Abstract:
A microphone includes elements to protect against overpressure, such as from sudden physical shock. A cavity between ambient atmosphere and the microphone diaphragm includes a movable seal, which blocks overpressure from reaching the diaphragm when closed, and allows ordinary pressure to reach the diaphragm when open. The cavity can also have an entrance from ambient atmosphere offset from an exit to the diaphragm, and can include a valve which vents overpressure, or balloons in response to overpressure, so that overpressure does not directly reach the diaphragm. The seal or valve can be kept open or kept closed, and moved between states in response to whether the microphone should be in use or protected.

Description:
TECHNICAL FIELD 
     This application generally relates to a microphone seal, and other matters. 
     BACKGROUND 
     It sometimes occurs that portable mobile devices are subject to sudden mechanical shock, such as when accidentally dropped, struck against obstacles, having a lid closed too rapidly, or otherwise. These shocks can have a substantial sonic or air pressure effect on relatively smaller cavities in the device, such as when sonic pressure is applied to an input port coupled to a microphone. For example, when portable mobile devices allow audio input, such as voice input from a user, a microphone (or a microphone assembly) included in the portable mobile device can include at least one such cavity. It sometimes occurs that the microphone (or a portion of the microphone, such as its diaphragm) can be subject to substantial damage by sonic pressure in the event of a sudden mechanical shock. 
     It also sometimes occurs that microphones in portable mobile devices can be subject to sudden atmospheric shock, such as when those devices are improperly handled at or near an input for the microphone. Similar to mechanical shocks described above, these can have a substantial sonic pressure effect on the microphone, with the possibility of subjecting the microphone (or a portion of the microphone, such as its diaphragm) to substantial damage. For example, when an electric discharge (such as an electrical spark) occurs at or near an input port coupled to the microphone (or a microphone assembly), sonic pressure might damage the microphone or its diaphragm. 
     Each of these examples, as well as other possible considerations, can cause one or more difficulties as a result of damage to the microphone of a portable mobile device. For a first example, the device can lose some of its intended function, such as that the user might become unable to use the voice input or other audio input features of the device. For a second example, the device can exhibit unexpected behavior, such as that the user might experience lesser tonal response or other audio response from the device than expected, or might experience increased noise effects from distortion or partial damage of the microphone. In contrast, the device can benefit from protecting against microphone damage. 
     SUMMARY OF THE DISCLOSURE 
     This application provides techniques, including devices and structures, and including method steps, that can protect a microphone (or other instruments sensitive to sonic pressure) from damage in the event of sudden shock. For example, sudden shock can include mechanical shock to the device, or other atmospheric shock occurring near the device. These techniques can be incorporated into one or more different devices that allow voice input or other audio input, or that otherwise respond to atmospheric effects. For example, these techniques can be incorporated into portable telephones or radiotelephonic devices, portable touch devices such as tablets or mini-tablets, portable computing devices such as laptops or netbooks, or other types of devices. 
     A microphone (or an assembly including a microphone) can include elements to protect against sonic pressure, such as from sudden physical shock or sudden atmospheric shock. For example, the microphone or assembly can include one or more elements to prevent the sonic pressure from reaching the microphone, such as mechanical elements that can be moved into a sonic pathway in the event of shock, and out of the sonic pathway when the microphone is intended to be in use. Alternatively, or in addition, a microphone (or an assembly including a microphone) can include elements to ameliorate one or more effects of sonic pressure. For example, the microphone or assembly can include one or more elements to vent the sonic pressure, such as one or more sonic pathways that can be opened in the event of shock, or closed when the microphone is intended to be in use. 
     In one embodiment, a cavity located between ambient atmosphere and the microphone diaphragm can include a movable seal, which can block sonic overpressure from reaching the diaphragm in a first state (such as when closed), and allows ordinary sound waves to reach the diaphragm in a second state (such as when open). For a first example, sonic overpressure can actuate the movable seal, such as by pushing the seal into place, which can alter the state of the movable seal to protect the microphone in the event of a sudden shock. For a second example, the shock itself can actuate the movable seal, such as by accelerating a portion of the seal or a weight attached thereto, which can alter the state of the movable seal, again, to protect the microphone in the event of a sudden shock. 
