Impact detection device, electronic apparatus, impact detection method, and impact detection program

Abstract

This impact detection device is provided with a communication unit that communicates with an acceleration sensor provided in an electronic apparatus, and a control unit that: when a fall signal indicating that the electronic apparatus has fallen is received from the acceleration sensor via the communication unit, refers to a notification signal received from the acceleration sensor via the communication unit within a certain period of time after receiving the fall signal, determines whether an impact due to the fall from a height equal to or more than a specific height is received in a state in which the electronic apparatus is not packaged, and performs recording when it is determined that at least the electronic apparatus has received the impact.

Description

Impact detection device, electronic device, impact detection method, and impact detection program

[0001] The present disclosure relates to an impact detection device, an electronic device, an impact detection method, and an impact detection program.

[0002] Patent Literature 1 discloses an apparatus that time-integrates each of the absolute value waveforms of three-axis acceleration values ​​detected by a three-axis acceleration sensor at predetermined time intervals and detects an impact when the voltage of the integration result exceeds a threshold. Patent Literature 2 discloses an electronic device that, when it is determined that an acceleration value detected at a predetermined time interval exceeds a first threshold, calculates a second threshold based on the maximum value of multiple acceleration values ​​detected over a predetermined period after the determination, and determines that multiple impacts have occurred when the number of accelerations whose acceleration values ​​exceed the second threshold exceeds a predetermined number. Patent Literature 3 discloses an apparatus for detecting an impact applied to a package.

[0003] JP 2008-020250 A JP 2017-054330 A JP 2017-156236 A

[0004] Syringe pumps, infusion pumps, and other pumps have an impact detection function that uses an acceleration sensor. For example, if the pump is dropped from a height of one meter, the impact detection is recorded in the operation history and the user is notified that the product's functionality may have been impaired by the impact.

[0005] There are two types of acceleration sensors, low-G acceleration sensors and high-G acceleration sensors, depending on the application. Low-G acceleration sensors can detect minute changes such as walking or body movement, but are not suitable for detecting large changes such as impacts. High-G acceleration sensors can detect large changes such as impacts, but are not suitable for detecting minute changes. Therefore, it is possible to incorporate both low-G and high-G acceleration sensors into the pump to detect both minute and large changes, but this would increase costs. In order to comply with RoHS, it may be necessary to use only low-G acceleration sensors, which are not suitable for detecting impacts. "RoHS" is an abbreviation for the Restriction of Hazardous Substances Directive.

[0006] When a pump is packaged, it is unlikely that the product's functionality will be impaired by the impact, even if it is dropped from a specific height, such as one meter. Therefore, it is desirable to be able to distinguish between a strong impact that occurs when an unpackaged pump is dropped from a specific height or higher, and a weak impact that occurs when a pump is dropped from a low place or when the pump is dropped while packaged.

[0007] An object of the present disclosure is to enable detection of strong impacts received when an electronic device is dropped from a specific height or higher while unpackaged, while distinguishing between strong impacts and weak impacts.

[0008] Some aspects of the present disclosure are set forth below.

[0009] [1] An impact detection device comprising: a communication unit that communicates with an acceleration sensor provided in an electronic device; and a control unit that, when a fall signal indicating that the electronic device has fallen is received from the acceleration sensor via the communication unit, determines whether the electronic device has received an impact due to being dropped from a specific height or higher while unpackaged, by referring to a notification signal received from the acceleration sensor via the communication unit within a certain period of time after receiving the fall signal, and records at least when it is determined that the electronic device has received the impact.

[0010] [2] The impact detection device according to [1], wherein the control unit receives a time series signal of acceleration along three axes as the notification signal, performs high-pass filtering on the time series signal, and determines whether the electronic device has received the impact based on whether the sum of a resultant vector of the acceleration along the three axes after the high-pass filtering is equal to or greater than a threshold value.

[0011] [3] The impact detection device according to [1], wherein the control unit increments a counter each time the control unit receives, as the notification signal, a signal indicating that an acceleration exceeding a reference value has been measured, and determines whether the electronic device has received the impact based on whether the value of the counter exceeds a threshold value within the certain period of time.

[0012] [4] The impact detection device according to any one of [1] to [3], wherein the fall signal is a time series signal of acceleration on three axes, and the acceleration on each axis is a signal that takes a value that is less than 1 G and is within a certain range around 0 G for a reference time or more.

