Patent Publication Number: US-2023145686-A1

Title: Drug Delivery Device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is the national stage entry of International Patent Application No. PCT/EP2021/060629, filed on Apr. 23, 2021, and claims priority to Application No. EP 20315207.9, filed on Apr. 23, 2020, the disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of drug delivery devices for administering of a dose of a medicament. The disclosure particularly relates to a drug delivery device operable to cooperate with an electronic data logging device, wherein the data logging device is further connectable to an external electronic device. The present disclosure particularly relates to the field of establishing or providing a communication link between a data logging device suitable for a drug delivery device and an external electronic device. The disclosure further relates to a method of pairing an electronic data logging device of a drug delivery device with an external electronic device. 
     BACKGROUND 
     Drug delivery devices for setting and dispensing a single or multiple doses of a medicament are as such well-known in the art. Generally, such devices may have substantially a similar purpose as that of an ordinary syringe. 
     Drug delivery devices, such as injection or inhaling devices, e.g. pen-type injectors, have to meet a number of user-specific requirements. For instance, with patient’s suffering chronic diseases, such like diabetes, the patient may be physically infirm and may also have impaired vision. Suitable drug delivery devices especially intended for home medication therefore need to be robust in construction and should be easy to use. Furthermore, manipulation and general handling of the device and its components should be intelligible and easy understandable. Such injection devices should provide setting and subsequent dispensing of a dose of a medicament of variable size. Moreover, a dose setting as well as a dose dispensing procedure must be easy to operate and has to be unambiguous. 
     The medicament to be dispensed or expelled by the drug delivery device may be provided and contained in a multi-dose cartridge. Such cartridges typically comprise a vitreous barrel sealed in distal direction by means of a pierceable seal and being further sealed in proximal direction by the bung. With reusable drug delivery devices an empty cartridge is replaceable by a new one. In contrast to that, drug delivery devices of disposable type are readily equipped with such a cartridge. They are to be entirely discarded when the medicament in the cartridge has been dispensed or used-up. 
     With some drug delivery devices, such as pen-type injection devices a user has to set a dose of equal or variable size by rotating a dose dial in a clockwise or counter clockwise direction relative to a body or housing of the injection device for increasing or decreasing of the dose. For injecting and expelling of a dose of a liquid medicament the user has to depress a trigger or dose button in a distal direction and hence towards the body or housing of the injection device. Typically, the user uses his thumb for exerting a distally directed pressure onto the dose button, which is located at a proximal end of the dose dial and the dose dial sleeve, while holding the housing of the injection device with the remaining fingers of the same hand. 
     For mechanically implemented injection devices it is desirable to enable a precise, reliable and quasi-automated supervision and/or collection of injection-related data during use of the injection device. Mechanically operated injection devices may be equipped with an electronically implemented add-on device or data logging device configured to monitor user-induced operation of the injection device. 
     Some data logging devices may be configured for attachment to an injection device. Some data logging device may be embedded or arranged in the injection device. Other drug delivery devices may be implemented electronically, hence they comprise an integrated electronic unit configured for and operable to monitor operation of the drug delivery device over time. Here, the data logging device is provided by the integrated electronic unit. 
     Administration details and patient specific data can be logged and stored in such data logging devices during repeated use of the respective drug delivery device. It is generally desirable to obtain access to the respective data as stored in the data logging device, e.g. for patient supervision and/or for optimizing a long-term therapy. The data logging device may be configured to establish a communication link with an external electronic device. The communication link may be of wireless or wired type. The data collected or at least temporally stored in the data logging device might be rather sensitive and/or delicate. Misuse or unauthorized access of this data should be prevented and avoided. 
     In order to prevent unauthorized access to the data, establishing of a communication link between the data logging device and the external electronic device may require an authorization. Here, the data logging device and/or the external electronic device may be implemented to establish the communication link only upon confirmation or entering of a suitable key or code. Generally, such a pairing code may provide security against misuse or unauthorized access to the data stored in the data logging device, provided that the pairing code is only known to authorized personnel. 
     On the one hand, such a key or code should be unequivocally available to authorized personnel, e.g. to the healthcare provider or to the patient. On the other hand, such a pairing code should not be directly discernible from outside the drug delivery device to provide sufficient data security. Regulatory requirements may further specify that such pairing codes have to be visible from outside the injection device or data logging device. 
     It is therefore a demand to provide an improved drug delivery device configured to provide a pairing code for establishing a communication link between an electronic data logging device and an external electronic device. On the one hand, the drug delivery device should prevent unauthorized access to the pairing code. On the other hand the drug delivery device should effectively provide unobstructed and unequivocal access to the pairing code for authorized personnel. 
     SUMMARY 
     In order to solve the above described demand there is provided an improved drug delivery device for administering of a dose of a medicament and a method of pairing an electronic data logging device of a drug delivery device with an external electronic device in accordance to the features of the independent claims. Further features of the device and the method are subject of the dependent claims. 
     In one aspect there is provided a drug delivery device for administering of a dose of a medicament. The drug delivery device is operable to cooperate with an electronic data logging device. The drug delivery device comprises a housing to accommodate the medicament. The housing is further configured to receive the electronic data logging device or to mechanically engage with the electronic data logging device. The housing may be configured to contain the data logging device. The data logging device may be either implemented as a separate device connectable to the housing of the drug delivery device or to a movable component of the drug delivery device. With other examples, the electronic data logging device is integrated into the drug delivery device and belongs to the drug delivery device. 
     The drug delivery device comprises a first device component. The drug delivery device further comprises a second device component. The first device component is movable relative to the second device component at least from a first positional state to at least a second positional state. 
     The first device component comprises a first outer surface. The second device component comprises a second outer surface. At least one of the first outer surface and the second outer surface comprises at least a first code portion of a pairing code. The pairing code is usable for establishing a communication link between the electronic data logging device and an external electronic device. The pairing code may be required for establishing the communication link. The pairing code may be a security code requested by at least one of the electronic data logging device and the external electronic device in order to establish the communication link. The pairing code may comprise or constitute a key required to establish the connection between the electronic data logging device and the external electronic device. Generally, the pairing code is usable or necessary for establishing a secure connection between the data logging device and the external electronic device. 
     The pairing code may comprise or may constitute also at least one of a bonding code or a session key. The pairing code may also serve as a password or passphrase to establish a long term authentication between the drug delivery device and the electronic data logging device. 
     Typically, the electronic data logging device and the external electronic device each comprise a wireless and hence mechanically contact-less communication interface. For establishing a communication link between the wireless communication interface of the electronic data logging device and the external electronic device at least one of the wireless communication interfaces is configured to execute a pairing routine or pairing procedure, e.g. based on a well-defined wireless communication standard. 
     Generally, the communication link and the way of communication between the data logging device and the drug delivery device is not limited to a particular wireless communication technology wireless communication standard. The present disclosure is generally applicable to all available types of mechanically contactless communication links that require authentication for and/or during establishing a secure connection between the communicating interfaces, e.g. of the data logging device and of the drug delivery device, respectively. 
     With some examples, the communication link is an electromagnetic communication link, that may provide or support contactless charging, radiofrequency based communication, such as WiFi, Bluetooth, RFID, NFC, GSM, UMTS, LTE or others. With further examples the communication link is based on optical transmission in the infrared or visible spectral range. With further examples the communication link is based on acoustic signals. 
     Execution of the pairing routine comprises an authentication step. Here, at least one of the external electronic device and the electronic data logging device is operable to request a pairing code associated with the other one of the external electronic device and the electronic data logging device. With some embodiments a pairing code, typically associated with the electronic data logging device, may be communicated or transmitted to the external electronic device. Before the respective communication link can be established, a user may be prompted to confirm the pairing code, either by entering the pairing code into an input interface of at least one of the electronic data logging device and the external electronic device. With other embodiments, at least one of the electronic data logging device and the external electronic device may be operable to visually or audibly present the pairing code, which has to be confirmed and/or approved by a user of the respective device before the communication link will be established. 
     With some examples the pairing code provided on the drug delivery device characterizes the drug delivery device and/or the medicament intended for the drug delivery device or arranged inside the drug delivery device. Hence, drug delivery devices of different type may distinguish from each other by different pairing codes. Identical drug delivery devices, i.e. drug delivery devices equipped with the same medicament may be provided with a common or with the same pairing code. 
     The pairing code may contain unique information or a unique identification of the medicament located inside the drug delivery device. This particularly applies, where the drug delivery device is a prefilled drug delivery device, e.g. a prefilled injection device, which is to equipped with only one type of a medicament. 
     By arranging or integrating the data logging device onto or into the housing of the drug delivery device the data logging device may keep track of a configuration of the drug delivery device. Upon pairing of the data logging device with the external electronic device and by e.g. entering or confirming the pairing code provided on the drug delivery device into or with the external electronic device, the external electronic device is inherently provided with the unique information or unique identification of the medicament located inside the drug delivery device. 
