Dropout detection techniques

Abstract

A method is provided for filtering a signal received from a sensor of a medication delivery device. In some embodiments, the method includes detecting a first transition of the signal to a first logic state from a second logic state, the first transition occurring at a first time point; determining, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detecting a second transition of the signal to the second logic state from the first logic state, the second transition occurring at a second time point after the first time point; and determining, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state.

Description

DROPOUT DETECTION TECHNIQUESBACKGROUND OF THE INVENTION

[0001] Patients suffering from various diseases must frequently inject themselves with medication. To allow a person to conveniently and accurately self-administer medicine, a variety of devices broadly known as pen injectors or injection pens have been developed. Generally, these pens are equipped with a cartridge including a piston and containing a multi-dose quantity of liquid medication. A drive member is movable forward to advance the piston in the cartridge to dispense the contained medication from an outlet at the distal cartridge end, typically through a needle.

[0002] Such devices may have components that physically interact with one another to result in a state change or an action by the device. For example, the device may have a dose button that may be rotated to a set dose and / or actuated to deliver a dose.

[0003] Such devices can include electronics, such as an integrated circuit with a processing unit and other components. For example, the electronics can include a sensing device in communication with a processing unit to detect the occurrence of such interactions.SUMMARY OF THE INVENTION

[0004] According to an exemplary embodiment of the present disclosure, a method for filtering a signal received from a sensor of a medication delivery device is provided. The sensor is operable to transition between an engaged state and a disengaged state. The method includes: detecting a first transition of the signal to a first logic state from a second logic state, the first transition occurring at a first time point; determining, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detecting a second transition of the signal to the second logic state from the first logic state, the second transition occurring at a second time point after the first time point; and determining, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.

[0005] According to an exemplary embodiment of the present disclosure, a medication delivery device is provided. The medication delivery device comprises: a housingcomprising a proximal portion and a distal portion, the distal portion containing a cartridge configured to hold a medication; a needle disposed in an outlet of the distal portion of the housing; and a dose detection system coupled to the proximal portion of the housing, the dose detection system comprising: a sensor configured to output a signal; a flange comprising teeth and being configured to rotate with respect to the sensor, wherein the teeth are configured to trigger the sensor to transition between an engaged state and a disengaged state as the flange rotates; and a controller configured to perform a method for filtering the signal output by the sensor, the method comprising: detecting a first transition of the signal to a first logic state from a second logic state, the first transition occurring at a first time point; determining, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detecting a second transition of the signal to the second logic state from the first logic state, the second transition occurring at a second time point after the first time point; and determining, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Additional embodiments of this disclosure, as well as features and advantages thereof, will become more apparent by reference to the description herein taken in conjunction with the accompanying drawings. The components in the figures are not necessarily to scale. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views.

[0007] FIG. l is a perspective view of a medication delivery device having a dose detection system according to aspects of the present disclosure.

[0008] FIG. 2 is a partially exploded perspective view of the medication delivery device of FIG. 1, showing a dose button having a support and a cover, where the cover is shown separated from the support.

[0009] FIG. 3 is a partially exploded perspective view of the medication delivery device of FIG. 1 showing the components of the dose detection system.

[0010] FIG. 4 is a cross-sectional view of the medication delivery device of FIG. 1.

[0011] FIG. 5 is a partial cutaway view of a proximal end of the medication delivery device of FIG. 1, showing components of the dose detection system.

[0012] FIG. 6 is an underside view of a portion of the dose button of FIG. 1, showing a printed circuit board held within the dose button cover.

[0013] FIG. 7 is an exploded view of the portion of the dose button shown in FIG. 6.

[0014] FIG. 8 is a perspective view of a flange of a dose detection system of a medication delivery device.

[0015] FIG. 9 is a top down view of the flange of FIG. 8.

[0016] FIG. 10 is a perspective view of a dose button support.

[0017] FIG. 11 is a top down view of the dose button support of FIG. 10.

[0018] FIG. 12 is an exemplary schematic diagram of a printed circuit board, according to some embodiments.

[0019] FIG. 13 is an exemplary plot showing the signal received from the sensor of a medication delivery device, according to some embodiments.

[0020] FIG. 14 and FIG. 15 are flowcharts showing an exemplary method for filtering a signal received from a sensor of a medication delivery device, according to some embodiments.

[0021] FIG. 16 is an exemplary plot showing the signal received from the sensor of a medication delivery device, according to some embodiments.DETAILED DESCRIPTION OF THE INVENTION

[0022] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.

[0023] Provided herein are techniques for filtering a signal received from a sensor of a medication delivery device. According to some embodiments, the sensor is operable to transition between an engaged state and a disengaged state. For example, the sensor may transition to an engaged state when it begins to interact with a sensed component of a medication delivery device. The sensor may transition to a disengaged state when it no longer interacts with the sensed component of the medication delivery device.

[0024] The engaged and / or disengaged state(s) can be used to determine information about the medication delivery device, such as dosing information. In some embodiments, the transitions of the sensor between the engaged state and the disengaged state may be used to determine a dosage of medication that has been delivered and / or was set to be delivered using the medication delivery device. As a nonlimiting example, the dosage of the medication may be determined based on the number of times that the sensor transitioned to an engaged state and / or to a disengaged state. Accordingly, the inventors have appreciated that it is important to accurately account for the number of times that the sensor has transitioned to the engaged state and / or disengaged state in order to accurately determine the dosage of medication delivered and / or set to be delivered using the medication delivery device. For example, a medication delivery device may include a flange with teeth that rotates as a dose is being dispensed by the device. As the flange rotates, the teeth can interact with a mechanical sensor to trigger the sensor. Every time the sensor is physically triggered by a tooth (e.g., when the sensor contacts a tooth and / or when the sensor is no longer contacting the tooth), the sensor can output an electrical signal that is counted by a processor of the medication delivery device. The processor can count these electrical signals to determine how much the flange has rotated and optionally, based on the rotation information, determine how much insulin was dispensed by the medication delivery device. Alternatively, the processor may communicate the rotation information to another device which determines, based on the rotation information, how much insulin was dispensed by the medication delivery device.

[0025] In some embodiments, a signal output by the sensor may be used to infer whether the sensor has transitioned between the engaged state and / or the disengaged state. For example, when the sensor is in the engaged state, it may be configured to output a signal in a first logic state, and when the sensor is in the disengaged state, it may be configured to output a signal in a second logic state that is different from the first logic state. Accordingly, when the sensor transitions between the engaged state and the disengaged state, the signal output by the sensor may transition between the first logic state and the second logic state. For example, the first logic state of the signal may be an asserted state (e.g., logic 1, high state, etc.), while the second logic state of the signal may be a deasserted state (e.g., logic 0, low state, etc.), or vice versa. While embodiments herein have been described assuming that the sensor outputs a signal in an asserted state when in the engaged state and outputs a signal in a de-asserted state when in the disengaged state, onecould easily reverse this with appropriate modifications. For example, the signal may be passed through an inverter before being processed to detect transitions between logic states.

[0026] However, the inventors have recognized that there are limitations to this approach. In particular, there may be signal dropouts associated with the transition of the sensor between the engaged state and the disengaged state. For example, as the sensor begins to engage with a sensed component, it may lose contact with the sensed component, such that the signal output by the sensor transitions to the second logic state when it should have remained in the first logic state. For example, internal to the sensor, there may be one or more contact surfaces that include a conductive surface (e.g., a conductive gold surface). Such a conductive surface within the sensor may become worn down after repeatedly sliding over the teeth of the medication delivery device. As a result, when the worn-down portion of the conductive surface contacts a tooth, the signal output by the sensor may momentarily transition from the first logic state (e.g., an asserted state) to the second logic state (e.g., the de-asserted state).

[0027] Furthermore, the inventors have recognized that, unlike spurious noise, there may be significant variation in the duration of a signal dropout. For example, the duration of a signal dropout may depend on the speed at which the flange of the medication delivery device rotates. If the flange rotates slowly, then a tooth of the flange will engage the conductive and non-conductive (e.g., worn down) portions of the contact surfaces internal to the sensor for relatively long durations, resulting in a signal that remains in a particular logic state for a relatively long duration. By contrast, if the flange rotates quickly, then the tooth will engage the conductive and non-conductive portions of the contact surfaces internal to the sensor for relatively short durations of time, resulting in a signal that remains in a particular logic state for a relatively short duration of time. Due to these variations, the inventors have recognized that it would be challenging to detect dropouts based on the absolute value of a duration that the signal is in a particular logic state (e.g., a de-asserted state). In particular, it would be challenging to establish a threshold that could be used to accurately distinguish between signal dropouts versus a transition of the sensor to the disengaged state.

[0028] Accordingly, the inventors have developed techniques for filtering a signal received from a sensor of a medication delivery device that address the above-described limitations of conventional techniques. In some embodiments, the techniques detecttransitions of the signal between logic states and use the detected transitions to determine whether the sensor has transitioned between an engaged state and / or a disengaged state. For example, in some embodiments, the techniques: (a) detect a first transition of the signal to a first logic state from a second logic state, the first transition occurring at a first time point; (b) detect a second transition of the signal to the second logic state from the first logic state, the second transition occurring at a second time point after the first time point; and (c) determine, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.

[0029] While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible. Accordingly, the embodiments described herein are examples, not the only possible embodiments and implementations. Furthermore, the advantages described above are not necessarily the only advantages, and it is not necessarily expected that all of the described advantages will be achieved with every embodiment.

