Method for testing piezoelectric acoustic transducers

Abstract

A method for testing a drug delivery device includes a piezoelectric transducer, a microcontroller, and a DC power supply, the piezoelectric transducer having an activated state and a non-activated state, the method includes providing a drive signal to the piezoelectric transducer of the drug delivery device, determining an activation voltage value or an activation current value, and comparing the activation voltage value or the activation current value with a baseline value to determine whether the piezoelectric transducer is in the activated state or the non-activated state.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 114,879, filed November 17, 2020, entitled "Method for Testing Piezoelectric Acoustic Transducers," which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to a method for testing a piezoelectric acoustic transducer for a drug delivery device. [Background technology]

[0003] Wearable medical devices, such as auto-injectors, have the advantage of providing treatment to patients at locations away from clinical facilities and / or while discretely worn under the patient's clothing. The wearable medical device can be configured to be applied to the patient's skin and automatically deliver a dose of a pharmaceutical composition within a predetermined time period, e.g., after a 27-hour delay, after application of the wearable medical device to the patient's skin. After the device delivers the pharmaceutical composition to the patient, the patient may then remove and discard the device.

[0004] Wearable medical devices may have audible, tactile, or visual indicators to indicate the status of the device, such as when drug delivery has begun or completed, or if a malfunction has been detected. Piezoelectric transducers are used to provide audible and / or tactile indicators for wearable medical devices. Because indicators for wearable medical devices play an important role in the function of the medical device, the functionality of the indicators is tested during the manufacturing of the medical device. One solution for testing audible indicators is to use a microphone to test the functionality of the audible indicator, which has limitations depending on the external noise level of the manufacturing or testing environment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 10,449,292 Summary of the Invention

[0006] In one aspect or embodiment, a method for testing a drug delivery device including a piezoelectric transducer, a microcontroller, and a DC power source, wherein the piezoelectric transducer has an operative state and an inoperative state, includes providing a drive signal to the piezoelectric transducer of the drug delivery device, determining an operative voltage value or an operative current value, and comparing the operative voltage value or the operative current value with a baseline value to determine whether the piezoelectric transducer is in an operative state or an inoperative state.

[0007] The actuation voltage value or actuation current value may be determined from an average of multiple values ​​measured during a predetermined period of time. The actuation voltage value or actuation current value may be determined from a subset of multiple values ​​measured during a predetermined period of time. Curve fitting may be used to determine the actuation voltage value or actuation current value. At least one of a Fourier transform and a fast Fourier transform may be used to determine the actuation voltage value or actuation current value. The signal used to determine the actuation voltage value or actuation current value may be calculated over a time period greater than 10 ms. The signal used to determine the actuation voltage value or actuation current value may be calculated over a time period greater than 1 ms.

[0008] The actuation voltage value may be the voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline value may be the known voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in an operating state. The actuation voltage value may be the frequency of the maximum voltage drop value when the drive signal is provided to the piezoelectric transducer, and the baseline value may be the known frequency of the maximum voltage drop value when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in an operating state.

[0009] The actuation voltage value may be the minimum and maximum voltage of the DC power supply when a drive signal is provided to the piezoelectric transducer, and the baseline value may be the known minimum and maximum voltage when a drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in an operating state.

[0010] The piezoelectric transducer may be determined to be in an operating state when the operating voltage value is within a predetermined range of the baseline value. The piezoelectric transducer may be activated in the operating state and not activated in the non-operating state. Determining the operating voltage value may include measuring the voltage at the terminals of a DC power source or the voltage at the terminals of the piezoelectric transducer. The DC power source may be a battery.

[0011] In a further aspect or embodiment, a computer-implemented method for testing a drug delivery device including a piezoelectric transducer, a microcontroller, and a DC power supply, wherein the piezoelectric transducer has an activated state and a non-activated state, includes providing a drive signal to the piezoelectric transducer of the drug delivery device, determining an activation voltage value or an activation current value, and using at least one processor, determining whether the piezoelectric transducer is in an activated state or a non-activated state by comparing the activation voltage value with a baseline voltage value.