[0013] [5] The impact detection device according to any one of [1] to [4], wherein the control unit, when determining that the electronic device has received the impact, notifies a user that the electronic device has fallen from a height equal to or greater than the specific height while unpackaged.

[0014] [6] An electronic device comprising: the impact detection device according to any one of [1] to [5]; and the acceleration sensor.

[0015] [7] The electronic device according to [6], which is a medical device.

[0016] [8] A shock detection method comprising: when a computer that communicates with an acceleration sensor provided in an electronic device receives a drop signal from the acceleration sensor indicating that the electronic device has fallen, determining whether the electronic device has received an impact due to being dropped from a specific height or more in an unpackaged state by referring to a notification signal received from the acceleration sensor within a certain time period after receiving the drop signal; and recording when the computer determines that at least the electronic device has received the impact.

[0017] [9] An impact detection program that causes a computer that communicates with an acceleration sensor provided in an electronic device to perform operations including: when a drop signal indicating that the electronic device has fallen is received from the acceleration sensor, determining whether the electronic device has been subjected to an impact due to being dropped from a specific height or more in an unpackaged state by referring to a notification signal received from the acceleration sensor within a certain period of time after receiving the drop signal; and recording at least when it is determined that the electronic device has been subjected to the impact.

[0018] According to the present disclosure, it is possible to distinguish and detect a strong impact caused by an electronic device being dropped from a specific height or higher while unpackaged from a weak impact.

[0019] Fig. 3 is a block diagram showing the configuration of an electronic device according to an embodiment of the present disclosure; Fig. 4 is a perspective view of an electronic device according to an embodiment of the present disclosure; Fig. 5 is a flowchart showing the operation of an impact detection device according to an embodiment of the present disclosure; Fig. 6 is a diagram showing an example of a waveform of triaxial acceleration during a fall; Fig. 7 is a diagram showing an example of a frequency spectrum of acceleration when not packed and when packed; Fig. 8 is a flowchart showing a modified example of the operation shown in Fig. 3;

[0020] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0021] In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0022] The configuration of an electronic device 10 according to this embodiment will be described with reference to FIG.

[0023] The electronic device 10 includes an acceleration sensor 11 and an impact detection device 20. In this embodiment, the electronic device 10 further includes a display 12 and a speaker 13, although these are not essential.

[0024] The electronic device 10 is a medical device. In this embodiment, as shown in FIG. 2 , the electronic device 10 is a syringe pump that delivers a drug filled in a syringe by pressing the syringe plunger of the syringe. However, the electronic device 10 may also be an infusion pump that delivers a drug flowing through an infusion tube by sequentially pressing the infusion tube, or may be any other type of medical device. Alternatively, the electronic device 10 may be a mobile device other than a medical device, such as a smartphone, tablet, laptop PC, or portable game console. "PC" is an abbreviation for personal computer.

[0025] The acceleration sensor 11 is a sensor that measures acceleration in three axes: the X axis, the Y axis perpendicular to the X axis, and the Z axis perpendicular to both the X axis and the Y axis. As shown in Fig. 2, the X axis extends in the length direction of the electronic device 10, the Y axis extends in the width direction of the electronic device 10, and the Z axis extends in the height direction of the electronic device 10. In this embodiment, the acceleration sensor 11 is a low-G acceleration sensor with a measurement range of approximately 8 G or less.

[0026] The display 12 is a device that displays various types of information related to the electronic device 10 on a screen. The display 12 is, for example, an LCD or an organic EL display. "LCD" is an abbreviation for liquid crystal display. "EL" is an abbreviation for electroluminescent.

[0027] The speaker 13 is a device that outputs various types of information related to the electronic device 10 by voice.

[0028] In this embodiment, the impact detection device 20 is mounted on the electronic device 10, but it may also be installed separately from the electronic device 10 and be able to communicate with the electronic device 10 directly or via a network such as a LAN or the Internet. "LAN" is an abbreviation for local area network. The impact detection device 20 is, for example, a microcomputer mounted on the electronic device 10, but it may also be a general-purpose computer such as a PC, a server computer such as a cloud server, a mobile device such as a smartphone or tablet, or a dedicated computer installed separately from the electronic device 10.

[0029] An outline of this embodiment will be described.