[0030] Devices described herein may comprise a medication, such as for example, within a reservoir or cartridge 20 (described below). In another embodiment, a system may comprise one or more devices including device 10 (described below) and a medication. The term “medication” refers to one or more therapeutic agents including but not limited to insulins, insulin analogs such as insulin lispro or insulin glargine, insulin derivatives, GLP-1 receptor agonists such as dulaglutide or liraglutide , glucagon, glucagon analogs, glucagon derivatives, gastric inhibitory polypeptide (GIP), GIP analogs, GIP derivatives, oxyntomodulin analogs, oxyntomodulin derivatives, therapeutic antibodies and any therapeutic agent that is capable of delivery by the devices described herein. The medication as used in the device may be formulated with one or more excipients. The device is operated in a manner generally as described above by a patient, caregiver or healthcare professional to deliver medication to a person.

[0031] An exemplary medication delivery device 10 is illustrated in FIGS. 1-4 as a pen injector configured to inject a medication into a patient through a needle. Device 10 includes a body 11 that may comprise an elongated, pen-shaped housing 12 including a distal portion 14 and a proximal portion 16. As used herein, the term “distal” refers to the direction and / or portion of a medication delivery device that is pointed towards (orlocated closer to) the site of injection, while the term “proximal” refers to the direction and / or portion of a medication delivery device that is pointed away from (or located further away from) the site of injection. Distal portion 14 may be received within a pen cap 18. Referring to FIG. 4, distal portion 14 may contain a reservoir or cartridge 20 configured to hold medication to be dispensed through the outlet 21 of the housing a dispensing operation. The outlet 21 of distal portion 14 may be equipped with an injection needle 24. In some embodiments, the injection needle is removable from the housing. In some embodiments, the injection needle is replaced with a new injection needle after each use.

[0032] A piston 26 may be positioned in reservoir 20. The medication delivery device may include an injecting mechanism positioned in proximal portion 16 that is operative to advance piston 26 toward the outlet of reservoir 20 during the dose dispensing operation to force the contained medicine through the needled end. The injecting mechanism may include a drive member 28, illustratively in the form of a screw, that is axially moveable relative to housing 12 to advance piston 26 through reservoir 20.

[0033] The device may include a dose-setting assembly coupled to the housing 12 for setting a dose amount to be dispensed by device 10. As best seen in FIGS. 3 and 4, in the illustrated embodiment, the dose-setting assembly includes a dose-setting screw 32 and a flange 38. The dose-setting screw 32 is in the form of a screw element operative to spiral (i.e., simultaneously move axially and rotationally) about a longitudinal axis AA of rotation relative to housing 12 during dose setting and dose dispensing. FIGS. 3 and 4 illustrate the dose-setting screw 32 fully screwed into housing 12 at its home or zero dose position. Dose-setting screw 32 is operative to screw out in a proximal direction from housing 12 until it reaches a fully extended position corresponding to a maximum dose deliverable by device 10 in a single injection. The extended position may be any position between a position corresponding to an incremental extended position (such as a dose setting a 0.5 or 1 unit) to a fully extended position corresponding to a maximum dose deliverable by device 10 in a single injection and to screw into housing 12 in a distal direction until it reaches the home or zero position corresponding to a minimum dose deliverable by device 10 in a single injection.

[0034] Referring to FIGS. 3 and 4, dose-setting screw 32 includes a helically threaded outer surface that engages a corresponding threaded inner surface 13 of housing 12 to allow dose-setting screw 32 to spiral (i.e. simultaneously rotate and translate) relative tohousing 12. Dose-setting screw 32 further includes a helically threaded inner surface that engages a threaded outer surface of sleeve 34 (FIG. 4) of device 10. The outer surface of dose-setting screw 32 includes dose indicator markings, such as numbers that are visible through a dosage window 36 to indicate to the user the set dose amount.

[0035] As mentioned above, in some embodiments, the dose-setting assembly further includes a tubular flange 38 that is coupled in the open proximal end of dose-setting screw 32 and is axially and rotationally locked to the dose-setting screw 32 by protrusions 40 received within openings 41 in the dose-setting screw 32. The protrusions 40 of the flange 38 can be seen in FIGS. 3, 8 and 9, and the openings 41 of the dose-setting screw 32 can be seen in FIG. 3.

[0036] As seen in FIGS. 3 and 4, delivery device 10 may include an actuator assembly having a clutch 52 and a dose button 30. The clutch 52 is received within the dose-setting screw 32, and the clutch 52 includes an axially extending stem 54 at its proximal end.The dose button 30 of the actuator assembly is positioned proximally of the dose-setting screw 32 and flange 38. Dose button 30 includes a support 42, also referred to herein as an “under button,” and a cover 56, also referred to herein as an “over button.” As will be discussed, the support 42 and cover 56 enclose electronics components used to store and / or communicate data relating to amount of dose delivered and / or set to be delivered by a medication delivery device.

[0037] The support 42 of the dose button may be attached to the stem 54 of the clutch 52, such as with an interference fit or an ultrasonic weld, so as to axially and rotatably fix together dose button 30 and clutch 52.

[0038] In some embodiments, a portion of the clutch may pass through a lumen 39 of the flange 38. The lumen 39 of the flange is best seen in FIGS. 8 and 9. The lumen 39 may, in some embodiments, serve to help center the clutch 52 in place.

[0039] Proximal face 60 of the dose button 30 may serve as a push surface against which a force can be applied manually, i.e., directly by the user to push the actuator assembly (dose button 30 and clutch 52) in a distal direction. A bias member 68, illustratively a spring, may be disposed between the distal surface 70 of support 42 and a proximal surface 72 of tubular flange 38 (FIGS. 8 and 9) to urge the support 42 of the actuation assembly and the flange 38 of the dose-setting assembly axially away from each other. Dose button 30 is depressible by a user to initiate the dose dispensing operation. In someembodiments, the bias member 68 is seated against this proximal surface 72 and may surround a raised collar 37 of the flange 38.

[0040] Delivery device 10 is operable in a dose setting mode and a dose dispensing mode. In the dose setting mode of operation, the dose button 30 is rotated relative to housing 12 to set a desired dose to be delivered by device 10. In some embodiments, rotating the dose button 30 in one direction relative to the housing 12 causes the dose button 30 to axially translate proximally relative to the housing 12, and rotating the dose button 30 in the opposite direction relative to the housing 12 causes the dose button 30 to axially translate distally relative to the housing. In some embodiments, clockwise rotation of the dose button moves the dose button 30 distally, and counter-clockwise rotation of the dose button moves the dose button proximally, or vice versa.

[0041] In some embodiments, rotating the dose button 30 to axially translate the dose button 30 in the proximal direction serves to increase the set dose, and rotating the dose button 30 to axially translate the dose button 30 in the distal direction serves to decrease the set dose. The dose button 30 is adjustable in pre-defined rotational increments corresponding to the minimum incremental increase or decrease of the set dose during the dose setting operation. The dose button may include a detent mechanism such that each rotational increment produces an audible and / or tactile “click.” For example, one increment or “click” may equal one-half or one unit of medication.

[0042] In some embodiments, the set dose amount may be visible to the user via the dial indicator markings shown through a dosage window 36. During the dose setting mode, the actuator assembly, which includes the dose button 30 and clutch 52, moves axially and rotationally with the dose-setting assembly, which includes the flange 38 and the dose-setting screw 32.

[0043] Dose-setting screw 32 and flange 38 are fixed rotationally to one another, and rotate and move proximally during dose setting, due to the threaded connection of the dose-setting screw 32 with housing 12. During this dose setting motion, the dose button 30 is rotationally fixed relative to the flange 38 and the dose-setting screw 32 by complementary splines 74 of flange 38 and clutch 52 (FIG. 4), which are urged together by the bias member 68. In the course of dose setting, the dose-setting screw 32, flange 38, clutch 52, and dose button 30 move relative to the housing 12 in a spiral manner (i.e., simultaneous rotation and axial translation) from a “start” position to an “end” position.This rotation and translation relative to the housing is in proportion to the amount of dose set by operation of the medication delivery device 10.

[0044] Once the desired dose is set, device 10 is manipulated so the injection needle 24 properly penetrates, for example, a user's skin. The dose dispensing mode of operation is initiated in response to an axial distal force applied to the proximal face 60 of dose button 30. The axial force is applied by the user directly to dose button 30. This causes axial movement of the actuator assembly (dose button 30 and clutch 52) in the distal direction relative to housing 12.

[0045] The axial shifting motion of the actuator assembly compresses biasing member 68 and reduces or closes the gap between dose button 30 and the tubular flange 38. This relative axial movement separates the complementary splines 74 on clutch 52 and flange 38, and thereby disengages the dose button 30 from being rotationally fixed to the flange 38 and the dose-setting screw 32. In particular, the dose-setting screw 32 is rotationally uncoupled from the dose button 30 to allow backdriving rotation of the dose-setting screw 32 relative to the dose button 30 and the housing 12. Also, while the dose-setting screw 32 and flange 38 are free to rotate relative to the housing 12, the dose button 30 is held from rotating relative to the housing 12 by the user’s engagement of dose button 30 by pressing against it.

[0046] As dose button 30 and clutch 52 are continued to be axially plunged without rotation relative to housing 12, dose-setting screw 32 screws back into housing 12 as it spins relative to dose button 30. The dose markings that indicate the amount still remaining to be injected are visible through window 36. As dose-setting screw 32 screws down distally, drive member 28 is advanced distally to push piston 26 through reservoir 20 and expel medication through needle 24.