[0012] In a further aspect or embodiment, a drug delivery device includes a DC power source, a cannula, a reservoir configured to receive a fluid, a pump configured to deliver the fluid from the reservoir to the cannula, a piezoelectric transducer having an operating state in which the piezoelectric transducer produces an audible sound and a non-operating state in which the piezoelectric transducer does not produce an audible sound, and a microcontroller including at least one processor programmed or configured to provide a drive signal to the piezoelectric transducer, determine an operating voltage value, and determine whether the piezoelectric transducer is in an operating state or a non-operating state by comparing, using the at least one processor, the operating voltage value or the operating current value to a baseline value.

[0013] In a further aspect or embodiment, a computer program product for testing a drug delivery device includes a piezoelectric transducer, a microcontroller, and a DC power supply, wherein the piezoelectric transducer has an operating state and a non-operating state, and the computer program product includes at least one non-transitory computer-readable medium including program instructions that, when executed by the microcontroller, cause the microcontroller to provide a drive signal to the piezoelectric transducer, determine an operating voltage value or an operating current value, and determine whether the piezoelectric transducer is in an operating state or a non-operating state by comparing the operating voltage value or the operating current value with a baseline value. [Brief explanation of the drawings]

[0014] The above and other features and advantages of the present disclosure, and the manner in which they are achieved, will become more apparent, and the disclosure itself will be better understood, by referring to the following description of embodiments of the disclosure in conjunction with the accompanying drawings. [Figure 1] 1 is a perspective view of a medication delivery device according to one aspect or embodiment of the present application; [Figure 2]FIG. 2 is a perspective view of the drug delivery device of FIG. 1 with the top cover removed. [Figure 3] FIG. 2 is a partial perspective view of the drug delivery device of FIG. 1. [Figure 4] FIG. 2 is a schematic diagram of the drug delivery device of FIG. 1. [Figure 5] FIG. 2 is a schematic diagram of a piezoelectric transducer circuit of the drug delivery device of FIG. 1 according to one aspect or embodiment of the present application. [Figure 6A] 2 is a graph of the voltage versus time of the power supply and piezoelectric transducer of the drug delivery device of FIG. 1 when the drug delivery device is activated and the piezoelectric transducer circuit is inactive. [Figure 6B] 6B is a histogram of the graph in FIG. 6A. [Figure 7A] 2 is a graph of the voltage versus time of the power supply and piezoelectric transducer of the drug delivery device of FIG. 1 when the drug delivery device is activated, the piezoelectric transducer circuit is activated, and the piezoelectric transducer is disconnected. [Figure 7B] 7B is a histogram of the graph in FIG. 7A. [Figure 8A] 2 is a graph of voltage versus time for the power supply and piezoelectric transducer of the drug delivery device of FIG. 1 when the drug delivery device is activated, the piezoelectric transducer circuit is activated, and the piezoelectric transducer is connected. [Figure 8B] 8B is a histogram of the graph in FIG. 8A. [Figure 9] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing the voltage with the piezoelectric transducer connected and the voltage with the piezoelectric transducer disconnected. [Figure 10] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing the frequency of maximum voltage drop. [Figure 11] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing a comparison of the voltage with the piezoelectric transducer connected and the voltage with the piezoelectric transducer not connected. [Figure 12] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing a comparison of the voltage frequency of the power supply with the piezoelectric transducer connected to the 250 Hz frequency of the piezoelectric transducer. [Figure 13] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing a comparison of the voltage frequency of the power supply with the piezoelectric transducer connected to the 500 Hz frequency of the piezoelectric transducer. [Figure 14] 2 is a graph of voltage versus time for the power supply of the drug delivery device of FIG. 1 showing a comparison of the voltage frequency of the power supply with the piezoelectric transducer connected and a 750 Hz frequency of the piezoelectric transducer. [Figure 15] 1 is a schematic diagram of a method for testing a drug delivery device according to one aspect or embodiment of the present application. [Figure 16] 2 is a graph of voltage versus sample number for the power supply of the drug delivery device of FIG. 1 showing the voltage with the piezoelectric transducer connected. [Figure 17] 10 is a graph of voltage versus sample number for the power supply of the drug delivery device of FIG. 1 showing the voltage with the piezoelectric transducer disconnected.