     Moreover, and alternatively, e.g. when the electronic data logging device is fixedly and non-detachable arranged inside or onto the drug delivery device the electronic data logging device may be preprogrammed and provided with sufficient information allowing to identify the type of the medicament and/or the type of the drug delivery device to which the electronic data logging device is actually attached to. Moreover, upon or during integration or assembly of the electronic data logging device into or with the drug delivery device, the pairing code can be provided on the first and/or second device components as well as in an electronic memory of the electronic data logging device. Also, there can be provided a unique assignment between the pairing code provided on the drug delivery device itself and irrespective pairing code stored in a memory of the electronic data logging device. 
     With some examples, the pairing code comprises at least 3 digits, at least 4 digits, at least 5 digits, at least 6 digits or any larger number of digits. Here, a digit may comprise a number, a letter or any other visually identifiable sign. 
     The pairing code is visually identifiable from outside the drug delivery device only when the first device component is in the second positional state relative to the second device component. Hence, when and as long as the first device component is in the second positional state the pairing code is discernible from outside the drug delivery device. In all other positional states, e.g. in the first positional state or in further positional states of the first device component relative to the second device component the pairing code is non-discernible from outside the drug delivery device. 
     Here, the pairing code or at least a portion thereof may be either concealed or covered by at least one of the first or second device component. With some examples, the pairing code may be visible from outside the drug delivery device even when the first device component is outside or offset from the second positional state. Here, the pairing code may be provided with a supplemental code, such as a concealing code portion indistinguishable from the pairing code. Even though the code may be visible it cannot be unequivocally identified visually as long as the first device component is outside the second positional state relative to the second device component. 
     The drug delivery device may be implemented as an inhaler, as an injection device or as an infusion device. The drug delivery device may be implemented as a pen-type injector. The electronic data logging device may be either integrated into the drug delivery device or it may be provided as a separate data logging device or add-on device configured for releasable or non-releasable attachment to the drug delivery device. Typically, the data logging device comprises at least one sensing arrangement configured to detect and/or to quantitatively determine setting and/or dispensing of a dose of the medicament. Typically, the data logging device comprises an integrated circuit, e.g. provided on a printed circuit board (PCB). The data logging device typically comprises a processor and a memory. The data logging device further comprises a communication interface. The communication interface may comprise a wireless transceiver in order to establish a wireless communication link to the external electronic device. 
     The external electronic device may be implemented as a personal digital device, such as a smart watch, an activity watch, a mobile phone, a tablet computer or a personal computer. The data logging device and the external electronic device may be implemented to establish a wireless communication link in accordance to a standardized wireless communication protocols, e.g. based on radio frequency communication, such as RFID, and NFC or Bluetooth. 
     A pairing routine of the electronic data logging device and the external electronic device is particularly implemented to request or to confirm a pairing code. The pairing code as provided by the drug delivery device may either have to be entered into at least one of the data logging device and the external electronic device. With some examples, the pairing code may be visually displayed to the user of the drug delivery device, e.g. by at least one of the data logging device and the external electronic device. The user may then be prompted to confirm, that the illustrated pairing code is identical with the pairing code provided on the drug delivery device. In this way, misuse of data stored in the electronic data logging device can be effectively prevented. 
     The pairing code which might be necessary to establish the communication link is only visually identifiable or discernible from outside the drug delivery device when the first device component is in the second positional state relative to the second device component. With all other available positional states of the first device component relative to the second device component the pairing code is either concealed or it cannot be distinguished from other code information provided on the outside of the first device component and/or the second device component. 
     In this way, the improvement of the drug delivery device provides two alternative approaches. With one approach, the pairing code provided on at least one of the first device component and the second device component is at least partially covered by the other one of the first and the second device components when and as long as the first device component is outside the second positional state or does not overlap with the second positional state relative to the second device component. With this approach, the first and the second device components are typically displaceable relative to each other in an interleaved manner. 
     Hence, that component of the first and second device components which is provided with at least the first code portion is at least partially received inside the other one of the first and second device components. Hence, at least a fraction of the first code portion provided on an outer surface of at least one of the first and second device component is concealed by the other one of the first and second device components. Here, first and second device component mutually overlap. They may be arranged in an interleave or at least partially nested manner. In the first positional state, the degree of overlapping is comparatively large, thereby covering or concealing at least a fraction of the first code portion. When in the second positional state, the degree of mutual overlap is reduced so as to reveal the first code portion or the entirety of the pairing code. 
     According to the second alternative approach, the pairing code is permanently visible on the outside of the first and second device component. Here, the pairing code is provided with a supplemental code, hence with a concealing code portion that is indistinguishable from the pairing code. As long as both, the pairing code and the supplemental concealing code portion are both visible on the outside of the drug delivery device the pairing code cannot be visually identified because the respective user does not know the total length and the position of the relevant pairing code in or from the indistinguishable combination of the pairing code and the concealing code. 
     Here, the pairing code made can be hidden among supplemental concealing code portions. It is only upon moving the first device component into the second positional state relative to the second device component, that the supplemental and/or concealing code portion(s) are concealed or covered so that the residual pairing code becomes discernible from outside the drug delivery device. 
     In the present context a positional state between first and second device component includes a relative position as well as a relative orientation between first and second device components. In the first and second positional states, at least one of the position and the orientation of the first device component differs from the respective position or orientation of the second device component. 
     First and second device components may be mechanically engaged either directly or indirectly. Furthermore, first and second device components may be one of threadedly engaged or slidably engaged. The first and the second device component may be rotationally engaged or may be rotationally locked. 
     A movement of the first device component from the first positional state towards and into the second positional state may comprise at least one of a rotational motion, a sliding motion or a helical motion, hence a combined rotating and sliding motion. The first and the second device components may be permanently connected, e.g. by a threaded engagement or by a slotted link. 
     The first positional state of first and second device components may coincide with an initial state of the respective component, e.g. in which the drug delivery device is handed out to the patient or customer. The second positional state of first and second device components may coincide with a particular device configuration. With some examples preparing of the drug delivery device for administering a dose of the medicament requires a movement of the first device component relative to the second device component. With some examples, setting of a dose of the medicament requires moving of the first device component relative to the second device component; or vice versa. With some examples expelling or dispensing of the dose of the medicament requires movement of the first device component relative to the second device component. 
     The second positional state of the first device component relative to the second device component is a characteristic relative position and/or relative orientation of the first device component relative to the second device component. The user of the drug delivery device is well aware of this characteristic portion and has only little difficulties to move the first device component relative to the second device component to arrive at the second positional state. 
     Typically, the second positional state, in which the pairing code is visually identifiable or in which the pairing code is discernible from outside the drug delivery device does not coincide with an initial device configuration. Making the pairing code visually identifiable from outside the drug delivery device always requires a well-defined user induced movement of the first device component relative to the current device component. 
     Generally, it is only relevant, that the first device component is moved relative to the second device component. Whether or not the first device component is actually subject to a movement relative to the environment is quite irrelevant. For arriving at the second positional state the first device component may be fixed, e.g. by a hand of a user while the second device component is moved relative to the first device component. 
     According to a further example the first code portion or the pairing code is provided on the first outer surface. At least a part of the first code portion or at least a part of the pairing code is concealed by the second device component when the first device component is outside the second positional state. In this way and as long as the first device component is outside or nonoverlapping with the second positional state the entirety of the pairing code is not yet visually identifiable from outside the drug delivery device. Here, the respective portion of the first outer surface provided with the first code portion or provided with the entirety of the pairing code is covered by the second device component. Typically, the second device component or at least a portion thereof spatially overlapping with the first device component is opaque. 
     In this way the first code portion or the entirety of the pairing code is revealed when the first device component arrives in the second positional state relative to the second device component. As long as the first device component and hence the first code portion or the entirety of the pairing code is in the first positional state, at least a fraction of the first code portion or a respective fraction of the entirety of the pairing code is non-discernible from outside the drug delivery device. In this positional state and as long as the first device component is outside the second positional state the pairing code in its entirety cannot be visually identified from outside the drug delivery device. A communicative pairing between the electronic data logging device, e.g. attached to or integrated into the drug delivery device and the external electronic device is not possible and data stored in the electronic data logging device is protected against misuse. 
     According to another example the first outer surface is provided with one of the first code portion and the pairing code. The first outer surface is further provided with a first concealing code portion. The concealing code portion is indistinguishable from the first code portion or from the pairing code. An indistinguishable composition of at least a portion of the concealing code portion and at least one of the first code portion and the pairing code is discernible from outside the drug delivery device when the first device component is outside the second positional state, e.g. when the first device component is in a third positional state relative to the second device component. 
