closed system. The method can comprise emitting, by the calibration tool, a calibrating sound having predetermined sound characteristics. The method can comprise receiving, using the microphone, one or more detected sound characteristics of the calibrating sound. In an instance in which a comparison of the one or more detected sound characteristics of the calibrating sound received by the microphone and the sound characteristics of the calibrating sound is indicative of a calibration error, calibrating the noise sensor relative to the calibrating sound.

The accompanying drawings, which constitute a part of the description, illustrate embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention.

In the field of hearing protection, hearing protection devices such as earmuffs may be used to protect a wearer's ears from excessive noise exposure. Such hearing protection devices may provide a passive and/or active noise dampening or noise cancellation effect for the wearer, often in an effort to reduce the total noise exposure for a wearer to below a regulated or suggested acute or chronic exposure limit. For instance, an <NUM> hour maximum daily exposure time may be associated with a noise exposure level of about <NUM> decibels (dBA), while a person may be limited to <NUM> hours of exposure time per day for a noise exposure level of <NUM> dBA, <NUM> minutes for a noise exposure level of <NUM> dBA, and seven minutes for a noise exposure level of <NUM> dBA. By wearing such hearing protection devices, a wearer is able to reduce their noise exposure level, thereby lengthening the maximum daily exposure time such that the wearer can, for example, remain in a higher ambient noise working environment for a longer period of time under such exposure limit regulations. In some embodiments discussed herein, to perform active noise cancellation and/or verify that the hearing protection device is effectively preventing noise exposure during use, one or more noise sensors can be placed in or about the hearing protection device (e.g., on or in an ear cup of a pair of earmuffs). Since these noise sensors must be quite small while also being effective, micro electro-mechanical system (MEMS) microphones can be used as the noise sensors. Embodiments of the present disclosure facilitate such noise sensors, and may reduce exposure to dust and other contaminants, may measure noise exposure in a manner that is true to the wearer's actual exposure, and may be calibrated reliably and/or without substantial disassembly of the hearing protection device while having a small footprint in the hearing protection device and being cost effective.

Microphones, such as MEMS microphones, for use as a noise exposure sensor in ear muffs or other such hearing protection can often comprise a vibrating diaphragm and a back electrode, forming a capacitor integrated on a silicon wafer, which thereby realizes the acoustic-electric conversion. Such a capacitive microphone may be provided with through holes on its back electrode in order to balance the pressure between the vibrating diaphragm and the back electrode. The microphone of such a structure, especially when the cavity about the microphone is sealed and filled with air, has higher acoustic impedance compared to the traditional microphone, and thereby has higher noise attenuation. Since a sealed, air-filled cavity about the microphone can be an important factor in achieving accurate detection of a calibrating noise during in situ calibration, such calibration of the noise sensor microphone and/or a printed circuit board thereof, especially in small and/or complex electronic equipment such as hearing protection devices, may be difficult or impossible for conventional hearing protection devices without significant disassembly of the hearing protection device, or may be completely impossible.

Systems, apparatuses, and methods disclosed herein generally relate to hearing protection devices and noise exposure sensor housings for the same. In some embodiments, a system can include an ear cup for a hearing protection device that defines an aperture on an exterior casing or other such surface. In some embodiments, the ear cup can further include a housing fixably disposed at or proximate the aperture and defining an axial bore therethrough. In some embodiments, the housing can have a proximal portion of the axial bore that is defined in part by a slot or ledge such that the proximal portion is configured to receive a microphone or other such sensor. In some embodiments, the housing can have a distal portion of the axial bore having an inner diameter that is less than the inner diameter of the proximal portion. In some embodiments, the ledge can be defined by the portion of the axial bore at the transition between the narrower distal portion and the wider proximal portion. In some embodiments, the ledge can be formed as a surface facing the proximal end of the housing. In some embodiments, the proximal portion of the axial bore can have a wider inner diameter at the transition point from the distal portion to the proximal portion, the transition point defining the ledge. In some embodiments, the inner diameter of the proximal portion can be smaller at one or more points proximal the transition point such that the slot is formed. In some embodiments, the slot can be the portion of the proximal portion or of the axial bore in general that has the largest inner diameter such that the noise sensor can be retained in that portion against axial movement by a reduced inner diameter both distal the slot and proximal the slot. In some embodiments, a narrower region of the proximal portion of the axial bore proximal the slot can be at least partially open in a radial direction, meaning a region of an outer wall of the housing aligned with the narrower region of the proximal portion can extend only part of the way around the axial bore, such that one or more components of the noise sensor can extend out radially from the proximal portion of the axial bore at a location proximal the slot. In some embodiments, the distal portion can be configured to receive ambient noise from the environment outside the ear cup and communicate that ambient noise to the microphone or other such sensor disposed and retained within the proximal portion (also known herein as the noise sensor receiving portion) of the housing. In some embodiments, the microphone or other such sensor disposed within the proximal portion of the housing can be connected to one or more printed circuit boards (PCB) having a somewhat planar structure or any other suitable form factor. In some embodiments, some or all of one or more PCBs may be flexible. In some embodiments, the one or more PCBs can include a microphone PCB operably coupled to the microphone or other such sensor and a flexible PCB operably connected to the microphone PCB.

In some embodiments, the ear cup can further include an internal dust protector disposed between the microphone and the housing at the proximal end of the distal portion of the axial bore such that the microphone can be exposed to ambient noise communicated through the distal portion of the axial bore without being exposed or with only slight exposure to contaminants such as dust from the environment outside the ear cup. In some embodiments, the ear cup can further include a removable securing collar disposed on and/or at or proximate the aperture of the external casing of the ear cup in such a way as to secure the housing at or proximate the aperture. In some embodiments, the removable securing collar can define an opening through a portion, such as the center, of the removable securing collar. In such a way, in some embodiments, the ambient noise from the environment outside the ear cup can be freely communicated through the opening of the removable securing collar, into the distal portion of the axial bore, and to the microphone or other such noise sensor assembly disposed within the proximal portion of the axial bore of the housing. In some embodiments, the ear cup can further include an external dust protector disposed within, on, or about the aperture of the external casing of the ear cup, between the distal end of the housing and the removable securing collar. In some embodiments, the internal dust protector and the external dust protector can together prevent contaminants such as dust and other debris common to construction sites and other similar environments from reaching the microphone and other electronics and circuitry within the ear cup.