[0015] Corresponding reference characters indicate corresponding parts throughout the several views. The illustrations presented herein illustrate exemplary embodiments of the present disclosure, and such illustrations should not be construed as limiting the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE INVENTION

[0016] Spatial or directional terms such as "left," "right," "inner," "outer," "above," "below," etc. should not be considered limiting as the present invention may assume various alternative orientations.

[0017] All numbers used in the specification and claims should be understood as modified in all instances by the term "about." By "about" is meant a range of plus or minus ten percent of the stated value. As used in the specification and claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "first," "second," etc. are not intended to refer to any particular order or chronology, but instead refer to different conditions, characteristics, or elements. "At least" means "greater than or equal to."

[0018] As used herein, "at least one" is synonymous with "one or more." For example, the phrase "at least one of A, B, and C" means any one of A, B, or C, or any combination of any two or more of A, B, or C. For example, "at least one of A, B, and C" includes one or more As alone, or one or more Bs alone, or one or more Cs alone, or one or more As and one or more Bs, or one or more As and one or more Cs, or one or more Bs and one or more Cs, or all one or more of A, B, and C.

[0019] As used herein, the term "processor" may refer to one or more electronic devices configured to process data. A processor, in some examples, may include components necessary to receive, process, and output data, such as a processor, a display, a memory, an input device, a network interface, and / or the like. A processor may be a mobile device. A processor may also be a desktop computer or other form of non-mobile computer.

[0020] 1-4 , drug delivery device 10 includes a reservoir 12, a power source 14, an insertion mechanism 16, control electronics 18, a cover 20, and a base 22. In one aspect or embodiment, drug delivery device 10 is a wearable automatic injector, such as an insulin or bone marrow stimulating agent delivery device. Drug delivery device 10 may be placed on a patient's skin and triggered to inject a pharmaceutical composition from reservoir 12 into the patient. Drug delivery device 10 may be pre-filled with the pharmaceutical composition or may be filled with the pharmaceutical composition by the patient or a medical professional prior to use.

[0021] The drug delivery device 10 is configured to deliver a pharmaceutical composition, e.g., a dose of any desired drug, into a patient's body via subcutaneous injection at a slow, controlled infusion rate. Exemplary time durations for delivery achieved by the drug delivery device 10 may range from about 5 minutes to about 60 minutes, but are not limited to this exemplary range. Exemplary volumes of the pharmaceutical composition delivered by the drug delivery device 10 may range from about 0.1 milliliters to about 10 milliliters, but are not limited to this exemplary range. The volume of the pharmaceutical composition delivered to the patient may be adjusted.

[0022] 1-4 , in one aspect or embodiment, the power supply 14 is a DC power supply including one or more batteries. The control electronics 18 include a microcontroller 24, sensing electronics 26, a pump and valve controller 28, sensing electronics 30, and deployment electronics 32, which control the operation of the drug delivery device 10. The drug delivery device 10 includes a fluidics subsystem including the reservoir 12, a volume sensor 34 for the reservoir 12, a reservoir fill port 36, and a metering subsystem 38 including a pump and valve actuator 40 and a pump and valve mechanism 42. The fluidics subsystem may further include an occlusion sensor 44, a deploy actuator 46, and a cannula 48 for insertion into the patient's skin. In one aspect or embodiment, the insertion mechanism 16 is configured to move the cannula 48 from a retracted position, where the cannula 48 is positioned fully within the drug delivery device 10, to an extended position, where the cannula 48 extends outside the drug delivery device 10. The drug delivery device 10 may operate in a manner similar to that discussed in U.S. Patent No. 6,275,999 to Pizzochero et al.

[0023] 3 and 5, the drug delivery device 10 also includes a piezoelectric transducer 50 configured to provide an audible and / or tactile indication to the user regarding the status of the drug delivery device 10. In one aspect or embodiment, the piezoelectric transducer 50 is connected to the control electronics 18 via one or more spring contacts 60. The piezoelectric transducer 50 has an operative state in which the piezoelectric transducer 50 is activated and generates an audible sound, movement, and / or vibration when provided with a signal generating system signal, such as the microcontroller 24, and a non-operative state in which the piezoelectric transducer 50 is not activated and does not generate an audible sound, movement, and / or vibration.