     The concealing code portion may be of the same type of code compared to the pairing code. With some examples, the pairing code may comprise a string of numbers or characters. The concealing code portion may comprise a comparable string of numbers or characters. The font, size and style of the strings of the pairing code and the concealing code potion may be identical or equivalent, hence indistinguishable. The concealing code portion may be directly aligned with the first code portion and/or with the pairing code. 
     The first code portion or the pairing code may be embedded or framed by the first concealing code portion. The user may not be aware about the length of the string of the composition of the first concealing code portion and at least one of the first code portion and the pairing code. The pairing code is hence blended or intermixed with the concealing code portion and becomes visually indistinguishable as long as both, the pairing code or the first code portion thereof is provided together with the first concealing code portion on the first outer surface. 
     With some examples, the first code portion or the entirety of the pairing code may be totally invisible and may be hence entirely concealed by the second device component when the first device component is in the first positional state. As the first device component is moved from the first positional state towards the second positional state, the first code portion or the entirety of the pairing code becomes successively visible. 
     When reaching the second positional state, the relevant first code portion or the entirety of the pairing code may be revealed from the second device component. As the second device component is moved further in the same direction towards a third positional state the concealing code portion provided on the first outer surface in addition to the first code portion and/or the entirety of the pairing code becomes visible and is revealed. 
     Since the first concealing code portion is generally indistinguishable from the first code portion or from the pairing code, the combination of the first concealing code portion with the first code portion and/or with the pairing code is effectively unusable for the user because the relevant pairing code or the relevant code portion thereof cannot be an identified in the indistinguishable code composition as provided on the first outer surface of the first device component. 
     This provides a further safety feature against misuse or unauthorized access to the data stored in the electronic data logging device with. Visually identifying the entirety of the pairing code requires knowledge about the rather specific and well-defined second positional state of the first device component relative to the second device component. 
     According to another example the first concealing code portion is concealed by the second device component when the first device component is in the second positional state. Here, the first concealing code portion may be masked or shielded by the second device component. Consequently and when in the second positional state the relevant portion, hence the first code portion or the entirety of the pairing code becomes distinguishable from or in the composition of the first concealing code portion with at least one of the first code portion and the pairing code. 
     According to another example the pairing code comprises the first code portion and a second code portion. The first code portion is provided on the first outer surface. The second code portion is provided on the second outer surface. Here, the entirety of the pairing code is split among the first and the second device components. The first code portion is provided on the first outer surface of the first device component and the second code portion is provided on the second outer surface of the second device component. The entirety of the pairing code is a combination of the first code portion and the second code portion. Hence, for visually identifying the entirety of the pairing code, the first code portion and the second code portion have to recombine and/or have to complement each other. 
     With this example, both, the first code portion and the second code portion may be permanently visible from outside the drug delivery device. For recombining the pairing code from the first code portion at the second code portion it may be necessary to arrange the first code portion and the second code portion in a well-defined or predefined manner. With some examples, the first code portion and the second code portion have to be aligned in a particular configuration only known to the user of the drug delivery device. 
     With some examples only one of the first and second code portions may be permanently visible on one of the first and second outer surfaces, respectively. Moving of the first device component relative to the second device component may lead to a modification of a mutual degree of spatial and non-translucent overlap of first and second outer surfaces. 
     Hence, in the first positional state only the second code portion may be visible from outside the drug delivery device whereas the first code portion or a fraction thereof remains revealed by the second device component. Moving of the first device component relative to the second device component into the second positional state comes along with a movement of the first code portion relative to the second code portion. Here, the first code portion may be revealed from the second device component. 
     In addition, the first code portion may complement the second code portion to constitute or to recombine the pairing code when the first device component is in the second positional state relative to the second device component. 
     The first code portion and the second code portion mutually recombine and constitute the pairing code when the first device component is in the second positional state. 
     With other configurations and when the first device component is outside the second positional state relative to the second device component the combination of the first code portion visible from outside the drug delivery device and the second code portion as visible from outside the drug delivery device may also mutually align or recombine but may be inoperable and may not provide the pairing code. In such positional states of the first device component and the second device component that distinguish or differ from the second positional date a recombination of first and second code portions distinguishes from the pairing code and does therefore not represent or reconstitute the pairing code required for setting up or to establish the communication link between the electronic data logging device and the external electronic device. 
     According to another example at least one of the pairing code and the first code portion extends along a first direction on at least one of the first and second device components, hence on at least one of the first outer surface and the second outer surface. Here, the first device component is movable along the first direction relative to the second device component. This is of particular use with e.g. the pairing code or the first code portion is provided on the first outer surface and wherein the first outer surface of the first device component is at least partially covered by the second device component, e.g. at least when the first device component is in the first positional date. As the first device component is moved towards the second positional state, more and more of the first outer surface made be revealed from the second device component. 
     With some examples at least a portion of the first device component may be located inside the second device component when in the first positional state. As the first device component is moved towards the second positional state, the first outer surface may continuously protrude from an end of the second device component or the respective first outer surface may extend into an aperture of the second device component, such that more and more of the first code portion or of the entirety of the pairing code becomes discernible and visible either by protruding from an end of the second device component or by appearing in the aperture of the second device component. 
     As the first device component is moved along the first direction relative to the second device component while being subject to a movement from the first positional state towards the second positional state a constantly increasing portion of the first code portion and the pairing code becomes discernible. 
     According to a further example the second outer surface of the second device component is further provided with a second concealing code portion. The second concealing code portion is indistinguishable from the second code portion provided on the second outer surface. The first code portion aligns with the second code portion when the first device component is in the second positional state. As long as the first device component is outside the second positional state, the first code portion may be offset from the second code portion. Here, the first code portion may align with a portion or with a fraction of the second concealing code. A combination and alignment of the second concealing code or a portion thereof with the first code portion may not constitute or recombine the pairing code. 
     According to a further example the second concealing code extends along a second direction on the second outer surface. Typically, the second direction may distinguish from the first direction, along which the first code portion extends. With some examples, the second concealing code may extend along a tangential direction of a tubular shaped and/or elongated second device component. The first code portion may extend along a first direction, which may coincide with a longitudinal axis of the elongated, e.g. tubular shaped first or second device component. 
     When the first code portion extends along a first direction and when the second code portion and/or the second concealing code extends along a second direction, wherein first and second directions extend at a predefined, non-zero angle relative to each other, recombining and constituting the pairing code may require that the first device component is moved from the first positional states towards the second positional state along the second direction. A movement of the first device component relative to the second device component along the first direction may be then only optional. 
     The first and second directions may extend perpendicular to each other. The pairing code may be recombined by a straight-line intersecting at least one of the first code portion and the second concealing code portion and a fraction of the other one of the first code portion and the second concealing code portion. 
     According to another example the first code portion or a fraction thereof aligns with the second concealing code portion when the first device component is outside the second positional state. The alignment of the first code portion with a fraction of the second concealing code portion is ineffective to recombine or to constitute the pairing code. When and as long as the first device component is outside of the second positional state the first code portion may exclusively align with the second concealing code portion or with a fraction thereof, thus effectively impeding to visually identify the pairing code in an overlap of the first code portion and the second concealing code portion. 
     According to a further example at least one of the second concealing code portion and the second code portion extends along a second direction. The first device component is movable along the second direction relative to the second device component. With some examples, the first direction extends along a symmetry axis or along a longitudinal axis of the housing of the drug delivery device. The second direction may extend in tangential or circumferential direction with regards to such an elongated, e.g. tubular shaped housing. The first and the second directions may extend at a predefined non-zero angle with respect to each other. The first and second directions may extend perpendicular to each other. 
     According to another example the drug delivery device comprises a first marker and a second marker. The first marker is provided by or is connected to the first device component. The second marker is provided by or is connected to the second device component. The first marker may be provided on the first outer surface. The second marker may be provided on the second outer surface. The first marker is subject to a movement relative to the second marker when the first device component moved relative to the second device component. 
     The first marker and the second marker visually align, visually overlap or mechanically engage when the first device component reaches the second positional state relative to the second device component. By means of the first marker and the second marker, the second positional state of the first device component and the second device component can be identified. At least one of the first and second markers is permanently visible to a user of the drug delivery device. The other one of the first and the second marker may be temporally concealed by the other one of the first and second respective device component. 
     Upon movement of the first device component relative to the second device component and upon reaching of the second positional state the first and second markers mutually align, visually overlap or mechanically engage, thereby indicating to the user, that the second positional state has been reached and that the pairing code is now visually identifiable from outside the drug delivery device. 
     With some examples, the first marker comprises an identification feature on the first surface of the first device component. The first marker may comprise a particular character or a visual sign, such as a letter or a number. The second marker may comprise a corresponding visual sign, character or number, e.g. on the second outer surface. With some examples, the second marker may comprise an aperture in the second device component. The second marker may also comprise a pointer. When for instance the second device component is the housing of the drug delivery device or when the second device component forms part of the housing of the drug delivery device it may comprise an aperture, through which at least a portion of the first device component, typically at least a portion of the first outer surface provided with the first marker can be visually identified or detected. 