[0047] During the dose dispensing operation, the amount of medicine expelled from the medication delivery device is proportional to the amount of rotational movement of the dose-setting screw 32 relative to the housing 12 as the dose-setting screw 32 screws back into housing 12. In some embodiments, because the dose button 30 is rotationally fixed relative to the housing 12 during the dose dispensing mode (e.g., due to engagement with the user’s finger), the amount of medicine expelled from the medication delivery device may be viewed as being proportional to the amount of rotational movement of the dosesetting screw 32 relative to the dose button 30 as the dose-setting 32 screws back intohousing 12. The injection is completed when the internal threading of dose-setting screw 32 has reached the distal end of the corresponding outer threading of sleeve 34 (FIG. 4). Device 10 is then once again arranged in a ready state or zero dose position as shown in FIGS. 2 and 4.

[0048] As discussed above, the dose delivered and / or set to be delivered may be derived based on the amount of rotation of the dose-setting assembly (flange 38 and dose-setting screw 32) relative to the actuator assembly (clutch 52 and dose button 30) during dose delivery. This rotation may be determined by detecting the incremental movements of the dose-setting assembly which are “counted” as the dose-setting assembly is rotated during dose delivery and / or prior to dose delivery (e.g., when a dose is being set to be delivered).

[0049] Further details of the design and operation of an exemplary delivery device 10 may be found in U.S. Patent No. 7,291,132, entitled Medication Dispensing Apparatus with Triple Screw Threads for Mechanical Advantage, the entire disclosure of which is hereby incorporated by reference herein. Another example of the delivery device is an auto-injector device that may be found in U.S. Patent No. 8,734,394, entitled “Automatic Injection Device With Delay Mechanism Including Dual Functioning Biasing Member,” which is hereby incorporated by reference in its entirety, where such device being modified with one or more various sensor systems described herein to determine an amount of medication delivered and / or set to be delivered from the medication delivery device based on the sensing of relative rotation within the medication delivery device. Another example of the delivery device is a reusable pen device that may be found in U.S. Patent No. 7,195,616, entitled “Medication Injector Apparatus with Drive Assembly that Facilitates Reset,” which is hereby incorporated by reference in its entirety, where such device being modified with one or more various sensor systems described herein to determine an amount of medication delivered and / or set to be delivered from the medication delivery device based on the sensing of relative rotation within the medication delivery device.

[0050] Described herein is a dose detection system that may be operable to determine the amount of dose delivered and / or set to be delivered based on relative rotation between a dose setting member and the device body. The dose detection system utilizes a dose setting member attached to the device body and rotatable relative to the device body about an axis of rotation during dose delivery. A sensed element is attached to and rotationally fixed with the dose setting member. An actuator is attached to the devicebody and is held against rotation relative to the device body during dose delivery. The sensed element thereby rotates relative to the actuator during dose delivery in relation to the amount of dose delivered and / or the amount of dose set to be delivered.

[0051] In some embodiments, the dose detection system comprises a rotational sensor attached to the actuator assembly and a sensed element that includes surface features that are equally radially spaced about the axis of rotation of the sensed element.

[0052] In some embodiments, the dose detection systems may include a sensor and a sensed component attached to components of the medication delivery device. The term “attached” encompasses any manner of securing the position of a component to another component or to a member of the medication delivery device such that they are operable as described herein. For example, a sensor may be attached to a component of the medication delivery device by being directly positioned on, received within, integral with, or otherwise connected to, the component. Connections may include, for example, connections formed by frictional engagement, splines, a snap or press fit, sonic welding or adhesive.

[0053] The term “directly attached” is used to describe an attachment in which two components, or a component and a member, are physically secured together with no intermediate member, other than attachment components. An attachment component may comprise a fastener, adapter or other part of a fastening system, such as a compressible membrane interposed between the two components to facilitate the attachment. A “direct attachment” is distinguished from attachment where the components / members are coupled by one or more intermediate functional members.

[0054] The term “fixed” is used to denote that an indicated movement either can or cannot occur. For example, a first member is “fixed rotationally” with a second member if the two members are required to move together in rotation. In one aspect, a member may be “fixed” relative to another member functionally, rather than structurally. For example, a member may be pressed against another member such that the frictional engagement between the two members fixes them together rotationally, while the two members may not be fixed together absent the pressing of the first member.

[0055] Various sensor arrangements are contemplated herein. In general, the sensor arrangements comprise a sensor and a sensed component. The term “sensor” refers to any component which is able to detect the relative position or movement of the sensedcomponent. The sensor may be used with associated electrical components to operate the sensor. The “sensed component” is any component for which the sensor is able to detect the position and / or movement of the sensed component relative to the sensor. For the dose detection system, the sensed component rotates relative to the sensor, which is able to detect the rotational movement of the sensed component. The sensor may comprise one or more sensing elements, and the sensed component may comprise one or more sensed elements. The sensor detects the movement of the sensed component and provides outputs representative of the movement of the sensed component.

[0056] Illustratively, the dose detection system includes an electronics assembly suitable for operation of the sensor arrangement as described herein. The medication delivery device may include a controller that is operably connected to the sensor to receive outputs from the sensor. The controller begins receiving generated signals from the sensor indicative of counts from first to last one for a total number of counts that is used for determining total displacement, e.g. angular displacement. In the case of detecting an angular movement of a dose-setting assembly, the controller may be configured to receive data indicative of the angular movement of the dose-setting assembly that can be used to determine from the outputs the amount of dose delivered and / or set to be delivered by operation of the medication delivery device. The controller may, optionally, be configured to determine from the outputs the amount of dose delivered and / or set to be delivered by operation of the medication delivery device. The controller may include conventional components such as a processor, power supply, memory, microcontrollers, etc. Additionally, or alternatively, at least some components may be provided separately, such as by means of a computer, smart phone or other device. Means are then provided to operably connect the external controller components with the sensor at appropriate times, such as by a wired or wireless connection. For example, the controller on board the medication delivery device may be configured to determine only the amount of angular movement of the dose-setting assembly and communicate this angular movement to the external controller. The external controller may then be configured to determine the amount of dose delivered and / or set to be delivered based on the angular movement information.

[0057] According to one aspect, the electronics assembly includes a sensor arrangement including one or more sensors operatively communicating with a processor for receiving signals from the sensor representative of the sensed rotation. An exemplary electronicsassembly 76 is shown in FIGS. 5-7 and can include a sensor 86, and a printed circuit board (PCB) 77 having a plurality of electronic components. The printed circuit board may be a flexible printed circuit board. The circuit board of the electronics assembly 76 may include a microcontroller unit (MCU) as the controller comprising at least one processing core and internal memory. The electronics assembly may include a power source 79, e.g. a battery, illustratively a coin cell battery, for powering the components. The controller of electronics assembly 76 may include control logic operative to perform the operations described herein, including detecting the angular movement of the dosesetting assembly during dose setting and / or dose delivery and / or detecting a dose delivered by medication delivery device 10 based on a detected rotation of the dosesetting assembly relative to the actuator assembly. Many, if not all of the components of the electronics assembly, may be contained in a compartment 85 within the dose button 30. In some embodiments, the compartment 85 may be defined between a proximal surface 71 of support 42 of the dose button and a distal surface 81 of the cover 56 of the dose button. In the embodiment shown in FIG. 5, the electronics assembly 76 is permanently integrated within the dose button 30 of the delivery device. In other embodiments, the electronics assembly is provided as a module that can be removably attached to the actuator assembly of the medication delivery device.

[0058] An underside view of the electronics assembly 76 held within the cover 56 is shown in FIG. 6, and an exploded view of the electronics assembly 76 is shown in FIG. 7. As shown in FIGS. 6 and 7, the electronics assembly 76 may include a printed circuit board (PCB) 77 and a sensor 86 having a contact surface 111. As shown in FIG. 7, the electronics assembly 76 may also include a battery 79 and a battery cage 87.

[0059] In some embodiments, at least a portion of the sensor 86 extends out of the compartment 85 of the dose button 30. As best seen in FIGS. 10 and 11, the support 42 of the dose button 30 may include one or more openings 45 through which the sensor 86 can extend through. In some embodiments, during assembly of the medication delivery device, the contact surface 111 of the sensor 86 is passed through the opening 45 of the support 42. This may permit the contact surface 111 of the sensor to interact with a component that is external to the compartment 85 of the dose button 30. In some embodiments, while only one of the openings 45 in the support 42 is needed to accommodate a sensor, a second opening may be provided, e.g. for symmetry of the support component, which help with manufacturing of the component and / or assembly ofthe component with the medication delivery device.

[0060] The controller of electronics assembly 76 may be operative to store the total angular movement used for determining dose delivery and / or the detected dose delivery in local memory (e.g., internal flash memory or on-board EEPROM). The controller may be further operative to wirelessly transmit a signal representative of the total counts, total angular movement, and / or detected dose to an external device, such as a user’s mobile device or a remote server. Transmission may, for example, be over a Bluetooth low energy (BLE) or other suitable short or long range wireless communication protocol. Illustratively, the BLE control logic and controller are integrated on the same circuit.

