METHODS AND APPARATUS FOR ASPECTS OF A DOSE DETECTION SYSTEM

The techniques described herein relate to computerized methods and apparatus of at least one of for determining whether a dose sensing module is attached to a medication delivery device, such as, for example, with dose detection sensors, for detecting a color of a portion of a medication delivery device to determine a medication contained in the medication delivery device, such as, for example, with a set of LEDs and light sensor for different temperature conditions, and for monitoring a battery life of a battery in the dose sensing module, such as, for example, with current/voltage detection for different temperature conditions. At least some of the information obtained from these techniques may be communicated to a paired remote electronic device, such as a user's smartphone.

TECHNICAL FIELD

The present disclosure relates to techniques for an electronic dose detection system for a medication delivery device, and in particular to techniques for detecting a connection to a medication delivery device, determining the type of medication delivery device, and monitoring battery life.

BACKGROUND

Patients suffering from various diseases must frequently inject themselves with medication. To allow a person to conveniently and accurately self-administer medicine, a variety of devices broadly known as pen injectors or injection pens have been developed. Generally, these pens are equipped with a cartridge including a piston and containing a multi-dose quantity of liquid medication. A drive member is movable forward to advance the piston in the cartridge to dispense the contained medication from an outlet at the distal cartridge end, typically through a needle. In disposable or prefilled pens, after a pen has been utilized to exhaust the supply of medication within the cartridge, a user discards the entire pen and begins using a new replacement pen. In reusable pens, after a pen has been utilized to exhaust the supply of medication within the cartridge, the pen is disassembled to allow replacement of the spent cartridge with a fresh cartridge, and then the pen is reassembled for its subsequent use.

Many pen injectors and other medication delivery devices utilize mechanical systems in which members rotate and/or translate relative to one another in a manner proportional to the dose delivered by operation of the device. Accordingly, the art has endeavored to provide reliable systems that accurately measure the relative movement of members of a medication delivery device in order to assess the dose delivered. Such systems may include a sensor which is secured to a first member of the medication delivery device, and which detects the relative movement of a sensed component secured to a second member of the device.

The administration of a proper amount of medication requires that the dose delivered by the medication delivery device be accurate. Many pen injectors and other medication delivery devices do not include the functionality to automatically detect and record the amount of medication delivered by the device during the injection event. In the absence of an automated system, a patient must manually keep track of the amount and time of each injection. Accordingly, there is a need for a device that is operable to automatically detect the dose delivered by the medication delivery device during an injection event. Further, there is a need for such a dose detection device to be removable and reusable with multiple delivery devices. In other embodiments, there is a need for such a dose detection device to be integral with the delivery device.

It is also important to deliver the correct medication. A patient may need to select either a different medication, or a different form of a given medication, depending on the circumstances. If a mistake is made as to which medication is in the medication delivery device, then the patient will not be properly dosed, and records of dose administration will be inaccurate. The potential for this happening is substantially diminished if a dose detection device is used which automatically confirms the type of medication contained by the medication delivery device.

SUMMARY

The present disclosure relates to techniques for a dose sensing module that can be removably attached to a medication delivery device. The techniques can include determining whether the dose sensing module is attached to the medication delivery device. Such techniques can, for example, ensure that the dose sensing module only senses, processes, and/or reports events detected when attached to a medication delivery device (as opposed to accidental activation when the dose sensing module is not coupled to a medication delivery device), and can be used to determine when the dose sensing module is changed to a new medication delivery device. The techniques can also include detecting the color of a portion of a medication delivery device to determine the medication contained in the medication delivery device. Such techniques can, for example, ensure a patient is administering the correct medication to avoid mistakes as to which medication is in the medication delivery device. The techniques can further include monitoring the battery life of the battery in the dose sensing module. Such techniques can, for example, allow a user or patient to monitor the battery life in a manner that allows the patient to know well-ahead of time, in a reliable manner, when the battery will die so that the user or patient can properly plan ahead.

DETAILED DESCRIPTION

The present disclosure relates to sensing systems for medication delivery devices. In one aspect, the sensing system is for determining whether the sensing system is mounted to a medication delivery device. The inventors have discovered and appreciated that it can be desirable to have a dose sensing system be removably coupled to a medication delivery device. However, the inventors have discovered and appreciated that given the various hardware, firmware and/or software desired to be included in such dose sensing systems, and a desire to keep the dose sensing system small, user friendly, and limited to only include components with a low likelihood of failure due to repeated use, it can be challenging to also incorporating additional components (e.g., switches, latches, and/or the like) to detect when the dose sensing system is connected to a medication delivery device. The techniques described herein provide for leveraging existing components of the dose sensing device to determine whether the dose sensing device is coupled to a medication delivery device. For example, a dose sensing device can include sensors (such as Hall effect sensors) and related hardware and/or software to determine the size of a dose administered by the medication delivery device. The techniques can leverage such hardware and/or software used to perform dose detection to also determine whether (or not) the dose sensing system is coupled to a medication delivery device.

In a second aspect, the sensing system is for determining the type of medication contained within the medication delivery device. As described herein, the inventors discovered and appreciated that issues can occur without being able to determine the medication within the medication delivery device. For example, an incorrect medication can be administered to a patient, which can result in an improper patient dosing, cause incorrect dose administration records, and/or the like. The techniques described herein provide for sensing the color of a component of the medication being administered by the medication delivery device, where the color is indicative of the type of medication. In some embodiments, the techniques leverage one or more light emitting diodes and a light sensor to illuminate the applicable colored component and process the illumination data to match the color to a stored set of colors and associated medications.

In a third aspect, the sensing system is for monitoring the battery life of the sensing system. The inventors discovered and appreciated that determining the remaining battery life of a battery is complicated by various factors, such as temperature, relaxation time, duration of use, load variation, battery brand, battery variability, and other parameters. The inventors developed techniques to monitor the battery based on the dose sensing device architecture and in a manner that incorporates other relevant data, such as temperature. The techniques can provide for battery life estimations that adjust the measurement process in a manner that avoids errors that could otherwise be caused by existing battery measurement techniques.

By way of illustration, the medication delivery device is described in the form of a pen injector. However, the medication delivery device may be any device which is used to set and to deliver a dose of a medication, such as an infusion pump, bolus injector or an auto injector device. The medication may be any of a type that may be delivered by such a medication delivery device.

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

Devices described herein, such as a device10, may further comprise a medication, such as for example, within a reservoir or cartridge20. In another embodiment, a system may comprise one or more devices including device10and a medication. The term “medication” refers to one or more therapeutic agents including but not limited to insulins, insulin analogs such as insulin lispro or insulin glargine, insulin derivatives, GLP-1 receptor agonists such as dulaglutide or liraglutide, glucagon, glucagon analogs, glucagon derivatives, gastric inhibitory polypeptide (GIP), GIP analogs, GIP derivatives, oxyntomodulin analogs, oxyntomodulin derivatives, therapeutic antibodies and any therapeutic agent that is capable of delivery by the above device. The medication as used in the device may be formulated with one or more excipients. The device is operated in a manner generally as described above by a patient, caregiver or healthcare professional to deliver medication to a person.

