Bullet counting system

Abstract

The invention discloses a bullet counting system which is used for solving the technical problem that normal shooting experience is affected due to the fact that the weight and the structure of a gun body are changed in the prior art, and belongs to the technical field of ammunition counting display. The system comprises a sensor module, a circuit module, a power supply and a counting display module, the power supply is connected with the circuit module through a power line and used for supplying power to the whole system, the sensor module comprises a piezoelectric pressure sensor, and the piezoelectric pressure sensor transmits collected signals to the circuit module through a signal line. The circuit module is used for conditioning and processing the received signal and transmitting an obtained result to the counting display module through a differential bus, and the counting display module is used for finally obtaining a counting result.

Description

Technical Field

[0001] This invention belongs to the field of ammunition counting and display technology, and specifically relates to a bullet counting system. Background Technology

[0002] When soldiers are conducting target practice, safety officers usually count the bullets fired by the soldiers. This undoubtedly increases the workload of the safety officers, and there are significant risks involved in the safety officers counting bullets by relying on their vision and hearing.

[0003] Besides relying on safety officers to count shots, existing bullet counters mainly fall into the following categories: 1. Counting using barrel vibration. This involves mounting the counter on the barrel and using the strong vibration signal from the barrel when a bullet is fired to count. 2. Counting using Hall effect sensors. This involves mounting the counter on the barrel and using the electromagnetic induction signal generated by the Hall effect sensor when a bullet is fired into the barrel to count. 3. Modifying the rifle magazine to count bullets fired based on the magazine's status. 4. Using multiple sensors to receive signals, collecting the flash and pressure values ​​at the moment of firing, and combining these two signal sources to determine the number of shots fired.

[0004] The disadvantages of the above method are as follows: the bullet counter must be mounted on the barrel, which changes the weight and structure of the gun and affects the normal shooting experience; the gun needs to be modified, which is not conducive to the use of existing firearms; and the cost is relatively high. Summary of the Invention

[0005] The purpose of this invention is to provide a bullet counting system to solve the technical problem that existing technologies have altered the weight and structure of the gun, affecting the normal shooting experience.

[0006] This invention is achieved using the following technical solution: A bullet counting system includes a sensor module, a circuit module, a power supply, and a counting display module. The power supply is connected to the circuit module via a power line and is used to power the entire system. The sensor module includes a piezoelectric pressure sensor, which transmits the collected signal to the circuit module via a signal line. The circuit module conditions and processes the received signal and transmits the result to the counting display module via a differential bus. The counting display module finally obtains the counting result.

[0007] During implementation, the rifle is placed on a target platform with the rifle fixed, and the piezoelectric pressure sensor is fixed 10cm away from the muzzle. The piezoelectric pressure sensor is connected to the circuit module through a signal line, the power supply is connected to the circuit module through a power line, and the counting and display module is connected to the circuit module through an RS485 line. The piezoelectric pressure sensor is used to collect the pressure signal generated when the bullet leaves the barrel.

[0008] More preferably, the sensor module further includes a sensor mounting structure. The piezoelectric pressure sensor is a Y1001T-01A general-purpose pressure sensor. The sensor mounting structure is a conical bevel shape and made of 304 stainless steel. The piezoelectric pressure sensor is mounted in the sensor mounting structure with K704 silicone rubber. The sensor mounting structure has a directional effect on the muzzle shock wave generated when the bullet is fired. The piezoelectric pressure sensor collects pressure signals and provides raw data for the technology.

[0009] More preferably, the circuit module includes the following components: a charge amplifier, a filter, a main control chip FPGA, a serial EEPROM memory, an RS-485 receiver, a crystal oscillator, a DC-DC converter, and a voltage regulator. The charge amplifier is a high-gain operational amplifier OPA656, the main control chip is a domestic FPGA chip EF2L15LG100B from Anlu Semiconductor, and the serial EEPROM memory is an AT93C56. The RS-485 receiver uses an ST3485EBDR, the crystal oscillator uses a SiT8008B programmable crystal oscillator, the DC-DC converter uses an LMZM23601SILR, and the voltage regulator uses an SPX3819M5-3.0 / 3.3. The piezoelectric pressure sensor is connected to the main control chip FPGA via a charge amplifier and a filter. The main control chip FPGA is connected to the counting display module via the RS-485 receiver. The crystal oscillator provides the clock signal to the main control chip FPGA. In practice, the piezoelectric pressure sensor is used to collect the pressure signal generated when the bullet leaves the barrel. That is, the pressure signal is converted into an electrical signal by the piezoelectric pressure sensor and transmitted to the charge amplifier. It also provides raw data for the algorithm inside the main control chip FPGA to determine the rise time, pulse width, and peak characteristics of the collected pressure signal. The charge amplifier converts the charge signal output by the sensor into a voltage signal and transmits it to the filter. That is, the charge amplifier converts the high-impedance charge signal output by the piezoelectric pressure sensor into a low-impedance voltage signal. The second-order low-pass filter filters out high-frequency noise >50kHz in the signal, retaining the effective frequency band of the gunshot pressure signal.