[0061] As discussed, according to one aspect, the dose detection system involves detecting relative rotational movement between two assemblies of the medication delivery device. With the extent of rotation having a known relationship to the amount of a delivered dose, the sensor operates to detect the amount of angular movement from the start of a dose injection to the end of the dose injection. For example, in some embodiments, the relationship for a pen injector is that an angular displacement of a dosesetting assembly of 18° is the equivalent of one unit of dose, although other angular relationships are also suitable, such as, for example, 9, 10, 15, 20, 24 or 36 degrees may be used for a unit or a half unit. The sensor system is operable to determine the total angular displacement of a dose setting member during dose delivery. Thus, if the angular displacement is 90°, then 5 units of dose have been delivered.

[0062] The angular displacement is determined by counting increments of dose amounts as the injection proceeds. For example, a sensing system may use a repeating pattern of a sensed element, such that each repetition is an indication of a predetermined degree of angular rotation. Conveniently, the pattern may be established such that each repetition corresponds to the minimum increment of dose that can be set with the medication delivery device.

[0063] The dose detection system components may be permanently or removably attached to the medication delivery device. In some embodiments, at least some of the dose detection system components are provided in the form of a module that is removably attached to the medication delivery device. In other embodiments, the dose detection system components are permanently attached to the medication delivery device.

[0064] In some embodiments, a sensor may detect, during dose delivery, the relativerotation of a sensed component that is rotationally fixed to the dose-setting screw 32, from which is determined the amount of a dose delivered by the medication delivery device. In an illustrative embodiment, a rotational sensor is attached, and rotationally fixed, to the actuator assembly. The actuator assembly does not rotate relative to the device housing during dose delivery.

[0065] In some embodiments, a sensed component is attached, and rotationally fixed, to the dose-setting screw 32, which rotates relative to the dose button 30 and the device housing 12 during dose delivery. In some of the embodiments described herein, the sensed component includes a ring structure having a plurality of proximally extending projections circumferentially disposed relative to one another. Projections are shaped and sized to deflect a movable element of the rotational sensor. One illustrative embodiment of such a sensed component is tubular flange 38, best seen in FIGS. 3, 5, 8, and 9. Embodiments described herein may be provided for a module that is removably attachable to the dose button of the delivery device or integrated within the dose button of the delivery device.

[0066] During dose delivery, dose-setting screw 32 is free to rotate relative to dose button 30. In the illustrative embodiment, the electronics assembly 76 is rotationally fixed with the dose button 30 and does not rotate during dose delivery.

[0067] As seen in FIGS. 2, 3 and 5, the dose button 30 comprises a cover 56 coupled to a support 42. An electronics assembly 76 may be at least partially contained within a compartment 85 defined between the cover 56 and the support. In some embodiments, the cover and support have corresponding splines that engage with one another to couple the cover and support together. For example, in some embodiments, the cover 56 may couple to the support 42 via one or more snaps 57 on the cover 56 and corresponding to one or more protrusions 43 on the support. As seen in FIG. 5 and 6, the snaps 57 on the cover 56 may be directed radially inwardly from an inner circumferential sidewall 73. As seen in FIGS. 5, 10 and 11, the protrusions 43 on the support 42 may be directed radially outwardly from an outer circumferential sidewall 75 of the support 42. The protrusions 43 may form a triangular ramp shape.

[0068] The snaps 57 on the cover 56 are configured to snap over and mate with the protrusions 43 on the support to couple the cover to the support. In some embodiments, the protrusion on the support comprises a continuous annular protrusion around the outercircumferential sidewall of the support. The cover 56 may attach to the support 42 via frictional engagement, interference fit or any other suitable fit. In some embodiments, the cover 56 is permanently fixed to the support 42 during assembly, e.g., via ultrasonic welding, adhesive, or other suitable fixation approach.

[0069] As seen in FIGS. 8 and 9, the tubular flange 38 may include a plurality of axially directed teeth 102 that are equally radially spaced about a rotation axis and arranged to correlate to the equivalent of one unit of dose. In this illustrative embodiment, the tubular flange 38 includes 20 teeth 102 that are equally rotationally spaced from one another, such that the rotation distance between two adjacent teeth corresponds to 18 degrees of rotation. Thus, with the tubular flange 38 of FIG. 8, 18 degrees of rotation of the tubular flange 38 may be used to represent one dosage unit or a half dosage unit. It should be appreciated that, in other embodiments, different total numbers of teeth may be used to create other angular relationships, such as, for example, 9, 10, 15, 18, 20, 24 or 36 degrees may be used for a unit or 0.5 unit.

[0070] A recess 124 may be defined between each pair of adjacent teeth 102. Each tooth 102 may have an approximately triangular shaped profile, each having a surface 120 against which a contact surface 111 of a sensor may slide.

[0071] In some embodiments, the sensor for detecting rotation of the tubular flange includes a movable element that has a contact portion capable of resting against the teeth of the tubular flange and is spring-biased such that the contact surface is configured to slide against and over the teeth during rotation of the flange relative to the actuator assembly during dose delivery. The sensor is responsive to the movement of the contact portion over the teeth and generates signals corresponding to the flange. A controller is responsive to the signals generated by the sensor to determine a dose count for determining the dosage delivered and / or a dosage set to be delivered based on the detected rotation of the flange relative to the actuator assembly during dose delivery.

[0072] The contact surface may be biased against the physical features of the tubular flange to ensure proper contact between the contact surface and the physical features during rotation. In one embodiment, the movable element is a resilient member having one portion attached to the actuator at a location displaced from the contact surface. In one example, the movable element is a following member comprising a beam attached at one end to the actuator and having the contact surface at the other end. The beam isflexed to urge the contact surface in the direction of the surface features. Alternatively, the movable element may be biased in any of a variety of other ways. In addition to the use of a resilient beam, the biasing may be provided, for example, by use of a spring component. Such spring component may for example comprise a compression, tension, or torsion coil spring. In yet other embodiments, the movable element may be biased against the surface features of the sensed element by a separate resilient member or spring component bearing against the movable element.

[0073] FIG. 5 depicts an illustrative embodiment of a sensor 86 having a contact surface 111 interacting with teeth 102 of a tubular flange 38. As the flange 38 rotates relative to the dose button 30 during delivery, the teeth 102 of the flange contact and slide against the contact surface 111 of the sensor 86, causing the contact surface 111 to move in an oscillating manner. The movement of the contact surface 111 may be a combination of axial and lateral movement as the contact surface 111 slides into and out of the recesses 124 defined between the teeth 102 of the flange 38. The sensor 86 may be configured to track the movement of the contact surface 111 and associate the movement with an output signal that is sent to a controller.

[0074] As an alternative to teeth on the tubular flange, surface features that interact with the sensor may comprise anything detectable by the sensor. The sensor arrangement may be based on a variety of sensed characteristics, including tactile, optical, electrical and magnetic properties, for example. In the illustrative embodiments shown in the figures, the surface features are physical features which allow for detection of incremental movements as the dose-setting assembly rotates relative to the actuator assembly. In alternative embodiments, the sensor may be a piezoelectric sensor, a magnetic sensor such as a Hall effect sensor, an accelerometer for detecting vibration, e.g. of a ratcheting or other detent mechanism, where vibration can be correlated with rotational movement, an optical sensor such as a reflective sensor, an interrupter sensor, or an optical encoder, or any other sensor suitable for sensing rotation of a first component relative to a second component.

[0075] In some embodiments, when a user presses axially on face 60 of the dose button 30, the dose button 30 advances distally relative to the housing 12, compressing spring 68. Continued pressing of the dose button 30 distally results in back driving of the dosesetting screw 32 in a spiral direction relative to housing 12. As a result, the dose-setting screw 32 and flange 38 are driven to rotate by the axially pressing upon the dose button30. In some embodiments, the dose detection system is operable for dose detection only while the dose button is being pressed.

[0076] In some embodiments, the electronics assembly may include a clock or timer to determine the time elapsed between counts caused by trigger of the rotational sensor from the surface features of the sensed element. When no counts have been detected by the controller after a period of time this may be used to indicate that the dose has completed.

[0077] In some embodiments, a single sensing system may be employed for both dose detection sensing and wake-up activation. For example, upon the initial sensing of rotation of the sensed element by the sensor, the controller is configured to allow wake-up or activation of the electronics assembly to a greater or full power state. The wake-up feature is configured to allow power transmission from the power source (shown as battery) for powering up the electronic components for dose sensing in order to minimize inadvertent power loss or usage when a dose dispensing event is not occurring. In other embodiments, a separate wake-up sensor may be provided and arranged within the dose button housing and triggered when the dose button is in its distal position. After activation of the electronics assembly, the controller begins receiving generated signals from the rotational sensor indicative of counts from first to last one for a total number of counts that is used for determining total angular displacement and thus the amount of dose delivered and / or set to be delivered.

[0078] In some embodiments, the electronics assembly may have a controller that is configured to receive an output signal from a rotational sensor. The controller of the electronics assembly may be programmed to convert the intermediate signal to a conditioned digital signal, which may be a single step / square wave with a predetermined width representing a predetermined time. In some embodiments, output signals that are less than a predetermined level may be filtered out and ignored.

[0079] As described herein, the printed circuit board (e.g., the printed circuit board 77) can include various processing circuitry and / or logic that generates data based on the operation of the medication delivery device. For example, the processing circuitry can count the number of times the sensor (e.g., the sensor 86) is activated or triggered during an injection, which can be used to determine a dose size of the injection (e.g., the dose a particular insulin injection). As described herein, the relative rotational movement between a dose-setting assembly and an actuator of the medication delivery device can besensed in order to determine the amount of a dose delivered and / or set to be delivered by a medication delivery device, because the sensed relative rotational movements can be correlated to the amount of the dose delivered and / or set to be delivered.