     In one embodiment, the movable seal can be actuated by an electromagnetic circuit, which can be responsive either to sonic overpressure or to a shock (such as in response to an accelerometer or another type of inertial response sensor). For a first example, the movable seal can be maintained in a first state (such as a closed state) or a second state (such as an open state) using a bimetallic strip, an electromagnetic strip, a memory-metal alloy, a solenoid, or another element having a mechanical response to an electrical or electromagnetic signal. 
     In such examples, the electrical or electromagnetic signal can be responsive either to sonic overpressure or to a shock, and the mechanical response can have the effect of altering the movable seal from the first state to the second state (or vice versa), to protect the microphone in the event of a sudden shock. In a first such case, a device can maintain the movable seal normally sealed, and can actuate the movable seal to become unsealed when the microphone is intended to be in use. In a second such case, the device can maintain the movable seal normally unsealed, and can actuate the movable seal to become sealed when a mechanical shock or sonic overpressure is detected. 
     In one embodiment, the cavity can include a partial seal having more than one stable state, such as a mesh have a relatively closed state (such as with a relatively tight mesh gap) and a relatively open state (such as with a relatively loose mesh gap). This can have the effect of providing a first state with relatively greater protection against sonic pressure, with the effect of protecting the microphone against damage, and a second state with relatively greater sensitivity to sound waves, with the effect of providing the microphone with sensitivity to acoustic signals. 
     In one embodiment, the cavity can include a bistable (or semi-stable) mechanical structure, such as a bistable dome, disposed for switching between a first stable state and a second stable state, such as mechanically, electrically or electro-mechanically, or otherwise. For example, a bistable dome can include a “popped-up” state in which the dome presents a bubble shape, and a “pushed-in” state in which the dome presents a dimpled shape, or other bistable or multi-stable, or semi-stable shapes. In a first such case, a bistable dome can be stable in both states, with one of the two states providing protection to the microphone against sonic pressure, and the other of the two states providing availability to the microphone of sound waves, such as from an acoustic signal. In a second such case, a semi-stable structure can be stable in one of two states, with one of the two states providing protection as described herein, and the other of the two states providing availability as described herein. Moreover, in such cases, the bistable or multi-stable, or semi-stable, structure can have its state altered using an electro-mechanical switch, a solenoid, or another type of device. 
     In one embodiment, the cavity can include an actuated opening or closing element that can enter a first state (such as an open position) or a second state (such as a closed position) with respect to a sonic pathway coupled to the microphone (or microphone assembly). For example, the actuated element can include a rotatable disk, having an opening that can be aligned or de-aligned with the sonic pathway. In such cases, the actuated element can be coupled to an actuator disposed outside the disk, such as an external motor or linear actuator. 
     In one embodiment, the cavity can include an expandable element having at least one stable state. At a relatively normal pressure the expandable element can allow the microphone to operate in a relatively normal manner, while at a relatively elevated pressure (such as might occur during a pressure overage) the expandable element can expand to absorb the increased pressure, to protect the microphone against the effect of sudden shock. For example, the expandable element can include a rubber gasket or other stretchable membrane, which can expand at a relatively elevated pressure to increase the volume of an enclosed portion of a microphone, with the effect of ameliorating the pressure on components of the microphone. In such examples, the expandable element can be disposed at a location so that atmospheric inflow from a sudden pressure change would be applied relatively directly to the expandable element, with the effect that the expandable element can relatively rapidly absorb the effect of the pressure change. In such examples, the expandable element can even be breakable, at least to the extent that breaking the expandable element would be superior to breaking the microphone. 
     In one embodiment, the cavity can include elements of a microphone disposed at an offset from a location where atmospheric inflow from a sudden pressure change would be applied. This can have the effect that an effect of a sudden pressure change would be mitigated, as the pressure change would tend to be distributed throughout the enclosed portion of the microphone, that is, would tend not to be directly applied to the elements of the microphone. This can have the effect that the elements of the microphone could be maintained away from the location where atmospheric inflow from a sudden pressure change would occur. 
