Hand-held terminal and drop detection method of hand-held terminal
By using an accelerometer to detect the free fall motion of the handheld terminal in low-power mode and employing an interrupt triggering mechanism to wake up the on-chip system, the system achieves accurate detection of fall events in sleep mode, solving the problem of excessive power consumption and extending the device's usage time.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-14
AI Technical Summary
Existing handheld devices require real-time monitoring when detecting drop events, which leads to rapid battery drain and shortens the device's continuous usage time.
An accelerometer is used to detect free fall motion in a low-power sleep mode. An interrupt triggering mechanism wakes up the on-chip system for accurate detection. The start and end times are recorded in stages, and the fall height is calculated by combining physical formulas.
Accurately detects drop events in sleep mode, reducing overall device operating time, lowering battery consumption, extending device lifespan, and providing reliable drop information support.
Smart Images
Figure CN121857955A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of handheld terminal technology, and in particular to a handheld terminal and a drop detection method for the handheld terminal. Background Technology
[0002] With the rapid development of mobile devices and the continuous improvement of people's living standards, the use of various handheld terminals is becoming more and more widespread. Handheld terminals have become an indispensable communication tool in people's production and life.
[0003] In the after-sales maintenance of handheld terminals, in order to monitor the cause of failure caused by drop damage, it is often necessary to add a sensor to the handheld terminal to monitor in real time whether the handheld terminal has been dropped and the drop height.
[0004] However, real-time monitoring of device status requires both the handheld device and the sensors to be constantly operational, which consumes a significant amount of battery power and greatly shortens the continuous usage time of the handheld device. Summary of the Invention
[0005] This application provides a handheld terminal and a drop detection method for the handheld terminal, so as to provide a technical solution that can detect free fall events even when the handheld terminal is in sleep mode, thereby saving power consumption.
[0006] In a first aspect, this application provides a drop detection method for a handheld terminal, applied to the system-on-a-chip of the handheld terminal; the method includes: When the handheld terminal is in sleep mode, the system-on-chip and the accelerometer are both controlled to be in low-power sleep mode. In response to the freefall interruption signal sent by the accelerometer, the on-chip system enters the working state from the low-power sleep mode based on the freefall interruption signal, and records the time of receiving the freefall interruption information as the start time of the freefall interruption event. The acceleration signal sent by the acceleration sensor is received through a preset bus, and the acceleration signal is monitored. When the current acceleration is detected to be greater than the ground contact threshold, the current time is recorded as the end time of the free fall interruption event. Based on the start time and the end time, free fall information is determined and the free fall information is output to the input / output device of the handheld terminal.
[0007] In one optional embodiment, the accelerometer includes a sensor front end; the sensor front end is used to sense the motion state of the handheld terminal in real time when the accelerometer is in a dormant state, and to generate a free fall simulation signal when the handheld terminal is detected to enter a free fall motion mode. The free fall interruption signal is an event obtained by performing a first processing on the free fall simulation signal.
[0008] In one optional implementation, the first process includes: The analog-to-digital signal conversion of the free-fall simulation signal is performed to obtain the free-fall digital signal; The free-fall digital signal is filtered to obtain a filtered free-fall digital signal; wherein, the free-fall digital signal is the free-fall interruption signal.
[0009] In one optional implementation, the step of receiving the acceleration signal sent by the acceleration sensor via a preset bus, monitoring the acceleration signal, and recording the current time as the end time of the free fall interruption event when the current acceleration is detected to be greater than the ground contact threshold includes: A data transmission link with the accelerometer is established through the preset bus to continuously receive acceleration signals sent by the accelerometer; wherein, the acceleration signal is an XYZ axis acceleration signal; In one optional implementation, determining free fall information based on the start time and the end time, and outputting the free fall information to the input / output device of the handheld terminal includes: The total free fall duration of the handheld terminal is obtained based on the end time, the start time, and the free fall trigger cycle of the accelerometer. The free fall height of the handheld terminal is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free-fall information is transmitted to the input / output device of the handheld terminal.
[0010] Secondly, this application provides a handheld terminal, the terminal including: a system-on-a-chip, an accelerometer, and an input / output device; The on-chip system is used to control itself and the accelerometer to be in a low-power sleep mode when the handheld terminal is in a sleep state. The accelerometer is used to detect the free fall motion of the handheld terminal in low-power sleep mode, enter the working state, generate the free fall interrupt signal of the handheld terminal, and send it to the system on chip. The on-chip system is used to respond to the free fall interruption signal sent by the accelerometer to the handheld terminal, enter the working state from the low power sleep mode, and record the time of receiving the free fall interruption information as the start time of the free fall interruption event. The on-chip system is used to receive the acceleration signal sent by the acceleration sensor through a preset bus, monitor the acceleration signal, and when the current acceleration is detected to be greater than the ground contact threshold, record the current time as the end time of the free fall interruption event. The on-chip system determines the free fall information based on the start time and the end time, and outputs the free fall information to the input / output device; The input / output device displays the free fall information to the user in an adaptive manner.
[0011] In one alternative implementation, the accelerometer includes a sensor front end, an analog-to-digital converter, a filter, and an input / output interface; The sensor front end is used to sense the motion state of the handheld terminal in real time when the accelerometer is in a dormant state, and to generate a free fall simulation signal when the handheld terminal is detected to enter a free fall motion mode. The analog-to-digital converter is used to convert the free-fall analog signal into a free-fall digital signal; The filter is used to filter the free-fall digital signal to obtain a filtered free-fall digital signal; wherein, the free-fall digital signal is the free-fall interruption signal; The input / output interface is used to send the free fall interrupt signal to the on-chip system.
[0012] In one alternative implementation, the system-on-a-chip includes a preset bus and a central processing unit; The input / output interface of the accelerometer is used to send the free fall interruption signal to the central processing unit via the preset bus; The central processing unit is used to: receive acceleration signals output by the acceleration sensor via the preset bus; wherein the acceleration signals are XYZ axis acceleration signals; The received XYZ axis acceleration signals are analyzed to extract the acceleration values in each axis direction. The central processing unit analyzes the received XYZ axis acceleration signals and extracts the acceleration values in each axis direction of the XYZ axis acceleration signals. The acceleration values in each axis direction are compared with a preset ground contact threshold. If the acceleration value in any of the axes directions is greater than the ground contact threshold, the handheld terminal is determined to have made contact with the ground, and the current time is recorded as the end time of the free fall interruption event.
[0013] In one alternative implementation, the central processing unit is specifically used for: The total free fall duration of the handheld terminal is obtained based on the end time, the start time, and the free fall trigger cycle of the accelerometer. The free fall height of the handheld terminal is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free-fall information is transmitted to the input / output device of the handheld terminal.
[0014] In one optional implementation, the system-on-a-chip further includes a power management module, and the handheld terminal further includes a battery; the power management module is connected to the central processing unit, the battery, and the accelerometer, respectively. The central processing unit is also used to send a sleep control signal to the power management module when the handheld terminal is in a sleep state; The power management module is used to adjust the electrical parameters output to the central processing unit and the accelerometer according to the sleep signal, so that both the central processing unit and the accelerometer are in a low-power sleep mode. The central processing unit is also configured to respond to a free fall interruption signal from the handheld terminal sent by the accelerometer, and send a working control signal to the power management module when the free fall interruption signal is greater than the interruption threshold. The power management module is used to adjust the power supply strategy according to the working control signal, and provide working voltage to the central processing unit and the accelerometer, so that the central processing unit and the accelerometer enter the working state from the low-power sleep mode.