FIG. 1Ais a diagram of an exemplary system120, according to some embodiments. The system101includes a sensing system103in communication with a remote computing device104through the communication unit106(e.g., via a wired and/or wireless connection). The communication unit106can be, for example, a WiFi transceiver, a Bluetooth transceiver, an RFID transceiver, a USB transceiver, a near-field communication (NFC) transceiver, a combination chip, and/or the like.

As described further herein, the sensing system103can be configured to determine illumination data indicative of a color of an object. The sensing system103includes a processing unit108(e.g., an MCU), in communication with a light sensor110and a control unit112. The light sensor110is in optical communication with the object116(e.g., a portion of a medication delivery device). In some embodiments, the light sensor110is an Ambient Light Sensor (ALS), e.g., working in reflective mode. The LED driver112is in communication with a set of light emitting diodes (LEDs)114A,114B and114C (collectively LEDs114) in optical communication with the object116. For example, the LEDs114can include a red LED, a blue LED, and/or a green LED. The light sensor110, the LEDs114, or both, are optionally in optical communication with the object116through an optional light guide118. The light guide118can be a transparent light guide, such as a Makrolon 2458 LightGuide. In some embodiments, the color sensor is made of separate LEDs, a single package RGB LEDs, or a combination thereof.

FIG. 1Billustrates a detailed example of the electronics assembly of the sensing module, referred to as1400, which can be included in any of the modules described herein. MCU is programmed to achieve the electronic features of the module. MCU includes control logic operative to perform the operations described herein, including detecting a connection to a medication delivery device, determining the type of medication delivery device, obtaining data used for determining a dose delivered by a medication delivery device, and monitoring the battery life of the medication delivery device. The MCU may be operable to obtain data by detecting and/or determining the amount of rotation of the rotation sensor fixed to the flange, which is determined by detecting the magnetic field of the rotation sensor by the sensing elements of the measurement sensor, such as, for example, Hall Effect sensors, of the system.

Assembly1400includes MCU that can be operably coupled to one or more of dose sensors1402A-E, memory1408, identification sensor1404, counter1414, light driver1411and light indicators1412, power-on module1406, communication module1410, display driver/display1416, power source1418, and presence module1420. Assembly1400may include any number of dose sensors, such as, for example, five magnetic sensors1402A-E (shown) or six sensors. The dose sensors can be used to determine the total units of rotation of components within the medication delivery device that can be used to determine an administered dose amount (e.g., as discussed further herein in conjunction withFIGS. 5-12), and can also be used to detect a connection to the medication delivery device. MCU may be configured via the presence module1420, shown in this embodiment to be optional by dashed lines, to determine via the triggering of the presence switch system whether the module is coupled to the device's button. MCU is configured to determine the color of the dose button via the identification sensor1404, and in some examples, associate the color data determined onboard, or off board with an external device (e.g., remote computing device104), the color corresponding to a particular medication (e.g., using the LEDs114, as discussed further herein). MCU is configured to determine triggering of the wake-up switch in order to power on the electronic assembly for use, shown as power-on module1406. In one example, the total rotation may be communicated to an external device that includes a memory having a database, look up table, or other data stored in memory to correlate the total rotational units to an amount of medication delivered for a given medication identified. In another example, MCU's may be configured to determine the amount of medication delivered. MCU may be operative to store the detected dose in local memory1408(e.g., internal flash memory or on-board EEPROM). MCU is further operative to wirelessly transmit a signal representative of device data, such as, for example, (any one or any combination thereof) the rotational units, medication identification (such as color) data, timestamp, time since last dose, battery charge status, module identification number, time of module attachment or detachment, time of inactivity, and/or other errors (such as for example dose detection and/or transmission error, medication identification detection and/or transmission error), to a paired remote electronic device, such as a user's smartphone, over a Bluetooth low energy (BLE) or other suitable short or long-range wireless communication protocol module1410, such as, for example, near-field communication (NFC), WiFi, or cellular network. Illustratively, the BLE control logic and MCU are integrated on a same circuit. In one example, any of the modules described herein may include the display module1420, shown in this embodiment to be optional by dashed lines, for indication of information to a user. Such a display, which may be LEDs, LCD, or other digital or analog displays, may be integrated with proximal portion finger pad. MCU includes a display driver software module and control logic operative to receive and processed sensed data and to display information on said display, such as, for example, dose setting, dosed dispensed, status of injection, completion of injection, date and/or time, or time to next injection. In another example, MCU includes a LED driver1411coupled to one or more LEDS1412, such as, for example, RGB LED, Orange LED and Green LED, used to communicate by sequences of on-off and different colors to the patient of whether data was successfully transmitted, whether the battery charge is high or low, or other clinical communications. Counter1414is shown as a real time clock (RTC) that is electronically coupled to the MCU to track time, such as, for example, dose time. Counter1414may also be a time counter that tracks seconds from zero based on energization. The time or count value may be communicated to the external device.

In some embodiments, as discussed further in conjunction withFIGS. 8-12, the sensing system103is configured to be connected to a medication delivery device. In some embodiments, the object116is a portion of a medication delivery device (e.g., a button, a label, a color of an external compartment, etc.) that can be used to identify an aspect of the medication delivery device based on the color of the object116. For example, the color of the object116can be indicative of a type of medication of the medication delivery device.

FIG. 1Cis a diagram of an exemplary system130, according to some embodiments. The system130includes aspects of a dose detection system, including sensing system132in communication with a remote computing device134through the communication unit136(e.g., via a wired and/or wireless connection). As described further herein, the sensing system132can be configured to determine a battery indicator indicative of a remaining life of the battery138. The apparatus132includes a processing unit140in communication with the communication unit136, the battery138and the temperature sensing unit142.

The exemplary aspects of a dose detection system described in conjunction withFIGS. 1A-1Care shown for exemplary purposes to highlight various aspects of dose detection systems. Aspects shown inFIGS. 1A-1Ccan be combined into a single apparatus, such as the dose delivery detection system80described in conjunction withFIGS. 8-12, and can be implemented using, for example, the various exemplary configurations discussed in conjunction with those figures.

Referring toFIG. 1A, in some embodiments, the sensing system103is configured to determine the color of the object (e.g., the button of a pen medication delivery device). In some embodiments, the sensing system determines the object color by switching on in sequence the LEDs114, and reading back the reflected beams through a wide spectra ambient light sensor110. The sensing system103can generate various values, such as three values for each of three LEDs114. The sensing system103can process the generated values to generate a final color value for matching. The sensing system103can check the final color value against a predefined set of colors to determine whether there is a match.

FIG. 2is a flow chart of an exemplary computerized method200for determining a color associated with an object, according to some embodiments. A processor, such as the processing unit108of the sensing system103, can execute computer readable instructions that cause the processor to perform the method200. At step202, the sensing system obtains illumination data of an object illuminated by a set of LEDs. The sensing system can optionally process the illumination data at steps204and/or206to generate processed illumination data. At step204, the sensing system optionally adjusts the illumination data based on the temperature. At step206, the sensing system optionally normalizes the illumination data. At step208, the sensing system causes the light sensor to capture illumination data of the object while the object is illuminated by the set of LEDs. At step208, the sensing system transmits the processed illumination data to a remote device (e.g., via a communication module in communication with the processor of the apparatus). At step210, the remote device determines whether the illumination metrics match a stored set of colors. If the remote device determines a match, at step212the remote device outputs the matched color (e.g., to a program, to a display, etc.). If the remote device does not determine a match, at step214the remote device outputs that a color match was not found (e.g., by returning an error code, a no match code, and/or the like).