[0024] 6A through 15 , according to one aspect or embodiment of the present application, a method for testing a drug delivery device 10 includes providing 72 a drive signal to a piezoelectric transducer 50 of the drug delivery device 10, measuring 74 an actuation voltage value, and comparing 76 the actuation voltage value to a baseline voltage value to determine whether the piezoelectric transducer 50 is in an actuated or non-actuated state. If the actuation voltage value is within a predetermined range of a baseline value, such as within 5% of the baseline value, the piezoelectric transducer 50 is determined to be in an actuated state and has a passed test status 78. If the actuation voltage value is not within a predetermined range of a baseline value, such as within 5% of the baseline value, the piezoelectric transducer 50 is determined to be in a non-actuated state and has a failed test status 80. One possible cause of a failed test is insufficient contact between the spring contacts 60 of the piezoelectric transducer 50 and the control electronics 18. The present method enables self-testing of the drug delivery device 10 to determine whether the piezoelectric transducer 50 is properly connected and operating without requiring dedicated circuitry or hardware, and without requiring separate data handling, data processing, and traceability. The present method 70 does not require any additional equipment and is insensitive to ambient noise. Furthermore, the present method 70 utilizes a voltage reading from the power supply 14, which is typically already monitored by the microcontroller 24 to detect the level of the power supply 14, as described in more detail below. Thus, the present method 70 does not require any additional connections between electronic components.

[0025] 6A to 14 , in one aspect or embodiment, the actuation voltage value is the voltage frequency of the DC power supply 14 when the voltage drive signal is provided to the piezoelectric transducer 50, and the baseline value is the known voltage frequency of the DC power supply 14 when the drive signal is provided to the piezoelectric transducer 50 and the piezoelectric transducer 50 is in an operating state. More specifically, the actuation voltage value is the frequency of the maximum voltage drop when the drive signal is provided to the piezoelectric transducer 50, and the baseline value is the known frequency of the maximum voltage drop when the drive signal is provided to the piezoelectric transducer 50 and the piezoelectric transducer 50 is in an operating state. In one aspect or embodiment, the drive signal is a square wave of a predetermined frequency. In a further aspect or embodiment, the actuation voltage value is the minimum and maximum voltage of the DC power supply 14 when the drive signal is provided to the piezoelectric transducer 50, and the baseline value is the known minimum and maximum voltage when the drive signal is provided to the piezoelectric transducer 50 and the piezoelectric transducer 50 is in an operating state. In a further aspect or embodiment, the operating frequency may be modulated over a second, lower frequency, essentially turning the transducer actuation circuit on and off as part of the test procedure. The voltage value may be calculated from the difference between actuation and non-actuation voltages measured at selected locations directly or indirectly connected to the piezoelectric transducer 50. The reference and measurement values ​​may be voltages or currents.

[0026] As shown in Figures 6A and 6B, when the drug delivery device 10 is activated or awake and no drive signal is provided, the voltage of the power supply 14 measured at the power supply terminals oscillates between 1.505 V and 1.525 V, while the drive signal remains constant at 1.5 V. As shown in Figures 7A and 7B, when the drug delivery device 10 is activated or awake, a drive signal is provided, and the piezoelectric transducer 50 is disconnected, the voltage of the power supply 14 measured at the power supply terminals oscillates between 1.425 V and 1.455 V, a shift of approximately 0.12 V from Figures 6A and 6B, while the drive signal oscillates between 1.358 V and 1.61 V. As will be explained in more detail below, a high-frequency spike of maximum voltage drop occurs when the drive signal voltage and the power supply voltage are equal. As shown in Figures 8A and 8B, when the drug delivery device 10 is activated or turned on, a drive signal is provided, and the piezoelectric transducer 50 is connected, the voltage of the power supply 14 measured at the power supply terminals oscillates between 1.41 V and 1.455 V, and the drive signal oscillates between 1.358 V and 1.61 V. Compared to the states of Figures 7A and 7B, the voltage distribution in Figures 8A and 8B shifts by approximately 5 mV. Therefore, when the piezoelectric transducer 50 is properly connected and in an operational state, the operational state of the piezoelectric transducer 50 can be determined by comparing the minimum and maximum voltages of the power supply with known minimum and maximum voltages. Also, as shown in Figure 8A, the pattern of high-frequency spikes or harmonics of the maximum voltage drop values ​​is different compared to the pattern in Figure 7A, which will be discussed in more detail below. The pattern can be observed by analyzing the signal in either the time domain or the frequency domain using a fast Fourier transform (FFT).