[0080] FIG. 12 is an exemplary schematic diagram of a printed circuit board 1200, according to some embodiments. The printed circuit board 1200 (e.g., printed circuit board 77) includes various components, including a sensor 1202 (e.g., sensor 86 in FIG. 6) that is in electrical communication with a microcontroller 1204.

[0081] As described herein, the microcontroller 1204 (e.g., including based on input from the sensor 1202) may be operative to process dose data and / or other data of the medication delivery device. For example, the microcontroller 1204 can be configured to store the total angular movement used for determining dose delivery and / or the detected dose delivery in local memory (e.g., internal flash memory or on-board EEPROM). The microcontroller 1204 may be further operative to wirelessly transmit a signal representative of the total counts, total angular movement, and / or detected dose to an external device, such as a user’s mobile device or a remote server (e.g., via BLE control logic and controller integrated on the printed circuit board 1200).

[0082] As described herein, in some embodiments, a medication delivery device includes a sensor (e.g., sensor 86 in FIG. 6, sensor 1202 in FIG. 12) that detects the movement of the sensed component and provides output representative of the movement of the sensed component. For example, the sensor may generate a signal indicative of whether the sensor is in an engaged state or a disengaged state.

[0083] In some embodiments, the state of the sensor depends on physical contact between the sensor and the sensed component. For example, the sensor may be considered to be in an engaged state when it is in physical contact with the sensed component or with an intermediate component positioned between the sensor and the sensed component. By contrast, the sensor may be considered to be in a disengaged state when the sensor is not in physical contact with the sensed component or with the intermediate component positioned between the sensor and the sensed component. As a nonlimiting example, the sensor may be in an engaged state when a contact portion of the sensor contacts a tooth (e.g., teeth 102 in FIGS. 8-9) of a tubular flange (e.g., flange 38 in FIGS. 5 and 8-9) of the medication delivery device. The sensor may be in a disengaged state when the contact portion of the sensor is not in contact with the tooth, such as when the contact portion ispositioned in the recesses (e.g., recesses 124 in FIG. 5) between the teeth of the tubular flange.

[0084] In some embodiments, the state of the sensor depends on the sensor arrangement.As described herein, the sensor arrangement may be based on a variety of sensed characteristics, including tactile, optical, electrical, and magnetic properties, for example. The sensor may be a piezoelectric sensor, a magnetic sensor such as a Hall effect sensor, an accelerometer for detecting vibration, an optical sensor, an interrupter sensor, or an optical encoder, or any other sensor suitable for sensing rotation of a first component relative to a second component. Therefore, it should be appreciated that the sensor may be considered to be in an engaged state when it senses any suitable sensed characteristic and that the sensor may be considered to be in a disengaged state when it does not sense the sensed characteristic, or vice versa.

[0085] In some embodiments, the sensor generates a signal in response to its interactions with a sensed component. For example, when the contact portion of a sensor is in contact with a tooth of a tubular flange, the sensor may generate a signal that is in a first logic state. When the contact portion of the sensor is not in contact with the sensed component (e.g., when the contact portion is positioned in the recesses between teeth), the sensor may generate a signal that is in a second logic state, different from the first logic state.For example, the first logic state of the signal may be an asserted state (e.g., logic 1, high state, etc.), while the second logic state of the signal may be a de-asserted state (e.g., logic 0, low state, etc.), or vice versa.

[0086] Accordingly, in some embodiments, the generated signal can be used to determine the rotation of the sensor with respect to the sensed component. Continuing with the example of the tubular flange (e.g., tubular flange 38), when the signal transitions between a first logic state and a second logic state five times, this may indicate that a contact portion of the sensor slid against and over five teeth of the medication delivery device. Given the separation between said teeth, it may be possible to determine the rotation of the dose setting assembly within the medication delivery device. As described herein, the rotation of the dose setting assembly may then be used to determine a dosage of medication delivered and / or set to be delivered using the medication delivery device.

[0087] However, the signal output by the sensor may include dropouts, such that it can be challenging to use the signal to determine whether the sensor is in an engaged state or adisengaged state. For example, as the sensor begins to engage with a sensed component, it may momentarily lose contact with the sensed component, such that the signal output by the sensor momentarily transitions to the second logic state when it should have remained in the first logic state. For example, internal to the sensor, there may be one or more contact surfaces that include a conductive surface (e.g., a conductive gold surface). Such a conductive surface within the sensor may become worn down after repeatedly sliding over the teeth of the medication delivery device. As a result, when the worn-down portion of the conductive surface contacts a tooth, the signal output by the sensor may momentarily transition from the first logic state (e.g., an asserted state) to the second logic state (e.g., the de-asserted state). Though not shown, the conductive surface referenced herein may be internal to the sensor 86 of FIGs. 5-7.

[0088] FIG. 13 is an exemplary plot showing the signal received from the sensor of a medication delivery device, according to some embodiments. Line 1300 indicates the times which the sensor of the medication delivery device actually transitioned between an engaged state (point “SI” along the y-axis) and a disengaged state (point “S2” along the y-axis). For example, this may correspond to the contact portion of the sensor sliding over three teeth of the tubular flange of the medication delivery device. Line 1350 indicates the signal output by the sensor, and in particular shows the times at which the signal transitioned between an asserted state (point “SI” along the y-axis) and a de-asserted state (point “S2” along the y-axis). As shown, the signal transitioned between an asserted state and a de-asserted state more times than the sensor actually transitioned between an engaged state and a disengaged state. In particular, there were two signal dropouts 1325 and 1335. Therefore, counting the number of times the signal is in the asserted state (e.g., 5 times) to infer the number of times the sensor is in an engaged state (e.g., 3 times) would lead to an overestimation of this value. This would in turn lead to an inaccurate determination of the rotation of a dose setting assembly, which would result in an inaccurate estimation of the dosage of medication delivered using the medication delivery device.

[0089] Accordingly, the inventors have developed techniques for filtering the signal from the sensor, such that the signal can be used to more reliably determine when the sensor transitioned between an engaged state and a disengaged state. In turn, the techniques can more reliably and accurately estimate the rotation of the dose setting assembly, and more reliably and accurately determine the dosage of medication delivered and / or set to bedelivered using the medication delivery device.

[0090] FIG. 14 is a flowchart showing an exemplary method 1400 for filtering a signal received from a sensor of a medication delivery device, according to some embodiments. Method 1400 may be implemented on any suitable processor, such as microcontroller 1204 and / or one or more processors external to the medication delivery device, for example.

[0091] In some embodiments, the processor receives data indicative of a signal from the sensor of a medication delivery device, such as the sensor 86 in FIGs. 5-7 and the sensor 1202 in FIG. 12, for example. In some embodiments, the processor receives the signal directly from the sensor. For example, sensor 1202 may be in electrical communication with an input (e.g., a logic input) of the processor, such as a GPIO pin input of the processor. Additionally, or alternatively, the processor may receive data indicative of the signal, after the signal has been processed using one or more suitable pre-processing steps. Additionally, or alternatively, the processor may receive data indicative of the signal from a different processor. For example, the processor may be external to the medication delivery device and receive the data indicative of the signal from a microcontroller included in the medication delivery device. In some embodiments, the raw or processed signal from sensor may be stored in memory for some time before the processor receives the data.

[0092] In some embodiments, processor continues to receive the data indicative of the signal during one or more of the steps of method 1400. For example, the method 1400 may be performed as the signal is being generated, and the processor may receive and process the data indicative of the newly generated portions of the signal at any time during method 1400.

[0093] At step 1402, the processor detects a first transition of the signal to a first logic state (e.g., an asserted state) from a second logic state (e.g., a de-asserted state). In some embodiments, the processor is configured to determine the time point (e.g., a first time point) at which the first transition occurred. The processor may determine the time point using any suitable technique. As an example, the processor may determine the time point using an interrupt handler implemented using software executing or configured to execute on the processor. In some embodiments, the interrupt handler is configured to log a timestamp indicating the time point at which the first transition occurred. For example,the interrupt handler may log the timestamp according to a timer included in the medication delivery device. Additionally, or alternatively, the processor may determine the time point by polling the timer included in the medication delivery device. For example, in some embodiments, a clock signal drives an incrementing counter in the medication delivery device. A hardware timer capture peripheral may latch the value of the counter when the signal transitions between logic states. The hardware timer capture peripheral may additionally, or alternatively, trip an interrupt that causes software to read the latched count value and the reason for the latch occurring (e.g., the signal transition to an asserted or de-asserted state).

[0094] At step 1404, the processor determines, based on the first transition of the signal, that the sensor transitioned to an engaged state from a disengaged state. In some embodiments, this determination is made in response to detecting the first transition from the second logic state to the first logic state. In some embodiments, this determination is made after detecting the first transition, and then determining that the signal remained in the first logic state for at least a threshold period of time. The threshold period of time may include any suitable period of time, as aspects of the technology described herein are not limited in this respect.

[0095] At step 1406, the processor detects a second transition of the signal to the second logic state (e.g., the de-asserted state) from the first logic state (e.g., the asserted state). In some embodiments, the processor is configured to determine the time point (e.g., a second time point after the first time point) at which the second transition occurred. The processor may determine the time point using any suitable technique such as those described herein with respect to step 1402.