In some embodiments, the ear cup can further include an ear pad dimensioned and configured to be sealably disposed to a wearer's head about a wearer's ears. In some embodiments, the ear pad can include or be made from a cushioning material, such as a deformable foam or rubber material such that ear pad has a noise dampening effect for the wearer when properly wearing the hearing protection device. In some embodiments, in addition to enclosing the wearer's ear within the ear cup and providing comfort, the ear pad can serve a similar purpose as the internal dust protector and/or the external dust protector, which is to at least reduce and possibly prevent the communication of dust and other contaminants into the ear cup, when properly worn by the wearer. In some embodiments, therefore, an interior space defined within the ear cup by at least the ear pad, the external casing of the ear cup, the housing disposed at or proximate the aperture of the external casing, and the microphone or other such sensor disposed within the proximal portion of the axial bore of the housing can be airtight or substantially airtight when properly worn by the wearer.

In some embodiments, the distal portion of the axial bore of the housing can be configured and dimensioned such that a noise sensor calibration tool can be securely inserted within the axial bore and sealed against the axial bore for microphone calibration by removing the removable securing collar, removing the external dust protector, and slidably disposing the noise sensor calibration tool into the axial bore via a distal opening of the axial bore. In some embodiments, securely engaging the noise sensor calibration tool within the axial bore for calibration of the microphone or other such noise sensor can ensure that ambient noise from the environment outside the ear cup is not detected by the microphone during calibration and that a calibrating noise emitted by the noise sensor calibration tool during in situ calibration of the microphone or other such noise sensor remains substantially within the axial bore and is not emitted to the interior space of the ear cup or the environment outside the ear cup. As such, in some embodiments, the microphone or other such noise sensor can be calibrated in place without significant disassembly of the hearing protection device and such that the space around the microphone is substantially airtight during calibration, increasing the accuracy of calibration.

In some embodiments, the housing may include a securing portion at the distal end of the housing that has a narrower portion relative to the outer diameter of the main body of the housing proximal the narrower portion and a wider portion distal the narrower portion. The securing portion, in combination with the remaining structure of the housing and casing, may ensure that the ear cup is airtight during operation. In some embodiments, an outer diameter of the narrower portion is dimensioned and configured to correspond substantially with an inner diameter of the aperture of the external casing of the ear cup or an intermediate component such as a contacting lip disposed proximate the aperture such that the housing can be inserted into the aperture and retained sealably in place when an outer surface of the narrower portion of the housing abuts an inner surface or an inner edge of the aperture. In some embodiments, the housing can be disposed within the ear cup without necessarily engaging the external casing of the ear cup. In some embodiments, the housing can be at least somewhat deformable such that the wider portion of the housing can be fit through the aperture of the external casing of the ear cup during assembly of the ear cup. In some embodiments, the ear cup can be assembled, at least in part, by temporarily deforming the wider portion at or near the distal end of the housing and fitting the wider portion through the aperture from the inside of the external casing of the ear cup, soldering or otherwise electrically coupling the microphone to the PCB, and disposing the microphone through an opening at the proximal end of the housing until the microphone comes to rest on the ledge or slot defined at a transition point where the proximal portion of the axial bore narrows to define a proximal end of the distal portion of the axial bore. In some embodiments, the housing can be a monolithic structure in order to facilitate the airtight nature of the interior region of the ear cup during use of the hearing protection device and the airtight nature of the axial bore during calibration of the microphone.

<FIG> show a hearing protection device <NUM> according to an embodiment described herein. The hearing protection device <NUM> as illustrated in <FIG> includes a supporting band <NUM> connecting a first ear cup 100a to a second ear cup 100b. An ear cup 100a,b can comprise a structural cup lined with sound-dampening material (also known herein as an "ear pad") dimensioned and configured to engage a wearer's head about the wearer's ears such that the sound-dampening material sealably engages the wearer's head. As such, when properly worn, the hearing protection device <NUM> can be configured to prevent at least some of the ambient noise to which the wearer would otherwise be exposed if not wearing the hearing protection device <NUM> from reaching the wearer's ears. In some embodiments, each of the ear cups 100a,b of the hearing protection device <NUM> can further include a noise sensor assembly 110a,b. The first ear cup 110a and the second ear cup 100b can be similar to, a mirror image configurationally of, dissimilar to, or identical to one another. As such, the ear cups 100a,b are hereinafter referred generally as an ear cup <NUM> and components thereof will be referred to as a noise sensor assembly <NUM>, a removable securing collar <NUM>, and the like, without identifying a particular ear cup.

In some embodiments, the noise sensor assembly <NUM> can be positioned anywhere on or near the external surface of the ear cup <NUM> such that ambient noise from nearby the wearer's ear, external to the ear cups can be measured using the noise sensor assembly <NUM>. This noise exposure signal can then be used in active noise cancellation to generate a destructively interfering audio signal that is generated via a processor and memory in one or both ear cups (e.g., on the main PCB of the ear cups) and output via the speakers shown in each ear cup. The noise exposure signal may additionally or alternatively be used to compare with a noise exposure signal from a microphone inside the ear cups to determine the drop in noise exposure between the exterior and interior of the ear cups (e.g., to confirm that the hearing protection device is working properly and is properly sealed and worn on the user's head). In some embodiments, the noise sensor assembly <NUM> can be positioned as close to the wearer's ear as possible, such as on an outer portion of the ear cup <NUM> near the sound-dampening material. Without wishing to be bound by any particular theory, placing the noise sensor assembly <NUM> on or in the ear cup <NUM> at a position sufficiently nearby the wearer's ear may increase the accuracy of the sensed noise relative to actual noise to which the wearer would be exposed were they not wearing the hearing protection device <NUM>. In some embodiments, the hearing protection device <NUM> can further include a removable securing collar <NUM> disposed about the noise sensor assembly <NUM> and configured to retain the noise sensor assembly <NUM> at or proximate an aperture of the ear cup <NUM>.

In some embodiments, the removable securing collar <NUM> can be disposed to an outer surface of the hearing protection device <NUM> and can be configured to span an aperture defined through the outer surface of the hearing protection device <NUM>. In some embodiments, the removable securing collar <NUM> can be configured to the noise sensor assembly <NUM> on, within, or partially within the hearing protection device <NUM>. In some embodiments, the removable securing collar <NUM> can include an opening dimensioned and configured to transmit sound therethrough to the noise sensor assembly <NUM>. In some embodiments, the hearing protection device <NUM> can further include an external dust protector disposed between the noise sensor assembly <NUM> and the removable securing collar <NUM>.