[0015] Based on the above, this application provides a drop detection method for a handheld terminal, applied to the system-on-a-chip (SoC) of the handheld terminal. The method includes: when the handheld terminal is in a sleep state, controlling both the SoC and the accelerometer to be in a low-power sleep mode; responding to a freefall interruption signal sent by the accelerometer, when the freefall interruption signal is greater than an interruption threshold, the SoC enters a working state from the low-power sleep mode and records the time of receiving the freefall interruption information as the start time of the freefall interruption event; receiving the acceleration signal sent by the accelerometer through a preset bus, monitoring the acceleration signal, and when the current acceleration is detected to be greater than a ground contact threshold, recording the current time as the end time of the freefall interruption event; determining freefall information based on the start time and the end time, and outputting the freefall information to the input / output device of the handheld terminal.
[0016] Based on this, in this embodiment, when the handheld terminal is in sleep mode, both the on-chip system and the accelerometer are in low-power sleep mode. This design avoids unnecessary power consumption during non-use periods (such as standby mode). The on-chip system only enters the working state from low-power sleep mode when the accelerometer detects the handheld terminal in free fall and sends an interrupt signal greater than the interrupt threshold. Compared to real-time device status detection, this reduces the overall operating time of the device, thereby effectively reducing battery consumption, extending the continuous use time of the handheld terminal, and improving the user experience.
[0017] Furthermore, in this embodiment, an accelerometer first sends a freefall interruption signal. After the on-chip system responds, it records the start time and then continuously monitors the acceleration signal. When the current acceleration is detected to be greater than the ground contact threshold, the end time is recorded. Freefall information is determined based on these two times. This phased detection method can accurately capture the entire process of the handheld terminal from the start of the fall to the ground, accurately determine whether a fall event has occurred, and obtain fall-related information, providing reliable data support for subsequent analysis of the causes of failure due to fall damage.
[0018] Based on the above description, this application provides a technical solution that can detect free fall events even when the handheld terminal is in sleep mode, thereby saving power consumption. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of a handheld terminal provided in an embodiment of this application; Figure 2 The flowchart of a drop detection method for a handheld terminal provided in this application embodiment Figure 1 ; Figure 3 The flowchart of a drop detection method for a handheld terminal provided in this application embodiment Figure 2 ; Figure 4 This is a schematic diagram illustrating the working process of an analog-to-digital converter provided in an embodiment of this application; Figure 5 This application provides a schematic diagram of the magnitude and direction of an acceleration signal on the XYZ axes. Figure 6 This is an example diagram showing the acceleration change and interruption change of a MEMS sensor under a single free fall, as provided in an embodiment of this application. Detailed Implementation
[0020] With the rapid development of mobile devices and the continuous improvement of people's living standards, the use of various handheld terminals is becoming more and more widespread. Handheld terminals have become an indispensable communication tool in people's production and life.
[0021] In the after-sales maintenance of handheld terminals, in order to monitor the cause of failure caused by drop damage, it is often necessary to add a sensor to the handheld terminal to monitor in real time whether the handheld terminal has been dropped and the drop height.
[0022] However, real-time monitoring of device status requires both the handheld device and the sensors to be constantly operational, which consumes a significant amount of battery power and greatly shortens the continuous usage time of the handheld device.
[0023] Based on this, the technical concept of this application embodiment is as follows: An interrupt-triggered mechanism is adopted for detection. The accelerometer continuously monitors with low power consumption. When the change in free-fall acceleration reaches an interrupt threshold, a signal is generated to wake up subsequent processes. A reasonable threshold is set to avoid false alarms and missed detections. The on-chip system is designed with a low-power mode. When idle, the on-chip system and sensor enter sleep mode. An interrupt signal triggers a tiered wake-up process: first, a preliminary judgment is made in an intermediate state; only after confirming a fall is the system fully awakened. This reduces overall power consumption and extends the battery life of the handheld terminal.
[0024] The technical solutions shown in this application will now be described in detail through specific embodiments. It should be noted that the following embodiments may exist independently or in combination with each other; for identical or similar content, the description will not be repeated in different embodiments.
[0025] Firstly, referring to Figure 1 This application provides a handheld terminal 10, which includes a system-on-a-chip, an accelerometer 200, and input / output devices.
[0026] The system-on-a-chip is used to control itself and the accelerometer 200 to be in a low-power sleep mode when the handheld terminal 10 is in a sleep state.
[0027] The accelerometer 200 is used to detect the free fall motion of the handheld terminal 10 in low-power sleep mode, enter the working state, generate the free fall interrupt signal of the handheld terminal 10, and send it to the system on chip.
[0028] The on-chip system is used to respond to the free fall interruption signal sent by the accelerometer 200 to the handheld terminal 10, enter the working state from the low power sleep mode, and record the time of receiving the free fall interruption information as the start time of the free fall interruption event.
[0029] The on-chip system is used to receive the acceleration signal sent by the acceleration sensor 200 through the preset bus 302, monitor the acceleration signal, and when the current acceleration is detected to be greater than the ground contact threshold, record the current time as the end time of the free fall interruption event.
[0030] The on-chip system determines the free fall information based on the start time and the end time, and outputs the free fall information to the input / output device 500.
[0031] The input / output device displays the free fall information to the user in an adaptive manner.
[0032] In this embodiment, the System-on-Chip (SoC) is the control and computing center of the terminal, undertaking functions such as power mode management, interrupt response, data parsing and computation, and result output. It is the control core of the entire drop detection process. The accelerometer 200 is the front-end sensing core of the drop event, which can realize the detection of free fall motion and the generation of interrupt signals in a low-power state, without having to operate at high power throughout the process. The input / output device is the human-computer interaction carrier, used to receive the free fall information output by the SoC and present it in a user-recognizable form (such as screen text display, indicator light prompts, etc.).
[0033] In this embodiment, when the handheld terminal 10 is in a non-use sleep state, the on-chip system actively controls itself and the accelerometer 200 to enter a low-power sleep mode simultaneously. The on-chip system stops high-power computing operations, and the accelerometer 200 retains only the front-end sensing function. Both operate with extremely low power consumption, significantly reducing the power consumption of the battery 400 and solving the problem of extremely fast power consumption in traditional solutions for all-time monitoring.
[0034] In this embodiment, the accelerometer 200, even in low-power sleep mode, continues to monitor the terminal's motion state through its front-end sensing module. When the handheld terminal 10 falls and enters freefall motion mode, the sensor immediately identifies this motion characteristic. The sensor switches from low-power sleep mode to operating mode, processes the collected motion signal, generates a freefall interrupt signal, and sends this signal to the on-chip system. In other words, in this embodiment, the accelerometer 200 only switches to operating mode when it detects valid freefall motion, avoiding meaningless high-power operation.
[0035] Upon receiving the freefall interrupt signal from the accelerometer 200, the on-chip system immediately wakes up from low-power sleep mode and switches to normal operation. Simultaneously, the on-chip system precisely records the moment the interrupt signal is received, defining it as the start time of the freefall interrupt event; this moment is the point at which the terminal begins to fall.