[0027] 9, a voltage drop of approximately 0.15 V occurs at the beginning of drive signal activation, and this occurs with the piezoelectric transducer 50 connected and with the piezoelectric transducer 50 disconnected. The 0.15 V voltage drop occurs over 0.005 seconds. However, as shown in FIG. 9, when the piezoelectric transducer 50 is connected, the voltage of the power supply 14 recovers at a slightly lower level, with a difference of approximately 0.02 V. In a further aspect or embodiment, a method 70 of testing a drug delivery device 10 to determine the operating state of the piezoelectric transducer 50 includes comparing voltage recovery values ​​after initially providing a drive signal.

[0028] Referring to FIG. 10, the power supply 14 is shown reversed while the piezoelectric transducer 50 is connected and operating at 2.9 kHz. The frequency of the maximum voltage drop or spike of the power supply 14 corresponds to the frequency of the drive signal, which occurs only when the piezoelectric transducer 50 is properly connected. Therefore, by comparing the frequency of the maximum voltage drop of the power supply 14 with the known frequency of the maximum voltage drop of the drive signal for a given frequency, the operational state of the piezoelectric transducer 50 can be determined. In other words, if the frequency of the maximum voltage drop of the power supply 14 matches the known frequency of the maximum voltage drop when the piezoelectric transducer 50 is properly connected, the piezoelectric transducer 50 can be determined to be in an operational state. If the frequency of the maximum voltage drop of the power supply 14 does not match the known frequency of the maximum voltage drop when the piezoelectric transducer 50 is properly connected, the piezoelectric transducer 50 can be determined to be in a non-operational state. If the maximum voltage drop spike or frequency is present but does not match the known value for a properly connected piezoelectric transducer 50, a determination can also be made that the drive signal is functional.

[0029] 11, a comparison of the voltage of the power supply 14 is shown with the drive signal applied and the piezoelectric transducer 50 disconnected, and with the piezoelectric transducer 50 connected. As discussed above, the frequency of the maximum voltage drop occurs only at the frequency of the drive signal when the piezoelectric transducer 50 is properly connected.

[0030] 12-14, maximum voltage drop values ​​are shown at drive signal frequencies of 250 Hz (FIG. 12), 500 Hz (FIG. 13), and 750 Hz (FIG. 14). The frequencies of maximum voltage drop values ​​occur at the drive signal frequencies when the piezoelectric transducer 50 is properly connected across the various frequencies of the drive signal.

[0031] In one aspect or embodiment, the voltage is measured further away from the power source 14, closer to where power is supplied to the piezoelectric transducer 50. In another aspect or embodiment, instead of measuring an actuation voltage value, an actuation current value is measured and utilized to determine whether the piezoelectric transducer 50 is in an actuated or inactive state. The actuation current value is utilized in the same manner as the actuation voltage value to determine whether the piezoelectric transducer 50 is in an actuated or inactive state, as described above. The actuation current value may be calculated by measuring a voltage drop across a resistor, although other suitable configurations for measuring the actuation current value may be utilized.