As illustrated in <FIG> and <FIG>, the ear cup <NUM> further includes a noise sensor assembly <NUM> comprising a housing <NUM> (e.g., 116a, 116b) fixably disposed at or proximate the aperture and defining an axial bore 123a, 123b therethrough. In some embodiments, the housing <NUM> has a proximal portion of the axial bore 123a, 123b that is defined in part by a slot or ledge (not shown) such that the proximal portion is configured to receive a microphone <NUM> or other such sensor. In some embodiments, the housing <NUM> has a distal portion of the axial bore 123a, 123b having an inner diameter that is less than the inner diameter of the proximal portion. In some embodiments, the distal portion of the housing <NUM> can be configured to receive ambient noise from the environment outside the ear cup <NUM> and communicate that ambient noise to the microphone <NUM> or other such sensor disposed and retained within the proximal portion (also known herein as a noise sensor receiving portion <NUM>) of the housing <NUM>. In some embodiments, the microphone <NUM> or other such sensor disposed within the proximal portion of the housing <NUM> can be disposed on one of the sensor printed circuit boards 114a, 114d (sensor PCBs 114a, 114d) and may be connected to one or more flexible printed circuit boards 114b, 114e (flexible PCB 114b, 114e). In some embodiments, the one or more flexible PCBs 114b, 114e can be operably coupled to one or more main PCBs 114c, 114f.

In some embodiments, the noise sensor assembly <NUM> can further include an internal dust protector <NUM> disposed between the microphone <NUM> and the housing <NUM> at the proximal end of the distal portion of the axial bore 123a, 123b (e.g., disposed between the sensor PCB 114a or 114d and the ledge) such that the microphone <NUM> can be exposed to ambient noise communicated through the distal portion of the axial bore 123a, 123b of the housing <NUM> without being exposed or with only slight exposure to contaminants such as dust from the environment outside the ear cup <NUM>.

In some embodiments, the ear cup <NUM> can further include the removable securing collar <NUM> disposed at or proximate the aperture defined through one or more components of a casing of the ear cup <NUM> in such a way as to secure the noise sensor assembly <NUM> within the ear cup <NUM> and as a way to access the noise sensor assembly <NUM> without disassembling the whole ear cup <NUM>. The casing can comprise one or more of a first external casing portion <NUM>, a second external casing portion <NUM>, an insert catch <NUM> coupled to one or more of the first external casing portions <NUM>, <NUM>, and a contacting lip <NUM> coupled to the insert catch <NUM>. Herein, the term "external casing" or "external casing <NUM>" is used to refer to any one or any combination of these or similar elements configured to define or partly define the aperture through which the microphone <NUM> can be in acoustic communication with the environment outside the ear cup <NUM>. In some embodiments, the hearing protection device <NUM> may be assembled at least in part by gluing or otherwise permanently adhering the ear pad 120a,b to the inside of the ear cup 100a,b, which can make it difficult to access the noise sensor assembly <NUM> by way of an inner surface 122a,b of the ear cup 100a,b. Likewise, the durability and air tightness of the ear cup <NUM> may be compromised if the ear cup <NUM> is opened along manufacturing lines, e.g., at a seam formed between the first and second portions of the external casing <NUM>, <NUM> of the ear cup <NUM>.

In some embodiments, the removable securing collar <NUM> can define an opening through a portion, such as the center, of the removable securing collar <NUM>, by which the noise sensor assembly <NUM> can be accessed without significant disassembly of the ear cup <NUM> and without compromising the hearing protection characteristics of the hearing protection device <NUM>. In some embodiments, the removable sealing collar <NUM> can further engage with the inset catch <NUM> of the external casing <NUM>. The external casing <NUM> may be configured to carry or define the contacting lip <NUM> either as an integral piece or a separately inserted element. In some embodiments, the distal end of the housing <NUM> can be configured to rest on one or both of the inset catch <NUM> or the contacting lip <NUM> such that the removable securing collar <NUM> or a portion thereof can be fixedly inserted between the external dust protector <NUM> and the inset catch <NUM>. As such, the external surface of the removable securing collar <NUM> can be flush or substantially flush with the outside surface of the external casing <NUM> of the ear cup <NUM>.

In such a way, in some embodiments, the ambient noise from the environment outside the ear cup <NUM> can communicate through the opening of the removable securing collar <NUM>, into the distal portion of the axial bore <NUM>, and to the microphone <NUM> or other such noise sensor disposed within the proximal portion of the axial bore <NUM> of the housing <NUM>. In some embodiments, the ear cup <NUM> can further include an external dust protector <NUM> disposed within, on, or about the aperture of the external casing <NUM> of the ear cup <NUM>, between the distal end of the housing <NUM> and the removable securing collar <NUM>. In some embodiments, the internal dust protector <NUM> and/or the external dust protector <NUM> can prevent contaminants such as dust and other debris common to construction sites and other similar environments from reaching the microphone <NUM> and other electronics and circuitry within the ear cup <NUM> while also preventing the axial bore <NUM> from becoming clogged and impairing the performance of the microphone <NUM>.

In some embodiments, the ear cups 100a,b can further include ear pads 120a,b dimensioned and configured to be sealably disposed to a wearer's head about a wearer's ear. In some embodiments, the ear pad <NUM> can include or be made from a cushioning material, such as a deformable foam or rubber material such that the ear pad <NUM> has a noise dampening effect for the wearer when properly wearing the hearing protection device <NUM>. In some embodiments, the ear pad <NUM> can serve a similar purpose as the internal dust protector <NUM> and/or the external dust protector <NUM>, which is to at least reduce and possibly prevent the communication of dust and other contaminants into the ear cup <NUM>, when properly worn by the wearer. In some embodiments, therefore, an interior space, defined within the ear cup <NUM> by at least the ear pad <NUM>, the external casing <NUM> of the ear cup <NUM>, the housing <NUM> disposed at or proximate the aperture of the external casing <NUM> of the ear cup <NUM>, and the microphone <NUM>, sensor PCB 114a, or other such sensor element disposed within the proximal portion of the axial bore <NUM> of the housing <NUM>, can be airtight or substantially airtight when properly worn by the wearer to provide effective noise reduction for the wearer.