[0036] After the on-chip system wakes up, it establishes a stable data link with the accelerometer 200, which has entered the working state, through a preset high-speed communication bus (such as I2C / I3C / SPI). The accelerometer 200 continuously outputs acceleration signals (including data on the magnitude and direction changes of the terminal's velocity in three-dimensional space) to the on-chip system, providing real-time data support for subsequent ground contact determination.
[0037] The on-chip system analyzes the received acceleration signal in real time, extracting the acceleration values in each axis direction. The on-chip system compares the real-time acceleration values with a preset ground contact threshold (this threshold is the characteristic acceleration value at the moment the terminal touches the ground, typically a large positive number, such as 80 m / s²). When the acceleration value on any axis is detected to be greater than the ground contact threshold, it is determined that the handheld terminal 10 has touched the ground; simultaneously, this moment is recorded as the end time of the free fall interruption event.
[0038] The on-chip system uses the start and end times as parameters and combines them with the physical formulas of free fall to calculate the terminal's drop height. The on-chip system integrates the drop event state and drop height into structured free fall information.
[0039] The on-chip system transmits the integrated freefall information to the input / output devices. The input / output devices then present the information to the user in an adapted manner (e.g., displaying on the screen that a fall event has occurred, with a fall height of XX meters), facilitating after-sales maintenance personnel to analyze the cause of the fault or allowing the user to understand the extent of damage to the terminal.
[0040] Based on this, in this embodiment, when the handheld terminal 10 is in sleep mode, both the on-chip system and the accelerometer 200 are in low-power sleep mode. This design avoids unnecessary power consumption during non-use periods (such as standby mode). The on-chip system only enters the working state from the low-power sleep mode when the accelerometer 200 detects the handheld terminal 10 in free fall and sends an interrupt signal that is greater than the interrupt threshold. Compared to real-time detection of device status, this reduces the overall working time of the device, thereby effectively reducing battery power consumption, extending the continuous use time of the handheld terminal 10, and improving the user experience.
[0041] Furthermore, in this embodiment, the accelerometer 200 first sends a freefall interruption signal. After the on-chip system responds, it records the start time and then continuously monitors the acceleration signal. When the current acceleration is detected to be greater than the ground contact threshold, the end time is recorded. Based on these two times, the freefall information is determined. This phased detection method can accurately capture the entire process of the handheld terminal 10 from the start of its fall to its ground contact, accurately determine whether a fall event has occurred, and obtain fall-related information, providing reliable data support for subsequent analysis of the causes of failures caused by fall damage.
[0042] Based on the above description, this application provides a technical solution that can detect free fall events even when the handheld terminal 10 is in sleep mode, so as to save power consumption.
[0043] In one optional implementation, the accelerometer 200 includes a sensor front end 201, an analog-to-digital converter 202, a filter 203, and an input / output interface 204. The sensor front end 201 is used to sense the motion state of the handheld terminal 10 in real time when the accelerometer 200 is in a dormant state, and to generate a free fall simulation signal when the handheld terminal 10 is detected to enter a free fall motion mode. The analog-to-digital converter 202 is used to convert the free-fall analog signal into a free-fall digital signal; The filter 203 is used to filter the free-fall digital signal to obtain a filtered free-fall digital signal; wherein, the free-fall digital signal is the free-fall interruption signal; The input / output interface 204 is used to send the free fall interruption signal to the on-chip system.
[0044] In this embodiment, the sensor front-end 201 is based on microelectromechanical systems (MEMS) technology and consists of a micromechanical movable mass block, fixed electrodes, and a support structure. When the accelerometer 200 is in a low-power sleep mode, the sensor front-end 201 does not need to switch to a high-power state; motion sensing can be achieved solely through the physical characteristics of the micromechanical structure. When the handheld terminal 10 enters free-fall motion mode, the terminal is only subject to gravity, causing a change in the relative position between the movable mass block and the fixed electrodes, resulting in regular fluctuations in the capacitance value between them. The front-end circuit converts these capacitance fluctuations into a continuously changing free-fall analog signal (voltage signal), completing the first conversion from motion state to electrical signal.
[0045] The analog-to-digital converter 202 samples, quantizes, and encodes the free-fall analog signal output from the sensor front-end 201. It discretizes the continuous analog voltage signal using a preset sampling frequency (e.g., 1kHz), then maps the sampled voltage values into binary digital quantities, ultimately outputting a free-fall digital signal. It should be understood that because the analog signal output from the sensor front-end 201 is susceptible to electromagnetic interference and cannot be directly processed by the digital circuitry of the system-on-a-chip (SoC), the analog-to-digital converter digitizes the signal, providing a computational signal carrier for subsequent filtering and judgment.
[0046] Filter 203 is used to filter the free-fall digital signal output from the analog-to-digital converter, removing high-frequency noise (such as interference signals generated by daily shaking of the terminal) and retaining effective characteristic signals related to free-fall motion. Filter 203 has a built-in preset free-fall trigger threshold (e.g., an acceleration threshold of 4.9 m / s²) and trigger period (e.g., 10 ms) to continuously monitor the filtered digital signal; a free-fall interrupt signal (level trigger signal) is generated only when the signal meets the acceleration threshold condition for 10 consecutive ms. Based on this, false triggering caused by transient interference signals can be avoided, ensuring the effectiveness of the interrupt signal.
[0047] The input / output interface 204 integrates a GPIO port, which sends the free fall interrupt signal generated by the filter 203 to the CPU of the on-chip system through the GPIO port, realizing low-latency wake-up command transmission.
[0048] Based on the above description, the sensor front-end 201 relies solely on the physical structure to sense motion in sleep mode, without needing to activate the computing module. All processing steps before the interrupt signal is generated are low-power logic operations, significantly reducing the sensor's standby power consumption compared to traditional all-time acquisition and all-time transmission solutions. Combined with the on-chip system's sleep-wake mechanism, the overall power consumption of the terminal is reduced from both the sensing and computing ends, effectively extending the continuous usage time of the handheld terminal 10.
[0049] Analog-to-digital conversion enables digital processing of signals, solving the problem of analog signals being susceptible to interference; the filtering stage further removes noise and retains effective motion characteristics; the dual judgment mechanism of threshold and period avoids false triggering in non-drop scenarios such as daily shaking and slight collisions of the terminal.
[0050] The standardized GPIO can be directly adapted to the on-chip system architecture of mainstream handheld terminals 10, without the need for additional dedicated communication modules; the sensor integrates a complete signal processing link, eliminating the need for the on-chip system to participate in front-end signal calculations, thus reducing the consumption of terminal computing power.
[0051] This sensor architecture is compatible with various handheld devices such as mobile phones, tablets, and portable industrial control terminals, and has strong technological promotion value.
[0052] Furthermore, the low latency of the GPIO port ensures that the interrupt signal can quickly wake up the on-chip system, avoiding the loss of critical time points in the drop event; the high-speed transmission capability of the bus interface meets the high sampling rate transmission requirements of subsequent acceleration data, providing data support for accurate calculation of the drop height.
[0053] Optionally, the system-on-a-chip includes a preset bus 302 and a central processing unit 301.