     In one embodiment, the cavity can include compressible or soft elements, disposed to expand the cavity in the event of sonic overpressure, or even to de-link from the cavity in the event of sonic overpressure and to vent overpressure to ambient (or to another cavity). For a first example, the cavity can include a compressible foam, a contractible or expandable bellows, or another type of device or structure for venting sonic overpressure. For a second example, the cavity can include devices or structures responsive to a detector (such as an accelerometer or another type of inertial response detector) that operate to expand the cavity or to open the cavity in the event of relatively high acceleration. 
     In one embodiment, the microphone can be reinforced with one or more compressible or soft elements, disposed to absorb forces on the microphone in the event of sonic overpressure, or even to de-link the microphone from the cavity in the event of sonic overpressure. For a first example, the microphone (or a portion thereof such as its diaphragm) can be coupled to a compressible form, a contractible or expandable bellows, or another type of device or structure for absorbing sonic overpressure. For a second example, the microphone can include devices or structures responsive to a detector (such as an accelerometer or another type of inertial response detector) that operate to absorb sonic overpressure on the microphone or its diaphragm in the event of relatively high acceleration. 
     Although this application describes exemplary embodiments and variations thereof, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. As will be realized, the disclosure is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present disclosure. The drawings and detailed description are intended to be illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a conceptual drawing of a microphone assembly. 
         FIG. 2  (collectively including  FIGS. 2A, 2B, 2C, 2D, and 2E ) shows conceptual drawings of blocking elements. 
         FIG. 3  shows a conceptual drawing of a method of operation. 
     
    
    
     DETAILED DESCRIPTION 
     Terms and Phrases 
     The text “actuator”, and variants thereof, generally refers to any device or assembly capable of controlling another device. For example, an actuator can include a motor or switch capable of exerting a mechanical effect, or such as an electrical device capable of generating an electrical or electronic signal, coupled to that other device. 
     The text “microphone”, and variants thereof, generally refers to any device or assembly capable of receiving sound waves, such as propagated through atmosphere or another gas, and in response thereto, generating an audio signal, such as an electrical signal representative of those sound waves. 
     The text “sonic pressure”, and variants thereof, generally refers to any pressure effect resulting from sound waves. For example, sonic pressure can include pressure propagated through atmosphere or another gas. Thus, air pressure can be one example of a sonic pressure induced in a particular medium. 
     Microphone Assembly 
       FIG. 1  shows a first conceptual drawing of a microphone assembly. 
     A microphone assembly  100  can be disposed near to an outside border  122 , such as an edge of a portable mobile device, or an edge of a subassembly, or other region from which external gas pressure might become applied. While this application primarily describes embodiments in which the outside border  122  is an outside edge of a portable mobile device, in the context of the invention, there is no particular requirement for any such limitation. For example, the outside border  122  could include an edge of a microphone subassembly disposed inside a portable mobile device, or otherwise. 
     The outside border  122  can be disposed near ambient atmosphere  124 , and be coupled to an input port  126 , such as including a pathway that allows sound waves to enter from the ambient atmosphere  124 . The input port  126  can be coupled to a cavity  128 , such as described in further detail herein, which can include a blocking element  130  that can either allow or prevent sound waves that enter the cavity  128  from continuing onward. The blocking element  130  can be coupled to one or more actuators or stabilizers (not shown), which can cause the blocking element  130  to maintain one of two or more states (such as “open” or “closed”) and can cause the blocking element  130  to transition between or among those states. 
     The cavity  128  can be coupled (on another side from the blocking element  130 ) to a microphone port  132 , such as including a pathway that allows sound waves to be coupled from the cavity  128  to a microphone  134 . As described herein, when the blocking element  130  is disposed to prevent sound waves that enter the cavity  128  from continuing onward, there is substantially no acoustic coupling between the input port  126  and the microphone port  132 . In contrast, when the blocking element  130  is disposed to allow sound waves that enter the cavity  128  from continuing onward, the cavity  128  allows substantially transparent acoustic coupling between the input port  126  and the microphone port  132 . 