[0010] More preferably, the main control chip FPGA can receive signals from a piezoelectric pressure sensor, analyze and judge the rise time, peak value, and pulse width of the muzzle shock wave signal through an internal algorithm, obtain the bullet firing result, store the counting result in a serial EEPROM memory, and transmit it to the counting display module through an RS-485 receiver. In practice, the filter transmits the filtered signal to the main control chip FPGA. The main control chip FPGA judges the rise time, pulse width, and peak value of the collected pressure signal through an internal algorithm, directly accumulates and counts the pulse signal, and transmits the count signal to the counting display module through the RS-485 receiver for counting display.

[0011] More preferably, the signal processing of the circuit module includes a three-parameter evaluation and counting algorithm for rise time, peak value, and pulse width.

[0012] More preferably, the power supply uses 24V, and the power supply provides power to the entire system through a DC-DC converter and a voltage regulator.

[0013] More preferably, the counting display module uses an X-SEG34 digital tube display screen and is connected to the circuit module via an RS-485 receiver.

[0014] In a further preferred embodiment, the sensor mounting structure has an inner wedge-shaped receiving port at the head and an external thread at the tail. An internal mounting cavity is provided for mounting the piezoelectric pressure sensor. Specifically, the sensor mounting structure forms an inner wedge-shaped receiving port at the sensitive surface of the piezoelectric pressure sensor, and the external thread at the tail is used to fix the sensor mounting structure. The inner wedge-shaped receiving port ensures stable mechanical coupling between the piezoelectric pressure sensor and the sensor mounting structure. Shock wave energy is effectively guided to the sensitive surface of the piezoelectric pressure sensor through the inner wedge-shaped receiving port, thereby maintaining the original signal characteristics and enhancing anti-interference capabilities.

[0015] More preferably, the piezoelectric pressure sensor is connected to the circuit module via a shielded wire, which can significantly enhance the system's resistance to electromagnetic and mechanical interference.

[0016] This invention utilizes only the muzzle shock wave generated when a bullet is fired as the signal source. Through non-contact installation with the firearm, it does not affect the normal firing of the weapon. Furthermore, the sensor is mounted in a specially designed bracket and employs a directional sensing design, thereby reducing interference from other firearms and effectively achieving accurate bullet counting. This invention also uses a low-cost pressure sensor mounted below the muzzle, avoiding interference with normal firing and effectively ensuring accurate bullet counting. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0020] Figure 2 This diagram illustrates the sensor module of the present invention.

[0021] Figure 3 This diagram illustrates the installation location of the sensor module of the present invention.

[0022] Figure 4 This is an amplified circuit diagram representing the circuit module of the present invention.

[0023] Figure 5 The circuit diagram shows the FPGA, the main control chip of the circuit module of this invention.

[0024] Figure 6 Circuit diagram showing the DC-DC converter of the circuit module of the present invention. Figure 7 The circuit diagram shows the voltage regulator of the circuit module of the present invention.

[0025] Figure 8 This is a circuit diagram illustrating the serial EEPROM memory of the circuit module of the present invention.

[0026] Figure 9 This is a circuit diagram showing the RS-485 receiver of the circuit module of the present invention.

[0027] In the diagram: 1-Display module, 2-Circuit module, 3-Sensor module, 4-Power supply, 5-Piezoelectric pressure sensor, 6-Sensor mounting structure, 7-Rifle, 8-Target stand, 9-Signal line, 10-U-shaped bracket. Detailed Implementation

[0028] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0029] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Example

[0032] A bullet counting system includes a sensor module 3, a circuit module 2, a power supply 4, and a counting display module 1. The power supply 4 is connected to the circuit module 2 via a power supply line 4 to supply power to the entire system. The sensor module 3 includes a piezoelectric pressure sensor 5, which transmits the collected signal to the circuit module 2 via a signal line 9. The circuit module 2 conditions and processes the received signal and transmits the result to the counting display module 1 via a differential bus. The counting display module 1 then obtains the counting result.