In some embodiments, the distal portion of the axial bore <NUM> of the housing <NUM> can be configured and dimensioned such that a noise sensor calibration tool comprising a calibration tube can be securely fixed within the axial bore <NUM> for microphone <NUM> calibration by removing the removable securing collar <NUM>, removing the external dust protector <NUM>, and slidably disposing the noise sensor calibration tool into the axial bore <NUM> via a distal opening of the axial bore <NUM> of the housing <NUM>. In some embodiments, securely fixing the noise sensor calibration tool or the calibration tube within the axial bore <NUM> of the housing <NUM> for calibration of the microphone <NUM> or other such noise sensor can help prevent or reduce ambient noise from the environment outside the ear cup <NUM> being detected by the microphone <NUM> during calibration and that a calibrating noise emitted by the noise sensor calibration tool during in situ calibration of the microphone <NUM> or other such noise sensor remains substantially within the axial bore <NUM> of the housing <NUM> and is not emitted to the interior space of the ear cup <NUM> or the environment outside the ear cup <NUM>. As such, in some embodiments, the microphone <NUM> or other such noise sensor can be calibrated in place without significant disassembly of the hearing protection device <NUM> and such that the space around the microphone <NUM> is substantially airtight during calibration, increasing the accuracy of calibration. For example, in some embodiments, the external dust protector <NUM> may be removed for calibration, while the internal dust protector <NUM> is left in place.

In some embodiments, such as when a hearing protection system and associated apparatus benefit from being airtight, during use and/or during calibration, it was found to be helpful to dimension and configure the housing <NUM> to have or define a securing portion at the distal end of the housing <NUM> that has a narrower portion relative to the outer diameter of the main body of the housing <NUM> proximal the narrower portion of the housing <NUM> and a wider portion of the housing <NUM> distal the narrower portion of the housing <NUM>. In some embodiments, an outer diameter of the narrower portion of the housing <NUM> can be dimensioned and configured to correspond substantially with an inner diameter of the aperture of the external casing <NUM> of the ear cup <NUM> (or as applicable, a narrower opening in the external casing, such as the contacting lip <NUM> shown in <FIG>) such that the housing <NUM> can be inserted into the aperture of the external casing <NUM> and retained sealably in place when an outer surface of the narrower portion of the housing <NUM> abuts an inner surface or an inner edge at or proximate aperture of the external casing <NUM> to at least partially seal the aperture. In some embodiments, the housing <NUM> can be at least somewhat deformable such that the wider portion of the housing <NUM> can be fit through the aperture of the external casing <NUM> of the ear cup <NUM> during assembly of the ear cup. In some embodiments, the ear cup <NUM> can be assembled, at least in part, by temporarily deforming the wider portion of the housing <NUM> at or near the distal end of the housing <NUM> and fitting the wider portion of the housing <NUM> through the aperture of the external casing <NUM> of the ear cup <NUM> from the inside of the ear cup <NUM>, soldering or otherwise electrically coupling the microphone <NUM> to the sensor PCB 114a, and disposing the microphone <NUM> through an opening at the proximal end of the housing <NUM> until the sensor PCB 114a comes to rest on the ledge or slot defined at a transition point where the proximal portion of the axial bore <NUM> of the housing <NUM> narrows to define a proximal end of the distal portion of the axial bore <NUM>. In some embodiments, the housing <NUM> can be a monolithic structure in order to facilitate the airtight nature of the interior region of the ear cup <NUM> during use of the hearing protection device <NUM> and the airtight nature of the axial bore <NUM> of the housing <NUM> during calibration of the microphone <NUM>.

In some embodiments, the external casing <NUM> of the hearing protection device <NUM> can include a first portion <NUM> and a second portion <NUM>. In some embodiments, the first portion <NUM> and/or the second portion <NUM> can be configured to at least partially define the aperture. In some embodiments, the external casing <NUM> can be configured to sealably retain the removable securing collar <NUM> in the aperture. In some embodiments, the second portion <NUM> of the external casing <NUM> can be configured to be sealed to the first portion <NUM> such that at least a portion of the first portion <NUM> of the external casing <NUM>, the second portion <NUM> of the external casing <NUM>, the removable securing collar <NUM>, the ear pad <NUM>, and/or the housing <NUM> define the inner space of the ear cup <NUM> of the hearing protection device <NUM>.

In some embodiments, the housing <NUM> comprises an inner surface defining an axial bore <NUM>. In some embodiments, a distal end of the axial bore <NUM> of the housing <NUM> is configured to acoustically communicate with an external environment via the aperture defined in the external casing <NUM>. In some embodiments, the housing <NUM> defines a noise sensor receiving portion <NUM> comprising a slot, a ridge, and/or a ledge configured to engage at least a portion of the noise sensor assembly <NUM>, such as the sensor PCB 114a and/or the microphone <NUM>. In some embodiments, the proximal portion of the axial bore <NUM> can comprise or define the noise sensor receiving portion <NUM>. In some embodiments, the noise sensor receiving portion <NUM> can be defined as a portion of the axial bore <NUM> between the proximal portion and the distal portion. In some embodiments, the slot 116r of the housing <NUM> is configured to retain the noise sensor <NUM>, such that the microphone <NUM> is configured to receive acoustic signals from the axial bore <NUM>, e.g., the distal end of the axial bore <NUM>. In some embodiments, in an instance in which the sensor PCB 114a is engaged with the housing <NUM>, the sensor PCB 114a is sealed against the housing <NUM> and the sensor PCB 114a and the housing <NUM> seal the aperture defined by the external casing <NUM> of the ear cup <NUM>. In other words, in some embodiments, the housing <NUM> can be secured at or proximate the aperture of the external casing <NUM> and the microphone <NUM> and sensor PCB 114a can be secured within the noise sensor receiving portion <NUM> of the housing <NUM> such that ambient noise from outside the ear cup <NUM> can reach the microphone <NUM> by way of the axial bore <NUM> defined by the housing <NUM>.

In some embodiments, the ear cup <NUM> can further include an interior region defined at least in part by the exterior casing <NUM> of the ear cup <NUM> and an ear pad <NUM> configured to contact a wearer's head about the wearer's ear. In some embodiments, the housing <NUM>, in conjunction with the microphone <NUM> and the ear pad <NUM>, can be configured such that the interior region of the ear cup <NUM> can be airtight or substantially air tight when the wearer is wearing the hearing protection device. In some embodiments, the ear cup <NUM> can further include a removable securing collar <NUM> configured to secure the housing <NUM> in place at or proximate the aperture of the external casing <NUM>. In some embodiments, the removable securing collar <NUM> can define an opening through the middle or substantially through the middle of the removable securing collar <NUM> such that ambient noise can travel through the opening of the removable securing collar <NUM>, into the axial bore <NUM> of the housing <NUM>, and reach the microphone <NUM>. In some embodiments, the ear cup <NUM> can further include an external dust protector <NUM> disposed between the distal end of the housing <NUM> and the removable securing collar <NUM>. In some embodiments, the external dust protector <NUM> can be configured to impede the communication of debris such as dust, dirt, moisture, and the like into the housing <NUM> without impeding the audible communication of ambient noise to the microphone <NUM> during use of the hearing protection device.