     Ameliorating Sonic Pressure 
     In one embodiment, the cavity  128  is disposed so that the input port  126  is located at an offset from the microphone port  132 , with the effect that sonic pressure that enters the cavity  128  is not directed at the microphone port  132 . Instead, sonic pressure that enters the cavity  128  is directed at one or more walls of the cavity  128 , and does not direct its force against the microphone  134 . 
     In one embodiment, the cavity  128  is disposed to include an expandable element  142 , such as a balloon or a relatively weaker metal portion of a wall of the cavity  128 . For example, the expandable element  142  can be located where sonic pressure entering the cavity  128  would be directed at the expandable element  142 . This could have the effect of causing the expandable element  142  to expand, in response to the sonic pressure entering the cavity  128 , thus reducing the effect of the sonic pressure on the microphone  134 . As an alternative, a relatively thin diaphragm may be situated between the expandable element  142  and cavity, and the expandable element may be relatively or fully constant in volume. Sonic or air pressure may break the diaphragm to permit air or pressure to enter the expandable element, thereby venting at least some of the pressure and protecting the microphone  134 . 
     In one embodiment, the cavity  128  is disposed to include one or more foam blocks  144 , or other compressible or expandable elements. For example, the cavity  128  can include one or more bellows or other structures that are compressible or expandable, in addition to or in lieu of the foam blocks  144 . This could have the effect of causing the compressible or expandable elements to increase the size of the cavity  128  in response to the sonic pressure entering the cavity  128 , thus reducing the amount of that pressure, and thus reducing the effect of that pressure on the microphone  134 . 
     In one embodiment, the microphone  134  has one or more foam blocks  144   a  and  144   b , or other compressible or expandable elements, disposed to absorb excess sonic pressure that might be applied to the microphone  134 . This could have the effect that energy from that excess sonic pressure would be dispersed, rather than applied directly to the parts of the microphone  134  (or the parts of a subassembly including the microphone  134 ), with the effect that the microphone  134  would be less subject to damage from excess sonic pressure. 
     For example, the foam block  144   a  can be disposed behind the microphone and capable of absorbing excess sonic pressure that might be applied to the microphone  134 . In such cases, the foam block  144   a  could be overpowered by the sonic pressure and thus compressed, forcing the microphone  134  away from the cavity  128 , removing the connection between the microphone port  132  and the cavity  128 , and isolating the sonic pressure from the microphone  134 . In such cases, the foam block  144   b  could be disposed in a ring shape about the microphone port  132 , with the effect that the foam block  144   b  could expand while the foam block  144   a  could be compressed, again having the effect of removing the connection between the microphone port  132  and the cavity  128 , and isolating the sonic pressure from the microphone  134 . 
     It should be appreciated that not all of the foam blocks  144   a ,  144   b , expandable element  142  and/or blocking elements  130  need be present in any given embodiment. Embodiments may have one, two or more of these items and the configuration and/or location of such items may vary. For example, the expandable element  142  may be positioned in a different part of the cavity  128 , or even may connect to the input port  126  instead of the cavity. Thus, although  FIG. 1  shows all of these elements, it should be appreciated that this is for the convenience of the reader and not intended as a requirement for any given embodiment. 
     Blocking Element 
       FIG. 2  (collectively including  FIGS. 2A, 2B, 2C, 2D, and 2E ) shows conceptual drawings of blocking elements, which may generally block sonic or air pressure from impacting the microphone or at least reduce such pressure. These various blocking elements are shown in cross-section and may be positioned approximately where the blocking element  130  is shown in  FIG. 1 . It should be appreciated that the blocking element may extend across an entirety of one or more dimensions of the cavity  128 , so that it (at least in certain configurations) interrupts free flow from the input port to the microphone port. Likewise, the blocking element or elements may define passages other than those seen in  FIGS. 2A-2E  either within their bodies or in cooperation with a wall of the cavity  128 , input port  126 , and/or microphone port  132 . As discussed below, a variety of the blocking elements may permit air flow and/or sonic pressure to pass through the element in certain configurations and block air flow and/or sonic pressure in other configurations. 