[0033] Sensor module 3 also includes sensor mounting structure 6. The piezoelectric pressure sensor 5 adopts the Y1001T-01A general-purpose pressure sensor. The sensor mounting structure 6 is a tapered bevel shape, made of 304 stainless steel. The piezoelectric pressure sensor 5 is mounted in the sensor mounting structure 6 with K704 silicone rubber. Due to environmental interference and noise interference from multiple guns firing simultaneously at the target range, this embodiment initially prepared three mounting structures. Finally, fluid-structure interaction (FSI) simulation was conducted on the ANSYS Fluent platform, verifying that the tapered bevel shape is closest to the unstructured shape in terms of fidelity in the three parameters (rise time, peak value, and pulse width), and can better maintain the original signal characteristics. It also verified its good anti-interference performance under multi-gun firing conditions at the target range. Therefore, the tapered bevel shape was ultimately selected as the sensor mounting structure 6.

[0034] Those skilled in the art can easily know that shock waves have extremely strong directionality and will be reflected and diffracted when they encounter uneven surfaces during propagation. Therefore, in this invention, the sensor mounting structure 6 is installed in the same direction as the muzzle and is positioned 10cm directly below the muzzle. In this way, the muzzle shock wave generated when the bullet is fired will enter the sensor mounting structure 6 in a sweeping manner and reach the sensitive surface of the piezoelectric pressure sensor 5. Meanwhile, the interference shock waves generated when the guns are fired from adjacent or separated target platforms 8 will be reflected due to the direction of the sensor mounting structure 6, thereby reducing the interference.

[0035] Circuit module 2 includes the following components: a charge amplifier, a filter, a main control chip FPGA, a serial EEPROM memory, an RS-485 receiver, a crystal oscillator, a DC-DC converter, and a voltage regulator. The charge amplifier uses a high-gain operational amplifier OPA656, the main control chip uses a domestic FPGA chip EF2L15LG100B from Anlu Company, the serial EEPROM memory uses an AT93C56, the RS-485 receiver uses an ST3485EBDR, the crystal oscillator uses a programmable crystal oscillator SiT8008B, the DC-DC converter uses an LMZM23601SILR, and the voltage regulator uses an SPX3819M5-3.0 / 3.3. The piezoelectric pressure sensor 5 is connected to the main control chip FPGA through the charge amplifier and the filter. The main control chip FPGA is connected to the counting display module 1 through the RS-485 receiver, and the crystal oscillator provides the clock signal to the main control chip FPGA. The working principle is as follows: The rifle 7 is placed on the target platform 8 that fixes the gun. The sensor mounting structure 6 is fixed 10cm away from the muzzle by the U-shaped bracket 10. The bottom end of the U-shaped bracket 10 is inserted into the ground and fixed in front of the shooting target platform 8. The tail of the sensor mounting structure 6 is provided with external threads, which can be fixed on the U-shaped seat of the U-shaped bracket 10, and is 10cm away from the muzzle.

[0036] The main control chip FPGA can receive signals from the piezoelectric pressure sensor 5. Through internal algorithms, it analyzes and judges the rise time, peak value, and pulse width of the muzzle shock wave signal to determine the bullet firing result. The counting result is stored in a serial EEPROM memory and transmitted to the counting display module 1 via an RS-485 receiver. In this embodiment, the main control chip FPGA embeds a joint algorithm for the three parameters (rise time, peak value, and pulse width). Through feature extraction, matrix operations, standardization, and weighted comparison, it extracts these three parameters from the acquired signal to jointly determine whether to count. This embodiment uses an X-SEG34 digital tube display screen, a three-digit LED display capable of displaying decimal numbers from 0 to 999. After the gun is fired, the main control chip FPGA analyzes the acquired signal, makes a judgment, and sends a command to the display module 1. The firing result will appear directly on the display module 1 in digital form.

[0037] Circuit module 2 signal processing includes a three-parameter evaluation counting algorithm for rise time, peak value, and pulse width.