     With some examples the first and the second marker comprise mutually corresponding and/or complementary shaped engaging features, such as a protrusion and a corresponding recess. In this way the first and the second marker may mechanically engage when the first and second device components reach the second positional state. 
     With some examples, the drug delivery device comprises a number sleeve with a sequence of numbers printed thereon. The sequence of numbers is indicative of a size of a dose actually set. The first marker may correspond to a particular predefined dose size, e.g. it may be represented by a dose size of a predefined number, e.g. of a dose size of 25 units. Here, the number sleeve may represent the first device component. The second device component may be represented by the housing of the drug delivery device, e.g. by a body of the housing or by a cartridge holder. 
     When implemented as the body of the housing of the drug delivery device the second device component may comprise an aperture or a window, through which at least a portion of the first device component located underneath is visible. With the first marker, e.g. in form of a particular and predefined dose size shows up in the aperture or in the dose window of the second device component, hence in the dosage window of the housing or body of the drug delivery device, this might be a clear indication to a user of the drug delivery device that the first device component has reached the predefined second positional state, in which the pairing code is discernible from outside the drug delivery device. 
     According to further examples the first device component is one of the dose dial, a dial extension, a number sleeve and a protective cap of a pen-type injection device. A dose dial is typically subject to a rotating movement during and/or for setting of a dose of variable size. During setting of a dose, the dose dial is typically subject to a rotation relative to the housing of the drug delivery device. The dose dial may be also subject to a combined longitudinal sliding movement relative to the housing, e.g. serving as the second device component according to the present terminology. Moreover, the dose dial may be subject to a combined rotational and longitudinal motion relative to the housing or body of the drug delivery device. Hence, the dose dial may be subject to a helical movement relative to the housing or body as a dose is set. 
     The same may apply to a dial extension. The dial extension may be subject to a longitudinal sliding motion during setting of a dose and/or during dispensing or expelling of the dose of the medicament. The dial extension may be subject to a combined longitudinal sliding movement and a rotational movement. A dial extension or components thereof may be subject to a helical movement relative to the housing of the drug delivery device, e.g. during and/or for setting or expelling of the dose of the medicament. The number sleeve may form part of a dial extension. 
     With some examples the number sleeve remains inside the housing of the drug delivery device. The number sleeve is rotationally supported in or on the housing of the drug delivery device. With some examples the number sleeve is locked in longitudinal direction relative to the housing. With further examples of the number sleeve is threadedly engaged with the housing. It may then follow a helical path relative to the housing when subject to a movement relative to the housing. 
     With other examples the protective cap configured to cover a dispensing or expelling end of the drug delivery device may be implemented as the first device component in accordance to the above terminology. The protective cap may be rotationally supported on the distal end of the housing of the drug delivery device. It may be freely oriented in numerous rotational states relative to the housing. The protective cap may be detachably locked to the housing with regard to the longitudinal direction. The protective cap may be clipped or snap fitted to the housing. 
     With other examples the second device component is one of a housing, a body of the housing and a cartridge holder of a pen-type injection device. 
     With some examples, the second device component may comprise a gauge element slidably supported in the housing of the drug delivery device and rotationally locked to the tubular shaped housing of the drug delivery device. The gauge element may be threadedly engaged, e.g. with a number sleeve. The gauge element may comprise a window or an aperture, through which a portion of the number sleeve is discernible or visible. With the implementation of a gauge element the number sleeve may be locked in longitudinal direction to the housing of the drug delivery device. It may be free to rotate relative to the housing. The gauge element may also belong to or may form part of a dial extension. 
     The gauge element acting as the second device component itself may be slidably supported in a longitudinal aperture of the housing. Here, the housing may act as the first device component. The gauge element may comprise a recess or a gauge aperture, through which a selected portion of the number sleeve located underneath is revealed. When threadedly engaged with the number sleeve, a rotation of the number sleeve leads to a longitudinal displacement of the gauge element relative to the aperture of the housing. 
     An outside surface of the gauge element may be provided with at least the first code portion of the pairing code. By setting of a dose of prescribed or predefined size the gauge element, i.e. the second device component is moved relative to the housing, i.e. relative to the first device component. In this way, the first device component may reach the second positional state relative to the second device component; and vice versa. In this positional state, at least the first code portion or the entire code as provided on the outside surface of the gauge element may become discernible in the longitudinal aperture of the housing. 
     During dialing or setting of a dose, the number sleeve may be subject to a rotational motion relative to the housing. Due to the threaded engagement with the number sleeve and the rotational interlock with the housing, the gauge element may slide along the rotating number sleeve, thus visually illustrating a sequence of consecutive numbers or dose size indications showing up in window or aperture of the gauge element. 
     A body of the housing is typically a proximal portion of the housing. The body may be configured to house or to accommodate a drive mechanism of the drug delivery device. The body may be either non-releasably or detachably connected to a cartridge holder of a pen-type injection device. The cartridge holder may be particularly adapted to accommodate a cartridge filled with a medicament. With disposable devices, a cartridge filled with a medicament is readily arranged inside the housing, typically inside the cartridge holder. The cartridge holder may be non-releasably or non-detachably connected to the body of the housing of the drug delivery device. 
     The above described concept of providing first and second device components of a drug delivery device movable relative to each other can be mapped and transferred to numerous components of a pen-type injection device. For instance, a first code portion may be provided at or near a proximal end of the protective cap and a consecutive second code portion may be provided at or near a distal end of the body of the housing of such a pen-type injector. The protective cap may be free to rotate with regard to the longitudinal axis relative to the body. Only in one or some further generally available positional states of the protective cap and the body the respective first and second code portions mutually align thus making the pairing code visually identifiable from outside the drug delivery device. With other configurations, the protective cap may be suitable to cover at least a portion of the pairing code when assembled or attached to the body. Detaching of the protective cap may then reveal the pairing code. 
     According to another example of the drug delivery device a cartridge filled with a medicament is arranged inside the housing. In this way, the drug delivery device is a drug device combination. It may be implemented as a disposable device with the cartridge readily assembled therein. It may be also configured and implemented as a reusable device. Here, the cartridge holder is detachably connected to the proximal body of the drug delivery or injection device thus allowing to replace an empty cartridge by a new, hence a filled one. 
     According to a further example the electronic data logging device is integrated in the drug delivery device. The data logging device may be integrated and/or assembled inside the drug delivery device, inside the housing of the drug delivery device or inside a dial extension of the drug delivery device. With other examples, the electronic data logging device is provided as a separate data logging device. It may comprise at least one fastening feature to engage with a correspondingly or complementary shaped fastening feature at a predefined position of the drug delivery device. 
     When implemented as a separate electronic data logging device, the data logging device may be attachable or may be readily attached e.g. to a proximal end of the drug delivery device. With some examples, the data logging device is attached to a dial extension and/or to at least one of a dose dial and a trigger of a pen-type injection device. 
     According to another aspect the present disclosure relates to a method of pairing an electronic data logging device of a drug delivery device with an external electronic device. The drug delivery device comprises a first device component movable relative to a second device component. The first device component comprises a first outer surface. The second device component comprises a second outer surface. At least one of the first outer surface and the second outer surface comprises at least a first code portion of a pairing code. The pairing code being visually identifiable from outside the drug delivery device only when the first device component is in a second positional state relative to the second device component. 
     The method comprises the step of setting at least one of the external electronic device and the data logging device into a pairing mode. Before, during or thereafter the first device component is moved relative to the second device component from a first positional state, in which the pairing code is indiscernible, into the second positional state, in which the pairing code is visually identifiable. Thereafter and when the first device component has reached the second positional state relative to the second device component the pairing code as it is now visually identifiable from outside the drug delivery device is actually visually identified or captured, e.g. by a person. 
     The identified pairing code is then used for establishing and/or for setting up a communication link between the external electronic device and the data logging device. Depending on the specific implementation of the pairing routine the user may be either prompted to enter the pairing code, e.g. into the external electronic device or into the data logging device. With other examples, the pairing code may be presented by at least one of the data logging device and the external electronic device, either visually or audibly. The user may be then prompted to confirm the pairing code. In case that a pairing code proposed by any one of the data logging device and the external electronic device in the course of pairing these two devices should not match with the pairing code visually identifiable from outside the drug delivery device the user should abort and cancel the pairing routine in order to prevent misuse or unauthorized use of the data stored in the data logging device. 
     It should be noted further, that the present method of pairing an electronic data logging device with an external electronic device with the help of the drug delivery device is universally applicable and executable by any type of a drug delivery device as described above. Therefore, any features, benefits and effects as described above in connection with the drug delivery device equally apply to the method of pairing; and vice versa. 