In some embodiments, the removable securing collar <NUM> and/or external dust protector <NUM> can be removed in order to access the axial bore <NUM> for in situ calibration of the microphone <NUM>. In other words, by removing the removable securing collar <NUM>, the calibration tool having a sufficient form factor can be slidably inserted into the axial bore <NUM> of the housing <NUM> such that a calibrating sounds can be emitted nearby the microphone <NUM>. In some embodiments, the removable securing collar <NUM> may be engaged with the external casing <NUM> via one or more securing tabs or other interference fit structures, such that adhesives and permanent affixation elements are not required. In some embodiments, it can be helpful or even necessary to form an airtight or substantially airtight seal between the calibration tool and the inner surface of the housing <NUM> such that the microphone <NUM> is not exposed to ambient noise in addition to the calibrating sound during calibration and so that the full measure of the calibrating sound reaches the microphone <NUM>.

In some embodiments, the housing <NUM> can be configured to have suitable mechanical properties such that the microphone <NUM> is securely retained within the housing <NUM>, while the housing <NUM> provides some amount of attenuation of vibrations caused by movement of the hearing protection device <NUM> by the wearer, by sound waves from nearby sound sources such as speakers and/or the environment outside the ear cup <NUM>, and the like. For example, the housing <NUM> may be made of rubber or a rubber-like material. Furthermore, in some embodiments in which the housing <NUM> is a monolithic structure formed as a single piece or component, some benefits of the invention include a reduction in number and complexity of components required for noise sensing in the hearing protection device leading to a reduction in manufacturing cost and complexity, a reduction in probability of component failure, and a reduced occupied volume leading to a smaller possible ear cup <NUM> profile. Also, since the microphone <NUM> can be calibrated, the accuracy of noise detection will be improved. Furthermore, since the microphone <NUM> can be calibrated without significant disassembly of the ear cup <NUM>, the cost, time, and complexity of calibration of the microphone <NUM> are reduced. Furthermore, since the axial bore <NUM> of the housing <NUM> is dimensioned and configured to slidably and sealably receive the standard calibration tool during calibration of the microphone <NUM>, the in situ calibration of the microphone <NUM> is more effective, meaning the accuracy of the calibrated microphone <NUM> for this hearing protection device <NUM> is greater than microphones of conventional hearing protection devices that are not able to be calibrated at all, not able to be calibrated after assembly of the hearing protection device, and/or can only be calibrated in less than airtight environments.

In some embodiments, the microphone <NUM>, which can be any suitable type of microphone such as a microelectro-mechanical systems- (MEMS)-based microphone or the like, can be mounted on, fixed to, electrically coupled to, soldered to, and/or otherwise coupled to the sensor PCB 114a. In some embodiments, the sensor PCB 114a can be particularly dimensioned and configured such that a portion of the sensor PCB 114a can be retained, with the microphone <NUM>, within the noise sensor receiving portion <NUM> of the housing <NUM>. In some embodiments, the sensor PCB 114a can have any suitable form factor such that the sensor PCB 114a can sealably abut a surface of the noise sensor receiving portion <NUM> of the housing <NUM>. For instance, the sensor PCB 114a can have a form factor that is substantially flat, planar, smooth, round, square, rectangular, quadrilateral, quadrangular, tubular, ellipsoidal, homogenous, even, symmetrical, asymmetrical, or the like. In some embodiments, the sensor PCB 114a or a portion thereof can be at least partially flexible. In some embodiments, the ear cup <NUM> can further comprise a main PCB 114c electrically connected via a flexible PCB 114b to the sensor PCB 114a, the sensor PCB 114a configured to be electrically coupled to the microphone <NUM>. In some embodiments, the main PCB 114c may comprise a processor and memory for performing the signal processing of at least a portion of the hearing protection device, such as the examples described herein.

In some embodiments, the slot of the noise sensor receiving portion <NUM> of the housing <NUM> can define a volume having extents and dimensions that can be substantially inversely similar to the dimensions of the sensor PCB 114a such that the sensor PCB 114a can be securely disposed within the receiving portion of the housing <NUM> without adhesive or fasteners or otherwise securing the sensor PCB 114a within the housing other than by the relative dimensions of either. In some embodiments, the noise sensor receiving portion <NUM> of the housing <NUM> can be configured and dimensioned to releasably retain the noise sensor, comprising the sensor PCB 114a and the microphone <NUM>, within the noise sensor receiving portion <NUM> of the housing <NUM>. In other words, the particular dimensions of the noise sensor receiving portion <NUM> of the housing <NUM> can be particularly configured to retain the sensor assembly, comprising the sensor PCB 114a and the microphone <NUM>, within the noise sensor receiving portion <NUM> of the housing <NUM>, thereby forming an airtight seal between at least one of the sensor PCB 114a and the microphone <NUM>, and the housing <NUM>.

As such, when the noise sensor assembly <NUM> is properly assembled, air and noise from the environment outside the ear cup <NUM> can be communicated into the distal portion of the axial bore <NUM> of the housing <NUM> and to the microphone <NUM> and/or the sensor PCB 114a, but is prevented from communicating through the axial bore <NUM> past the microphone <NUM> and/or the sensor PCB 114a. As such, noise from the environment outside the ear cup <NUM> can be freely measured using the noise sensor assembly <NUM> but the interior space of the ear cup <NUM>, including the proximal portion of the axial bore <NUM> of the housing <NUM> is not substantially exposed to the noise, air, contaminants, and the like from the environment outside the ear cup <NUM> due to the airtight seal and noise reduction technologies described herein.

In some embodiments, the exterior casing <NUM> of the ear cup <NUM> and the removable securing collar <NUM> can comprise or be formed from any suitably durable yet light material, such as a plastic material like acrylonitrile butadiene styrene (ABS) or the like. In some embodiments, the internal dust protector <NUM> can comprise or be formed from any suitable filtering material, such as Gore filtration material PE <NUM> and other suitable ingress protection (IP) filter materials. In some embodiments, the internal dust protector <NUM> can be further configured to prevent flux of water between the distal portion of the axial bore <NUM> of the housing <NUM> and the noise sensor assembly disposed in the noise sensor receiving portion <NUM> proximate the distal portion of the axial bore <NUM> of the housing <NUM>, thus preventing moisture damage to the sensor PCB 114a and/or the microphone <NUM>. In some embodiments, the housing <NUM> can comprise or be formed from any suitably durable and yet deformable material, such as a synthetic rubber like ethylene propylene diene monomer (EPDM) rubber and the like. In some embodiments, the external dust protector <NUM> can comprise or be formed from any suitable dust filtering material such as a foam, a mesh, a woven fiber, and the like.