[0096] At step 1408, the processor determines whether the sensor transitioned from the engaged state to the disengaged state at the second time point. In some embodiments, the determination is based at least in part on (a) a first time period beginning at the first time point and ending at the second time point, and (b) a second time point beginning at the second time point and ending at a third time point after the second time point. For example, the third time point may include at time point at which the signal transitioned from the second logic (e.g., the de-asserted state) to the first logic state (e.g., the asserted state). Example techniques for detecting a third transition of the signal at a third time point are described herein including at least with respect to step 1508 of method 1500 described herein with respect to FIG. 15.

[0097] In some embodiments, determining whether the sensor transitioned from the engaged state to the disengaged state at the second time point includes analyzing the signal during the first time period (e.g., the time period that the signal was in the asserted logic state) and the second time period (e.g., the time period that the signal was in the deasserted logic state) in the context of other portions of the signal. For example, this may include determining whether the duration of the first time period, the duration of the second time period, and / or a combination of the duration of the first time period and the duration of the second time period are relatively short compared to the durations of other time periods during which the signal was in an asserted state and / or a de-asserted state. If the durations of the first time period and / or second time period were relatively short, this may indicate that the second transition does not correspond to the transition of the sensor to the disengaged state, but rather is the result of some error (e.g., a lost electrical connection due to wear on a conductive surface internal to the sensor). Example techniques for determining whether the sensor transitioned from an engaged state to a disengaged state are described herein including at least with respect to step 1514 of method shown in FIG. 15 and the example shown in FIG. 16.

[0098] FIG. 15 is a flowchart showing an exemplary method 1500 for filtering a signal received from a sensor of a medication delivery device, according to some embodiments. Method 1500 may be implemented using any suitable processor, such as microcontroller 1204 and / or one or more processors external to the medication delivery device, for example.

[0099] At step 1502, the processor detects a first transition of the signal to a first logic state (e.g., an asserted state) from a second logic state (e.g., a de-asserted state). In some embodiments, the processor determines a time point (e.g., a first time point) at which the first transition occurred. For example, the first transition may include transition 1620 occurring at time point “B” (e.g., the first time point”) shown in the example of FIG. 16. Techniques for detecting a first transition of a signal and for determining a first time point are described herein including at least with respect to step 1402 of method 1400 shown in FIG. 14.

[0100] At step 1504, the processor determines, based on the first transition of the signal, that the sensor transitioned to an engaged state from a disengaged state. Techniques for determining whether a sensor transitioned to an engaged state from a disengaged state are described herein including at least with respect to step 1404 of method 1400 shown inFIG. 14.

[0101] At step 1506, the processor detects a second transition of the signal to the second logic state (e.g., the de-asserted state) from the first logic state (e.g., the asserted state). In some embodiments, the processor determines a time point (e.g., a second time point after the first time point) at which the second transition occurred. For example, the second transition may include transition 1630 occurring at time point “C” (e.g., the second time point) shown in the example of FIG. 16. Techniques for detecting a second transition of a signal and for determining a second time point are described herein including at least with respect to step 1406 of method 1400 shown in FIG. 14.

[0102] At step 1508, the processor detects a third transition of the signal to the first logic state (e.g., the asserted state) from the second logic state (e.g., the de-asserted state). In some embodiments, the processor is configured to determine the time point (e.g., a third time point after the second time point) at which the third transition occurred. The processor may determine the time point using any suitable technique such as those described herein with respect to step 1402 of method 1400 described herein with respect to FIG. 14. For example, the third transition may include transition 1640 occurring at time point “D” (e.g., the third time point) shown in the example of FIG. 16.

[0103] At step 1510, the processor detects a fourth transition of the signal to the second logic state (e.g., the de-asserted state) from the first logic state (e.g., the asserted state). In some embodiments, the processor is configured to determine the time point (e.g., a fourth time point preceding the first time point) at which the fourth transition occurred. The processor may determine the time point using any suitable techniques such as those described herein including with respect to step 1402 of method 1400 described herein with respect to FIG. 14. For example, the fourth transition may include transition 1610 occurring at time point “A” (e.g., the fourth time point) shown in the example of FIG. 16.

[0104] At step 1512, the processor detects a fifth transition of the signal to the second logic state (e.g., the de-asserted state) from the first logic state (e.g., the asserted state). In some embodiments, the processor is configured to determine the time point (e.g., a fifth time point following the third time point) at which the fifth transition occurred. The processor may determine the time point using any suitable techniques such as those described herein including with respect to step 1402 of method 1400 shown in FIG. 14. For example, the fifth transition may include transition 1660 occurring at time point “E”(e.g., the fifth time point) shown in the example of FIG. 16.

[0105] At step 1514, the processor determines whether the sensor transitioned from the engaged state to the disengaged state at the second time point. For example, the sensor may determine whether the sensor transitioned to the disengaged state based on: (a) a first time period beginning at the first time point and ending at the second time point, (b) a second time period beginning at the second time point and ending at the third time point, (c) a third time period beginning at the third time point and ending at the fifth time point, and (d) a fourth time period beginning at the fourth time point and ending at the first time point. For example, with reference to FIG. 16, the first time period may be time period 1625, the second time period may be time period 1635, the third time period may be time period 1645, and the fourth time period may be time period 1615.

[0106] In some embodiments, determining whether the sensor transitioned from the engaged state to the disengaged state includes using the durations of the first, second, third, and / or fourth time period to determine a metric indicative of whether the sensor transitioned from the engaged to the disengaged state. In some embodiments, this includes determining one or more ratios between the durations of the first, second, third, and / or fourth time periods. For example, the durations of the first, second, and third time periods may be used to determine a ratio between the cumulative duration of first and second time periods and the cumulative duration of the first, second, and third time periods. For example, Equation 1 may be used to determine the ratio RError, • - (Equation 1)where1is the duration of the first time period, D2is the duration of the second time period, and D3is the duration of the third time period. Additionally, or alternatively, the durations of the first, second, third, and fourth time periods may be used to determine a ratio between the duration of the fourth time period (e.g., the time period during which the sensor was previously in a disengaged state) and the cumulative duration of all four time periods. For example, Equation 2 may be used to determine the ratio Roe-Assert '- (Equation 2)st time period, D2is the duration of the second time period, D3is the duration of the third time period, and 04is the duration of the fourth time period.

[0107] In some embodiments, the determined ratios are used to determine a metric indicative of whether the sensor transitioned from an engaged state to a disengaged state. The metric may be one of the determined ratios (e.g., RErroror RDe-Assert) or a combination of the determined ratios. For example, Equation 3 may be used to determine the metric:(Equation 3)

[0108] Regardless of whether the metric is one of the determined ratios or a combination of the determined ratios, the metric may be used to determine whether the sensor transitioned to the disengaged state at the second time point. For example, if RErroris relatively large, this may indicate that the signal transition at the second time point is due to signal dropout and not the result of the sensor transitioning to the disengaged state. If ^De-Assert is relatively small this may also indicate that the signal transition at the second time point due to signal dropout rather than the sensor transitioning to the disengaged state. If Rmetric is relatively large, this may also indicate that the signal transition at the second time point due to signal dropout rather than the sensor transitioning to the disengaged state.

[0109] However, the inventors have recognized that, in some cases, using RError, Roe-Assert,or^metric to determine whether the sensor has transitioned to the disengaged state may result in false positives. For example, if the duration of either the third time period (e.g., when the signal transitions back to the asserted state after the potential dropout) or the fourth time period (e.g. when the sensor was in the disengaged state preceding the potential dropout) is excessively long, this may result in a false positive. Accordingly, in some embodiments, step 1514 includes determining a corrected metric to negate or substantially negate the impact of a long third and / or fourth time period. For example, the corrected metric may be determined using Equations 4 and 5:MetricMetric Corrected (Equation 4)Correction(o3+o4)2Correction = (Equation 5)(o3xo4) where Metric is RError, Roe-Assert,or^metric, D3is the duration of the third time period, and D4is the duration of the fourth time period.

[0110] In some embodiments, the metric (e.g., corrected metric) is used to determinewhether the sensor transitioned to a disengaged state at the second time point. In some embodiments, determining whether the sensor transitioned to the disengaged state at the second time point includes comparing the metric to a threshold. In some embodiments, if the metric is less than or equal to the threshold, then it is determined that the sensor transitioned to the disengaged state at the second time point (i.e., no signal dropouts are detected). The threshold may be any suitable threshold, as aspects of the technology described herein are not limited in this respect. For example, the threshold may be a value between 0.05 and 3.0, between 0.1 and 2.5, between 0.15 and 2.0, between 0.2 and 1.5, between 0.25 and 1.0, or may be a value within any other suitable range of values. For example, the threshold may be .2, .25, .3, .35, .4, .5, .6, .7, .8, 1.0, or any other suitable value.[OHl] At step 1516, the processor determines an amount of dose delivered and / or set to be delivered by the medication delivery device. In some embodiments, the determination is based on the number of times the sensor transitioned from the disengaged state to the engaged state. In some embodiments, if the processor determines, at step 1514, that the sensor did not transition to the disengaged state at the second time point, then the processor may consider the sensor to be in an engaged state during the entirety of the first, second, and third time periods, and thus there was only a single transition from the disengaged state to the engaged state at the first time point (e.g., time point “B” shown in FIG. 16). However, if the processor determines, at step 1514, that the sensor did transition to the disengaged state at the second time point, then the processor may identify a first transition of the sensor from the disengaged state to the engaged state at the first time point (e.g., time point “B” shown in FIG. 16), and a second transition of the sensor from the disengaged state to the engaged state at the third time point (e.g., time point “D” shown in FIG. 16). Example techniques for determining a dose delivered and / or set to be delivered by a medication delivery device based on transitions of the sensor from a disengaged state to an engaged state are described herein.