[0038] Power supply 4 uses 24V power supply and supplies power to the entire system through a DC-DC converter and a voltage regulator.

[0039] The counting display module 1 uses an X-SEG34 digital tube display screen and is connected to the circuit module 2 via an RS-485 receiver.

[0040] The sensor mounting structure 6 has an inner wedge-shaped receiving port at the head and an external thread at the tail. An internal mounting cavity is provided for mounting the piezoelectric pressure sensor 5. The piezoelectric pressure sensor 5 is inserted into the rear cavity of the sensor mounting structure 6, with its sensitive surface facing the inner wedge-shaped receiving port. Simultaneously, the sensor mounting structure 6 is fixedly mounted on the U-shaped bracket 10 via the external thread. Furthermore, a sealing element is provided between the rear cavity of the sensor mounting structure 6 and the piezoelectric pressure sensor 5.

[0041] The piezoelectric pressure sensor 5 is connected to the circuit module 2 via a shielded wire.

[0042] The sensor mounting structure 6 has an inner wedge-shaped receiving port at the head that communicates with the mounting cavity at the tail.

[0043] The working principle is as follows: This specific embodiment uses a single piezoelectric pressure sensor 5, which has the advantages of simple structure and easy installation. In addition, the sensor module 3 and sensor mounting structure 6 have a directional function, which can effectively shield the interference generated by other guns firing, and make the counting more accurate.

[0044] This specific implementation uses a three-parameter joint algorithm to determine the count. Key technical points of the algorithm within the FPGA main control chip are as follows: To address residual interference remaining after the installation of the internal wedge-shaped receiver port, a three-dimensional observation vector is constructed, characterized by rise time, peak shock wave value, and effective pulse width. Based on a large number of labeled firing and noise samples, the sample mean vector μ and covariance matrix Σ are calculated to characterize the mean and correlation of the three parameters. The Mahalanobis distance discrimination method is used to calculate the Mahalanobis distance of the observation vector x relative to the model. And compare it with the chi-square threshold with 3 degrees of freedom. In comparison, if If the result is positive, it is initially determined to be a valid shot; at the same time, the three parameters are normalized and weighted. This constitutes the weighted judgment amount. The weight and judgment threshold Cross-validation was used to determine if... If the result is true, it is considered a valid firing. Finally, a fusion decision logic is adopted: a counting pulse is output only when both the Mahalanobis distance decision and the normalized weighted decision are true, so as to significantly reduce the false alarm probability caused by a single decision and improve robustness. In order to meet the real-time requirements, this invention further deploys the algorithm in a pipelined parallel manner on the domestic FPGA - EF2L15LG100B.

[0045] The present invention has the following advantages: 1. Non-contact installation with the firearm: This invention uses pressure recognition technology and the internal algorithm of the main control chip FPGA to count bullets. That is, when soldiers are conducting target practice, the rifle 7 is placed on the target platform 8 that fixes the firearm, and the sensor mounting structure 6 is fixed at a distance of 10cm from the muzzle through the U-shaped bracket 10. It is connected to the circuit module 2 through the signal line 9. There are no parts that come into contact with the firearm, so it does not affect the normal shooting training of soldiers.

[0046] 2. Circuit module 2 adopts a low-power design, and the power supply 4 can provide power for more than a week.

[0047] 3. The structure is easy to install and the counting display is convenient.

[0048] The piezoelectric pressure sensor 5 outputs a weak charge. Existing front-ends often cause false triggering, baseline drift, or high resonance wave interference in rifle shooting ranges. The amplification circuit in the invention adopts a combination topology of charge amplifier + second-order active low-pass filter, which significantly improves the ability to capture the rising edge of shock wave (retaining a sufficiently high bandwidth) while suppressing high-frequency interference (preventing false triggering).

[0049] In high-performance analog front-end systems, general-purpose FPGAs are prone to clock interference and power supply transients coupled to the ADC / analog input due to I / O multiplexing and the coexistence of multiple peripherals, which can impair counting accuracy and system stability. By using a domestically produced FPGA as the main control chip and clearly dividing the FPGA's banks according to their functions, the impact of digital switching noise on analog input is significantly reduced, the signal-to-noise ratio (SNR) and counting stability are improved, and the embedded joint algorithm can effectively improve counting accuracy.