     In one embodiment, the blocking element  130  can be coupled to one or more walls of the cavity  128 . This can have the effect that when the blocking element  130  is closed, sonic pressure cannot penetrate the blocking element  130 , and cannot propagate from the input port  126  to the microphone port  124 . This can have the effect that the blocking element  130  provides a function of blocking sonic pressure, as described herein. 
     In one embodiment, one or more of the described possible blocking elements  130  can be incorporated into apparatus that protects the microphone input port  124  and the microphone  126  from sonic pressure. For example, one or more of the described possible blocking elements  130  can be disposed in series, such as one after the other, with the effect of blocking sonic pressure by each such possible blocking element  130  in turn. In alternative embodiments, one or more of the described possible blocking elements  130  may be disposed in parallel, such as one next to the other, with the effect of blocking sonic pressure in the alternative by distinct blocking elements  130 . 
     In one embodiment, one or more of the described possible blocking elements  130  can be can be opened or closed by an actuator (not shown). 
     For a first example, the actuator can be responsive to sonic pressure, with the effect that one or more of the described possible blocking elements  130  closes due to sonic pressure whenever that sonic pressure exceeds some selected amount. For example, if normal sound waves exhibit air pressure with a maximum of about 2 PSI, the flexible structure can be disposed to close when sonic pressure exceeds 5 PSI. These particular values are only exemplary. Other values for normal sound waves or for a sound pressure selected for closing the flexible structure could be used. 
     For a second example, the actuator can be responsive to acceleration, with the effect that the flexible structure closes due to application of sufficient acceleration. For example, if the microphone  126 , or the device including the microphone  126 , is normally subject to acceleration with a maximum of about 2 g (gravities), the flexible structure can be disposed to close when acceleration exceeds 5 g. These particular values are only exemplary. Other values for normal acceleration or for an undesired acceleration selected for closing the flexible structure could be used. 
       FIG. 2A  shows a conceptual drawing of a first type of blocking element. 
     In one embodiment, a blocking element  130  can include a flap or other flexible structure, the flexible structure being responsive to sonic pressure, with the effect that the flexible structure closes due to sonic pressure whenever that sonic pressure exceeds some selected amount. 
     In one embodiment, the blocking element  130  can include, either in addition or instead, a weight or other structure that is sensitive to acceleration, with the effect that the flexible structure closes due to application of sufficient acceleration. 
       FIG. 2B  shows a conceptual drawing of a second type of blocking element. 
     In one embodiment, the blocking element  130  can include a bistable, multi-stable, or semi-stable element, such as a pop-up button. In the figure, a pop-up button is shown as an example blocking element  130 , the pop-up button having two stable states, “closed” (popped-up) and “open” (pushed-in), and an actuator that can alter the blocking element  130  from one state to another. 
     For a first example, the blocking element  130  can be maintained in a “closed” state by being set to popped-down (e.g., in the position shown in phantom in  FIG. 2B ), in which case the blocking element  130  blocks passage of sound pressure into or through the cavity  128 . For a second example, the blocking element  130  can be maintained in an “open” state by being set to pushed-in, in which case the blocking element  130  allows free passage of sound waves into or through the cavity  128  (such as by allowing venting between the sides of the blocking element  130  and the walls of the cavity). 
     While this application shows the blocking element  130  as having two stable states, in the context of the invention, there is no particular requirement for any such limitation. For a first example, the blocking element  130  can have more than two stable states, such as a first state similar to the “closed” state described above, a second state similar to the “open” state described above, and a third state being partially open or partially closed. For a second example, the blocking element  130  may be semi-stable, or may have only one stable state. In such cases, the non-stable state may involve being actuated to be maintained. One such case might include a pop-up button that is stable when open, and which is actuated to be maintained in a closed state. 