[0030] When the impact detection device 20 receives a drop signal from the acceleration sensor 11 indicating that the electronic device 10 has fallen, the impact detection device 20 determines whether the electronic device 10 has received an impact due to being dropped from a specific height or higher in an unpackaged state by referring to a notification signal received from the acceleration sensor 11 within a certain time period after receiving the drop signal. The impact detection device 20 records at least when it determines that the electronic device 10 has received an impact.

[0031] According to this embodiment, it is possible to distinguish and detect a strong impact that occurs when the electronic device 10 is dropped from a specific height or higher while unpackaged from a weak impact.

[0032] The configuration of an impact detection device 20 according to this embodiment will be described with reference to FIG.

[0033] The impact detection device 20 includes a control unit 21 , a storage unit 22 , and a communication unit 23 .

[0034] The control unit 21 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for specific processing. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. An example of the programmable circuit is an FPGA. "FPGA" is an abbreviation for field-programmable gate array. An example of the dedicated circuit is an ASIC. "ASIC" is an abbreviation for application specific integrated circuit. The control unit 21 controls each part of the shock detection device 20 and executes processing related to the operation of the shock detection device 20.

[0035] The storage unit 22 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, a RAM, a ROM, or a flash memory. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read only memory. RAM is, for example, an SRAM or a DRAM. "SRAM" is an abbreviation for static random access memory. "DRAM" is an abbreviation for dynamic random access memory. ROM is, for example, an EEPROM. "EEPROM" is an abbreviation for electrically erasable programmable read only memory. Flash memory is, for example, an SSD. "SSD" is an abbreviation for solid-state drive. Magnetic memory is, for example, an HDD. "HDD" is an abbreviation for hard disk drive. The storage unit 22 functions, for example, as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 22 stores data used in the operation of the impact detection device 20 and data obtained by the operation of the impact detection device 20 .

[0036] The communication unit 23 includes at least one communication module. The communication module is, for example, a module that supports a serial communication standard such as SPI or I2C, a wired LAN communication standard such as Ethernet (registered trademark), a wireless LAN communication standard such as IEEE 802.11, a mobile communication standard such as LTE, 4G standard, or 5G standard, or a short-range wireless communication standard such as Bluetooth (registered trademark). "SPI" is an abbreviation for Serial Peripheral Interface. "I2C" is an abbreviation for Inter-Integrated Circuit. "IEEE" is an abbreviation for Institute of Electrical and Electronics Engineers. "LTE" is an abbreviation for Long Term Evolution. "4G" is an abbreviation for 4th generation. "5G" is an abbreviation for 5th generation. The communication unit 23 communicates with the acceleration sensor 11. Specifically, the communication unit 23 communicates with the acceleration sensor 11 via serial communication such as SPI or I2C. The communication unit 23 may communicate with the display 12. The communication unit 23 may communicate with the speaker 13. The communication unit 23 receives data used in the operation of the impact detection device 20, and transmits data obtained by the operation of the impact detection device 20.

[0037] The functions of the shock detection device 20 are realized by executing a shock detection program according to this embodiment on a processor serving as the control unit 21. That is, the functions of the shock detection device 20 are realized by software. The shock detection program causes a computer to execute the operations of the shock detection device 20, thereby causing the computer to function as the shock detection device 20. That is, the computer functions as the shock detection device 20 by executing the operations of the shock detection device 20 in accordance with the shock detection program.

[0038] The program can be stored on a non-transitory computer-readable medium. Examples of the non-transitory computer-readable medium include flash memory, magnetic recording devices, optical disks, magneto-optical recording media, and ROMs. The program can be distributed by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs that store the program. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read only memory. The program can also be distributed by storing it in the storage of a server and transferring it from the server to another computer. The program can also be provided as a program product.

[0039] A computer temporarily stores a program stored on a portable medium or transferred from a server in its main storage device. The computer then reads the program stored in the main storage device with a processor and executes processing in accordance with the read program. The computer may also read the program directly from the portable medium and execute processing in accordance with the program. The computer may also execute processing in accordance with the received program each time a program is transferred from the server to the computer. Processing may also be executed using a so-called ASP-type service that realizes functions simply by issuing execution instructions and obtaining results, without transferring the program from the server to the computer. "ASP" is an abbreviation for application service provider. Programs include information used for processing by a computer that is equivalent to a program. For example, data that is not a direct instruction to a computer but has properties that define computer processing falls under the category of "equivalent to a program."