In some embodiments, the ear cup <NUM> can further comprise an internal microphone <NUM> configured as a noise sensor to sense noise exposure within the inner space of the ear cup <NUM>. For instance, the internal microphone <NUM> can be configured to measure noise from outside the ear cup <NUM> that is communicated into the inner space of the ear cup <NUM>. As such, the hearing protection device <NUM> can be configured such that the noise sensor assembly <NUM>, the internal microphone <NUM>, other suitable computing devices and/or circuitry, or other devices can be caused to transmit and/or store noise exposure data during use of the hearing protection device <NUM>. In some embodiments, a signal indicative of a magnitude of noise exposure can be transmitted from the microphone <NUM> and/or the internal microphone <NUM> to the main PCB 114c or other suitable computing devices or circuitry, a memory device, or the like. In some embodiments, the magnitude of noise exposure measured by the microphone <NUM> can be compared to the magnitude of noise exposure measured by the internal microphone <NUM> to determine the effectiveness of the active and/or passive noise dampening capabilities of the hearing protection device <NUM>, to identify improper use by the wearer such as when an ear cup <NUM> is not properly fitted against the wearer's head about the wearer's ears, and to identify when a noise sensor is in need of calibration or is malfunctioning.

Referring now to <FIG>, an ear cup (e.g., <NUM>) for a hearing protection device (e.g., <NUM>) can include a housing <NUM> as illustrated, according to an embodiment of the present disclosure. Unless otherwise stated, the features of the housing <NUM> shown in <FIG> may be included in the depicted housing <NUM> in <FIG>, and vice versa. As illustrated, the housing <NUM> is dimensioned and configured to be fixably disposed at or proximate an aperture defined through an external casing of the ear cup. The housing <NUM> defines an axial bore 216c therethrough between a proximal end <NUM> and a distal end (i.e., 216f). In some embodiments, the housing <NUM> has a proximal portion 216b of the axial bore 216c that is defined in part by a slot 216r and/or ledge <NUM> such that the proximal portion 216b is configured to receive a microphone (e.g., <NUM>) or other such sensor. In some embodiments, the housing <NUM> can comprise a distal portion 216d of the axial bore 216c having an inner diameter that is less than the inner diameter of the proximal portion 216b. In some embodiments, the ledge <NUM> can be defined by the portion of the axial bore 216c at the transition between the narrower distal portion 216d and the wider proximal portion 216b. In some embodiments, the ledge <NUM> can be formed as a surface facing the proximal end <NUM> of the housing <NUM> and configured to engage the microphone PCB. In some embodiments, the proximal portion 216b of the axial bore 216c can have a wider inner diameter at a transition point <NUM> from the distal portion 216d to the proximal portion 216b, the transition point <NUM> at least partly defining the ledge <NUM>. In some embodiments, the inner diameter of the proximal portion 216b can be smaller at one or more points proximal the transition point <NUM> such that the slot 216r is formed. In some embodiments, the slot 216r can be the portion of the proximal portion 216b or of the axial bore 216c in general that has the largest inner diameter such that the noise sensor can be retained in the slot 216r against movement in an axial direction by a reduced inner diameter both distal the slot and proximal the slot 216r. In some embodiments, a narrower region (e.g., defined by one or more internal surfaces <NUM><IMG>, 216t) of the proximal portion 216b of the axial bore 216c proximal the slot 216r can be at least partially open in a radial direction (e.g., a cutout in the side wall of the portion of the axial bore proximal to the slot), meaning, in some embodiments, a region of an outer wall (e.g., 216a, 216q, <NUM>) of the housing <NUM> aligned with the narrower region of the proximal portion 216b may extend only part of the way around the axial bore 216c, such that one or more components of the noise sensor can extend out radially from the proximal portion 216b of the axial bore 216c at a location proximal the slot 216r.

In some embodiments, the distal portion 216d of the housing <NUM> can be configured to receive ambient noise from the environment outside the ear cup and communicate that ambient noise to the microphone or other such sensor disposed and retained within the proximal portion 216b (or a portion thereof known herein as a noise sensor receiving portion 216r) of the housing <NUM>. In some embodiments, the microphone or other such sensor disposed within the proximal portion of the housing <NUM> can be connected to a printed circuit board (PCB, e.g., the PCB 114a) having a suitable form factor such that at least a portion of the PCB is retained within a noise sensor receiving portion 216j of the axial bore 216c of the housing <NUM>. In some embodiments, the proximal portion 216b can comprise or define the noise sensor receiving portion 216j. In some embodiments, the noise sensor receiving portion 216j can be defined as a portion of the axial bore 216c within the proximal portion 216b and adjacent the distal portion 216d. In some embodiments, the one or more PCBs can include a microphone PCB 114a operably coupled to the microphone <NUM> or other such sensor, a flexible PCB 114b operably connected to the microphone PCB 114a, and a main PCB 114c to which the flexible PCB 114b is operably coupled.

In some embodiments, the distal portion 216d of the axial bore 216c of the housing <NUM> can be configured and dimensioned such that a noise sensor calibration tool can be securely fixed within the axial bore 216c for microphone calibration slidably disposing the noise sensor calibration tool through the distal end of the axial bore 216d and towards the proximal portion 216b of the housing <NUM>. In some embodiments, securely fixing the noise sensor calibration tool within the axial bore 216c of the housing <NUM> for calibration of the microphone or other such noise sensor can help prevent or reduce ambient noise from the environment outside the ear cup being detected by the microphone during calibration and can prevent or reduce emission of a calibrating noise emitted by the noise sensor calibration tool during in situ calibration of the microphone or other such noise sensor to outside the housing <NUM>, such as to the interior space of the ear cup or the environment outside the ear cup. As such, in some embodiments, the microphone or other such noise sensor can be calibrated in place without significant disassembly of the hearing protection device and such that the space around the microphone is substantially airtight during calibration, increasing the accuracy of calibration.