[0054] The input / output interface 204 of the acceleration sensor 200 is used to send the free fall interruption signal to the central processing unit 301 via the preset bus 302.
[0055] The central processing unit 301 is used to: receive the acceleration signal output by the acceleration sensor 200 through the preset bus 302; wherein the acceleration signal is an XYZ axis acceleration signal.
[0056] The received XYZ axis acceleration signals are analyzed to extract the acceleration values in each axis direction.
[0057] The central processing unit 301 analyzes the received XYZ axis acceleration signals and extracts the acceleration values in each axis direction of the XYZ axis acceleration signals.
[0058] The acceleration values in each axis direction are compared with a preset ground contact threshold. If the acceleration value in any of the axes is greater than the ground contact threshold, the handheld terminal 10 is determined to have made contact with the ground, and the current time is recorded as the end time of the free fall interruption event.
[0059] In this embodiment, the preset bus 302 adopts a standardized communication bus (such as I2C / I3C / SPI), which is a high-speed data interaction channel between the on-chip system and the accelerometer 200, used for continuous sampling and transmission of acceleration signals; its standardized characteristics can be adapted to the mainstream accelerometer 200 hardware interface, reducing the complexity of hardware integration.
[0060] The central processing unit 301 (CPU) is the core of the on-chip system for computation and control. It is responsible for receiving and parsing various signals transmitted by the accelerometer 200, executing the ground contact determination logic, and recording key timing parameters.
[0061] In this embodiment, when the central processing unit 301 responds to the interrupt signal and controls the on-chip system to enter the working state, the accelerometer 200 synchronously switches to the working mode and continuously outputs XYZ axis acceleration signals to the central processing unit 301 through the preset bus 302. This signal contains the real-time acceleration values of the handheld terminal 10 in the three-dimensional space X, Y, and Z axes (such as gravitational acceleration components and motion acceleration components), which is the data basis for ground contact determination.
[0062] The central processing unit 301 can perform noise reduction and normalization calibration on the received XYZ axis acceleration signals. The noise reduction operation can eliminate electromagnetic interference introduced during transmission and thermal noise of the sensor itself; the normalization calibration, based on the sensor's factory parameters, converts the digital signal into a physically meaningful acceleration value, solving the problem of signal amplitude differences between different sensors.
[0063] The preprocessed signal is analyzed to separate and extract the real-time acceleration values corresponding to the X, Y, and Z axes. Since the attitude of the handheld terminal 10 during a drop is random, and the drop direction may correspond to any axis, the three-axis data needs to be extracted and monitored independently to avoid missed detections due to attitude issues.
[0064] Based on the extracted three-axis acceleration values, the central processing unit 301 retrieves a preset ground contact threshold (this threshold is the impact acceleration characteristic value of the handheld terminal 10 at the moment of ground contact, usually a value much greater than the acceleration due to gravity, and can be flexibly configured according to the terminal's hardware material and structural characteristics). The extracted real-time acceleration values of the X, Y, and Z axes are compared one by one with the ground contact threshold. If the acceleration value of any axis is greater than the preset ground contact threshold, it can be determined that the handheld terminal 10 has contacted the ground, because the terminal generates instantaneous impact acceleration upon ground contact, and this acceleration will show a significant peak value in at least one axis. When the ground contact determination condition is met, the central processing unit 301 immediately records the current moment and defines it as the end moment of the free fall interruption event. The time difference between this moment and the previously recorded start moment is the time parameter for subsequent calculation of the free fall height.
[0065] Based on the above description, this application embodiment solves the problem of randomness in the drop posture of the handheld terminal 10 by monitoring and comparing the XYZ three-axis acceleration, ensuring that the moment of impact can be accurately determined regardless of the angle at which the terminal hits the ground, thus avoiding missed detection.
[0066] In some examples, the central processing unit 301 is specifically used for: The total free fall duration of the handheld terminal 10 is obtained based on the end time, the start time, and the free fall trigger cycle of the acceleration sensor 200. The free fall height of the handheld terminal 10 is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free fall information is transmitted to the input / output device of the handheld terminal 10.
[0067] In this embodiment of the application, the central processing unit 301 is based on: The start time of the free fall interruption event: that is, the moment when the CPU receives the free fall interrupt signal, which corresponds to the starting time point when the terminal's falling motion is detected by the sensor; The end time of the free fall interruption event: that is, the moment when the CPU detects that the acceleration value is greater than the ground contact threshold, which corresponds to the time when the terminal touches the ground; Free fall trigger period: This is the minimum duration (e.g., 10ms) for the accelerometer 200 to determine a free fall event. This parameter represents the delay time from when the sensor recognizes the motion characteristics to when it generates an interrupt signal.
[0068] The central processing unit 301 derives the fall height based on the physical free fall motion model and the calculated total free fall time.
[0069] The free fall information includes: event status information, which records the determination result of the free fall event occurring on the handheld terminal 10; Key timing parameters: total free fall duration, trigger period, and timestamps for start and end times; Quantitative test data: The final calculated free fall height and the peak acceleration value at the moment of impact.
[0070] The central processing unit 301 transmits the integrated structured free-fall information to the input / output device of the handheld terminal 10 via the on-chip system's internal data bus. During transmission, the CPU can adapt the data format according to the type of input / output device: for example, outputting visual information of text and numerical values to the screen, or outputting a standardized data file that can be stored to the data interface, ensuring that the information can be presented in a user-friendly manner.
[0071] In one optional implementation, the system-on-a-chip further includes a power management module 303, and the handheld terminal 10 further includes a battery 400; the power management module 303 is connected to the central processing unit 301, the battery 400 and the accelerometer 200 respectively. The central processing unit 301 is also used to send a sleep control signal to the power management module 303 when the handheld terminal 10 is in a sleep state; The power management module 303 is used to adjust the electrical parameters output to the central processing unit 301 and the accelerometer 200 according to the sleep signal, so that both the central processing unit 301 and the accelerometer 200 are in a low-power sleep mode. The central processing unit 301 is also used to respond to the free fall interruption signal of the handheld terminal 10 sent by the acceleration sensor 200, and send a working control signal to the power management module 303 based on the free fall interruption signal. The power management module 303 is used to adjust the power supply strategy according to the working control signal, and provide working voltage to the central processing unit 301 and the accelerometer 200, so that the central processing unit 301 and the accelerometer 200 enter the working state from the low power sleep mode.
[0072] In this embodiment, the power management module 303 serves as the power distribution hub between the battery 400 and the various core components of the terminal, establishing bidirectional communication and power supply links with the battery 400, the central processing unit 301, and the accelerometer 200, respectively. Connection to battery 400: Responsible for collecting the voltage and charge status of battery 400, and receiving the input power from battery 400; Connection with the central processing unit 301: On the one hand, it receives the sleep / work control signal issued by the CPU, and on the other hand, it outputs voltage and current to the CPU that are adapted to its working mode; Connection with accelerometer 200: Adjust the electrical parameters output to the sensor according to the control command to realize the switching between low-power sleep mode and normal operation mode of the sensor.
[0073] Specifically, when the handheld terminal 10 is in a non-use sleep state, the central processing unit 301 actively sends a sleep control signal to the power management module 303, which carries a clear power consumption mode instruction.