[0040] Some or all of the functions of the impact detection device 20 may be realized by a programmable circuit or a dedicated circuit as the control unit 21. In other words, some or all of the functions of the impact detection device 20 may be realized by hardware.

[0041] The operation of the shock detection device 20 according to this embodiment will be described with reference to Fig. 3. The operation described below corresponds to the shock detection method according to this embodiment. That is, the shock detection method according to this embodiment includes steps S101 to S108 shown in Fig. 3.

[0042] When the acceleration sensor 11 interrupts the impact detection device 20 while the electronic device 10 is in standby mode, the electronic device 10 switches to a power-on state and starts step S101. When the acceleration sensor 11 interrupts the impact detection device 20 while the electronic device 10 is in a power-on state, step S101 starts immediately.

[0043] In S101, the control unit 21 determines whether an activity interrupt has been input from the acceleration sensor 11. The activity interrupt is a signal indicating that an acceleration exceeding an activity standard has been measured. For example, the activity interrupt is an input signal from the acceleration sensor 11 to the impact detection device 20 when the acceleration on any of the three axes, i.e., the X-axis, Y-axis, or Z-axis, exceeds ±4 G. That is, for example, the "activity standard" is 4 G. The "activity standard" may be changed as appropriate.

[0044] If it is determined in S101 that an activity interrupt has been input, step S102 is executed. If it is determined in S101 that an activity interrupt has not been input, step S101 is executed again.

[0045] In S102, the control unit 21 acquires acceleration values ​​for each axis for a reference time or longer. Specifically, the control unit 21 receives time-series signals of acceleration along three axes for a reference time or longer from the acceleration sensor 11 via the communication unit 23. For example, the time-series signals of acceleration along three axes for a reference time or longer are signals indicating 170 samples for each axis stored in a FIFO memory built into the acceleration sensor 11 before an activity interrupt. "FIFO" is an abbreviation for first in, first out. For example, the "reference time" is 360 milliseconds. 144 samples out of the 170 samples correspond to 360 milliseconds' worth of samples. The "reference time" may be changed as appropriate.

[0046] In S103, the control unit 21 determines whether a fall of the electronic device 10 from a height equal to or greater than a specified height has been detected. Specifically, the control unit 21 determines whether the time-series signal of the acceleration along three axes received in S102 is a fall signal indicating that the electronic device 10 has fallen. A fall signal is a signal in which the acceleration along each axis continues to be less than 1 G for a reference time or longer and takes a value within a certain range around 0 G. For example, a fall signal is a signal that satisfies the following conditions for 144 consecutive samples: -200 mG < (X-axis acceleration - X-axis adjustment value) < 200 mG, -300 mG < (Y-axis acceleration - Y-axis adjustment value) < 300 mG, and -400 mG < (Z-axis acceleration - Z-axis adjustment value) < 400 mG. That is, for example, the "certain range" for each axis is -200 mG < (X-axis acceleration - X-axis adjustment value) < 200 mG, -300 mG < (Y-axis acceleration - Y-axis adjustment value) < 300 mG, and -400 mG < (Z-axis acceleration - Z-axis adjustment value) < 400 mG. In this example, the "certain range" is set so that a free fall of one meter or more can be detected. The "certain range" may be changed as appropriate, and in order to accurately determine a free fall of one meter or more, a two-stage determination may be made, for example, by using a threshold corresponding to a height of 0.5 meters in combination. In this case, a fall from a height of 0.5 meters or less is not determined to be a fall.

[0047] If it is determined in S103 that a drop of the electronic device 10 has been detected, the step S104 is executed. If it is determined in S103 that a drop of the electronic device 10 has not been detected, the step S101 is executed again.

[0048] In S104, the control unit 21 acquires acceleration values ​​for each axis within a certain time period. Specifically, within a certain time period after receiving the fall signal, the control unit 21 receives a time-series signal of acceleration along three axes as a notification signal from the acceleration sensor 11 via the communication unit 23. For example, the time-series signal of acceleration along three axes within a certain time period is a signal indicating 80 acceleration values ​​for each axis acquired from the acceleration sensor 11 at 10-millisecond intervals. That is, for example, the "certain time period" during which acceleration values ​​along each axis are acquired is 800 milliseconds. The "certain time period" is preferably set to a short period to reduce power consumption, and corresponds to the time from a first point in time at which recording can be started to a second point in time at which sufficient acceleration value data can be acquired. For example, the first point in time is 200 milliseconds after the occurrence of an activity interrupt. Since the "certain time period" is 800 milliseconds, the second point in time is 1 second after the occurrence of the activity interrupt. The second point in time is preferably within a range of 500 milliseconds to 3 seconds, at which the amount of fluctuation in acceleration values ​​stabilizes. That is, the "fixed time" is preferably set to 300 milliseconds or more and 2800 milliseconds or less. More preferably, the "fixed time" is set to 500 milliseconds or more and 1 second or less. The "fixed time" and "period" may be changed as appropriate.