[0050] For the same board, efficiency and noise are usually contradictory; this invention adopts a layered power supply 4 system (high-efficiency main step-down + local low-noise LDO), which minimizes the noise of the analog front-end power supply 4 while maintaining overall energy efficiency, thereby improving the stability and thermal reliability of the system under multi-emission / continuous operation.

[0051] The system needs to reliably save calibration parameters, count accumulation, and operating modes. This invention uses AT93C56 as the memory and implements a transactional write process with CRC or check code at the FPGA layer. It reads and verifies before writing and reads back to verify after writing to ensure the consistency of EEPROM contents and the success rate of data retention under power failure transients, thus ensuring the reliability of data during long-term field operation.

[0052] In environments with long-term cable connections and strong electromagnetic interference, differential buses are susceptible to common-mode voltage, electromagnetic pulses, or grounding displacement, often leading to communication errors or device damage. This invention addresses this by implementing termination matching and biasing networks at both ends of the differential bus, and connecting a common-mode choke and a transient suppressor in parallel at the transceiver input to counteract electromagnetic pulses. The transceiver's enable pin is dynamically controlled by a controller to achieve node isolation and ensure signal integrity.

[0053] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A bullet counting system, characterized in that: The system includes a sensor module (3), a circuit module (2), a power supply (4), and a counting display module (1). The power supply (4) is connected to the circuit module (2) via a power supply (4) line and is used to power the entire system. The sensor module (3) includes a piezoelectric pressure sensor (5). The piezoelectric pressure sensor (5) transmits the collected signal to the circuit module (2) via a signal line (9). The circuit module (2) conditions and processes the received signal and transmits the result to the counting display module (1) via a differential bus. The counting display module (1) finally obtains the counting result.

2. A bullet counting system according to claim 1, characterized in that: The sensor module (3) also includes a sensor mounting structure (6). The piezoelectric pressure sensor (5) is a Y1001T-01A general-purpose pressure sensor. The sensor mounting structure (6) is a tapered bevel shape and made of 304 stainless steel. The piezoelectric pressure sensor (5) is mounted in the sensor mounting structure (6) by K704 silicone rubber.

3. A bullet counting system according to claim 2, characterized in that: The circuit module (2) includes the following components: a charge amplifier, a filter, a main control chip FPGA, a serial EEPROM memory, an RS-485 receiver, a crystal oscillator, a DC-DC converter, and a voltage regulator. The charge amplifier is a high-gain operational amplifier OPA656, the main control chip is a domestic FPGA chip EF2L15LG100B from Anlu Company, the serial EEPROM memory is an AT93C56, the RS-485 receiver is an ST3485EBDR, the crystal oscillator is a programmable crystal oscillator SiT8008B, the DC-DC converter is an LMZM23601SILR, and the voltage regulator is an SPX3819M5-3.0 / 3.

3. The piezoelectric pressure sensor (5) is connected to the main control chip FPGA through the charge amplifier and the filter. The main control chip FPGA is connected to the counting display module (1) through the RS-485 receiver. The crystal oscillator provides a clock signal to the main control chip FPGA.

4. A bullet counting system according to claim 3, characterized in that: The main control chip FPGA can receive the signal from the piezoelectric pressure sensor (5), analyze and judge the three parameters of the muzzle shock wave signal rise time, peak value and pulse width through the internal algorithm, obtain the bullet firing result, and store the counting result through the serial EEPROM memory and transmit it to the counting display module (1) through the RS-485 receiver.

5. A bullet counting system according to claim 1, characterized in that: The circuit module (2) signal processing includes a three-parameter evaluation counting algorithm for rise time, peak value, and pulse width.

6. A bullet counting system according to claim 1, characterized in that: The power supply (4) is powered by 24V and supplies power to the entire system through a DC-DC converter and a voltage regulator.

7. A bullet counting system according to claim 1, characterized in that: The counting display module (1) uses an X-SEG34 digital tube display screen and is connected to the circuit module (2) via an RS-485 receiver.

8. A bullet counting system according to claim 4, characterized in that: The sensor mounting structure (6) has an inner wedge-shaped receiving port at the head and an external thread at the tail. It also has an internal mounting cavity for mounting a piezoelectric pressure sensor (5).

9. A bullet counting system according to claim 8, characterized in that: The piezoelectric pressure sensor (5) is connected to the circuit module (2) via a shielded wire.

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