[0074] After receiving the sleep control signal, the power management module 303 immediately adjusts the electrical parameters output to the central processing unit 301 and the accelerometer 200. For the central processing unit 301: reduce the supply voltage to the low power threshold, cut off the power supply to non-core computing units, and only retain the power supply to the interrupt signal receiving module; For the accelerometer 200: power is supplied only to the micromechanical sensing structure and signal preprocessing unit of the sensor front end 201, and the high-speed data transmission and complex computing modules of the sensor are turned off to ensure that the sensor maintains motion sensing capability with minimal power consumption.
[0075] Ultimately, the central processing unit 301 and the accelerometer 200 enter a low-power sleep mode, significantly reducing the standby power consumption of the terminal.
[0076] The power management module 303 adjusts the power supply strategy according to the working control signal to complete the mode switching from low power consumption to normal operation: For the central processing unit 301: restore the power supply voltage to the normal operating threshold, provide sufficient power to the CPU's arithmetic unit and data receiving unit, and support the CPU to perform tasks such as acceleration signal analysis, ground contact determination, and altitude calculation; For the accelerometer 200: Power is supplied to all modules of the sensor, including the analog-to-digital converter, filter 203, and input / output interface 204, to ensure that the sensor can output complete XYZ axis acceleration signals.
[0077] The response latency of this process is controlled at the microsecond level, ensuring that the central processing unit 301 can capture the key timing parameters of the drop event in a timely manner and avoid data loss.
[0078] Based on the above description, the power management module 303 does not require complex calculations to respond to the sleep control signal / work control signal. It relies on the voltage switching logic at the hardware level, and the response delay is much lower than that of the software control scheme. It ensures that the central processing unit 301 can immediately receive the acceleration signal after being woken up, accurately record the start and end times, and provide reliable timing data support for high-precision computing.
[0079] Furthermore, the power management module 303 can monitor the status of the battery 400 in real time and dynamically adjust the power supply parameters according to the remaining power of the battery 400. For example, in low power scenarios, it can appropriately reduce the power supply of the working mode to prioritize the normal operation of the drop detection function; at the same time, it can avoid problems such as CPU calculation errors and sensor signal distortion caused by voltage fluctuations, thereby improving the overall operational stability of the terminal.
[0080] Reference Figure 1 The following is a detailed description of the structure of the aforementioned handheld terminal: Handheld Terminal 10: It is a small electronic device that integrates multiple functions such as data acquisition, processing and communication. It is mainly composed of MEMS sensors (200), system on chip (SoC) (300), battery (400), input and output devices such as screen / buttons (500).
[0081] The accelerometer 200, a MEMS accelerometer, is a miniature sensor manufactured using Micro-Electro-Mechanical Systems (MEMS) technology. It is used to detect and measure physical quantities such as acceleration, tilt, and vibration. Its primary function is to detect the free-fall motion and acceleration signals of an object. Free fall refers to the motion of an object under the influence of gravity alone, typically manifested as the process of an object falling downwards. Acceleration signals refer to the changes in the magnitude and direction of an object's velocity along the XYZ axes.
[0082] The sensor front end 201 detects acceleration by measuring the capacitance change between the micromechanical movable mass block and the fixed electrode. The circuit outputs the capacitance change as a voltage signal; one end of the signal is connected to an analog-to-digital converter (ADC).
[0083] The analog-to-digital converter (ADC) 202 acquires analog signals at fixed time intervals through a switching circuit, converting continuously changing analog signals (such as voltage) into binary digital codes for output (digital signals). Its output is connected to a filter, transmitting the digital signal to the filter for filtering.
[0084] Filter 203's primary function is to process digital signals. It filters out noise, retains useful motion information, and triggers a freefall interrupt when the output signal exceeds a preset threshold. One end is connected to an input / output interface, accepting threshold settings from the System-on-Chip (SoC) and outputting freefall interrupts (GPIO / INT) and acceleration information to the SoC.
[0085] Input / output interface 204, GPIO is a general-purpose digital input / output port that allows MEMS sensors to interact with the System-on-a-Chip (SoC) via level signals. Here, it is mainly used to receive threshold setting information input from the SoC and output detected free-fall interrupt information (GPIO / INT) to the SoC. I2C, I3C, and SPI are three different communication bus technologies that meet the high sampling rate and low latency requirements of embedded devices such as handheld terminals. They are used for high-speed data transmission, primarily transmitting acceleration information (the magnitude and direction changes of an object's velocity along the XYZ axes) to the SoC.
[0086] The System-on-Chip 300 (SoC) integrates all the key components of a computer system (such as CPU, I2C / I3C / SPI bus, power management module, etc.) onto a single chip. Its main functions are to improve integration, reduce power consumption, and reduce size.
[0087] The Central Processing Unit (CPU) 301 is the computing and control core of the System-on-Chip (SoC). Composed of very large-scale integrated circuits, it is responsible for executing program instructions, processing data, and controlling system operation. One end connects to the input / output interface of the MEMS sensor via GPIO, used to send free-fall trigger threshold information and receive free-fall interrupt triggers; another end connects to the I2C / I3C / SPI bus, responsible for receiving acceleration information (the magnitude and direction of the object's velocity along the XYZ axes) from the MEMS sensor; the other end connects to the power management module, responsible for managing the power supply and sleep / wake-up functions of the entire SoC and MEMS sensor.
[0088] The default bus 302, an I2C / I3C / SPI bus, serves as the common communication trunk connecting all components of the handheld terminal, responsible for data transmission, exchange, and logic control. The CPU can send data to the controlled components via the bus, and the controlled components can also send data to the CPU via the bus; however, whether the controlled components receive or send data is controlled by the CPU. One end of the bus connects to the CPU, and the other end connects to the MEMS sensor.
[0089] The power management module 303 is a hardware / software component within the System-on-Chip (SoC) responsible for power distribution, power consumption control, and state transitions. Its main functions include: regulating voltage / current output, managing different operating modes (sleep / wake-up), monitoring battery status, and optimizing system energy efficiency. One end connects to the battery to monitor its status; another end connects to the CPU to power the SoC, manage different operating modes, and optimize system energy efficiency; and the third end connects to the MEMS sensor to regulate voltage / current output and manage different operating modes.
[0090] Battery 400 is a device that converts chemical energy into electrical energy to provide power to handheld terminals. One end of it is connected to the power management module.
[0091] Input / output device 500, including screen / buttons, etc., is a hardware component used for user interaction to realize human-computer interaction and data transmission.
[0092] Secondly, referring to Figure 2 This application provides a drop detection method for a handheld terminal, applied to the system-on-a-chip of the handheld terminal; the method includes: S1, when the handheld terminal is in sleep mode, control the on-chip system and the accelerometer to both be in low-power sleep mode.
[0093] In this embodiment, the CPU sends a sleep control signal to the power management module; the power management module adjusts the power supply parameters to reduce the voltage and current output to the CPU and the accelerometer; the CPU shuts down non-core computing units, retaining only the interrupt signal receiving function; the accelerometer shuts down the high-speed data transmission module, retaining only the motion sensing function of the front-end micromechanical structure; and finally, the on-chip system and the accelerometer synchronously enter a low-power sleep mode.