[0049] In S105, the control unit 21 performs high-pass filtering. Specifically, the control unit 21 performs high-pass filtering on the time-series signal received in S104. For example, assuming that y is the acceleration after filtering, x is the raw acceleration value, A is an attenuation coefficient of 0.1, k is the current sample data, and k-1 is the data from one sample ago, the control unit 21 performs high-pass filtering by calculating y[k] = A y[k-1] + A (x[k] - x[k-1]). However, since y[k-1] and x[k-1] do not exist for the first sample, y[k-1] = 0 and x[k-1] = 0. The "attenuation coefficient" may be changed as appropriate.

[0050] In S106, the control unit 21 calculates the sum of the resultant vector of the accelerations of the three axes. Specifically, the control unit 21 calculates the sum of the resultant vector of the accelerations of the three axes after the high-pass filter processing in S105.

[0051] In S107, the control unit 21 determines whether an impact requiring notification has been detected. Specifically, if the sum of the resultant vectors calculated in S106 is equal to or greater than a threshold, the control unit 21 determines that the electronic device 10 has received an impact due to being dropped from a specific height or greater while unpackaged. On the other hand, if the sum of the resultant vectors calculated in S106 is less than the threshold, the control unit 21 determines that the electronic device 10 has not received an impact due to being dropped from a specific height or greater while unpackaged. For example, the "threshold" is 8500 mG. In this example, the "threshold" is set so that an impact is detected when the electronic device 10 is dropped from a height of one meter or greater while unpackaged, but is not detected when the electronic device 10 is dropped from a height of one meter or less while packed. It is desirable that the detection rate for an impact when the electronic device 10 is dropped from a height of one meter or greater is 50% or greater. It is desirable that the detection rate for an impact when the electronic device 10 is dropped from a height of 0.5 meters or less while unpackaged is 10% or less. The "threshold" may be changed as appropriate, and may be set to make a judgment so that an impact is not detected even if the electronic device 10 is dropped from a height of 0.5 meters or less while unpackaged.

[0052] If it is determined in S107 that a shock requiring notification has been detected, step S108 is executed. If it is determined in S107 that a shock requiring notification has not been detected, step S101 is executed again.

[0053] In S108, the control unit 21 records the impact in the history. Specifically, the control unit 21 records the detected impact in the memory unit 22 or an external storage accessible via the communication unit 23. For example, the control unit 21 stores data indicating that the unpackaged electronic device 10 has fallen from a height of one meter or more, along with the date and time of the fall, in the memory unit 22 or in an external storage system via the communication unit 23. The control unit 21 may display a message indicating that the unpackaged electronic device 10 has fallen from a height of one meter or more on the display 12, output the message as audio from the speaker 13, or transmit the message to the user terminal via the communication unit 23. In other words, when the control unit 21 determines that the electronic device 10 has received an impact requiring notification, the control unit 21 may notify the user that the unpackaged electronic device 10 has fallen from a specific height or more.

[0054] As shown in FIG. 4 , when the electronic device 10 is dropped, one large impact occurs, followed by multiple smaller impacts until the electronic device 10 stabilizes. The inventors discovered that the frequency characteristics of the impact differ between when the electronic device 10 is dropped alone and when it is dropped in its packaged state, as shown in FIG. 5 . Therefore, the impact detection device 20 according to the present embodiment is configured to determine whether the electronic device 10 was dropped alone or in its packaged state based on the difference in frequency characteristics. Packaging boxes, such as cardboard boxes, Styrofoam boxes, and cardboard boxes containing Styrofoam as cushioning, have a lower elastic modulus than the pump itself, resulting in a longer impact duration and significant low-frequency components. Packaging boxes have high plasticity and energy absorption, which means they tend to stabilize quickly after being dropped.