Referring to step202, the sensing system can be configured to capture first illumination data when the object is not illuminated by the set of LEDs, second illumination data when the object is illuminated by each LED of the set of LEDs, or both. For example, the apparatus can be configured to capture illumination data for the object when the object is illuminated just by ambient light when the LEDs are not turned on. In some embodiments, the sensing system can include an exposure time during which to capture the dark illumination data.

As another example, if the set of LEDs comprises different color LEDs, the apparatus can be configured to capture illumination data of the object when the object is illuminated by each LED. For example, as shown inFIG. 1A, in some embodiments the apparatus includes a red LED114A, a blue LED114B, and a green LED114C. The apparatus can be configured to coordinate the light sensor110and the LED driver112to coordinate lighting the LEDs114and capturing illumination data such that the light sensor110captures illumination data when the object is illuminated by the red LED114A (and not the other LEDs), illumination data when the object is illuminated by the blue LED114B, and illumination data when the object is illuminated by the green LED114C. In some embodiments, the sensing system can be configured to use an exposure time during which to capture the illumination data, which can be the same for each LED and/or different for one or more LEDs.

Referring to step204, the illumination data can be adjusted based on temperature. In some embodiments, the temperature is taken of the ambient air, the sensing system, and/or of the medication delivery device. In some embodiments, the sensing system can capture a plurality of temperature measurements and average the values to determine and averaged temperature to use for adjusting the illumination data. In some embodiments, the sensing system can adjust each illumination data value (X) using Equation 1:

rgbTempX is the adjusted illumination data value determined for each color, such as a red value, a green value, and a blue value, depending on which color Equation 1 is being computed for;rgbX is each original illumination data value, such as a red value, a green value, and a blue value;TempCoefficientX is a temperature coefficient for each value, which can allow the various temperature measurements to be tracked using one coefficient (e.g., since there may be performance drift in different temperature measurements);CalTemp is a temperature measured during calibration of the sensing system, which can be used to account for temperature variation (e.g., for non-calibration measurements); andTemp is the measured (e.g., averaged) temperature.

Referring to step206, the sensing system can normalize the (temperature adjusted) illumination data based on the dark illumination data captured without illumination of the LEDs. In some embodiments, the sensing system can normalize the illumination data based on one or more illumination measurements determined during calibration. For example, Equation 2 can be used to normalize each illumination data value (X):

bNormX is the normalized illumination value, such as the red, green or blue normalizated value, depending on which color Equation 2 is being computed for (in percent, multiplied by 100);whiteX represents illumination values, such as the red, green and blue values, obtained during the calibration phase when using a white target object (described further in conjunction withFIG. 3);blackX represents illumination values, such as the red, green and blue values, obtained during the calibration phase when using a black target object (described further in conjunction withFIG. 3);calDark is a dark illumination value (with the LEDs off) determined during the calibration phase (described further in conjunction withFIG. 3); anddarkValue is the dark illumination value determined during step202.

Referring to step210, the remote device can be configured to determine lightness A B (LABc) values. The system can determine the LABc values based on any of the illumination values, whether it be the raw illumination data or illumination data that is temperature adjusted and/or normalized illumination data. For illustrative purposes, the following examples refer to normalized illumination data for simplicity. The A value can be calculated depending on the normalized illumination values. For example, depending on whether rgbNormRed determined using Equation 2 is greater than rgbNormGreen, then one of either Equations 3 or 4 is used to determine the A value:

The B value can also be calculated depending on the normalized illumination values. For example, depending on whether rgbNormBlue determined using Equation 2 is greater than rgbNormGreen, then one of either Equations 5 or 6 is used to determine the B value. For equations 3-6, Kn is a coefficient used for the RGB to LABc transformation so that the A and B values will be in the range of −100 to 100, and that L is in the range 0 to 100 (e.g., 20, 21.5, 23, etc.).

The L value can be calculated using Equation 7:

In some embodiments, the remote device can include a table of metrics used for determining whether the illumination data meets a color. The remote device can include a set of colors (e.g., grey, blue, dark blue, red, and/or other colors), where each color has an associated set of data. The data associated with each color can include average data and/or sigma variation data determined during calibration and/or design of the system. In some embodiments, each color can include an average for each of the A, B and L values and a sigma variation value for each of the A, B and L values. The remote device can determine the sigma distance for the illumination data and each color in the stored set of colors. For example, Equation 8 can be used to determine the sigma distance for each color in the set of colors:

SigmaDistanceX is the sigma distance for the color (X) under consideration from the set of colors;For the real-time measurement:L is calculated using Equation 7;A is calculated using either Equation 3 or 4;B is calculated using either Equation 5 or 6;For the color (X) under consideration:μLX is the average of the L value for color (X);σLX is the sigma variation of the L value for color (X);μAX is the average of the A value for color (X);σAX is the sigma variation of the A value for color (X);μBX is the average of the B value for color (X); andσBX is the sigma variation of the B value for color (X).

The remote device can determine whether the illumination data matches a color in the set of colors using the sigma distances. For example, the remote device can select the minimum among the sigma distance values (Min1) as the most likelihood matched color. The second smallest value (Min2) can be used for a match color check, as discussed further herein.

The sensing system and/or remote device can be configured to perform one or more checks for the illumination data. For example, the dark illumination data can be checked to determine whether the subsequent measurements under LED illumination are interfered with by ambient light. As another example, the acquired illumination data for the LEDs can be checked to ensure the illumination data is within an expected threshold between a lowest black value and a highest white value. As a further example, the LABc values can be checked to determine whether they are within acceptable ranges (e.g., −100 to 100 for A or B, 0 to 100 for L). As another example, a match color check can be performed to ensure that Min1 and/or Min2 are within acceptable values. For example, Min1 can be checked to ensure Min1 is below a maximum sigma distance for an expected color match, and/or the ratio of Min2/Min1 can be compared to a minimum ratio between the two minimum values for an acceptable match.

During calibration, the sensing device can take various measurements that can be used to calibrate the real-time measurements of an object. The calibration measurements can include the temperature and various light measurements, such as measurements using a white target, a black target, and dark illumination without any LEDs on.FIG. 3is a flow chart of an exemplary computerized method300for generating calibration parameters, according to some embodiments. At step302, the apparatus measures the temperature. At step304, the apparatus captures illumination data for a white target object (e.g., a white object). At step306, the apparatus captures illumination data for a black target (e.g., a black object). At step308, the apparatus captures illumination data for dark light without the LEDs on. At step310, the apparatus generates a set of calibration parameters. The calibration parameters can include an exposure time (or maximum/minimum exposure times) to use for dark measurement and/or for each LED (e.g., for red, green and blue LEDs), counts read during calibration for each LED for each of the white and/or black object, temperature, a temperature margin, and/or other calibration parameters.

As described herein, the dose sensing system includes a sensing module with various components, including a processor/MCU, sensors, LEDs, among other components. In some embodiments, the sensing module can be powered by a battery. Referring toFIG. 1C, for example, the sensing system132includes a battery138that powers the dose sensing system, including the exemplary components shown inFIG. 1C. The techniques described herein can be used to monitor the battery life of a dose sensing system. The battery life can be monitored to provide information to a user, such as a battery status indicator that tracks the life of the battery, alerts related to the battery (e.g., to alert the user to a low battery life, when to change the battery, etc.), and/or the like. For example, the dose sensing system can alert the user, whether it be through the sensing module or a remote computing device, when the battery will run out in a manner that provides the user with sufficient time to replace the battery (e.g., one or two weeks prior to the end of life of the battery).