[0094] S2, in response to the free fall interrupt signal sent by the accelerometer, the on-chip system enters the working state from the low power sleep mode based on the free fall interrupt signal, and records the time of receiving the free fall interrupt information as the start time of the free fall interrupt event.
[0095] In this embodiment, the on-chip system captures the freefall interrupt signal sent by the accelerometer; the CPU immediately sends a working control signal to the power management module, triggering a power supply strategy switch. The power management module restores normal power supply, and the on-chip system switches from low-power sleep mode to working state; the CPU records the moment the interrupt signal is received, defining it as the start time of the freefall interrupt event (i.e., the time when the terminal's fall motion is identified). Based on this, this embodiment only wakes up the system when a real fall event occurs, avoiding meaningless high-power operation.
[0096] S3, receive the acceleration signal sent by the acceleration sensor through the preset bus, monitor the acceleration signal, and when the current acceleration is detected to be greater than the ground contact threshold, record the current time as the end time of the free fall interruption event.
[0097] In this embodiment, the on-chip system establishes a high-speed data link with the accelerometer via a preset bus (such as I2C / I3C / SPI) to continuously receive the acceleration signal output by the sensor. The CPU compares the acceleration value with a preset ground contact threshold in real time; when the acceleration value is detected to be greater than the ground contact threshold, it is determined that the terminal has made contact with the ground, and the CPU immediately records this moment as the end time of the free fall interruption event.
[0098] S4. Based on the start time and the end time, determine the free fall information and output the free fall information to the input / output device of the handheld terminal.
[0099] In this embodiment, the CPU calculates the total freefall duration based on the recorded start and end times, combined with the freefall trigger cycle of the accelerometer, and then derives the fall height using the freefall motion formula. Data such as the fall event status, total freefall duration, fall height, and peak ground acceleration are integrated into structured freefall information. The on-chip system transmits this structured information to the input / output devices (such as a screen or data interface) of the handheld terminal via an internal data bus, ultimately presenting it to the user in a visual format such as text and numerical values.
[0100] Based on the above description, in this embodiment, when the handheld terminal is in sleep mode, both the on-chip system and the accelerometer are in low-power sleep mode. This design avoids unnecessary power consumption during non-use periods (such as standby mode). The on-chip system only enters the working state from low-power sleep mode when the accelerometer detects the handheld terminal in free fall and sends an interrupt signal greater than the interrupt threshold. Compared to real-time device status detection, this reduces the overall operating time of the device, effectively reducing battery consumption, extending the continuous use time of the handheld terminal, and improving the user experience.
[0101] Furthermore, in this embodiment, an accelerometer first sends a freefall interruption signal. After the on-chip system responds, it records the start time and then continuously monitors the acceleration signal. When the current acceleration is detected to be greater than the ground contact threshold, the end time is recorded. Freefall information is determined based on these two times. This phased detection method can accurately capture the entire process of the handheld terminal from the start of the fall to the ground, accurately determine whether a fall event has occurred, and obtain fall-related information, providing reliable data support for subsequent analysis of the causes of failure due to fall damage.
[0102] Based on the above description, this application provides a technical solution that can detect free fall events even when the handheld terminal is in sleep mode, thereby saving power consumption.
[0103] In one optional embodiment, the accelerometer includes a sensor front end; the sensor front end is used to sense the motion state of the handheld terminal in real time when the accelerometer is in a dormant state, and to generate a free fall simulation signal when the handheld terminal is detected to enter a free fall motion mode. The free fall interruption signal is a level trigger signal generated after the free fall simulation signal has undergone a first processing and meets the preset trigger conditions.
[0104] The first process includes: The analog-to-digital signal conversion of the free-fall simulation signal is performed to obtain the free-fall digital signal; The free-fall digital signal is filtered to obtain a filtered free-fall digital signal; The filtered free-fall digital signal is continuously monitored. If the filtered free-fall digital signal meets the preset free-fall trigger threshold and the duration reaches the preset free-fall trigger period, then the free-fall interruption signal is generated.
[0105] In this embodiment, the sensor front-end is designed based on MEMS (Micro-Electro-Mechanical Systems) technology. Its core structure consists of a movable micromass block, fixed electrodes, and a supporting cantilever. When the handheld terminal is stationary or experiencing minor daily shaking, the relative position of the micromass block and the fixed electrodes remains stable, and the capacitance between them remains constant. When the terminal enters free-fall motion mode, the micromass block is in a weightless state, and its relative position with the fixed electrodes shifts regularly, causing continuous fluctuations in the capacitance value. The capacitance detection circuit at the front end converts these capacitance fluctuations into a continuous voltage signal related to the motion state, i.e., a free-fall simulation signal. This process does not require activating the sensor's computation module; it relies solely on the deformation of the physical structure and the signal conversion of the basic circuitry, resulting in extremely low power consumption.
[0106] Based on the above description, the filtering process removes invalid signals such as daily shaking and electromagnetic interference, eliminating most sources of interference; the dual judgment mechanism of threshold and period further avoids false triggering caused by instantaneous signal fluctuations (such as scenarios such as casual placement of the terminal or slight collision).
[0107] Furthermore, the digitization, filtering, and judgment of the signal are all completed within the sensor. The on-chip system does not need to participate in front-end signal processing; it only needs to receive the final interrupt signal, which significantly reduces the computational power required by the on-chip system. The interrupt signal is a level-triggered instruction, and the transmission delay can be controlled at the microsecond level, ensuring that the on-chip system can respond quickly to drop events, accurately record the start time, and provide reliable timing data for subsequent height calculations.
[0108] Optionally, the step of receiving the acceleration signal sent by the acceleration sensor via a preset bus, monitoring the acceleration signal, and recording the current time as the end time of the free fall interruption event when the current acceleration is detected to be greater than the ground contact threshold includes: A data transmission link with the accelerometer is established through the preset bus to continuously receive acceleration signals sent by the accelerometer; wherein, the acceleration signal is an XYZ axis acceleration signal; The XYZ axis acceleration signals are analyzed to separate and extract the acceleration values corresponding to the X, Y, and Z axes respectively. The acceleration values corresponding to the X-axis, Y-axis, and Z-axis are compared one by one with the preset ground contact threshold. If the acceleration value of any axis is detected to be greater than the ground contact threshold, and the duration of this state reaches the preset ground contact determination period, then the handheld terminal is determined to have contacted the ground, and the moment when the handheld terminal contacts the ground is determined to be the end moment of the free fall interruption event.
[0109] In this embodiment, after being awakened by the free fall interruption signal, the on-chip system establishes a stable data transmission link with the acceleration sensor through a preset standardized bus (such as I2C / I3C / SPI), and configures a sampling frequency that matches the drop detection requirements to ensure that the time resolution of signal acquisition is sufficient to capture the acceleration peak at the moment of impact.
[0110] In working mode, the accelerometer continuously outputs XYZ axis acceleration signals. These signals contain real-time acceleration data of the terminal in three directions: X (left and right), Y (front and back), and Z (up and down) in three-dimensional space. This can cover any posture of the terminal during a fall and avoid missed detections due to a single fall angle.
[0111] The on-chip system's central processing unit performs structured analysis on the received raw XYZ axis acceleration signals. Using a signal separation algorithm, it breaks down the fused three-axis data into independent acceleration values for each of the X, Y, and Z axes. This step aims to eliminate coupling interference between the three-axis signals, ensuring that acceleration data for each axis can be monitored independently, thus providing an accurate data source for subsequent threshold comparisons.
[0112] The central processing unit retrieves the preset ground contact threshold, which is the impact acceleration characteristic value of the terminal at the moment of ground contact. It is usually much greater than the acceleration due to gravity. Its value needs to be customized according to the terminal's hardware material (such as glass body, metal frame) and structural strength.
[0113] The processor compares the parsed X-axis, Y-axis, and Z-axis acceleration values with the ground contact thresholds in real time and independently. Since the ground contact angle of the terminal during a drop is random, any axis may produce an impact peak. Therefore, comparing the three axes one by one ensures the comprehensiveness of the judgment.
[0114] When the acceleration value of any axis is detected to be greater than the ground contact threshold, ground contact is not directly determined. Instead, a ground contact determination cycle is initiated for verification. Only when the acceleration value of that axis remains greater than the ground contact threshold for the duration of the determination cycle is the handheld terminal determined to have made stable contact with the ground. After the determination is successful, the central processing unit immediately records this moment as the end time of the free fall interruption event. The time difference between this moment and the previously recorded start time is the core parameter for calculating the free fall duration and drop height.
[0115] In this embodiment of the application, the logic of independent monitoring and one-by-one comparison of the XYZ three axes is adopted, which covers all possible drop postures of the terminal and solves the problem of missed judgment caused by the deviation of the ground contact angle in single-axis monitoring; the addition of the ground contact judgment cycle effectively avoids misjudgment caused by instantaneous interference signals (such as air collisions and signal noise).
[0116] In one optional implementation, determining free fall information based on the start time and the end time, and outputting the free fall information to the input / output device of the handheld terminal includes: The total free fall duration of the handheld terminal is obtained based on the end time, the start time, and the free fall trigger cycle of the accelerometer. The free fall height of the handheld terminal is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free-fall information is transmitted to the input / output device of the handheld terminal.
[0117] In this embodiment, by introducing a free fall trigger cycle to supplement the duration calculation, the problem of height calculation deviation caused by sensor judgment delay in traditional solutions is solved; the structured information on whether a fall has occurred also provides key quantitative data such as fall height and fall duration, which after-sales personnel can use to quickly determine the degree of damage to the terminal (such as a fall from a height can easily lead to motherboard desoldering and screen breakage), greatly improving repair efficiency.
[0118] Furthermore, the entire calculation process is based on the difference between fundamental physical formulas and timing parameters, without the need to call complex algorithm models or occupy a large amount of memory resources; data transmission and format adaptation adopt lightweight logic, the computing load of the central processing unit is extremely low, and it will not affect the core functions of the handheld terminal such as calls, Internet access, and application operation, ensuring the overall smooth operation of the terminal.
[0119] In a specific example, refer to Figure 3 Drop detection methods for handheld terminals include: S100, the handheld terminal 10 is in sleep mode; that is, both the MEMS sensor 200 and the system-on-chip 300 are in sleep low-power mode.
[0120] S200, the sensor front end 201 detects that the handheld terminal has begun to fall and generates an analog signal.
[0121] S300, the analog-to-digital converter 202 quantizes, encodes, and converts analog signals into digital signals for output.
[0122] Reference Figure 4 , will continuously simulate analog signals (Figure 4 The red curve in the middle is discretized into a finite number of values (sample values) according to the amplitude range. For example, the amplitude of the analog signal is divided into the range of 0~8, corresponding to sample values 2, 3, 5, etc. (sample value column in the table). The quantized sample values are then converted into binary numbers (encoded values), for example, sample value 2 corresponds to binary 010, sample value 5 corresponds to binary 101, etc. Figure 4 The encoded binary sequence is then concatenated in chronological order to form the final digital signal (the binary sequence at the bottom).
[0123] Taking samples 1 to 10 as an example: The amplitude of the analog signal (red curve) at sample 1 corresponds to the quantized sample value 2, encoded as binary 010; the amplitude of the analog signal reaches its peak at sample 4, quantized as sample value 8, encoded as 111; after concatenating the binary codes of all samples in sequence, the output digital signal is 010 011 111 101 000 101 001 111 001 101 011 (…). Figure 4 (Middle and bottom sequence).
[0124] S400, filter 203 filters digital signals; S500: When the MEMS sensor 200 is in a low-power sleep state, it continuously detects the free fall trigger threshold and free fall trigger period of the digital signal. If the digital signal meets the conditions, a free fall interruption event is triggered. For example, if the free fall trigger period is 10ms and the free fall trigger threshold is 4.9m / s2, then if the velocity change in a certain direction exceeds 4.9m / s within 10ms, a free fall interruption event is triggered.
[0125] S501, when the MEMS sensor 200 is in operation, refer to Figure 5 It processes digital signals into acceleration signals of an object (changes in the magnitude and direction of velocity along the XYZ axes) and outputs them.
[0126] S600, the input / output interface 204 feeds back the freefall interrupt event to the CPU 301 of the system-on-chip 300 and wakes up the system-on-chip SoC to put it into operation. This time is the start time of the freefall interrupt event.
[0127] S601, the input / output interface 204 continuously feeds back the changes in the magnitude and direction of the acceleration signal on the XYZ axes to the preset bus 302 (I2C / I3C / SPI) of the system on the chip 300 for operation, and finally passes it to the CPU 301 for processing.
[0128] The S700, a system-on-a-chip 300, continuously monitors acceleration signals (changes in velocity magnitude and direction along the XYZ axes). When the detected acceleration exceeds the ground contact threshold, it indicates that the object has reached the ground. For example, if the ground contact threshold is 80 m / s², the object experiences a significant stopping acceleration upon contact with the ground; this time is the end time of the free fall interruption event.
[0129] Specifically, refer to Figure 6 In the figure, the three curves X, Y, and Z represent the three-axis acceleration changes of the MEMS sensor; the horizontal axis is the time axis, and the vertical axis is the acceleration amplitude.
[0130] The free fall trigger threshold is the critical acceleration value for determining whether one enters free fall (usually close to 0g, corresponding to a weightless state). Free fall region: The region where the acceleration is near the trigger threshold, representing that the terminal is in a state of weightlessness and free fall; Free fall trigger period: This is the shortest duration for which acceleration is maintained in the free fall region (this duration must be met to trigger an interruption and avoid misjudgment).
[0131] Reference Figure 6 When the terminal moves from rest to free fall; initial state: the acceleration of the X / Y / Z axes corresponds to the gravitational components when the terminal is resting (for example, the Z axis may be close to 1g, and the X / Y axis may be close to 0g); when the terminal starts to fall freely, the acceleration of the X / Y / Z axes converges rapidly to 0g and enters the free fall region.
[0132] When the duration of the triaxial acceleration in the free fall region reaches the free fall trigger cycle, the MEMS sensor determines that a real free fall has occurred. At this time, the sensor generates an interrupt signal. Figure 6 The interrupt triggers the corresponding blue signal transition and sends the signal to the on-chip system of the handheld terminal, triggering the system to wake up from low-power sleep mode.