[0055] In this embodiment, if the acceleration in three axes near 0G continues for a certain period of time, it is determined that the electronic device 10 has fallen by more than one meter. The frequency characteristics of the acceleration sensor 11 change depending on the hardness or rigidity of the object that received the impact, and this is used to distinguish between impacts in a packaged state and impacts in a standalone state. For example, FIG. 5 shows the frequency spectra obtained when the electronic device 10 is dropped one meter in both a packaged and standalone state. The horizontal axis represents frequency, and the vertical axis represents spectral intensity. This diagram shows that the spectrum obtained when the electronic device is dropped unpackaged, i.e., when the electronic device is dropped standalone, has a characteristic characteristic at higher frequencies compared to when the electronic device is dropped packaged.

[0056] According to this embodiment, it is possible to detect a fall or impact using a low-G acceleration sensor. In other words, the function of a high-G acceleration sensor can be realized using only a low-G acceleration sensor. As a result, costs can be reduced and it becomes easier to comply with RoHS.

[0057] A modification of the operation shown in FIG. 3 will be described with reference to FIG.

[0058] When the acceleration sensor 11 interrupts the impact detection device 20 while the electronic device 10 is in standby mode, the electronic device 10 switches to a power-on state and starts step S201. When the acceleration sensor 11 interrupts the impact detection device 20 while the electronic device 10 is in a power-on state, step S201 starts immediately.

[0059] In S201, the control unit 21 determines whether a free fall interrupt has been input from the acceleration sensor 11. The free fall interrupt corresponds to a fall signal indicating that the electronic device 10 has fallen. That is, the control unit 21 determines whether a fall signal has been received from the acceleration sensor 11 via the communication unit 23. For example, the free fall interrupt is an input signal from the acceleration sensor 11 to the impact detection device 20 when the acceleration along all three axes, i.e., the X-axis, Y-axis, and Z-axis, falls below ±312.5 mG ​​for 370 consecutive milliseconds. In this example, the condition for inputting the free fall interrupt is defined so that a free fall of one meter or more is detected. This condition may be changed as appropriate.

[0060] If it is determined in S201 that a free fall interrupt has been input, step S202 is executed. If it is determined in S201 that a free fall interrupt has not been input, step S201 is executed again.

[0061] In S202, the control unit 21 changes the setting to a single tap interrupt.

[0062] In S203, the control unit 21 waits for a first reference time. For example, the "first reference time" is 10 milliseconds. The "first reference time" may be changed as appropriate.

[0063] In S204, the control unit 21 determines whether a single tap interrupt has been input from the acceleration sensor 11 as a notification signal. The single tap interrupt is a signal indicating that an acceleration exceeding the single tap criterion has been measured. For example, the single tap interrupt is an input signal from the acceleration sensor 11 to the impact detection device 20 when the acceleration on any of the three axes, i.e., the X-axis, Y-axis, or Z-axis, exceeds ±8 G. That is, for example, the "single tap criterion" is 8 G. The "single tap criterion" may be changed as appropriate.

[0064] If it is determined in S204 that a single tap interrupt has been input, the process proceeds to step S205. If it is determined in S204 that a single tap interrupt has not been input, the process proceeds to step S206.

[0065] In S205, the control unit 21 increments the counter for counting the number of interrupts, and then the step S203 is executed again.

[0066] In S206, the control unit 21 determines whether a second reference time has elapsed since the previous interrupt. For example, the "second reference time" is 500 milliseconds. The "second reference time" may be changed as appropriate.

[0067] If it is determined in S206 that the second reference time has elapsed, step S207 is executed, whereas if it is determined in S206 that the second reference time has not elapsed, step S203 is executed again.

[0068] In S207, the control unit 21 determines whether a notification-requiring impact has been detected. Specifically, if the value of the interrupt counter exceeds the threshold within a certain period of time after receiving the drop signal, the control unit 21 determines that the electronic device 10 has received an impact due to being dropped from a specific height or higher while unpackaged. On the other hand, if the value of the interrupt counter does not exceed the threshold within a certain period of time after receiving the drop signal, the control unit 21 determines that the electronic device 10 has not received an impact due to being dropped from a specific height or higher while unpackaged. The "certain period of time" corresponds to the "second reference time." That is, for example, the "certain period of time" is 500 milliseconds. The "certain period of time" is preferably set to a short period of time to reduce power consumption, and corresponds to the time from a first point in time at which recording can be started to an arbitrary second point in time thereafter. For example, the "threshold" for the number of interrupts is 5 if the electronic device 10 was in standby mode before the start of step S201, and 8 if the electronic device 10 was powered on before the start of step S201. In this example, the "threshold" is set so that an impact is detected when the electronic device 10 is dropped from a height of one meter or more while unpackaged, but not when the electronic device 10 is dropped from a height of one meter or less while packaged. It is desirable that the impact detection rate when the electronic device 10 is dropped from a height of one meter or more while unpackaged is 50% or more. It is desirable that the impact detection rate when the electronic device 10 is dropped from a height of 0.5 meters or less while unpackaged is 10% or less. The "certain period of time" and "threshold" may be changed as appropriate.

[0069] If it is determined in S207 that a shock requiring notification has been detected, step S208 is executed, whereas if it is determined in S207 that a shock requiring notification has not been detected, step S209 is executed.

[0070] Step S208 is the same as step S108 shown in FIG. 3, and therefore a description thereof will be omitted.

[0071] In S209, the control unit 21 initializes the settings, and then step S201 is executed again.

[0072] As described above, the control unit 21 may increment a counter each time it receives a single tap interrupt as a notification signal, and determine whether the electronic device 10 has received an impact requiring notification based on whether the counter value exceeds a threshold within a certain period of time after receiving a free fall interrupt.

[0073] The present disclosure is not limited to the above-described embodiments. For example, two or more blocks shown in the block diagrams may be integrated, or one block may be divided. Two or more steps shown in the flowcharts may be executed in parallel or in a different order, instead of being executed in chronological order as described, depending on the processing capabilities of the device executing each step, or as needed. Other modifications are possible within the scope of the present disclosure.

[0074] REFERENCE SIGNS LIST 10 Electronic device 11 Acceleration sensor 12 Display 13 Speaker 20 Impact detection device 21 Control unit 22 Storage unit 23 Communication unit

Claims

1. A shock detection device comprising: a communication unit that communicates with an acceleration sensor provided in an electronic device; and a control unit that, when receiving a drop signal indicating that the electronic device has dropped from the acceleration sensor via the communication unit, refers to a notification signal received from the acceleration sensor via the communication unit within a certain time after receiving the drop signal, determines whether the electronic device has received an impact due to dropping from a specific height or more in an unpacked state, and records at least when it is determined that the electronic device has received the impact.

2. The shock detection device according to claim 1, wherein the control unit receives a time-series signal of three-axis acceleration as the notification signal, performs high-pass filter processing on the time-series signal, and determines whether the electronic device has received the impact based on whether the sum of the composite vectors of the three-axis acceleration after the high-pass filter processing is equal to or greater than a threshold value.

3. The shock detection device according to claim 1, wherein the control unit increments a counter each time a signal indicating that an acceleration having a magnitude exceeding a reference has been measured is received as the notification signal, and determines whether the electronic device has received the impact based on whether the value of the counter exceeds a threshold value within the certain time.

4. The shock detection device according to claim 1, wherein the drop signal is a time-series signal of three-axis acceleration, and is a signal in which the acceleration of each axis continuously takes a value within a certain range around 0G and less than 1G for a reference time or more.

5. The shock detection device according to claim 1, wherein when the control unit determines that the electronic device has received the impact, it notifies the user that the electronic device has dropped from a height equal to or greater than the specific height in an unpacked state.

6. An electronic device comprising the shock detection device according to any one of claims 1 to 5 and the acceleration sensor.

7. The electronic device according to claim 6, which is a medical device.

8. When a computer that communicates with an acceleration sensor provided in an electronic device receives a drop signal indicating that the electronic device has dropped from the acceleration sensor, the computer refers to a notification signal received from the acceleration sensor within a certain period of time after receiving the drop signal, and determines whether the electronic device has received an impact due to dropping from a specific height or more in an unpacked state; and the computer includes recording at least when it is determined that the electronic device has received the impact. An impact detection method.

9. A computer that communicates with an acceleration sensor provided in an electronic device, when receiving a drop signal indicating that the electronic device has dropped from the acceleration sensor, refers to a notification signal received from the acceleration sensor within a certain period of time after receiving the drop signal, and determines whether the electronic device has received an impact due to dropping from a specific height or more in an unpacked state; and executes an operation including recording at least when it is determined that the electronic device has received the impact. An impact detection program.

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