       FIG. 2C  shows a conceptual drawing of a third type of blocking element. 
     In one embodiment, the blocking element  130  can include a sliding element, such as a sliding door moved by an actuator. Similar to other possible blocking elements  130  described herein, this can have the effect that when the blocking element  130  is closed, sonic pressure cannot penetrate the blocking element  130 , and cannot propagate from the input port  126  to the microphone port  124 . This can have the effect that the blocking element  130  provides a function of blocking sonic pressure, as described herein. 
       FIG. 2D  shows a conceptual drawing of a fourth type of blocking element. 
     In one embodiment, the blocking element  130  can include a rotatable element, such as a rotatable disk. In the figure, a rotatable element is shown edge-on, so that an axis of turning the rotatable element is substantially parallel to the plane of the figure. The rotatable element can include a hole, with the effect that when the hole is substantially aligned with the input port  126 , sound waves can enter or penetrate the cavity  128 . This also has the effect that when the hole is substantially unaligned with the input port  126 , sound pressure cannot enter or penetrate the cavity  128 . 
     In one embodiment, the rotatable element can be moved by an actuator (not shown). For a first example, the actuator can be coupled to an edge of the rotatable element, and cause the rotatable element to rotate. For a second example, the actuator can be coupled to a surface of the disk of the rotatable element, and cause the rotatable element to rotate. 
     In one embodiment, the rotatable element can include a ratchet or similar structure, with the effect that when rotated, the rotatable element does not easily reverse rotation. 
       FIG. 2E  shows a conceptual drawing of a fifth type of blocking element. 
     In one embodiment, the blocking element  130  can include a mesh, weave, or similar structure that presents one or more passages through the mesh, and which can be substantially tightened or loosened (such as by an actuator). This can have the effect that the mesh can block sound pressure when maintained in a relatively tighter mesh form, and can allow passage of sound waves when maintained in a relatively looser mesh form. The mesh may have a thickness equal to that of the side walls to which the mesh is affixed or otherwise attached. Alternatively, the mesh may be thinner than the thickness of the side walls or greater than the thickness of the side walls. Likewise, it should be appreciated that the mesh may define a passage upward or downward with respect to the orientation shown in  FIG. 2E , or inward or outward with respect to that orientation. 
     In one embodiment, the mesh, weave, or similar structure associated with the blocking element  130  can be tightened or loosened by an actuator (not shown). For a first example, the actuator can be activated by a measurement of sound pressure, such as a measurement of sound pressure that indicates an amount of sound pressure greater than ordinary sound waves, as described above. For a second example, the actuator can be activated by a measurement of acceleration, such as a measurement of acceleration that indicates an amount of acceleration greater than ordinary usage, as described above. The sensed input may cause the actuator to mechanically tighten or loosen the weave of the mesh, depending on the input. For example, a measurement of increased sound pressure, velocity or acceleration may cause the mesh to tighten, while a measurement of decreased pressure, velocity or acceleration may cause the mesh to loosen. The actuator may tighten or loosen the mesh through mechanical application of force, through electrostatics or otherwise through the application of an electric field, voltage or current, through magnetism, or the like. For example, in one embodiment the mesh may be an electroactive polymer or made from electroactive polymer fibers that are pulled tight when a voltage is applied thereto. As another example, the mesh may be formed from any suitable fibers in a weave and mechanically pulled to tighten the mesh. 
     Method of Operation 
       FIG. 3  shows a conceptual drawing of a method of operation. 
     A method  300  includes a set of flow points and method steps. 
     Although these flow points and method steps are shown performed in a particular order, in the context of the invention, there is no particular requirement for any such limitation. For example, the flow points and method steps could be performed in a different order, concurrently, in parallel, or otherwise. Similarly, although these flow points and method steps are shown performed by a general purpose processor in a force sensitive device, in the context of the invention, there is no particular requirement for any such limitation. For example, one or more such method steps could be performed by special purpose processor, by another circuit, or be offloaded to other processors or other circuits in other devices, such as by offloading those functions to nearby devices using wireless technology or by offloading those functions to cloud computing functions. 