[0032] 16 and 17 , in a further aspect or embodiment, a method 70 for testing a drug delivery device 10 includes activating the piezoelectric transducer 50 in an on / off pattern at a rate of 5 Hz for 1 second, recording the battery voltage at the beginning of the second on / off sequence, recording 12 voltage value samples at a sampling frequency of 120 Hz during seven on / off periods, calculating and storing the average of the on / off voltage values, using a least squares method to fit a line to all data points during the seven recorded on / off periods, calculating the perpendicular distance from the seven average value points to the fitted line, returning the minimum value of the distance, and determining whether the minimum value of the distance is less than 1.5. In one aspect or embodiment, if the minimum value of the distance is less than 1.5, the piezoelectric transducer 50 is determined to be disconnected. In one aspect or embodiment, if the final recorded voltage value is less than 2 V, the drug delivery device 10 is determined to have failed. In one aspect or embodiment, rather than recording 12 voltage value samples, two or more voltage value samples are recorded. In one aspect or embodiment, rather than recording voltage values ​​during seven on / off periods, voltage values ​​are recorded over two or more on / off periods. Furthermore, although a sampling frequency of 120 Hz is discussed, other suitable sampling frequencies may be utilized.

[0033] While the present invention has been described in detail for purposes of illustration, based on what are presently considered to be the most practical and preferred embodiments, it should be understood that such detail is for that purpose only, and that the present invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. 1. A method for testing a drug delivery device including a piezoelectric transducer, a microcontroller, and a DC power supply, the piezoelectric transducer having an activated state and a non-activated state, the method comprising: providing, by the microcontroller, a drive signal from the DC power supply to the piezoelectric transducer of the drug delivery device; determining, via a sensing circuit, an operating voltage value or an operating current value in response to the drive signal; comparing, by the microcontroller, the operating voltage or current value with a predetermined baseline value stored in memory corresponding to an operational characteristic of the transducer in an operating state; generating, by the microcontroller, a pass / fail result based on the comparison, indicating whether the piezoelectric transducer is in the activated state or the non-activated state; and storing or outputting the pass / fail result for device readiness certification.

2. The method of claim 1, further comprising a step of disabling the function of the drug delivery device if the pass / fail result indicates that the piezoelectric transducer is in an inoperative state.

3. 2. The method of claim 1, wherein the operating voltage value or the operating current value is determined from an average of a plurality of values ​​measured during a predetermined period of time or from a subset of a plurality of values ​​measured during a predetermined period of time.

4. 4. The method of claim 2 or claim 3, wherein curve fitting is used to determine the operating voltage or current values.

5. 5. The method according to claim 2, wherein at least one of a Fourier transform and a fast Fourier transform is used to determine the operating voltage value or the operating current value.

6. 6. A method according to any one of claims 1 to 5, wherein the signals used to determine the operating voltage or current values ​​are calculated over a period of more than 10 ms.

7. 6. A method according to any one of claims 1 to 5, wherein the signals used to determine the operating voltage or current values ​​are calculated over a period of more than 1 ms.

8. The method of claim 1, further comprising a step of determining the operating voltage value, wherein the operating voltage value comprises a voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer, and wherein the baseline value comprises a known voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

9. A method as described in claim 1 or claim 8, characterized in that it includes a step of determining the operating voltage value, wherein the operating voltage value includes a frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer, and the baseline value includes a known frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

10. A method according to any one of claims 1, 8 and 9, characterized in that it includes a step of determining the operating voltage value, the operating voltage value comprising the minimum and maximum voltage of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline value comprising the known minimum and maximum voltage when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

11. 11. The method of any one of claims 1 and 8 to 10, wherein the piezoelectric transducer is determined to be in the operating state when the operating voltage value is within a predetermined range of the baseline value.

12. 12. The method of any one of claims 1 and 8 to 11, wherein the piezoelectric transducer is activated in the activated state and is not activated in the non-activated state.

13. A method according to any one of claims 1 and 8 to 12, characterized in that it includes a step of determining the operating voltage value, and the step of determining the operating voltage value includes a step of measuring the voltage at the terminals of the DC power supply.

14. 14. The method of any one of claims 1 and 8 to 13, wherein the DC power source comprises a battery.