[0133] S800, System-on-Chip 300 is in working state and calculates the free fall height using the formula. For example, the free fall height of an object = 1 / 2 × gravitational acceleration (9.8 m / s2) × (free fall trigger cycle + (free fall interrupt event end time - free fall interrupt event start time)2).
[0134] An example of a method for calculating the height of free fall:
[0135] Where y(t) represents the free fall height (cm), g is the gravitational acceleration 9.8m / s2, and t is the free fall end time - free fall start time - free fall trigger period.
[0136]
[0137] The S900, System-on-Chip 300, outputs the freefall event and the freefall height of the object to the input / output device 500 such as the screen / button for display and presentation to the end user.
[0138] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.
Claims
1. A drop detection method for a handheld terminal, characterized in that, The system-on-a-chip applied to the handheld terminal; the method includes: When the handheld terminal is in sleep mode, the system-on-chip and the accelerometer are both controlled to be in low-power sleep mode. In response to the freefall interruption signal sent by the accelerometer, the on-chip system enters the working state from the low-power sleep mode and records the time of receiving the freefall interruption information as the start time of the freefall interruption event. The acceleration signal sent by the acceleration sensor is received through a preset bus, and the acceleration signal is monitored. When the current acceleration is detected to be greater than the ground contact threshold, the current time is recorded as the end time of the free fall interruption event. Based on the start time and the end time, free fall information is determined and the free fall information is output to the input / output device of the handheld terminal.
2. The method according to claim 1, characterized in that, The accelerometer includes a sensor front end; the sensor front end is used to sense the motion state of the handheld terminal in real time when the accelerometer is in a dormant state, and to generate a free fall simulation signal when the handheld terminal is detected to enter a free fall motion mode. The free fall interruption signal is a level trigger signal generated after the free fall simulation signal has undergone a first processing and meets the preset trigger conditions.
3. The method according to claim 2, characterized in that, The first process includes: The analog-to-digital signal conversion of the free-fall simulation signal is performed to obtain the free-fall digital signal; The free-fall digital signal is filtered to obtain a filtered free-fall digital signal; The filtered free-fall digital signal is continuously monitored. If the filtered free-fall digital signal meets the preset free-fall trigger threshold and the duration reaches the preset free-fall trigger period, then the free-fall interruption signal is generated.
4. The method according to any one of claims 1-3, characterized in that, The process of receiving the acceleration signal sent by the acceleration sensor via a preset bus, monitoring the acceleration signal, and recording the current time as the end time of the free fall interruption event when the current acceleration is detected to be greater than the ground contact threshold includes: A data transmission link with the accelerometer is established through the preset bus to continuously receive acceleration signals sent by the accelerometer; wherein, the acceleration signal is an XYZ axis acceleration signal; The XYZ axis acceleration signals are analyzed to separate and extract the acceleration values corresponding to the X, Y, and Z axes respectively. The acceleration values corresponding to the X-axis, Y-axis, and Z-axis are compared one by one with the preset ground contact threshold. If the acceleration value of any axis is detected to be greater than the ground contact threshold, and the duration of this state reaches the preset ground contact determination period, then the handheld terminal is determined to have contacted the ground, and the moment when the handheld terminal contacts the ground is determined to be the end moment of the free fall interruption event.
5. The method according to any one of claims 1-3, characterized in that, Determining free fall information based on the start time and the end time, and outputting the free fall information to the input / output device of the handheld terminal, includes: The total free fall duration of the handheld terminal is obtained based on the end time, the start time, and the free fall trigger cycle of the accelerometer. The free fall height of the handheld terminal is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free-fall information is transmitted to the input / output device of the handheld terminal.
6. A handheld terminal, characterized in that, The terminal includes: a system-on-a-chip, an accelerometer, and input / output devices; The on-chip system is used to control itself and the accelerometer to be in a low-power sleep mode when the handheld terminal is in a sleep state. The accelerometer is used to detect the free fall motion of the handheld terminal in low-power sleep mode, enter the working state, generate the free fall interrupt signal of the handheld terminal, and send it to the system on chip. The on-chip system is used to respond to the free fall interruption signal sent by the accelerometer to the handheld terminal, enter the working state from the low power sleep mode, and record the time of receiving the free fall interruption information as the start time of the free fall interruption event. The on-chip system is used to receive the acceleration signal sent by the acceleration sensor through a preset bus, monitor the acceleration signal, and when the current acceleration is detected to be greater than the ground contact threshold, record the current time as the end time of the free fall interruption event. The on-chip system determines the free fall information based on the start time and the end time, and outputs the free fall information to the input / output device; The input / output device displays the free fall information to the user in an adaptive manner.
7. The handheld terminal according to claim 6, characterized in that, The accelerometer includes a sensor front-end, an analog-to-digital converter, a filter, and an input / output interface; The sensor front end is used to sense the motion state of the handheld terminal in real time when the accelerometer is in a dormant state, and to generate a free fall simulation signal when the handheld terminal is detected to enter a free fall motion mode. The analog-to-digital converter is used to convert the free-fall analog signal into a free-fall digital signal; The filter is used to filter the free-fall digital signal to obtain a filtered free-fall digital signal; wherein, the free-fall digital signal is the free-fall interruption signal; The input / output interface is used to send the free fall interrupt signal to the on-chip system.
8. The handheld terminal according to claim 6, characterized in that, The system-on-a-chip includes a preset bus and a central processing unit; The input / output interface of the accelerometer is used to send the free fall interruption signal to the central processing unit via the preset bus; The central processing unit is used to: receive acceleration signals output by the acceleration sensor via the preset bus; wherein the acceleration signals are XYZ axis acceleration signals; The received XYZ axis acceleration signals are analyzed to extract the acceleration values in each axis direction. The central processing unit analyzes the received XYZ axis acceleration signals and extracts the acceleration values in each axis direction of the XYZ axis acceleration signals. The acceleration values in each axis direction are compared with a preset ground contact threshold. If the acceleration value in any of the axes directions is greater than the ground contact threshold, the handheld terminal is determined to have made contact with the ground, and the current time is recorded as the end time of the free fall interruption event.
9. The handheld terminal according to claim 8, characterized in that, The central processing unit is specifically used for: The total free fall duration of the handheld terminal is obtained based on the end time, the start time, and the free fall trigger cycle of the accelerometer. The free fall height of the handheld terminal is obtained based on the total free fall time. Based on the free fall height and the total free fall duration, structured free fall information is obtained; The structured free-fall information is transmitted to the input / output device of the handheld terminal.
10. The handheld terminal according to claim 8, characterized in that, The system-on-a-chip also includes a power management module, and the handheld terminal also includes a battery; the power management module is connected to the central processing unit, the battery, and the accelerometer. The central processing unit is also used to send a sleep control signal to the power management module when the handheld terminal is in a sleep state; The power management module is used to adjust the electrical parameters output to the central processing unit and the accelerometer according to the sleep signal, so that both the central processing unit and the accelerometer are in a low-power sleep mode. The central processing unit is also used to respond to the free fall interruption signal of the handheld terminal sent by the accelerometer, and to send a working control signal to the power management module based on the free fall interruption signal; The power management module is used to adjust the power supply strategy according to the working control signal, and provide working voltage to the central processing unit and the accelerometer, so that the central processing unit and the accelerometer enter the working state from the low-power sleep mode.