     At a flow point  300 A, the method  300  is ready to begin. 
     At a step  310 , the method  300  initializes the blocking element  130  in its default state. In embodiments in which the default state is “unlocked” (that is, allowing passage of sound waves), the method  300  sets the blocking element  130  to unlocked, such as by disposing the blocking element  130  in a position or orientation that allows sound waves to reach the microphone port  132  and the microphone  134  from the ambient atmosphere  124  and the input port  126 . In embodiments in which the default state is “locked” (that is, blocking sonic pressure), the method  300  proceeds with the flow point  320 . 
     At a step  312 , the method  300  determines if audio input is expected in the near future, such as for the next several dozen milliseconds. If so, the method  300  proceeds with the next step. If not, the method  300  proceeds with the flow point  320 . 
     At an (optional) step  314 , the method  300  determines if sonic pressure at the input port  126  exceeds a maximum safe amount. For example, if a normal sound wave can reach a regular pressure amount of about 2 PSI, the maximum safe amount of sonic pressure might be set to be about 5 PSI, or some amount near to that. If not, the method  300  proceeds with the next step. If so, the method  300  proceeds with the flow point  320 . 
     At an (optional) step  316 , the method  300  determines if a measure of acceleration of the device exceeds a maximum safe amount. For example, if a normal acceleration can reach a normal acceleration of about 2 g (gravities), the maximum safe amount of acceleration might e set to be about 5 g, or some amount near to that. If not, the method  300 , having determined there is no current reason to protect against sonic pressure, returns to the flow point  300 A, where it re-begins. If so, the method  300  proceeds with the flow point  320 . 
     While this application describes both the step  314  (in which the method  300  determines if there is excess sonic pressure) and the step  316  (in which the method  300  determines if there is excess acceleration) as optional, at least one of these steps should be performed, if the method  300  is going to protect the microphone against excess sonic pressure. However, if the method  300  is alternatively going to ameliorate excess sonic pressure instead, it is possible that neither such optional step is performed, and the method need not perform either such optional step. 
     At a flow point  320 , the method  300  is ready to protect the microphone against excess sonic pressure. 
     At an (optional) step  322 , the method  300  alters the state of the blocking element  130  to a “locked” state (that is, blocking sonic pressure), 
     For a first example, as further described with respect to the  FIG. 2A , the method  300  can cause a flap to close, either in response to the step  314  (when a maximum safe amount of sonic pressure was measured) or in response to the step  316  (when a maximum safe acceleration was measured). In such cases, the method  300  can cause the flap to close automatically, such as due to the excess sonic pressure pushing the flap closed, or such as the excess acceleration causing the flap, or a weight on the flap, to move to close the flap. 
     For a second example, as further described with respect to the  FIG. 2B , the method  300  can cause a bistable, multi-stable, or meta-stable element to close, again, either in response to the step  314  (when a maximum safe amount of sonic pressure was measured) or in response to the step  316  (when a maximum safe acceleration was measured). In such cases, the method  300  can cause the bistable, multi-stable, or meta-stable element to close in response to the step  314  or in response to the step  316 , using an actuator, such as described with respect to the  FIG. 2B . 
     For a third example, as further described with respect to the  FIG. 2C , the method  300  can cause a rotatable element to move (such as to close a path between the input port  126  and the microphone port  132 ), either in response to the step  314  or in response to the step  316 , using an actuator, such as described with respect to the  FIG. 2C . 
     For a fourth example, as further described with respect to the  FIG. 2D , the method  300  can cause a linear element to move (such as to close a path between the input port  126  and the microphone port  132 ), either in response to the step  314  or in response to the step  316 , using an actuator, such as described with respect to the  FIG. 2D . 
     For a fifth example, as further described with respect to the  FIG. 2E , the method  300  can cause a mesh to become relatively closed (such as to restrict the flow of sonic pressure and sound waves between the input port  126  and the microphone port  132 ), either in response of the step  314  or in response to the step  316 , using an actuator, such as described with respect to the  FIG. 2E . 