The inventors have discovered and appreciated that estimating battery life, such as by using battery voltage measurements, can be complicated due to the fact that the battery behavior can depend on a number of variables, such as temperature, relaxation time from measure to measure, duration of an injection of an attached medication delivery device, load variation, battery brand, battery variability, and other parameters. To address such issues, which are often not controllable by the device provider, the inventors have developed techniques to monitor the battery based on the device architecture in a manner that provides sufficient margin on the battery life to compensate for the potential error(s) and variabilities that the inventors have appreciated can otherwise occur during battery measurement.

FIG. 4is a flow chart of an exemplary computerized method400for determining a battery indication, according to some embodiments. A processor, such as the processing unit140of the apparatus132inFIG. 1B, can be configured to execute computer readable instructions that cause the processor to perform the method400. At step402, the apparatus obtains a set of voltage measurements of the battery. At step404, the apparatus obtains a temperature measurement (e.g., via the temperature sensing module). At step406, the apparatus determines a set of temperature-adjusted battery indications based on the temperature measurement. At step408, the apparatus determines a battery indicator indicative of a remaining life of the battery based on the temperature-adjusted battery indications and the set of voltage measurements.

Referring to step402, the apparatus (e.g., the MCU) can obtain various voltage measurements when the battery is under different loads and/or at different operating states of the apparatus. In some embodiments, the apparatus obtains (a) a startup battery voltage when the apparatus is powered on, (b) a high current battery voltage when the processor is running at a maximum speed, (c) a low current battery voltage when the processor is running in a low-power mode, or some combination thereof. The startup battery voltage can be determined, for example, by obtaining a high current battery voltage within a certain amount of time from the sensing module being powered on. For example, when the apparatus is woken up (e.g., following a button press) the apparatus may increase the draw from the battery. In some embodiments, when woken up the apparatus may initiate a boot process. The boot-up process may increase the draw from the battery due to, for example, various self-tests, the booting operation, and/or the like. In some embodiments, when woken up the apparatus may take magnetic measurements (e.g., to determine a starting position of one or more components). Such a boot-up process and/or magnetic sensing may therefore provide a high current battery voltage for measurement as the startup battery voltage.

The high current battery voltage can capture a high (e.g., maximum) current peak, e.g., which can be used to measure the voltage drop at that point. The high current battery voltage can be determined, for example, by running the microcontroller at maximum speed and all the other loads in low power mode for a predetermined time (e.g., in ms), and measuring the high current battery voltage. In some embodiments, the high current battery voltage is an average voltage computed based on a set of measurements. In some embodiments, the high current battery voltage can be calculated at the beginning of and/or at the end of the magnetic sensor activity. For example, a maximum voltage drop of the system may be obtained when the magnetic sensor(s) have completed a measurement.

The low current battery voltage can be used to measure the voltage drop with a lowest current load, e.g., to simulate an open circuit voltage check for the battery. The low current battery voltage can be determined, for example, by having the firmware running on the MCU put all the loads (e.g., including the MCU) in low power mode for a predetermined time (e.g., a rest period specified in ms), and measuring the low current battery voltage. In some embodiments, the low current battery voltage is an average voltage computed by averaging a set of measurements. In some embodiments, the low current battery voltage is determined after determining the high current battery voltage measurement.

As described herein, one or more voltage measurements can be used for step402. For example, in some embodiments the voltages can be taken in a manner designed to obtain a voltage reading at a high and/or maximum current consumption (e.g., the point with a maximum voltage drop) and a representative open circuit voltage measurement for a low/lowest current consumption. The voltages can be used, as described herein, to estimate the remaining battery energy. In some embodiments, the techniques may use, for example, a single voltage drop, such as the maximum voltage drop, to estimate the remaining battery energy (e.g., since the maximum voltage drop may be more dependent on battery status compared to other voltage drops, which may be more capacitive driven). For example, the power-on/start-up voltage drop can simply be used for comparison with the maximum voltage drop. For example, if the voltage drop during power on is bigger than a measured maximum drop of the system, the comparison can indicate there is a risk that the component may reset.

Referring to step406, the apparatus can store battery indication tables at various temperatures. For example, the apparatus can store a set of low temperature battery indications that includes a set of battery indications that each have an associated voltage for a low temperature. Table 1 is an example of a set of low temperature battery indications (e.g., at 0° C.):

As another example, the apparatus can store a set of high temperature battery indications that includes a set of high temperature battery indications that each have an associated voltage for a high temperature. Table 2 is an example of a set of high temperature battery indications (e.g., at 22-24° C.):

The sensing system can determine, based on the set of low temperature battery indications, the set of high temperature battery indications, and the temperature measurement(s) obtained at step402, a set of temperature-adjusted battery indications. In some embodiments, the sensing system (e.g., via firmware executing on the MCU) can determine a correction factor based on the temperature measured at step404. For example, the sensing system can determine a correction factor based on the measured temperature and one or more correction factors. A logarithmic (shown below) and/or linear relationship may be developed to characterize the correction factor. For example, the sensing system can use Equation 9 to determine the correction factor:

corrFactor is the correction factor;A, B and C are coefficients (e.g., determined based on collected data to provide a desired degrees of freedom for determining the correction factor); andLogOffset is a coefficient (e.g., determined based on collected data to provide a desired degrees of freedom for determining the correction factor).

The sensing system can determine a corrected set of battery indications (e.g., a corrected battery table) based on the temperature correction factor. In some embodiments, the sensing system can determine the corrected battery indications based on both the low and high temperature battery table. For example, the sensing system can use Equation 10 to determine each corrected battery voltage associated with each indicator:

corrBatCurvexis the corrected battery curve voltage for row X;VoltageTEMPHIxis the voltage for row X in the high temperature battery table;VoltageTEMPLOxis the voltage for row X in the low temperature battery table;TEMPHI is the temperature used when determining the high temperature battery table;TEMPLO is the temperature used when determining the low temperature battery table; andcorrFactor is the correction factor determined using Equation 9.

Referring to step408, the apparatus can determine the battery indicator based on a previous battery indicator. For example, the apparatus can obtain the previous battery indicator for the battery, determine a current battery indicator for the battery based on the temperature-adjusted battery indications in the corrected battery table and the set of voltage measurements, and determine the battery indicator based on the previous battery indicator and the current battery indicator.

In some embodiments, the sensing system can determine the current battery indicator based on the stored battery tables and/or corrected battery table. For example, the sensing system can interpolate the points in the corrected battery table with the high current battery voltage (e.g., measured at step402inFIG. 4). For example, if the high current battery voltage is equal to a voltage value in the table, the sensing system can determine that the battery indicator is the associated indicator for that row. As another example, if the high current battery voltage is between two voltage values in the table, the sensing system can interpolate the two associated battery indicators to determine an associated battery indication.