15. 1. A computer-implemented method for testing a drug delivery device, the method including a piezoelectric transducer, a microcontroller, and a DC power supply, the piezoelectric transducer having an activated state and a non-activated state, the method comprising: providing, by at least one processor, a drive signal from the DC power source to the piezoelectric transducer of the drug delivery device; determining, by the at least one processor, an actuation voltage value in response to the drive signal; comparing, by the at least one processor, the operating voltage value to a predetermined baseline voltage value stored in memory corresponding to an operational characteristic of the transducer in an operating state; generating, by the at least one processor, a pass / fail result based on the comparison, indicating whether the piezoelectric transducer is in the operative state or the non-operative state; and storing or outputting said pass / fail result for device readiness certification.

16. 16. The method of claim 15, wherein the operating voltage value comprises a voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline voltage value comprises a known voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

17. 17. The method of claim 15 or 16, wherein the operating voltage value comprises a frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer, and the baseline voltage value comprises a known frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

18. 18. The method of any one of claims 15 to 17, wherein the operating voltage values ​​comprise minimum and maximum voltages of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline voltage values ​​comprise known minimum and maximum voltages when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

19. A DC power supply; A cannula and a reservoir configured to receive a fluid; a pump configured to deliver fluid from the reservoir to the cannula; a piezoelectric transducer having an operative state in which the piezoelectric transducer produces audible sound and a non-operative state in which the piezoelectric transducer does not produce audible sound; providing a drive signal to the piezoelectric transducer; determining an operating voltage value or an operating current value in response to the drive signal; and comparing, by at least one processor, the actuation voltage value or the actuation current value to a predetermined baseline value stored in memory corresponding to an operational characteristic of the piezoelectric transducer in an operating state; generating, by the at least one processor, a pass / fail result based on the comparison, indicating whether the piezoelectric transducer is in the operative state or the non-operative state; a microcontroller including said at least one processor programmed or configured to store or output said pass / fail result for device readiness certification; A drug delivery device comprising:

20. The device described in claim 19, further comprising determining the operating voltage value, wherein the operating voltage value comprises a voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer, and wherein the baseline value comprises a known voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

21. A device as described in claim 19 or claim 20, characterized in that it includes determining the operating voltage value, the operating voltage value comprising a frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer, and the baseline value comprising a known frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

22. A device as described in any one of claims 19 to 21, characterized in that it includes determining the operating voltage value, wherein the operating voltage value comprises a minimum and maximum voltage of the DC power supply when the drive signal is provided to the piezoelectric transducer, and wherein the baseline value comprises a known minimum and maximum voltage when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

23. 1. A non-transitory computer readable medium containing program instructions for testing a drug delivery device including a piezoelectric transducer, a microcontroller, and a DC power supply, the piezoelectric transducer having an activated state and a non-activated state, the program instructions, when executed by the microcontroller, causing the microcontroller to: providing a drive signal from the DC power supply to the piezoelectric transducer; determining an actuation voltage value or an actuation current value in response to the drive signal; comparing the operating voltage or current values ​​to predetermined baseline values ​​stored in memory corresponding to operational characteristics of the transducer under operating conditions; generating a pass / fail result based on the comparison, indicating whether the piezoelectric transducer is in the activated state or the non-activated state; and A non-transitory computer-readable medium containing program instructions that cause the pass / fail result to be stored or output for device readiness certification.

24. The non-transitory computer-readable medium of claim 23, characterized in that the program instructions, when executed by the microcontroller, cause the microcontroller to determine the operating voltage, the operating voltage value comprising a voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline value comprising a known voltage frequency of the DC power supply when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

25. A non-transitory computer-readable medium as described in claim 23 or claim 24, characterized in that the program instructions, when executed by the microcontroller, cause the microcontroller to determine the operating voltage, the operating voltage value including a frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer, and the baseline value including a known frequency of a maximum voltage drop value when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

26. A non-transitory computer-readable medium as described in any one of claims 23 to 25, characterized in that the program instructions, when executed by the microcontroller, cause the microcontroller to determine the operating voltage, the operating voltage value comprising a minimum and maximum voltage of the DC power supply when the drive signal is provided to the piezoelectric transducer, and the baseline value comprising a known minimum and maximum voltage when the drive signal is provided to the piezoelectric transducer and the piezoelectric transducer is in the operating state.

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