In some embodiments, such as when a hearing protection system and associated apparatus benefit from being airtight, during use and/or during calibration, it was found to be helpful to dimension and configure the housing <NUM> to have or define a securing portion 216n at or near the distal end of the housing <NUM>, the securing portion 216n comprising a narrower portion <NUM> relative to the outer diameter of the main body of the housing <NUM> proximal the narrower portion of the securing portion 216n and a wider portion 216f of the securing portion 216n distal the narrower portion <NUM> of the securing portion 216n. In some embodiments, an outer diameter of the narrower portion <NUM> of the securing portion 216n can be dimensioned and configured to correspond substantially with an inner diameter of the aperture of the external casing of the ear cup or one or more intermediate components (e.g., the contacting lip <NUM>) such that the housing <NUM> can be inserted into the aperture of the external casing and retained sealably in place when an outer surface of the narrower portion <NUM> of the securing portion 216n abuts an inner surface or an inner edge of the aperture of the external casing or other intermediate component at the aperture. In some embodiments, the housing <NUM> can be at least somewhat deformable such that the wider portion 216f of the securing portion 216n can be fit through the aperture of the external casing of the ear cup during assembly of the ear cup. In some embodiments, the ear cup can be assembled, at least in part, by temporarily deforming the wider portion 216f of the securing portion 216n at or near the distal end of the housing <NUM> and fitting the distal portion 216f of the housing <NUM> through the aperture of the external casing of the ear cup from the inside of the ear cup, soldering or otherwise electrically coupling the microphone to the PCB, and disposing the microphone and a portion of the PCB into the proximal end of the axial bore 216c of the housing <NUM> until the microphone and/or the portion of the PCB come(s) to rest in the slot 216r and/or on the ledge <NUM>, the ledge <NUM> defined as an internal surface perpendicular to the axial bore 216c and positioned at a transition point <NUM> where the proximal portion 216b of the axial bore 216c of the housing <NUM> narrows to define a proximal end of the distal portion 216d of the axial bore 216c. In some embodiments, the ledge <NUM> can comprise a ridge 216u raised above the surface of the ledge <NUM> in a proximal direction and configured to sealably engage at least one of the sensor PCB 114a and the microphone <NUM>. In some embodiments, the housing <NUM> can be a monolithic structure in order to facilitate the airtight nature of the interior region of the ear cup during use of the hearing protection device and the airtight nature of the axial bore of the housing <NUM> during calibration of the microphone.

In some embodiments, the distal portion 216d of the axial bore 216c of the housing <NUM> is configured to acoustically communicate with an external environment via the aperture defined in the external casing of the ear cup. In some embodiments, the housing <NUM> can define a noise sensor receiving portion 216j comprising the slot 216r, the ledge <NUM> and the ridge 216u, the slot 216r, the ledge <NUM>, and/or the ridge 216u configured to engage the PCB and/or the microphone of the noise sensor assembly. In some embodiments, the slot 216r and/or the ledge <NUM> of the housing <NUM> can be configured to retain the noise sensor, such that the microphone faces the axial bore, e.g., the distal end of the axial bore. In some embodiments, in an instance in which the noise sensor is engaged with the housing <NUM>, the noise sensor can be sealed or substantially sealed against the housing <NUM> and the noise sensor and the housing <NUM> can be configured to seal the aperture defined by the external casing of the ear cup. In other words, in some embodiments, the housing <NUM> can be secured at or proximate the aperture of the external casing and the microphone and/or PCB can be secured within the noise sensor receiving portion 216j of the housing <NUM> such that ambient noise from outside the ear cup can reach the microphone by way of the distal portion 216d of the axial bore 216c.

In some embodiments, the distal portion 216d of the axial bore 216c of the housing <NUM> can be accessible for in situ calibration of the microphone either during normal use of the hearing protection device or after only removing minimal components, such as only the removable sealing collar or only the removable sealing collar and an external dust protector. In other words, in some embodiments, a calibration tool having a sufficient form factor can be slidably inserted into the axial bore 216c of the housing <NUM> such that a calibrating sound can be emitted nearby the microphone. In some embodiments, it can be helpful or even necessary to form an airtight or substantially airtight seal with the inner surface of the distal portion 216d of the axial bore 216c such that the microphone is not exposed to ambient noise in addition to the calibrating sound during calibration and so that the full magnitude of the calibrating sound reaches the microphone.

In some embodiments, the housing <NUM> can be configured to have suitable mechanical properties such that the microphone is securely retained within the housing <NUM>, but that the housing <NUM> provides some amount of attenuation of vibrations caused by movement of the hearing protection device by the wearer, by sound waves from nearby sound sources such as speakers and/or the environment outside the ear cup, and the like. Furthermore, in some embodiments in which the housing <NUM> is a monolithic structure formed as a single piece or component, some benefits of the invention include a reduction in number and complexity of components required for noise sensing in the hearing protection device leading to a reduction in manufacturing cost and complexity, a reduction in probability of component failure, and a reduced occupied volume leading to a smaller possible ear cup profile. Also, since the microphone can be calibrated, the accuracy of noise detection will be improved. Furthermore, since the microphone can be calibrated without significant disassembly of the ear cup, the cost, time, and complexity of calibration of the microphone are reduced. Furthermore, since the axial bore of the housing <NUM> is dimensioned and configured to slidably and sealably receive standard calibration tools during calibration of the microphone, the in situ calibration of the microphone is more effective, meaning the accuracy of the calibrated microphone for this hearing protection device is greater than microphones of conventional hearing protection devices that are not able to be calibrated at all, not able to be calibrated after assembly of the hearing protection device, and/or can only be calibrated in less than airtight environments.

In some embodiments, the housing <NUM> comprises a rounded exterior surface 216q, one or more flat exterior surfaces 216a, <NUM> on the outside of the housing <NUM> oriented parallel to the axial bore 216c, and one or more other flat exterior surfaces <NUM>, 216p, 216i on the outside of the housing <NUM> oriented perpendicular to the axial bore 216c. In some embodiments, the rounded exterior surface 216q and/or the one or more flat exterior surfaces 216a, <NUM> may be configured to abut a portion or component of the ear cup. In some embodiments, the rounded exterior surface 216q and/or the one or more flat exterior surfaces 216a, <NUM> may be configured to abut a portion or component of the ear cup such that the housing <NUM> is prevented from rotation relative to an orientation of the rest of the ear cup. In some embodiments, the proximal portion 216b of the axial bore 216c of the housing <NUM> may comprise or be adjoining one or more flat interior surfaces <NUM><IMG> such that a cut-out is defined between the one or more flat interior surfaces <NUM><IMG> and through a portion of a flat exterior surface <NUM> or a rounded exterior surface 216q. In some embodiments, the PCB may be disposed within the noise sensor receiving portion 216j of the housing <NUM> along with the microphone, while another portion of the PCB extends from the axial bore 216c, through the cut-out portion of the flat exterior surface <NUM> or the rounded exterior surface 216q of the housing <NUM>, and into the interior space of the ear cup such that the PCB can be electrically coupled to other electronic components such as another PCB, a microprocessor or the like. In some embodiments, the portions of the housing surrounding the cut-out may define a horseshoe shape to facilitate insertion of the PCB by separating or pulling apart the distal ends of the horseshoe shape (e.g., with pliers) to allow the microphone PCB to insert into the slot.