In some embodiments, the sensing system can determine a new battery indicator based on the previous battery indicator (e.g., which can be stored in storage on the sensing system, such as in EEPROM). For example, the sensing system can use Equation 11 to determine the new battery indicator:

newBatInd is the new battery indicator;batInd is the previous battery indicator (e.g., obtained from EEPROM);curBatInd is the current determined battery indicator; andFILTER is a filter value. FILTER can be determined based on the amount of time lapsed since the last operation associated with the sensing system (e.g., a communication sync with a remote computing device, such as remote computing device104), a bonding event with a remote computing device, and/or detection of a dose administered by an associated medication delivery device).

The sensing system can store the determined new battery indicator (e.g., into EEPROM). In some embodiments, additional data can be stored with the new battery indicator, such as a timestamp, a number of remaining injections, and/or the like. For example, an initial injection number can be configured by the system that is associated with a new sensing system and/or new battery, and the sensing system can be configured to decrease the injection number for each sensed injection through the medication delivery device.

The apparatus of can transmit the battery indicator to a remote device (e.g., remote computing device104). The remote device can process the new battery indicator. For example, the remote device can be configured to determine a battery status based on the battery indicator. As an example, the following Table 3 illustrates exemplary battery statuses and associated battery indicators:

In some embodiments, the sensing device can enter a low battery state once the sensing device raises a low battery flag for the first time (e.g., when the device is unlikely to be able to provide more than a certain number of injections, such as 120 injections). The sensing device, once entering a low battery state, can avoid changing out of the low battery state for that battery (e.g., to avoid moving back-and-forth from a low battery state and a non-low battery state). In some embodiments, the sensing device can be configured to decrease the battery indicator by one for each new operation (e.g., a sync, bonding, or dose event) of the sensing device once it is in a low power state. In some embodiments, the sensing device can be configured to decrease the number of remaining injections by one for each new operation of the sensing device once it is in a low power state. Once the battery indicator equals zero, the sensing system can enter an end of life state. In some embodiments, the battery can be changed and the sensing system can reset upon detecting a new battery. In some embodiments, the sensing system is disposable and can be disposed upon reaching and end of life state.

In some embodiments, the sensing system can perform one or more checks on data obtained and/or measurements made during the battery monitoring processes. For example, the MCU can raise a low battery warning once the new battery indicator falls below a predetermined threshold. As another example, the sensing system can check whether sensed voltages are within predetermined acceptable ranges, whether temperature measurements are within predetermined acceptable ranges, and/or the like.

As described herein, the techniques can be used with various types of medication delivery devices, including medication delivery devices that incorporate the aspects described herein, as well as add-on components that can be attached to a medication delivery device. For illustrative purposes,FIGS. 5-12describe exemplary medication delivery devices and dose sensing systems into which the techniques can be incorporated. Such techniques are discussed further in PCT Application No. PCT/US19/18780 filed on Feb. 20, 2019, which is hereby incorporated by reference herein.

FIGS. 5-6illustrate an exemplary medication delivery device10, according to some examples. The medication delivery device10is a pen injector configured to inject a medication into a patient through a needle. Pen injector10includes a body11comprising an elongated, pen-shaped housing12including a distal portion14and a proximal portion16. Distal portion14is received within a pen cap18. Referring toFIG. 6, distal portion14contains the reservoir or cartridge20configured to hold the medicinal fluid of medication to be dispensed through its distal outlet end during a dispensing operation. The outlet end of distal portion14is equipped with a removable needle assembly22including an injection needle24enclosed by a removable cover25. A piston26is positioned in reservoir20. An injecting mechanism positioned in proximal portion16is operative to advance piston26toward the outlet of reservoir20during the dose dispensing operation to force the contained medicine through the needled end. The injecting mechanism includes a drive member28, illustratively in the form of a screw, axially moveable relative to housing12to advance piston26through reservoir20.

A dose setting member30is coupled to housing12for setting a dose amount to be dispensed by device10. In the illustrated embodiment, dose setting member30is in the form of a screw element operative to spiral (e.g., simultaneously move axially and rotationally) relative to housing12during dose setting and dose dispensing.FIGS. 5 and 6illustrate the dose setting member30fully screwed into housing12at its home or zero dose position. Dose setting member30is operative to screw out in a proximal direction from housing12until it reaches a fully extended position corresponding to a maximum dose deliverable by device10in a single injection.

Referring toFIGS. 6-8, dose setting member30includes a cylindrical dose dial member32having a helically threaded outer surface that engages a corresponding threaded inner surface of housing12to allow dose setting member30to spiral relative to housing12. Dose dial member32further includes a helically threaded inner surface that engages a threaded outer surface of sleeve34(FIG. 6) of device10. The outer surface of dial member32includes dose indicator markings, such as numbers that are visible through a dosage window36to indicate to the user the set dose amount. Dose setting member30further includes a tubular flange38that is coupled in the open proximal end of dial member32and is axially and rotationally locked to dial member32by detents40received within openings41in dial member32. Dose setting member30may further include a collar or skirt42positioned around the outer periphery of dial member32at its proximal end. Skirt42is axially and rotationally locked to dial member32by tabs44received in slots46. Further embodiments described later shown examples of the device without a skirt.

Dose setting member30therefore may be considered to comprise any or all of dose dial member32, flange38, and skirt42, as they are all rotationally and axially fixed together. Dose dial member32is directly involved in setting the dose and driving delivery of the medication. Flange38is attached to dose dial member32and, as described later, cooperates with a clutch to selectively couple dial member32with a dose button56. Skirt42provides a surface external of body11to enable a user to rotate the dial member32for setting a dose. For embodiments without the skirt, the dosage button56includes an outer wall that extends distally to form a surface to for the user to rotate.

Skirt42illustratively includes a plurality of surface features48and an annular ridge49formed on the outer surface of skirt42. Surface features48are illustratively longitudinally extending ribs and grooves that are circumferentially spaced around the outer surface of skirt42and facilitate a user's grasping and rotating the skirt. In an alternative embodiment, skirt42is removed or is integral with dial member32, and a user may grasp and rotate dose button56and/or dose dial member32for dose setting. In the embodiment ofFIG. 8, a user may grasp and rotate the radial exterior surface of one-piece dose button56, which also includes a plurality of surface features, for dose setting.

Delivery device10includes an actuator50having a clutch52which is received within dial member32. Clutch52includes an axially extending stem54at its proximal end. Actuator50further includes dose button56positioned proximally of skirt42of dose setting member30. Dose button56includes a mounting collar58(FIG. 6) centrally located on the distal surface of dose button56. Collar58is attached to stem54of clutch52, such as with an interference fit or an ultrasonic weld, so as to axially and rotatably fix together dose button56and clutch52.

Dose button56includes a disk-shaped proximal end surface or face60and an annular wall portion62extending distally and spaced radially inwardly of the outer peripheral edge of face60to form an annular lip64there between. Proximal face60of dose button56serves as a push surface against which a force can be applied manually, i.e., directly by the user to push actuator50in a distal direction. Dose button56illustratively includes a recessed portion66centrally located on proximal face60, although proximal face60alternatively may be a flat surface. A bias member68, illustratively a spring, is disposed between the distal surface70of button56and a proximal surface72of tubular flange38to urge actuator50and dose setting member30axially away from each other. Dose button56is depressible by a user to initiate the dose dispensing operation.