[0112] It should be appreciated that exemplary method 1500 may be performed once or multiple times. For example, exemplary method 1500 may have been performed for one or more transitions in the signal preceding the transition to the second logic state at the second time point such as, for example, the transition of the signal to the second logic state at the fifth time point. Additionally, or alternatively, method 1500 may be repeated for one or more transitions in the signal following the transition at the second time point.For example, the method 1500 may be repeated for the transition to the second logic state at the fourth time point.

[0113] Techniques operating according to the principles described herein may be implemented in any suitable manner. The processing and decision blocks of the flow charts above represent steps and acts that may be included in algorithms that carry out these various processes. Algorithms derived from these processes may be implemented as software integrated with and directing the operation of one or more single- or multipurpose processors, may be implemented as functionally-equivalent circuits such as a Digital Signal Processing (DSP) circuit or an Application-Specific Integrated Circuit (ASIC), or may be implemented in any other suitable manner. It should be appreciated that the flow charts included herein do not depict the syntax or operation of any particular circuit or of any particular programming language or type of programming language. Rather, the flow charts illustrate the functional information one skilled in the art may use to fabricate circuits or to implement computer software algorithms to perform the processing of a particular apparatus carrying out the types of techniques described herein. It should also be appreciated that, unless otherwise indicated herein, the particular sequence of steps and / or acts described in each flow chart is merely illustrative of the algorithms that may be implemented and can be varied in implementations and embodiments of the principles described herein.

[0114] Accordingly, in some embodiments, the techniques described herein may be embodied in computer-executable instructions implemented as software, including as application software, system software, firmware, middleware, embedded code, or any other suitable type of computer code. Such computer-executable instructions may be written using any of a number of suitable programming languages and / or programming or scripting tools, and also may be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.

[0115] When techniques described herein are embodied as computer-executable instructions, these computer-executable instructions may be implemented in any suitable manner, including as a number of functional facilities, each providing one or more operations to complete execution of algorithms operating according to these techniques. A “functional facility,” however instantiated, is a structural component of a computer system that, when integrated with and executed by one or more computers, causes the one or more computers to perform a specific operational role. A functional facility may be aportion of or an entire software element. For example, a functional facility may be implemented as a function of a process, or as a discrete process, or as any other suitable unit of processing. If techniques described herein are implemented as multiple functional facilities, each functional facility may be implemented in its own way; all need not be implemented the same way. Additionally, these functional facilities may be executed in parallel and / or serially, as appropriate, and may pass information between one another using a shared memory on the computer(s) on which they are executing, using a message passing protocol, or in any other suitable way.

[0116] Generally, functional facilities include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically, the functionality of the functional facilities may be combined or distributed as desired in the systems in which they operate. In some implementations, one or more functional facilities carrying out techniques herein may together form a complete software package. These functional facilities may, in alternative embodiments, be adapted to interact with other, unrelated functional facilities and / or processes, to implement a software program application.

[0117] Some exemplary functional facilities have been described herein for carrying out one or more tasks. It should be appreciated, though, that the functional facilities and division of tasks described is merely illustrative of the type of functional facilities that may implement the exemplary techniques described herein, and that embodiments are not limited to being implemented in any specific number, division, or type of functional facilities. In some implementations, all functionality may be implemented in a single functional facility. It should also be appreciated that, in some implementations, some of the functional facilities described herein may be implemented together with or separately from others (i.e., as a single unit or separate units), or some of these functional facilities may not be implemented.

[0118] Computer-executable instructions implementing the techniques described herein (when implemented as one or more functional facilities or in any other manner) may, in some embodiments, be encoded on one or more computer-readable media to provide functionality to the media. Computer-readable media include magnetic media such as a hard disk drive, optical media such as a Compact Disk (CD) or a Digital Versatile Disk (DVD), a persistent or non-persistent solid-state memory (e.g., One-Time Programmable (OTP) Memory, Flash memory, Magnetic RAM, etc.), or any other suitable storagemedia. Such a computer-readable medium may be implemented in any suitable manner. As used herein, “computer-readable media” (also called “computer-readable storage media”) refers to tangible storage media. Tangible storage media are non-transitory and have at least one physical, structural component. In a “computer-readable medium,” as used herein, at least one physical, structural component has at least one physical property that may be altered in some way during a process of creating the medium with embedded information, a process of recording information thereon, or any other process of encoding the medium with information. For example, a magnetization state of a portion of a physical structure of a computer-readable medium may be altered during a recording process.

[0119] Further, some techniques described above comprise acts of storing information (e.g., data and / or instructions) in certain ways for use by these techniques. In some implementations of these techniques — such as implementations where the techniques are implemented as computer-executable instructions — the information may be encoded on a computer-readable storage media. Where specific structures are described herein as advantageous formats in which to store this information, these structures may be used to impart a physical organization of the information when encoded on the storage medium. These advantageous structures may then provide functionality to the storage medium by affecting operations of one or more processors interacting with the information; for example, by increasing the efficiency of computer operations performed by the processor(s).

[0120] In some, but not all, implementations in which the techniques may be embodied as computer-executable instructions, these instructions may be executed on one or more suitable computing device(s) operating in any suitable computer system, or one or more computing devices (or one or more processors of one or more computing devices) may be programmed to execute the computer-executable instructions. A computing device or processor may be programmed to execute instructions when the instructions are stored in a manner accessible to the computing device or processor, such as in a data store (e.g., an on-chip cache or instruction register, a computer-readable storage medium accessible via a bus, a computer-readable storage medium accessible via one or more networks and accessible by the device / processor, etc.). Functional facilities comprising these computerexecutable instructions may be integrated with and direct the operation of a single multipurpose programmable digital computing device, a coordinated system of two or moremulti-purpose computing device sharing processing power and jointly carrying out the techniques described herein, a single computing device or coordinated system of computing device (co-located or geographically distributed) dedicated to executing the techniques described herein, one or more Field-Programmable Gate Arrays (FPGAs) for carrying out the techniques described herein, or any other suitable system.

[0121] A computing device may comprise at least one processor, a network adapter, and computer-readable storage media. A computing device may be, for example, a desktop or laptop personal computer, a personal digital assistant (PDA), a smart mobile phone, a server, or any other suitable computing device. A network adapter may be any suitable hardware and / or software to enable the computing device to communicate wired and / or wirelessly with any other suitable computing device over any suitable computing network. The computing network may include wireless access points, switches, routers, gateways, and / or other networking equipment as well as any suitable wired and / or wireless communication medium or media for exchanging data between two or more computers, including the Internet. Computer-readable media may be adapted to store data to be processed and / or instructions to be executed by processor. The processor enables processing of data and execution of instructions. The data and instructions may be stored on the computer-readable storage media.

[0122] A computing device may additionally have one or more components and peripherals, including input and output devices. These devices can be used, among other things, to present a user interface. Examples of output devices that can be used to provide a user interface include printers or display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that can be used for a user interface include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets. As another example, a computing device may receive input information through speech recognition or in other audible format.

[0123] Embodiments have been described where the techniques are implemented in circuitry and / or computer-executable instructions. It should be appreciated that some embodiments may be in the form of a method, of which at least one example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, eventhough shown as sequential acts in illustrative embodiments.

[0124] Various aspects of the embodiments described above may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0125] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0126] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0127] The word “exemplary” is used herein to mean serving as an example, instance, or illustration. Any embodiment, implementation, process, feature, etc. described herein as exemplary should therefore be understood to be an illustrative example and should not be understood to be a preferred or advantageous example unless otherwise indicated.

[0128] To clarify the use of and to hereby provide notice to the public, the phrases “at least one of , , . . . and <N>” or “at least one of , , . . . <N>, or combinations thereof’ or “, , . . . and / or <N>” are defined by the Applicant in the broadest sense, superseding any other implied definitions hereinbefore or hereinafter unless expressly asserted by the Applicant to the contrary, to mean one or more elements selected from the group comprising A, B, . . . and N. In other words, the phrases mean any combination of one or more of the elements A, B, . . . or N including any one element alone or the one element in combination with one or more of the other elements which may also include, in combination, additional elements not listed.

[0129] While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible.Accordingly, the embodiments described herein are examples, not the only possible embodiments and implementations. Furthermore, the advantages described above are not necessarily the only advantages, and it is not necessarily expected that all of the described advantages will be achieved with every embodiment.

[0130] Various aspects are described in this disclosure, which include, but are not limited to, the following aspects:

[0131] 1. A medication delivery device comprising: a housing comprising a proximal portion and a distal portion, the distal portion containing a cartridge configured to hold a medication; a needle disposed in an outlet of the distal portion of the housing; and a dose detection system coupled to the proximal portion of the housing, the dose detection system comprising: a sensor configured to output a signal; a flange comprising teeth and being configured to rotate with respect to the sensor, wherein the teeth are configured to trigger the sensor to transition between an engaged state and a disengaged state as the flange rotates; and a controller configured to filter the signal output by the sensor, the controller configured to: detect a first transition of the signal to a first logic state from a second logic state at a first time point; determine, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detect, at a second time point after the first time point, a second transition of the signal to the second logic state from the first logic state; and determine, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.