Referring now to FIGS. 3A-3D, a noise sensor assembly <NUM> comprises at least a microphone <NUM> and a sensor printed circuit board (PCB) 214a. In some embodiments, the sensor PCB 214a can be electrically and/or operably coupled to the microphone <NUM>. In some embodiments, the sensor PCB 214a can be electrically and/or operably coupled to a flexible PCB 214b and the flexible PCB 214b can be operably coupled to a main PCB 214c. In some embodiments, the noise sensor assembly <NUM> or a portion thereof can be disposed within a portion of the housing <NUM>, such as the noise sensor receiving portion 216j. In some embodiments, the microphone <NUM> can be any suitable type of microphone such as a microelectro-mechanical systems- (MEMS)-based microphone or the like, can be mounted on, fixed to, electrically coupled to, soldered to, and/or otherwise coupled to the sensor PCB 214a. In some embodiments, the sensor PCB 214a can be particularly dimensioned and configured such that at least a portion of the sensor PCB 214a can be retained, with the microphone <NUM>, within the noise sensor receiving portion 216j of the housing <NUM>. In some embodiments, the sensor PCB 214a can have any suitable form factor such that the sensor PCB 214a can sealably abut a surface of the receiving portion of the housing <NUM>. For instance, the sensor PCB 214a can have a form factor that is substantially flat, planar, smooth, round, square, rectangular, quadrilateral, quadrangular, tubular, ellipsoidal, homogenous, even, symmetrical, asymmetrical, or the like. In the embodiment depicted in <FIG>, the sensor PCB 214a forms a substantially circular shape corresponding to the shape of the slot 216r shown in <FIG>. In some embodiments, the electrical components mounted to the sensor PCB 214a may be offset from the edges such that the housing <NUM> can grip the sensor PCB 214a.

In some embodiments, the noise sensor receiving portion 216j of the housing <NUM> can define a volume having extents and dimensions that can be substantially inversely similar to the dimensions of the sensor PCB 214a such that at least a portion of the sensor PCB 214a can be securely disposed within the receiving portion of the housing <NUM> without adhesive or fasteners or otherwise securing the sensor PCB 214a within the housing <NUM> other than by the relative dimensions of either. In some embodiments, the noise sensor receiving portion 216j of the housing <NUM> can be configured and dimensioned to releasably retain the noise sensor, comprising the sensor PCB 214a and the microphone <NUM>, within the noise sensor receiving portion 216j of the housing <NUM> in a similar manner. In other words, the particular dimensions of the noise sensor receiving portion 216j of the housing <NUM> can be particularly configured to retain the sensor assembly, comprising the sensor PCB 214a and the microphone <NUM>, within the noise sensor receiving portion 216j of the housing <NUM>, thereby forming an airtight seal between at least one of the sensor PCB 214a and the microphone <NUM>, and the housing <NUM>.

In some embodiments, the sensor PCB 214a can have any suitable form factor such that the sensor PCB 214a can sealably abut a surface of the receiving portion of the housing <NUM>. In some embodiments, the sensor PCB 214a, the flexible PCB 214b and/or the main PCB 214c can have a form factor that is substantially flat, planar, smooth, round, square, rectangular, quadrilateral, quadrangular, tubular, ellipsoidal, homogenous, even, symmetrical, asymmetrical, or the like. In some embodiments, the sensor PCB 214a or a portion thereof can be at least partially flexible. In some embodiments, the sensor PCB 214a can be electrically connected via the flexible PCB 216b to the main PCB 214c or other such computing device or circuitry, and the sensor PCB 214a can be electrically connected to the microphone <NUM>.

As such, when the noise sensor assembly <NUM> is properly assembled, air and noise from the environment outside the ear cup can be communicated into the distal portion 216d of the axial bore 216c of the housing <NUM> and to the microphone <NUM> and/or the sensor PCB 214a, but is prevented from communicating through the axial bore 216c to locations proximal the microphone <NUM> and/or the sensor PCB 214a. As such, noise from the environment outside the ear cup can be freely measured using the noise sensor assembly <NUM> but the interior space of the ear cup, including the proximal portion 216b of the axial bore 216c of the housing <NUM> is substantially not exposed to the noise, air, contaminants, and the like from the environment outside the ear cup based upon the air tightness and noise reduction techniques described herein.

In some embodiments, the microphone <NUM> can comprise a silicon wafer having a movable membrane and a fixed back plate over a cavity in the base wafer. In some embodiments, the sensor back plate can have a stiff perforated structure. In some embodiments, the microphone <NUM> can be a microelectro-mechanical system (MEMS) microphone. Without wishing to be bound by any particular theory, in response to air movements related to noise exposure, the movable membrane of the microphone <NUM> can move, causing a change in a magnitude of a capacitance between the movable membrane and the fixed back plate, which can be converted by any suitable ASIC to an electrical signal. For instance, the ASIC can use a charge pump to place a fixed charge on the movable membrane of the microphone <NUM>, and the ASIC can then measure voltage variations caused by capacitance changes related to movements of the movable membrane relative to the fixed back plate. While the microphone <NUM> can comprise the above-mentioned components according to some embodiments, the microphone <NUM> can comprise any suitable combination of components such that noise exposure can be sensed.

Claim 1:
A hearing protection device (<NUM>) comprising:
a printed circuit board, PCB;
a noise sensor comprising a microphone (<NUM>, <NUM>) mounted on the PCB and electrically coupled to the PCB;
a housing (<NUM>, <NUM>) dimensioned and configured to be fixably disposed at or proximate an aperture defined in an outer surface of an external casing of the hearing protection device,
wherein the housing (<NUM>, <NUM>) comprises an inner surface defining an axial bore (216c),
wherein a distal end of the axial bore (216c) is configured to acoustically communicate with an external environment via the aperture,
wherein the housing (<NUM>, <NUM>) defines a noise sensor receiving portion (<NUM>, 216j) comprising a slot (216r) configured to engage the PCB,
wherein the slot (216r) of the housing (<NUM>, <NUM>) is configured to retain the noise sensor, such that the microphone (<NUM>, <NUM>) faces the axial bore (216c),
wherein, in an instance in which the noise sensor is engaged with the housing (<NUM>, <NUM>), the noise sensor is sealed against the housing (<NUM>, <NUM>), and
wherein the housing (<NUM>, <NUM>) further defines a securing portion (216n) at a distal end, the securing portion (216n) adapted to contact and secure the housing (<NUM>, <NUM>) with respect to a portion of the outer surface of the hearing protection device (<NUM>).