Delivery device10is operable in both a dose setting mode and a dose dispensing mode. In the dose setting mode of operation, dose setting member30is dialed (rotated) relative to housing12to set a desired dose to be delivered by device10. Dialing in the proximal direction serves to increase the set dose, and dialing in the distal direction serves to decrease the set dose. Dose setting member30is adjustable in rotational increments (e.g., clicks) corresponding to the minimum incremental increase or decrease of the set dose during the dose setting operation. For example, one increment or “click” may equal one-half or one unit of medication. The set dose amount is visible to the user via the dial indicator markings shown through dosage window36. Actuator50, including dose button56and clutch52, move axially and rotationally with dose setting member30during the dialing in the dose setting mode.

Dose dial member32, flange38and skirt42are all fixed rotationally to one another, and rotate and extend proximally of the medication delivery device10during dose setting, due to the threaded connection of dose dial member32with housing12. During this dose setting motion, dose button56is rotationally fixed relative to skirt42by complementary splines74of flange38and clutch52(FIG. 6), which are urged together by bias member68. In the course of dose setting, skirt42and dose button56move relative to housing12in a spiral manner from a “start” position to an “end” position. This rotation relative to the housing is in proportion to the amount of dose set by operation of the medication delivery device10.

Once the desired dose is set, device10is manipulated so the injection needle24properly penetrates, for example, a user's skin. The dose dispensing mode of operation is initiated in response to an axial distal force applied to the proximal face60of dose button56. The axial force is applied by the user directly to dose button56. This causes axial movement of actuator50in the distal direction relative to housing12.

The axial shifting motion of actuator50compresses biasing member68and reduces or closes the gap between dose button56and tubular flange38. This relative axial movement separates the complementary splines74on clutch52and flange38, and thereby disengages actuator50, e.g., dose button56, from being rotationally fixed to dose setting member30. In particular, dose setting member30is rotationally uncoupled from actuator50to allow back-driving rotation of dose setting member30relative to actuator50and housing12. The dose dispensing mode of operation may also be initiated by activating a separate switch or trigger mechanism.

As actuator50is continued to be axially plunged without rotation relative to housing12, dial member32screws back into housing12as it spins relative to dose button56. The dose markings that indicate the amount still remaining to be injected are visible through window36. As dose setting member30screws down distally, drive member28is advanced distally to push piston26through reservoir20and expel medication through needle24(FIG. 6).

During the dose dispensing operation, the amount of medicine expelled from the medication delivery device is proportional to the amount of rotational movement of the dose setting member30relative to actuator50as the dial member32screws back into housing12. The injection is completed when the internal threading of dial member32has reached the distal end of the corresponding outer threading of sleeve34(FIG. 6). Device10is then once again arranged in a ready state or zero dose position as shown inFIGS. 6 and 7.

The start and end angular positions of dose dial member32, and therefore of the rotationally fixed flange38and skirt42, relative to dose button56provide an “absolute” change in angular positions during dose delivery. Determining whether the relative rotation was in excess of 360° is determined in a number of ways. By way of example, total rotation may be determined by also taking into account the incremental movements of the dose setting member30which may be measured in any number of ways by a sensing system.

Various sensor systems are contemplated herein. In general, the sensor systems comprise a sensing component and a sensed component. The term “sensing component” refers to any component which is able to detect the relative position of the sensed component. The sensing component includes a sensing element, or “sensor”, along with associated electrical components to operate the sensing element. The “sensed component” is any component for which the sensing component is able to detect the position and/or movement of the sensed component relative to the sensing component. For the dose delivery detection system, the sensed component rotates relative to the sensing component, which is able to detect the angular position and/or the rotational movement of the sensed component. For the dose type detection system, the sensing component detects the relative angular position of the sensed component. The sensing component may comprise one or more sensing elements, and the sensed component may comprise one or more sensed elements. The sensor system is able to detect the position or movement of the sensed component(s) and to provide outputs representative of the position(s) or movement(s) of the sensed component(s).

A sensor system typically detects a characteristic of a sensed parameter which varies in relationship to the position of the one or more sensed elements within a sensed area. The sensed elements extend into or otherwise influence the sensed area in a manner that directly or indirectly affects the characteristic of the sensed parameter. The relative positions of the sensor and the sensed element affect the characteristics of the sensed parameter, allowing a microcontroller unit (MCU) of the sensor system to determine different rotational positions of the sensed element.

Suitable sensor systems may include the combination of an active component and a passive component. With the sensing component operating as the active component, it is not necessary to have both components connected with other system elements such as a power supply or MCU.

Any of a variety of sensing technologies may be incorporated by which the relative positions of two members can be detected. Such technologies may include, for example, technologies based on tactile, optical, inductive or electrical measurements. Such technologies may include the measurement of a sensed parameter associated with a field, such as a magnetic field. In one form, a magnetic sensor senses the change in a sensed magnetic field as a magnetic component is moved relative to the sensor. In another embodiment, a sensor system may sense characteristics of and/or changes to a magnetic field as an object is positioned within and/or moved through the magnetic field. The alterations of the field change the characteristic of the sensed parameter in relation to the position of the sensed element in the sensed area. In such embodiments the sensed parameter may be a capacitance, conductance, resistance, impedance, voltage, inductance, etc. For example, a magneto-resistive type sensor detects the distortion of an applied magnetic field which results in a characteristic change in the resistance of an element of the sensor. As another example, Hall effect sensors detect changes in voltage resulting from distortions of an applied magnetic field.

In one aspect, the sensor system detects relative positions or movements of the sensed elements, and therefore of the associated members of the medication delivery device. The sensor system produces outputs representative of the position(s) or the amount of movement of the sensed component. For example, the sensor system may be operable to generate outputs by which the rotation of the dose setting member during dose delivery can be determined. MCU is operably connected to each sensor to receive the outputs. In one aspect, MCU is configured to determine from the outputs the amount of dose delivered by operation of the medication delivery device.

The dose delivery detection system involves detecting relative rotational movement between two members. With the extent of rotation having a known relationship to the amount of a delivered dose, the sensor system operates to detect the amount of angular movement from the start of a dose injection to the end of the dose injection. For example, a typical relationship for a pen injector is that an angular displacement of a dose setting member of 18° is the equivalent of one unit of dose, although other angular relationships are also suitable. The sensor system is operable to determine the total angular displacement of a dose setting member during dose delivery. Thus, if the angular displacement is 90°, then 5 units of dose have been delivered.

One approach for detecting the angular displacement is to count increments of dose amounts as the injection proceeds. For example, a sensor system may use a repeating pattern of sensed elements, such that each repetition is an indication of a predetermined degree of angular rotation. Conveniently, the pattern may be established such that each repetition corresponds to the minimum increment of dose that can be set with the medication delivery device.

An alternative approach is to detect the start and stop positions of the relatively moving member, and to determine the amount of delivered dose as the difference between those positions. In this approach, it may be a part of the determination that the sensor system detects the number of full rotations of the dose setting member. Various methods for this are well within the ordinary skill in the art, and may include “counting” the number of increments to assess the number of full rotations.

The sensor system components may be permanently or removably attached to the medication delivery device. In an illustrative embodiment, as least some of the dose detection system components are provided in the form of a module that is removably attached to the medication delivery device. This has the advantage of making these sensor components available for use on more than one pen injector.