     According to a further aspect, the present disclosure relates to a medicament injection system. The injection system comprises a drug delivery device or an injection device as described above. The injection system further comprises a data logging device, either integrated into the drug delivery device or attachable to the drug delivery device. Here, the data logging device is configured and implemented to establish or to set up a communication link, e.g. a wireless communication link, to an external electronic device, such as a smart watch, a mobile phone, a tablet computer or a personal computer. Insofar, all features, effects and benefits as described above equally apply to the medicament injection system. 
     According to another aspect, the medicament injection system further comprises the external electronic device configured to establish and/or to set up a communication link, e.g. a wireless communication link, to the data logging device. 
     The injection system further comprises an external electronic device configured to establish a communication link to the data logging device. 
     Generally, the scope of the present disclosure is defined by the content of the claims. The injection device is not limited to specific embodiments or examples but comprises any combination of elements of different embodiments or examples. Insofar, the present disclosure covers any combination of claims and any technically feasible combination of the features disclosed in connection with different examples or embodiments. 
     In the present context the term ‘distal’ or ‘distal end’ relates to an end of the injection device that faces towards an injection site of a person or of an animal. The term ‘proximal’ or ‘proximal end’ relates to an opposite end of the injection device, which is furthest away from an injection site of a person or of an animal. 
     The terms “drug” or “medicament” are used synonymously herein and describe a pharmaceutical formulation containing one or more active pharmaceutical ingredients or pharmaceutically acceptable salts or solvates thereof, and optionally a pharmaceutically acceptable carrier. An active pharmaceutical ingredient (“API”), in the broadest terms, is a chemical structure that has a biological effect on humans or animals. In pharmacology, a drug or medicament is used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. A drug or medicament may be used for a limited duration, or on a regular basis for chronic disorders. 
     As described below, a drug or medicament can include at least one API, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Examples of API may include small molecules having a molecular weight of 500 Da or less; polypeptides, peptides and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes); carbohydrates and polysaccharides; and nucleic acids, double or single stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids may be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more drugs are also contemplated. 
     The drug or medicament may be contained in a primary package or “drug container” adapted for use with a drug delivery device. The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., short-or long-term storage) of one or more drugs. For example, in some instances, the chamber may be designed to store a drug for at least one day (e.g., 1 to at least 30 days). In some instances, the chamber may be designed to store a drug for about 1 month to about 2 years. Storage may occur at room temperature (e.g., about 20° C.), or refrigerated temperatures (e.g., from about -4° C. to about 4° C.). In some instances, the drug container may be or may include a dual-chamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and/or during dispensing into the human or animal body. For example, the two chambers may be configured such that they are in fluid communication with each other (e.g., by way of a conduit between the two chambers) and allow mixing of the two components when desired by a user prior to dispensing. Alternatively or in addition, the two chambers may be configured to allow mixing as the components are being dispensed into the human or animal body. 
     The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and/or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as Rote Liste 2014, for example, without limitation, main groups 12 (antidiabetic drugs) or 86 (oncology drugs), and Merck Index, 15th edition. 
     Examples of APIs for the treatment and/or prophylaxis of type 1 or type 2 diabetes mellitus or complications associated with type 1 or type 2 diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-1), GLP-1 analogues or GLP-1 receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-4 (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms “analogue” and “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and/or exchanging at least one amino acid residue occurring in the naturally occurring peptide and/or by adding at least one amino acid residue. The added and/or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as “insulin receptor ligands”. In particular, the term “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g. a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide may have been deleted and/or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide. Examples of insulin analogues are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin (insulin glulisine); Lys(B28), Pro(B29) human insulin (insulin lispro); Asp(B28) human insulin (insulin aspart); human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val or Ala and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin. 
     Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl- ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-gamma-glutamyl)-des(B30) human insulin, B29-N-omega-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin. 
     Examples of GLP-1, GLP-1 analogues and GLP-1 receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-4, Byetta®, Bydureon®, a 39 amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), rExendin-4, CJC-1134-PC, PB-1023, TTP-054, Langlenatide / HM-11260C (Efpeglenatide), HM-15211, CM-3, GLP-1 Eligen, ORMD-0901, NN-9423, NN-9709, NN-9924, NN-9926, NN-9927, Nodexen, Viador-GLP-1, CVX-096, ZYOG-1, ZYD-1, GSK-2374697, DA-3091, MAR-701, MAR709, ZP-2929, ZP-3022, ZP-DI-70, TT-401 (Pegapamodtide), BHM-034. MOD-6030, CAM-2036, DA-15864, ARI-2651, ARI-2255, Tirzepatide (LY3298176), Bamadutide (SAR425899), Exenatide-XTEN and Glucagon-Xten. 
     An example of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia or RG012 for the treatment of Alport syndrom. 
     Examples of DPP4 inhibitors are Linagliptin, Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine. 
     Examples of hormones include hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, and Goserelin. 
     Examples of polysaccharides include a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra-low molecular weight heparin or a derivative thereof, or a sulphated polysaccharide, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and/or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium. An example of a hyaluronic acid derivative is Hylan G-F 20 (Synvisc®), a sodium hyaluronate. 
     The term “antibody”, as used herein, refers to an immunoglobulin molecule or an antigen-binding portion thereof. Examples of antigen-binding portions of immunoglobulin molecules include F(ab) and F(ab′)2 fragments, which retain the ability to bind antigen. The antibody can be polyclonal, monoclonal, recombinant, chimeric, de-immunized or humanized, fully human, non-human, (e.g., murine), or single chain antibody. In some embodiments, the antibody has effector function and can fix complement. In some embodiments, the antibody has reduced or no ability to bind an Fc receptor. For example, the antibody can be an isotype or subtype, an antibody fragment or mutant, which does not support binding to an Fc receptor, e.g., it has a mutagenized or deleted Fc receptor binding region. The term antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and/or a dual variable region antibody-like binding protein having cross-over binding region orientation (CODV). 
     The terms “fragment” or “antibody fragment” refer to a polypeptide derived from an antibody polypeptide molecule (e.g., an antibody heavy and/or light chain polypeptide) that does not comprise a full-length antibody polypeptide, but that still comprises at least a portion of a full-length antibody polypeptide that is capable of binding to an antigen. Antibody fragments can comprise a cleaved portion of a full length antibody polypeptide, although the term is not limited to such cleaved fragments. Antibody fragments that are useful in the present disclosure include, for example, Fab fragments, F(ab′)2 fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, tetraspecific and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), monovalent or multivalent antibody fragments such as bivalent, trivalent, tetravalent and multivalent antibodies, minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art. 
     The terms “Complementarity-determining region” or “CDR” refer to short polypeptide sequences within the variable region of both heavy and light chain polypeptides that are primarily responsible for mediating specific antigen recognition. The term “framework region” refers to amino acid sequences within the variable region of both heavy and light chain polypeptides that are not CDR sequences, and are primarily responsible for maintaining correct positioning of the CDR sequences to permit antigen binding. Although the framework regions themselves typically do not directly participate in antigen binding, as is known in the art, certain residues within the framework regions of certain antibodies can directly participate in antigen binding or can affect the ability of one or more amino acids in CDRs to interact with antigen. 
     Examples of antibodies are anti PCSK-9 mAb (e.g., Alirocumab), anti IL-6 mAb (e.g., Sarilumab), and anti IL-4 mAb (e.g., Dupilumab). 
     Pharmaceutically acceptable salts of any API described herein are also contemplated for use in a drug or medicament in a drug delivery device. Pharmaceutically acceptable salts are for example acid addition salts and basic salts. 
     Those of skill in the art will understand that modifications (additions and/or removals) of various components of the APIs, formulations, apparatuses, methods, systems and embodiments described herein may be made without departing from the full scope and spirit of the present disclosure, which encompass such modifications and any and all equivalents thereof. 
     It will be further apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope of the disclosure. Further, it is to be noted, that any reference numerals used in the appended claims are not to be construed as limiting the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       In the following, numerous examples of the injection device and the method of pairing a data logging device with an external electronic device will be described in greater detail by making reference to the drawings, in which: 
         FIG.  1    schematically illustrates an example of a drug delivery device implemented as an injection device, 
         FIG.  2    schematically illustrates numerous components of the drug delivery device of  FIG.  1   , 
         FIG.  3    is a schematic block diagram of an example of an electronic data logging device, 
         FIG.  4    schematically illustrates an electronic data logging device integrated into a drug delivery device, 
         FIG.  5    schematically illustrates a portion of the drug delivery device with first and second device components carrying a pairing code portion for setting of a communication link between the data logging device and the external electronic device, wherein first and second device components are in a first positional state, 
         FIG.  6    shows the example of  FIG.  5   , wherein first and second device components are in a second positional state, 
         FIG.  7    schematically illustrates another example of a drug delivery device provided with a pairing code, wherein first and second device components are in a first positional state, 
         FIG.  8    shows the example of  FIG.  7   , wherein the first and second device components are in a second positional state, 
         FIG.  9    shows first and second device components of  FIGS.  7  and  8    in a third positional state, and 
         FIG.  10    shows a flowchart of executing a method of pairing an electronic data logging device with an external electronic device by using a pairing code as provided by the drug delivery device in accordance to any of the  FIGS.  1 - 9   . 
     
    
    
     DETAILED DESCRIPTION 
     One example of a drug delivery device  1  for administering of a dose of a medicament  27  is illustrated in  FIGS.  1  and  2   . The drug delivery device  1  is implemented as an injection device  30 . The injection device  30  is a handheld pen-type injector. The injection device  30  may be implemented as a disposable injection device  30 . It may comprise a pre-filled cartridge  6  arranged inside a cartridge holder  14 . With a disposable injection device  30 , the cartridge holder  14  may be non-detachably connected to a body  10  of a housing  32  of the injection device  30 . 
     With other examples, the injection device  30  is a re-usable injection device, wherein the cartridge holder  14  is detachably connected to the body  10  for replacing an empty cartridge  6 . At or near a distal end of the housing  32 , hence at the distal end of the cartridge holder  14 , there is provided a socket  28  configured to mount or to engage with an injection needle  15 . The socket  28  may be implemented as a threaded socket and the injection needle  15  may comprise a needle hub begin correspondingly threaded to provide a threaded engagement with the socket  28 . 
     Typically, the injection needle  15  is protected by an inner needle cap  16  and either by an outer needle cap  17  and/or a protective cap  18  that is configured to enclose and to protect a distal section of the housing  32  of the injection device  30 . The body  10  may comprise and form a main housing part configured to accommodate a drive mechanism  34  as shown in  FIG.  2   . The cartridge holder  14  may be regarded as a distal housing component of the injection device  30 . The cartridge holder  14  may be permanently or releasably connected to the body  10  or main housing. 
     The cartridge  6  comprises a cylindrically-shaped or tubular-shaped barrel  25  sealed in proximal direction  3  by a bung  7  located inside the barrel  25 . The cartridge six may be prefilled with a liquid medicament  27 . The bung  7  is displaceable relative to the barrel  25  of the cartridge  6  in a distal direction  2  by means of a piston rod  20  of the drive mechanism  34 . A distal end of the cartridge  6  is sealed by a pierceable seal  26  configured as a septum and being pierceable by a proximally directed tipped end of the injection needle  15 . By attaching the injection needle  15  to the distal end of the cartridge holder  14  the seal  26  of the cartridge  6  is penetrated thereby establishing a fluid transferring access to the interior of the cartridge  6 . 
     When the injection device  1  is configured to administer e.g. human insulin, the dosage set by a dose dial  12  at a proximal end of the injection device  1  may be displayed in so-called international units (IU, wherein 1 IU is the biological equivalent of about 45.5 µg of pure crystalline insulin (1/22 mg). The dose dial  12  may comprise a sleeve shaped knob at the proximal end of the housing  32  of the injection device  30 . 
     As shown further in  FIGS.  1  and  2   , the body  10  comprises a dosage window  13  that may be in the form of an aperture in the body  10 . The dosage window  13  permits a user to view a limited portion of a number sleeve  80  that is configured to move when the dose dial  12  is turned. The number sleeve  80  and the dosage window  13  provide a visual indication of a dose currently set. The dose dial  12  may be rotated on a helical path with respect to the body  10  when turned during setting and/or dispensing or expelling of a dose. 
     With some other type of injection device, the dose dial  12  may be locked in longitudinal direction to the body  10 . It may be then limited to a rotational movement relative to the body  10  for setting of the dose. 
     The injection device  30  may be configured so that turning the dosage knob  12  causes a mechanical click sound to provide acoustical feedback to a user. The number sleeve  80  mechanically interacts with a piston in the insulin cartridge  6 . When the needle  15  is stuck into a skin portion of a patient, and when the trigger  11  or injection button is pushed, the insulin dose displayed in the dosage window  13  will be ejected from injection device  1 . When the needle  15  of the injection device  1  remains for a certain time in the skin portion after the trigger  11  is pushed, a high percentage of the dose is actually injected into the patient’s body. Ejection of an insulin dose may also cause a mechanical click sound, which is however different from the sounds produced when using the dose dial  12 . 
     In the illustrated embodiment, during delivery of the insulin dose, the dose dial  12  is turned to its initial position in an axial movement, that is to say without rotation, while the number sleeve  80  is rotated to return to its initial position, e.g. to display a dose of zero units. 
     The injection device  30  may be used for several injection processes until either the cartridge  6  is empty or the expiration date of the medicament in the injection device  1  (e.g.  28  days after the first use) is reached. 
     At least some components of an example of a drive mechanism  34  are illustrated in more detail in  FIG.  2   . The drive mechanism  34  comprises numerous mechanically interacting components. A flange like support of the housing  10  comprises a threaded axial through opening threadedly engaged with a thread  22  of the piston rod  20 . The distal end of the piston rod  20  comprises a bearing  21  on which a pressure foot  23  is free to rotate with the longitudinal axis of the piston rod  20  as an axis of rotation. The pressure foot  23  is configured to axially abut against a proximally facing thrust receiving face of the bung  7  of the cartridge  6 . During a dispensing action the piston rod  20  rotates relative to the housing  10  thereby experiencing a distally directed advancing motion relative to the housing  10  and hence relative to the barrel  25  of the cartridge  6 . As a consequence, the bung  7  of the cartridge  6  is displaced in distal direction  2  by a well-defined distance due to the threaded engagement of the piston rod  20  with the housing  10 . 
     Furthermore, there is provided a dose dial sleeve also denoted as number sleeve  80 . The number sleeve  80  is located radially inward of the housing  10 . A helical groove  81  is provided about an outer surface of the number sleeve  80 . The body  10  is provided with the dosage window  13  through which a part of the outer surface of the number sleeve  80  can be seen. The body  10  is further provided with a helical rib at an inside sidewall portion of an insert piece  62 , which helical rib is to be seated in the helical groove  81  of the number sleeve  80 . The tubular shaped insert piece  62  is inserted into the proximal end of the tubular shaped body  10 . Alternatively, such a helical rib may be also provided directly on an inside of the sidewall of the body  10 . The helical rib as well as the insert piece  62  is rotationally and axially fixed to the body  10 . There may be provided first and second stops on the body  10  to limit a dose setting procedure during which the number sleeve  80  is rotated in a helical motion relative to the housing  10 . 
     The dose dial  12  in form of a dose dial grip is disposed about an outer surface of the proximal end of the number sleeve  80 . An outer diameter of the dose dial  12  typically corresponds to and matches with the outer diameter of a proximal end of the body  10 . The dose dial  12  is secured to the number sleeve  80  to prevent relative movement there between. The dose dial  12  is provided with a central opening. 
     A trigger  11 , also denoted as dose button is substantially T-shaped. It is provided at a proximal end of the injection device  10 . A stem  64  of the trigger  11  extends through the opening in the dose dial  12 . The stem  64  and hence the trigger  11  is retained for limited axial movement relative to the number sleeve  80 . A head of the trigger  11  is generally circular. The trigger side wall or skirt extends from a periphery of the head and is further adapted to be seated in a proximally accessible annular recess of the dose dial  12 . 
     To dial a dose a user rotates the dose dial  12 , along a dose incrementing direction  4 , e.g clockwise. Dialing of a dose may be accompanied by a clicking sound. In this way, audible and/or tactile feedback of the dose being dialed is provided. Dialing of a dose is further accompanied by a rotation of the number sleeve  80 , which starts to extend from the body  10  towards the proximal direction  3  when dialed along a dose incrementing direction  4 , e.g in a clockwise sense. 
     The number sleeve  80 , the dose dial  12  and the trigger may form part of a dial extension  70 , hence and assembly of components of the drive mechanism  34  that starts to extend or to displace from the proximal end of the body  10  as a dose is dialed. During dispensing of a dose, hence when a user depresses the trigger  11  in distal direction  2 , the dial extension  70  is subject to a distally directed movement relative to the body  10 , hence along the distal direction  2 . During such a dispensing motion, the number sleeve  80  is subject to a rotation along a dose decrementing direction  5 , e.g. counter-clockwise. 
     The expelling mechanism or drive mechanism  34  as described above is only exemplary for one of a plurality of differently configured drive mechanisms that are generally implementable in a disposable or re-usable pen-injector. The drive mechanism as described above is explained in more detail e.g. in WO2004/078239A1, WO 2004/078240A1 or WO 2004/078241A1 the entirety of which being incorporated herein by reference. 
     The drug delivery device  1 , hence the injection device  30  may be further equipped with a data logging device  100  as indicated in  FIGS.  3  or  4   . The data logging device  100  may be integrated into the injection device  30 . It may be positioned in a hollow receptacle provided by at least one of the trigger  11  and the dose dial  12 . With other examples, the data logging device  100  is a separate component detachably connectable to the body  10  or to some other portion of the housing  32  of the injection device  30 . 