     While this application describes each of the examples (first with respect to  FIG. 2A , second with respect to  FIG. 2B , third with respect to  FIG. 2C , fourth with respect to  FIG. 2D , and fifth with respect to  FIG. 2E ) as separate examples, in the context of the invention, there is no particular requirement for any such limitation. For example, two or more such examples can be performed by the method  300 . 
     While this application describes the step  342 , and each of its examples, as optional, at least one of these steps should be performed, if the method  300  is going to protect the microphone against excess sonic pressure. However, if the method  300  is alternatively going to ameliorate excess sonic pressure instead, it is possible that the method need not perform either such optional step. 
     At a flow point  340 , the method  300  is ready to ameliorate excess sonic pressure. 
     At an (optional) step  342 , the method  300  allows excess sonic pressure into the cavity  128 , wherein the input port  124  is disposed at an offset location from the microphone port  132 . This can have the effect that the excess sonic pressure is allowed to expand and dissipate, with the effect of ameliorating its effect, on the microphone port  132  and the microphone  134 . 
     At an (optional) step  344 , the method  300  allows excess sonic pressure into the cavity  128 , wherein the input port  124  is disposed near to (such as directly opposite) an expandable element  142 . This can have the effect that the expandable element  142  can receive the sonic pressure, and expand in response thereto. The expandable element  142  can expand the cavity  128 , ameliorating the effect of the sonic pressure on the microphone port  132  and the microphone  134 . Alternatively, the expandable element  142  can receive the brunt of the sonic pressure, ameliorating the effect of the sonic pressure on the microphone port  132  and the microphone  134 . 
     In one embodiment, the expandable element  142  can be allowed to expand sufficiently that it actually breaks, leaving an acoustic pathway between the cavity  128  and other elements of the device. While this is not a generally desirable result, it can be superior to allowing the microphone  134  to break. Should this occur, the microphone  134  might exhibit reduced function, such as due to noise from the acoustic pathway between the cavity  128  and other elements of the device. However, this example of reduced function might be considered superior to breaking the microphone  134  itself, which would cause the microphone  134  to exhibit substantially no function, which is typically inferior to exhibiting reduced function. 
     At an (optional) step  346 , the method  300  allows the cavity  128  to expand, such as by compressing a foam block  144  (or other compressible element) to absorb sonic pressure, or such as by allowing a bellows (not shown) to expand. After reading this application, those skilled in the art will recognize that the expandable element  142  is a form of bellows, but that a more general bellows, such as one that allows the entire cavity  128  to expand under sonic pressure, might also be desirable. 
     Similarly, as part of the step  346 , the method  300  can allow one or more foam blocks  144  (or other compressible elements) to absorb excess sonic pressure on the microphone  134 . For example, excess sonic pressure on the microphone  134  can be absorbed by the one or more foam blocks  144  (or other compressible elements), with the effect that excess sonic pressure on the on the microphone  134  can be reduced to the point where damage to the microphone  134  is minimized or perhaps even averted. 
     While this application describes each of the steps  342  (in which the method  300  allows excess sonic pressure into the cavity  128 ), the step  344  (in which the method  300  causes an expandable element to operate), and the step  346  (in which the method  300  allows the cavity  128  to expand) as optional, at least one of these steps should be performed, if the method  300  is going to ameliorate the effect of excess sonic pressure. However, if the method  300  is alternatively going to prevent excess sonic pressure from reaching the microphone  134  instead, it is possible that neither such optional step is performed, and the method need not perform either such optional step. 
     After the step  346 , the method  300  determines if it should continue. If so, the method  300  proceeds with the flow point  300 A, where the method  300  is ready to re-begin. If not, the method  300  proceeds with the flow point  300 B, where the method  300  is done. 
     At a flow point  300 B, the method  300  is over. In one embodiment, the method  300  repeats so long as the force sensitive device is powered on.