In some embodiments, a sensing component is mounted to the actuator and a sensed component is attached to the dose setting member. The sensed component may also comprise the dose setting member or any portion thereof. The sensor system detects during dose delivery the relative rotation of the sensed component, and therefore of the dose setting member, from which is determined the amount of a dose delivered by the medication delivery device. In an illustrative embodiment, a rotation sensor is attached, and rotationally fixed, to the actuator. The actuator does not rotate relative to the body of the medication delivery device during dose delivery. In this embodiment, a sensed component is attached, and rotationally fixed, to the dose setting member, which rotates relative to the actuator and the device body during dose delivery. The sensed component may also comprise the dose setting member or any portion thereof. In an illustrative embodiment, the rotation sensor is not attached directly to the relatively rotating dose setting member during dose delivery.

Referring toFIG. 9, there is shown in diagrammatic form a dose delivery detection system80including one example of a module82useful in combination with a medication delivery device, such as device10. Module82carries a sensor system, shown generally at as a rotation sensor86(or more than one rotation sensor) and other associated components such as a processor, memory, battery, etc. Module82is provided as a separate component which may be removably attached to the actuator.

Dose detection module82includes a body88attached to dose button56(shown in dashed lines). Body88illustratively includes a cylindrical side wall90and a top wall92, spanning over and sealing side wall90. Dose detection module82may alternatively be attached to dose button56via any suitable fastening means, such as a snap or press fit, threaded interface, etc., provided that in one aspect module82may be removed from a first medication delivery device and thereafter attached to a second medication delivery device. The attachment may be at any location on dose button56, provided that dose button56is able to move any required amount axially relative to dose setting member30, as discussed herein.

During dose delivery, dose setting member30is free to rotate relative to dose button56and module82. In the illustrative embodiment, module82is rotationally fixed with dose button56and does not rotate during dose delivery. This may be provided structurally, such as with tabs, or by having mutually-facing splines or other surface features on the module body88and dose button56engage upon axial movement of module82relative to dose button56. In another embodiment, the distal pressing of the module provides a sufficient frictional engagement between module82and dose button56as to functionally cause the module82and dose button56to remain rotationally fixed together during dose delivery.

Top wall92is spaced apart from face60of dose button56and thereby provides a cavity96in which some or all of the rotation sensor and other components may be contained. Cavity96may be open at the bottom, or may be enclosed, such as by a bottom wall98. Bottom wall98may be positioned in order to bear directly against face of dose button56. Alternatively, bottom wall98if present may be spaced apart from dose button56and other contacts between module82and dose button56may be used such that an axial force applied to module82is transferred to dose button56. In another embodiment, module82may be rotationally fixed to the one-piece dose button configuration.

In an alternate embodiment, module82during dose setting is instead attached to dose setting member30. For example, side wall90may include a lower wall portion100having inward projections in the form of coupling arms102that engage with button sidewall. In this approach, module82may effectively engage the proximal face60of dose button56and the distal side of annular ridge49. In this configuration, lower wall portion100may be provided with surface features which engage with the surface features of dose button to rotationally fix module82with dose button. Rotational forces applied to housing82during dose setting are thereby transferred to dose button by virtue of the coupling of lower wall portion100with sidewall of the dose button. Light guide118is shown disposed between the LEDs114A-C and light sensor110, shown collectively at a single location of the electronics assembly, and the face of the dosage button56when present. Battery138is shown disposed above the light system89and part of the electronics assembly.

An exemplary electronics assembly120comprises a flexible printed circuit board (FPCB) having a plurality of electronic components. The electronics assembly comprises a sensor system including one or more rotation sensors86operatively communicating with a processor for receiving signals from the sensor representative of the sensed relative rotation. The electronics assembly further includes the MCU comprising at least one processing core and internal memory. One example of an electronics assembly schematic is shown inFIG. 1B.

Referring toFIGS. 10A, 10B, 11A, and 11B, there is shown an exemplary magnetic sensor system150including as the sensed element an annular, ring-shaped, bipolar magnet152having a north pole154and a south pole156. Magnets described herein may also be referred to as diametrically magnetized ring. Magnet152is attached to flange38and therefore rotates with the flange during dose delivery. Magnet152may alternately be attached to dose dial32or other members rotationally fixed with the dose setting member. Magnet152may configured from a variety materials, such as, rare-earth magnets, for example, neodymium, and others.

Sensor system150further includes a measurement sensor158including one or more sensing elements160operatively connected with sensor electronics (not shown) contained within module82. The sensing elements160of sensor158are shown inFIG. 11Aattached to printed circuit board162which is turn attached module82, which is rotationally fixed to dose button56. Consequently, magnet152rotates relative to sensing elements160during dose delivery. Sensing elements160are operable to detect the relative angular position of magnet152. Sensing elements160may include inductive sensors, capacitive sensors, or other contactless sensors when the ring152is a metallic ring. Magnetic sensor system150thereby operates to detect the total rotation of flange38relative to dose button56, and therefore the rotation relative to housing12during dose delivery. In one example, magnetic sensor system150including magnet152and sensor158with sensing elements160may be arranged in the modules.

In one embodiment, magnetic sensor system150includes four sensing elements160equi-radially spaced within module82to define a ring pattern as shown. Alternative numbers and positions of the sensing elements may be used. For example, in another embodiment, shown inFIG. 11B, a single sensing element160is used. Further, sensing element160inFIG. 11Bis shown centered within module82, although other locations may also be used. In another embodiment, shown inFIG. 12, for example, five sensing elements906equi-circumferentially and equi-radially spaced within the module. In the foregoing embodiments, sensing elements160are shown attached within module82. Alternatively, sensing elements160may be attached to any portion of a component rotationally fixed to dose button56such that the component does not rotate relative to housing12during dose delivery.

For purposes of illustration, magnet152is shown as a single, annular, bi-polar magnet attached to flange38. However, alternative configurations and locations of magnet152are contemplated. For example, the magnet may comprise multiple poles, such as alternating north and south poles. In one embodiment the magnet comprises a number of pole pairs equaling the number of discrete rotational, dose-setting positions of flange38. Magnet152may also comprise a number of separate magnet members. In addition, the magnet component may be attached to any portion of a member rotationally fixed to flange38during dose delivery, such as skirt42or dose dial member32.

Alternatively, the sensor system may be an inductive or capacitive sensor system. This kind of sensor system utilizes a sensed element comprising a metal band attached to the flange similar to the attachment of the magnetic ring described herein. Sensor system further includes one or more sensing elements, such as the four, five, six or more independent antennas or armatures equi-angularly spaced along the distal wall of the module housing or pen housing. These antennas form antenna pairs located 180 degrees or other degrees apart and provide a ratio-metric measurement of the angular position of metal ring proportional to the dose delivered.

The metal band ring is shaped such that one or more distinct rotational positions of metal ring relative to the module may be detected. Metal band has a shape which generates a varying signal upon rotation of metal ring relative to antennas. Antennas are operably connected with electronics assembly such that the antennas function to detect positions of metal ring relative to sensors, and therefore relative to housing12of pen10, during dose delivery. Metal band may be a single, cylindrical band attached to the exterior of the flange. However, alternate configurations and locations of the metal band are contemplated. For example, the metal band may comprise multiple discrete metal elements. In one embodiment the metal band comprises a number of elements equal to the number of discrete rotational, dose-setting positions of flange. The metal band in the alternative may be attached to any portion of a component rotationally fixed to flange38during dose delivery, such as dial member32. The metal band may comprise a metal element attached to the rotating member on the inside or the outside of the member, or it may be incorporated into such member, as by metallic particles incorporated in the component, or by over-molding the component with the metal band. MCU is operable to determine the position of the metal ring with the sensors.