       FIG.  2    is thus illustrative of a medicament injection system  102 . The medicament injection system  102  comprises the injection device  30  and at least the data logging device  100 . The data logging device  100  may be attachable to the injection device  30 . It may be detachably connectable or detachably fixable to the housing  32  of the injection device  30 . Alternatively, the data logging device  100  is integrated into the injection device  30 . The medicament injection system  102  may further comprise the external electronic device  65 . The external electronic device  65  may be implemented as a portable electronic device. It may comprise a smart watch, a smart phone, a tablet computer or a personal computer. The external electronic device  65  and the data logging device  100  are configured to establish a communication link  66 , e.g. a wireless communication link, in order to transfer data therebetween. 
     The data logging device  100  as schematically indicated in  FIG.  3    typically comprises a sensor, e.g. in form of rotation sensing arrangement  200 , by way of which a relative rotation of at least one component of the drug delivery device  1  relative to another component of the drug delivery device  1  can be determined or quantitatively measured, e.g. during at least one of setting of the dose and dispensing of the dose. 
     The data logging device  100  may be either integrated into the drug delivery device  1  or may be provided as a separate add-on device. When provided as a separate add-on device the data logging device  100  may be provided with an own housing  101  attachable to the housing  32  of the drug delivery device  1  or injection device  30 . 
     The data logging device  100  comprises one or more processors  240 , such as a microprocessor, a Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or the like, together with a memory  114 . The memory may  114  include a program memory and main memory, which can store software for execution by the processor  240  and data generated or captured during use of the data logging device  100  such as counted pulses, derived dose size, time stamp, etc. An optional switch  122  connects a power source  120  to the electronic components of the data logging device  100 , including the rotation sensing arrangement  200 . A display  118  may or may not be present. The rotation sensing arrangement  200  may be coupled to a first member  201  and a second member  202 . It comprises at least one sensor  220  connected or attached to the second member  202  and further comprises at least one signal generator  210  connected or attached to the first member  201 . 
     With the present implementation of the rotation sensing arrangement  200  in a data logging device  100  one of the first member  201  and the second member  202  can be connected or fastened to the housing  32  of the injection device  30  and the other one of the first member  201  and the second member  202  is for instance connectable or fastenable to the rotatable dose dial  12  of the injection device  30 . 
     The data logging device  100  typically comprises an interface  124  connected to the processor  240 . The interface  124  may be a wireless communications interface for communicating with another external electronic device  65 , e.g. in form of a portable electronic device, via a wireless communication protocol or network such as Wi-Fi or Bluetooth®, RFID or NFC (near field communication). The wireless communication interface may be operable in the radio frequency range. For instance, the wireless communication interface may be based on radio-frequency identification technology (known as RFID) which allows compatible hardware to both supply power to and communicate with an otherwise unpowered and passive electronic tag using radio waves. It may be hence used for identification, authentication and tracking. 
     With other examples, the interface  124  is implemented as a wired communications link, such as a socket for receiving a Universal Series Bus (USB), mini-USB or micro-USB connector. For this, the interface  124  comprises a transceiver  126  configured for transmitting and receiving data.  FIG.  3    depicts an example of an injection system in which the add-on device  100  is connected to an external electronic device  65 , via a communication link  66  for data transfer. The data connection  66  may be of wired or wireless type. 
     For example, the processor  240  may store determined delivered medicament amounts and time stamps for the injections as they are administered by the user and subsequently, transfer that stored data to the external electronic device  65 . The device  65  maintains a treatment log and/or forwards treatment history information to a remote location, for instance, for review by a medical professional. 
     The add-on device  100  or data collection device may be configured to store data such as delivered medicament amounts and time stamps of numerous injection events, such as  35  or more injection events. According to a once-daily injection therapy this would be sufficient to store a treatment history of about one month. The data memory  114  may be organized in a first-in first-out manner ensuring that most recent injection events are always present in the memory of the data collection device  100 . Once transferred to an external electronic device  65  the injection event history in the add-on device  100  might be deleted. Alternatively, the data remains in the add-on device  100  and the oldest data is deleted automatically once new data is stored. This way the log in the data collection device is built up over time during usage and will always comprise the most recent injection events. Alternatively, other configuration could comprise a storage capacity of 70 (twice daily), 100 (three months) or any other suitable number of injection events depending on the therapy requirements and/or the preferences of the user. 
     In another embodiment, the interface  124  may be configured to transmit information using a wireless communications link and/or the processor  240  may be configured to transmit such information to the external electronic device  65  periodically. 
     The processor  240  may control the optional display  118  to show the determined medicament dose information, and/or to show an elapsed time since a last medicament dose was delivered. For example, the processor  240  may cause the display  118  to switch periodically between displaying the most recent determined medicament dosage information and the elapsed time. 
     The power source  120  may be a battery. The power source  120  may be a coin cell, or multiple coin cells arranged in series or parallel. A timer  115  may be also provided. In addition to, or instead of, switching the add-on device  100  on and off, the switch  122  may be arranged to trigger the timer  115  when engaged and/or disengaged. For example, if the timer  115  is triggered on both engagement or disengagement of the first and second electrical contacts of the switch or both operation and ceasing of operation of the switch  122 , then the processor  240  may use the output from the timer  115  to determine a length of time during which the trigger  11  was pressed, for example to determine the duration of an injection. 
     Alternatively, or additionally, the processor  240  may use the timer  115  to monitor a length of time that has elapsed since an injection was completed, as indicated by a time of disengagement of respective switch components or ceasing of operation of the switch  122 . Optionally, the elapsed time may be shown on the display  118 . Also optionally, when the switch  122  is next operated, the processor  240  may compare the elapsed time with a predetermined threshold, to determine whether a user may be attempting to administer another injection too soon after a previous injection and, if so, generate an alert such as an audible signal and/or a warning message on the display  118  or via the output  116 . The output  160  may be configured to generate an audible sound or to induce a vibration hence to produce a tactile signal, e.g. for alerting the user. 
     The sensing arrangement  200  as shown in  FIG.  3    might be implemented as a rotation sensing arrangement. It may comprise a first member  201  and a second member  202 . The first member  201  is rotatable relative to the second member  202  with regards to an axis of rotation  203 . Typically, the first member  201  and the second member  202  are arranged coaxial with regards to the axis of rotation  203 . With some examples, the first member  201  and the second member  202  are arranged axially adjacent with regard to the axis of rotation  203 . The first member  201  and the second member  202  may be directly mechanically engaged. With other examples, the first member  201  and the second member  202  are mechanically disengaged from each other. Here, the first member  201  and the second member  202  may be separately arranged or rotationally supported in or at a housing  32  of the injection device  30  or in or at a respective housing  101  of a separate add-on device  100 . 
     At least one of the first member  201  and the second member  202  is typically rotationally supported in or on the housing  10  of the injection device  1 . With some examples, both, the first member  201  and the second member  202  can be rotationally supported on or with regard to the housing  32 . Typically, and depending on the specific implementation or integration of the rotation sensing arrangement  200  in the injection device  30  one of the first member  201  and the second member  202  is rotationally locked to the housing  32  whereas the other one of the first member  201  and the second member  202  is rotationally movable relative to the housing  10 . Typically, one of the first member  201  and the second member  202  is rotatable relative to the housing  32  with regard to the axis of rotation  203 . The second member  202  may be represented by the dose dial  12 . The first member  201  may be represented by the trigger  11 . During at least one of setting and dispensing of the dose, the second member  202  is subject to a rotation relative to the first member  201 . A degree of relative rotation between the first member  201  and the second member  202  is directly indicative of the size of the dose actually set and/or dispensed. 
     The rotation sensing arrangement  200  may comprise a printed circuit board  260  as illustrated in  FIG.  4   . On the printed circuit board  260  there may be provided the processor  240  together with the at least one sensor  220 . The printed circuit board  260  may be further provided with a power source  120 . The power source  120  may be located on one side of the printed circuit board  260 . On the same side or on the opposite side of the printed circuit board  260  there may be provided the processor  240  and/or the at least one sensor  220 . 
     In order to provide sufficient data security establishing of a communication link  66  between the data logging device  100  and an external electronic device  65  requires use of a pairing code  320 . Due to regulatory requirements the pairing code  320  may have to be visible or discernible from outside the drug delivery device  1 . However, it should not be directly visible to any person gaining access to the drug delivery device  1 . In order to prevent unauthorized pairing of the electronic data logging device  100  with the external electronic device  65  the pairing code  320  is either concealed by a component of the drug delivery device  1  and has to be revealed by an action of a user. According to other options, the pairing code  320  is split or distributed on at least two device components  301 ,  302 . For recombining of the pairing code  320 , the first and second device components  301 ,  302  will have to be moved into a predefined positional state. 
     In the example of  FIGS.  5  and  6   , at least one of a dial extension  70  and a number sleeve  80  provides a first device component  301  movable relative to a second device component  302 . The second device component  302  may be provided by the body  10  of the housing  32  of the injection device  30 . The first device component  301  is at least partially contained or received inside a hollow section of the second device component  302 . As it is apparent from a comparison of  FIGS.  5  and  6   , the first device component  301  is displaceable or movable relative to the second device component  302  along a longitudinal direction, hence towards a proximal direction  3 . Optionally, the first device component  301  may be also rotatable relative to the second device component  302 . 
     Mutual engagement of the first and second device components  301 ,  302  may only allow and support a helical motion of the first device component  301  relative to the second device component  302 . The first device component  301  is provided with a first outer surface  311 . On the first outer surface  311  there is provided at least a first code portion again  321  of a pairing code  320 . Typically, the entirety of the pairing code is required for establishing or for setting up of the communication link  66  between the data logging device  100  and the external electronic device  65 . 
     The second device component  302  comprises a second outer surface  312 . On the second outer surface  312  there is provided a second code portion  322 . A recombination of the second code portion  322 , hence the character “B” and the sequence of numbers and characters “123ABC” of the first code portion  321  complement or constitute the pairing code  320 . The pairing code  320  is only complemented and recombined from the first code portion  321  and the second code portion  322  when the first device component  301  is in a predefined second positional state  352  relative to the second device component  302 . 
     This particular positional state is characterized by a relative position of first and second device component  301 ,  302  and/or by a predefined rotational orientation of the first and second device components  301 ,  302  relative to each other. The second positional state  352  may be characterized and may be identified by a first marker  303  of the first device component  303  configured to coincide, to align or to spatially overlapping with a second marker  304  provided by the second device component  302 . Here, the second marker  304  is an aperture in the sidewall of the first device component  302 . The aperture  304  may coincide with the above-mentioned the dosage window  13 . The first marker  303  may be a selected or predefined number or symbol of numerous available numbers or symbols as provided on the outer surface  311  of the first device component  301 , e.g. implemented as a number sleeve  80 . In the presently illustrated example, the first marker  303  is number 25, also indicating that a dose of 25 units has been actually set in the present configuration of first and second device components  301 ,  302 . 
     In the presently illustrated example also the second device component  302  is provided with a second code portion  322 . The second code portion  322  and the first code portion  321  have to be aligned along a straight line or along a helical line so as to reconstitute the pairing code  320  required for establishing or for setting up the communication link  66 . 
     With the presently illustrated example, the second code portion  322  is provided on the second outer surface  312  in combination with a second concealing code portion  336 . The second concealing code portion  336  provides some further or supplemental code portion that is generally indistinguishable from the second code portion  322 . The second concealing code portion  336  may comprise numerous characters, symbols or numbers aligned with the second code portion  322 . When not being appropriately informed, e.g. by a user manual of the drug delivery device, it is not known to authorized user of the drug delivery device  1 , which one of the second concealing code portions  336 , e.g. letters “A” or “C” and the second code portion  322 , character “B” should align with the first code portion  321  in order to recombine and to constitute the pairing code  320 . 
     In the example of  FIGS.  5  and  6   , the second concealing code portion  336  extends along a second direction  4 . The second direction may extend at a predefined angle relative to a first direction  3 . The first code portion extends along the first direction  3  and the second concealing code portion  336  extends along or parallel to the second direction  4 . When the first device component  301  is subject to both, a movement along the first direction  3  and along the second direction  4  relative to the second device component  302  for arriving at the second positional state  352  an intersection of a longitudinal extension of the first code portion  321  with the second concealing code portion  336  may point to or indicate the second code portion  322 . 
     In the presently illustrated example and when for instance a dose of the medicament should be dialed that does not match with the first marker  303 , there will be an alignment mismatch between the first code portion  321  and the second code portion  322  and thus the pairing code  320  will not show up appropriately. 
     In another example as illustrated in the sequence of  FIGS.  7 - 9   , the second device component  302  is void of a second code portion  322  or a second concealing code portion  336 . There, the second device component  302  is opaque and receives at least a portion of the first device component  301  in its hollow interior. In the first positional state  351  as illustrated in  FIG.  7   , the first outer surface  311  of the first device component  301  is hardly visible from outside the injection device  30 . It is upon a movement of the first device component  301  relative to the second device component  302 , that a portion of the first outer surface  311  is revealed from the second device component  302 . 
     The movement of the first device component  301  relative to the second device component  302  from the first positional state  351  as shown in  FIG.  7    towards and into the second positional state  352  as shown in  FIG.  8    may be conducted in the course of setting of a dose of the medicament. Hence, the user manual for pairing of the electronic data logging device  100  and the external electronic device  65  may instruct the user of the injection device  30  to dial a number of 25 standard units. This dialing or dose setting motion, e.g. conducted by the movement of the first device component  301  relative to the second device component  302 , leads to a combined rotational and longitudinal displacement of the first device component  301  relative to the second device component  302 . 
     As illustrated in  FIG.  8   , the first device component  301  protrudes in longitudinal direction from a longitudinal end, hence from the proximal end of the first device component  302 . As a consequence, a respective portion of the first outer surface  311  appears. When arriving at the second positional state  352  as illustrated in  FIG.  8   , it is only the entirety of the pairing code  320  that is visually identifiable from outside the drug delivery device  30 . Here, it is only and exclusively the pairing code  320  that is revealed. 
     As it is apparent from the further illustration of  FIG.  9   , and hence when the first device component  301  is moved further and beyond the second positional state, e.g. along the proximal direction  3  relative to the first device component  302  a further portion of the first outer surface  311  reveals. The further portion of the first outer surface  311  is provided with a first concealing code portion  335 . The first concealing code portion  335  is indistinguishable from the first code portion  321  or from the pairing code  320 . Hence, in the configuration as shown in  FIG.  9   , a user of the device will be unable to visually identify which part of the indistinguishable combination of the pairing code  320  and the first concealing code portion  335  should be used or which part thereof is relevant for initiating or approving the pairing between the data logging device  100  and the external electronic device  65 . 
     With typical implementations of the drug delivery device  30 , the first device component  301  is movable relative to the second device component  302  from the first positional state  351 , such as illustrated in  FIGS.  5  and  7    to the second positional state  352  as illustrated in  FIGS.  6  and  8    and vice versa from the second positional state  352  towards and into the first positional state  351  without the necessity to dispense a dose of the medicament  27 . 
     In  FIG.  10   , a flowchart of a method of pairing of the data logging device  100  with the external electronic device  65  is illustrated. Typically, the method of pairing can be conducted with a drug delivery device  1  or with an injection device  30  as described above in connection with an external electronic device  65  and a data logging device  100 , either provided as a separate data logging device  100  or integrated into the drug delivery device  1 . 
     For setting up a communication link  66  between the data logging device  100  and the external electronic device  65  in a first step  400 , at least one of the external electronic device  65  and the data logging device  100  is set into a pairing mode. Typically, the external electronic device  65  and the data logging device  100  are configured to set up a wireless communication link, e.g. using a standardized RF connection protocol, such as Bluetooth. In a subsequent step  402  the first device component  301  is moved relative to the second device component  302  from a first positional state  351 , in which the pairing code  320  is non-discernible, into the second positional state  352 . In a subsequent step  404 , the pairing code  320  is visually identified by a user of the drug delivery device. In a further step  406 , the pairing code  320  as identified by the user in step  404  is used to establish or to approve the communication link  66  between the external electronic device  65  and the data logging device  100 . 
     List of reference numbers
       1  drug delivery device     2  distal direction     3  first direction     4  second direction     5  dose decrementing direction     6  cartridge     7  bung     8  drive mechanism     9  dose setting mechanism     10  body     11  trigger     12  dose dial     13  dosage window     14  cartridge holder     15  injection needle     16  inner needle cap     17  outer needle cap     18  protective cap     19  protrusion     20  piston rod     21  bearing     22  threaded section     23  pressure foot     25  barrel     26  seal     27  medicament     28  socket     30  injection device     32  housing     34  drive mechanism     62  insert piece     64  stem     65  external electronic device     66  communication link     70  dial extension     80  number sleeve     81  groove     100  data logging device     101  housing     102  medicament injection system     114  memory     115  timer     116  output     118  display     120  power source     122  switch     124  interface     126  transceiver     200  sensing arrangement     201  first member     202  second member     203  axis of rotation     210  signal generator     220  sensor     240  processor     260  printed circuit board     301  device component     302  device component     303  marker     304  marker     311  outer surface     312  outer surface     320  pairing code     321  code portion     322  code portion     335  code portion     336  code portion     351  positional state     352  positional state     353  positional state