[0132] 2. The medication delivery device of aspect 1, wherein determining whether the signal transitioned from the engaged state to the disengaged state based on the durations of the first time period and the second time period comprises: determining a metric based on the durations of the first time period and the second time period; comparing the metric to a threshold; and determining whether the sensor transitioned from the engaged state to the disengaged state based on a result of comparing the metric to the threshold.

[0133] 3. The medication delivery device of any one of aspects 1-2, wherein the controller is further configured to: detect, at a third time point after the second time point, a third transition of the signal to the first logic state from the second logic state, wherein the first time period ends at the second time point and the second time period ends at thethird time point.

[0134] 4. The medication delivery device of aspect 3, wherein determining whether the sensor transitioned from the engaged state to the disengaged state is further based on a duration of a third time period beginning at the third time point.

[0135] 5. The medication delivery device of any one of aspects 3-4, wherein the controller is further configured to: detect, at a fourth time point preceding the first time point, a fourth transition of the signal to the second logic state from the first logic state, wherein determining whether the signal transitioned from the engaged state to the disengaged state is further based on a duration of a fourth time period beginning at the fourth time point.

[0136] 6. The medication delivery device of aspect 5, wherein determining whether the sensor transitioned from the engaged state to the disengaged state based on the durations of the first time period, the second time period, the third time period, and the fourth time period comprises determining ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period.

[0137] 7 The medication delivery device of aspect 6, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a first sum of the duration of the first time period, the duration of the second time period, and the duration of the third time period; determining a second sum of the duration of the first time period and the duration of the second time period; and determining a ratio of the first sum relative to the second sum.

[0138] 8. The medication delivery device of any one of aspects 6-7, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a third sum of the durations of the first time period, the second time period, the third time period, and the fourth time period; and determining a ratio of the third sum relative to the duration of the fourth time period.

[0139] 9. The medication delivery device of any one of aspects 5-8, wherein the controller is further configured to: determine that the sensor transitioned to the disengaged state at the fourth time point.

[0140] 10. The medication delivery device of any one of aspects 5-9, wherein the thirdtime period ends at a fifth time point after the third time point, and wherein the fourth time period ends at the first time point.

[0141] 11. The medication delivery device of any one of aspects 1-10, wherein the controller is further configured to: determine a number of times that the sensor transitioned from the disengaged state to the engaged state; and determine, based on the number of times that the sensor transitioned from the disengaged state to the engaged state, an amount of dose delivered by the medication delivery device.

[0142] 12. The medication delivery device of any one of aspects 1-11, wherein the controller is further configured to: receive data indicative of the signal from the sensor of the medication delivery device.

[0143] 13. The medication delivery device of any one of aspects 1-12, wherein the controller is further configured to: determine that the sensor transitioned to a disengaged state at the second time point.

[0144] 14. A method for filtering a signal received from a sensor of a medication delivery device, wherein the sensor is operable to transition between an engaged state and a disengaged state, the method comprising: detecting a first transition of the signal to a first logic state from a second logic state, the first transition occurring at a first time point; determining, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detecting a second transition of the signal to the second logic state from the first logic state, the second transition occurring at a second time point after the first time point; and determining, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.

[0145] 15. The method of aspect 14, wherein determining whether the signal transitioned from the engaged state to the disengaged state based on the durations of the first time period and the second time period comprises: determining a metric based on the durations of the first time period and the second time period; comparing the metric to a threshold; and determining whether the sensor transitioned from the engaged state to the disengaged state based on a result of comparing the metric to the threshold.

[0146] 16. The method of any one of aspects 14-15, further comprising: detecting a third transition of the signal to the first logic state from the second logic state, the third transitionoccurring at a third time point after the second time point, wherein the first time period ends at the second time point and the second time period ends at the third time point.

[0147] 17. The method of aspect 16, wherein determining whether the sensor transitioned from the engaged state to the disengaged state is further based on a duration of a third time period beginning at the third time point.

[0148] 18. The method of any one of aspects 16-17, further comprising: detecting a fourth transition of the signal to the second logic state from the first logic state, the fourth transition occurring at a fourth time point preceding the first time point, wherein determining whether the signal transitioned from the engaged state to the disengaged state is further based on a duration of a fourth time period beginning at the fourth time point.

[0149] 19. The method of aspect 18, wherein determining whether the sensor transitioned from the engaged state to the disengaged state based on the durations of the first time period, the second time period, the third time period, and the fourth time period comprises determining ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period.

[0150] 20. The method of aspect 19, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a first sum of the duration of the first time period, the duration of the second time period, and the duration of the third time period; determining a second sum of the duration of the first time period and the duration of the second time period; and determining a ratio of the first sum relative to the second sum.

[0151] 21. The method of any one of aspects 19-20, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a third sum of the durations of the first time period, the second time period, the third time period, and the fourth time period; and determining a ratio of the third sum relative to the duration of the fourth time period.

[0152] 22. The method of any one of aspects 18-21, further comprising: determining that the sensor transitioned to the disengaged state at the fourth time point.

[0153] 23. The method of any one of aspects 18-22, wherein the third time period ends at a fifth time point after the third time point, and wherein the fourth time period ends at the first time point.

[0154] 24. The method of any one of aspects 14-23, further comprising: determining a number of times that the sensor transitioned from the disengaged state to the engaged state; and determining, based on the number of times that the sensor transitioned from the disengaged state to the engaged state, an amount of dose delivered by the medication delivery device.

[0155] 25. The method of any one of aspects 14-24, further comprising: receiving data indicative of the signal from the sensor of the medication delivery device.

[0156] 26. A system, comprising: at least one processor; and at least one non-transitory computer-readable storage medium storing processor executable instructions that, when executed by the at least one processor, cause the at least one processor to perform the method of any one of aspects 14-25.

[0157] 27. At least one non-transitory computer-readable storage medium storing processor-executable instructions that, when executed by at least one processor, cause the at least one processor to perform the method of any one of aspects 14-25.

Claims

CLAIMSWe claim:

1. A medication delivery device comprising: a housing comprising a proximal portion and a distal portion, the distal portion containing a cartridge configured to hold a medication; a needle disposed in an outlet of the distal portion of the housing; and a dose detection system coupled to the proximal portion of the housing, the dose detection system comprising: a sensor configured to output a signal; a flange comprising teeth and being configured to rotate with respect to the sensor, wherein the teeth are configured to trigger the sensor to transition between an engaged state and a disengaged state as the flange rotates; and a controller configured to filter the signal output by the sensor, the controller configured to: detect a first transition of the signal to a first logic state from a second logic state at a first time point; determine, based on the first transition of the signal, that the sensor transitioned to an engaged state at the first time point; detect, at a second time point after the first time point, a second transition of the signal to the second logic state from the first logic state; and determine, based at least in part on a duration of a first time period beginning at the first time point and a duration of a second time period beginning at the second time point, whether the sensor transitioned from the engaged state to the disengaged state at the second time point.

2. The medication delivery device of claim 1, wherein determining whether the signal transitioned from the engaged state to the disengaged state based on the durations of the first time period and the second time period comprises: determining a metric based on the durations of the first time period and the second time period; comparing the metric to a threshold; and determining whether the sensor transitioned from the engaged state to the disengaged state based on a result of comparing the metric to the threshold.

3. The medication delivery device of any one of claims 1-2, wherein the controller is further configured to: detect, at a third time point after the second time point, a third transition of the signal to the first logic state from the second logic state, wherein the first time period ends at the second time point and the second time period ends at the third time point.

4. The medication delivery device of claim 3, wherein determining whether the sensor transitioned from the engaged state to the disengaged state is further based on a duration of a third time period beginning at the third time point.

5. The medication delivery device of any one of claims 3-4, wherein the controller is further configured to: detect, at a fourth time point preceding the first time point, a fourth transition of the signal to the second logic state from the first logic state, wherein determining whether the signal transitioned from the engaged state to the disengaged state is further based on a duration of a fourth time period beginning at the fourth time point.

6. The medication delivery device of claim 5, wherein determining whether the sensor transitioned from the engaged state to the disengaged state based on the durations of the first time period, the second time period, the third time period, and the fourth time period comprises determining ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period.

7. The medication delivery device of claim 6, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a first sum of the duration of the first time period, the duration of the second time period, and the duration of the third time period; determining a second sum of the duration of the first time period and the duration of the second time period; and determining a ratio of the first sum relative to the second sum.

8. The medication delivery device of any one of claims 6-7, wherein determining the ratios between the durations of the first time period, the second time period, the third time period, and the fourth time period comprises: determining a third sum of the durations of the first time period, the second time period, the third time period, and the fourth time period; and determining a ratio of the third sum relative to the duration of the fourth time period.

9. The medication delivery device of any one of claims 5-8, wherein the controller is further configured to: determine that the sensor transitioned to the disengaged state at the fourth time point.

10. The medication delivery device of any one of claims 5-9, wherein the third time period ends at a fifth time point after the third time point, and wherein the fourth time period ends at the first time point.

11. The medication delivery device of any one of claims 1-10, wherein the controller is further configured to: determine a number of times that the sensor transitioned from the disengaged state to the engaged state; and determine, based on the number of times that the sensor transitioned from the disengaged state to the engaged state, an amount of dose delivered by the medication delivery device.

12. The medication delivery device of any one of claims 1-11, wherein the controller is further configured to: receive data indicative of the signal from the sensor of the medication delivery device.

13. The medication delivery device of any one of claims 1-12, wherein the controller is further configured to: determine that the sensor transitioned to a disengaged state at the second time point.

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