MCU is operable to determine the start position of magnet152by averaging the number of sensing elements160(for example, four) at a maximum sampling rate according to standard quadrature differential signals calculation. During dose delivery mode, sampling at a targeted frequency is performed by MCU to detect the number of revolutions of magnet152. At end of dose delivery, MCU is operable to determine the final position of magnet152by averaging the number of sensing elements160(for example, four) at a maximum sampling rate according to standard quadrature differential signals calculation. MCU is operable to determine from calculation of the total rotational angle of travel from the determined start position, number of revolutions, and the final position. MCU is operable to determine the number of dose steps or units by dividing the total rotational angle of travel by a predetermined number (such as 10, 15, 18, 20, 24) that is correlated with the design of device and medication.

Referring further toFIG. 12,FIG. 12illustrates another example of a magnetic sensor system900, including as the sensed element the diametrically magnetized ring902having the north pole903and the south pole905. Magnetized ring902is attached to the dose setting member, such as, for example the flange, as previously described. The radial placement of the magnetic sensors906, such as, for example, hall-effect sensors, relative to the magnetized ring902, can be in an equi-angularly relative to one another in a ring pattern. In one example, the magnetic sensors906are disposed radially in an overlapping relationship with the outer circumferential edge902A of the magnetized ring902such that a portion of the magnetic sensor906resides over the magnetized ring902and the remaining portion resides outside the magnetized ring902.

In some embodiments, the sensing system is configured to determine whether the sensing system is coupled to a medication delivery device.FIG. 13shows an exemplary computerized method1300for determining whether the apparatus is removably coupled to a medication injection device, according to some embodiments. The sensing system, such as the dose delivery detection system, includes a plurality of sensing elements. For example, the sensing system includes a number of sensing elements, such as four or five sensing elements, that are equi-circumferentially and equi-radially spaced within the apparatus. As described herein, the plurality of sensing elements can include a plurality of Hall effect sensors. In some embodiments, five Hall effect sensors are equally spaced at 72 degrees apparat around a circle with a diameter designed based on the magnetic component of the medication delivery device being sensed. For example, a diameter of approximately 14 mm can be used such that the sensors insist on an envelope described by the maximum of the Z component of the magnetic field when the magnet rotates around its axis. The sensing system also includes a processor (e.g., MCU) in communication with the set of sensing elements.

The sensing system (via its processor, MCU, etc.) is configured to execute computer-readable instructions that cause the processor to execute the computerized method1300. At step1302, the sensing system obtains a set of voltage measurements from each of the plurality of sensing elements. At step1304, the sensing system determines two-dimensional data representative of a magnetic field of a magnetic component of the medication injection device. At step1306, the sensing system determines one-dimensional data based on the two-dimensional data. At step1308, the sensing system determines, based on the one-dimensional data, whether the set of voltage measurements is indicative of the apparatus being coupled to the medication injection device.

Referring to step1302, when a power on button to the sensing system is pressed by the user, the sensing system is woken up and the firmware running on the processor switches on the sensing elements (e.g., magnetic sensors) in order to take the starting position of the magnetic component of the medication delivery device (e.g., before any rotation takes place). During this phase it is important to take the sensors reading shortly after wake-up, to avoid taking measurements during rotation. In some embodiments, the sensing system can average a number of samples of each sensor (e.g., 5, 10, 15, etc. of each sensor), e.g., to reduce noise.

Referring to step1304, in some embodiments the sensing system determines a quadrature signal comprising an inphase (I) part and a quadrature (Q) part. The system can determine the I and Q values based on a summation of each sensor value. In some embodiments, the sensing system uses coefficients when summing the sensor values. For example, the system can store one or more coefficients for each sensor. In some embodiments, the sensing system stores one coefficient for each sensor that the sensor value is multiplied by during the summation to determine the I value, and a second coefficient for each sensor that the sensor value is multiplied by during the summation to determine the value. In some embodiments, the coefficients can be used to combine the results of the multiple sensors (e.g., such as five sensors equally spaced at 72 degrees from each other) for the I and Q calculation. In some embodiments, the coefficients can be obtained by solving a system of equations that force the results of the quadrature calculation to have zero error compared to the nominal angle, in front of offset, 2nd harmonic distortion, 3 harmonic distortion in the measured signal, and/or the like.

Referring to step1306, in some embodiments the sensing system determines a scale factor based on the two-dimensional signal (e.g., the quadrature signal) determined at step1304. In some embodiments, the sensing system determines the scale factor based on the quadrature signal and one or more of a predetermined offset and a predetermined gain. For example, the processor can determine the scale factor based on the following Equation 12:

ScaleFactor is the scale factor;I is the inphase part of the quadrature signal;Q is the quadrature part of the quadrature signal;OI is an offset measured on the I signal during calibration;OQ is an offset measured on the Q signal during calibration;GI is a gain measured on the I signal during calibration; andGQ is a gain measured on the Q signal during calibration.

Such exemplary I and Q offsets and gains can be used since quadrature works well when I and Q are well balanced, such as with an offset equal to zero and a gain equal to one. The calibration process can be used to determine offsets/gains that balance the measured I and Q to achieve sufficient values, to remove skew between I and Q, and/or the like. In some embodiments, the sensing system can be configured to normalize the I and Q values, and to use the I and Q values to determine the normalized angle of the Z component of the magnetic field. After a dose is administered, the sensing system can then monitor the ending position of the magnetic component of the medication delivery device to determine the amount of injected dose (e.g., using similar techniques as described herein to monitor the rotation of the magnet and/or to determine the ending position of the magnet).

Referring to step1308, the sensing system can determine whether the one-dimensional data is indicative of the sensing system being coupled (or not being coupled) to a medication delivery device. The sensing system can use the scale factor to determine whether the sensing system is mounted or coupled to the medication delivery device. For example, if the scale factor is between predetermined thresholds, then the sensing system can determine that the sensing system is mounted to the medication delivery device. If the scale factor is not between the predetermined thresholds, the sensing system can determine that the sensing system is likely not mounted to the medication delivery device. In some embodiments, the sensing system can check the scale factor against a low amplitude margin and a high amplitude margin to determine whether the magnet that the module is monitoring is the expected magnet (e.g., where +/−25% around nominal is acceptable) so that only a desired amplitude will be accepted by the module.

The dose detection systems have been described by way of example with particular designs of a medication delivery device, such as a pen injector. However, the illustrative dose detection systems may also be used with alternative medication delivery devices, and with other sensing configurations, operable in the manner described herein. For example, any one or more of the various sensing and switch systems may be omitted from the module.

In this respect, various inventive concepts may be embodied as at least one non-transitory computer readable storage medium (e.g., a computer memory, one or more floppy discs, compact discs, optical discs, magnetic tapes, flash memories, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, etc.) encoded with one or more programs that, when executed on one or more computers or other processors, implement the various embodiments of the present invention. The non-transitory computer-readable medium or media may be transportable, such that the program or programs stored thereon may be loaded onto any computer resource to implement various aspects of the present invention as discussed above.

The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This allows elements to optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified.