A paper page number detection method and system, and a capacitor-to-frequency circuit

Abstract

The present invention relates to the technical field of paper page number detection, and specifically discloses a paper page number detection method and system, and a capacitance-to-frequency circuit. The method measures the capacitance value of a stack of paper to be detected, and converts it into a corresponding frequency characteristic value. Finally, the specific number of paper is obtained through the correspondence between the number of paper and the frequency characteristic value, and the paper test result can be displayed within 2 seconds. The system measures the capacitance value of the paper to be tested between two electrode plates through a capacitance-to-frequency circuit module, detects the frequency characteristic value through a frequency measurement module, and calculates the frequency characteristic value through a main control chip module to obtain the specific number of paper pages. The capacitance-to-frequency circuit has a picofarad level of capacitance perception sensitivity, and has a high conversion accuracy. It measures the capacitance value based on an RC oscillation circuit and a high-speed comparator chip to convert capacitance and frequency, and then determines the number of paper. It can work stably even when the environment changes greatly, and the circuit has a high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of paper page number detection, and in particular to a paper page number detection method and system, and a capacitor-to-frequency circuit. Background Art

[0002] In many aspects of daily life and industrial production, the number of paper pages needs to be accurately measured. For example, in automatic banknote counting, most banknote counting machines currently use mechanical paging technology, which requires each page of banknotes to be separated and then counted one by one. This method has disadvantages such as high noise, limited banknote counting speed, large volume, and banknote jamming. For another example, in the production and manufacturing of notebooks, the number of pages needs to be counted before binding the notebooks to prevent the occurrence of missing pages and avoid affecting the corporate image.

[0003] In the field of paper page count measurement, image recognition technology is generally used. First, a high-definition picture of the paper cross section needs to be taken, and then the image processing algorithm is used to identify and count the number of sheets of paper. However, this method has high requirements on the image pixels and the overall cost is high.

[0004] At present, there is no simple, convenient and low-cost method to measure the number of paper pages. Summary of the invention

[0005] The present invention provides a paper page number detection method and system, and a capacitor-to-frequency circuit, which solve the technical problem that the paper page number detection technology using image recognition or mechanical paging is not simple, convenient, and low-cost enough.

[0006] In order to solve the above technical problems, the present invention provides a method for detecting the number of paper pages, comprising the steps of:

[0007] S1. Collect the capacitance value of a stack of paper to be tested;

[0008] S2. Converting the capacitance value into a frequency characteristic;

[0009] S3. Convert the frequency feature into the corresponding number of paper pages.

[0010] Furthermore, the step S1 specifically includes the steps of:

[0011] S11. The paper to be tested is placed between two electrode plates and clamped;

[0012] S12. Obtain the capacitance value detected by the two electrode plates.

[0013] Furthermore, the step S2 specifically includes the steps of:

[0014] S21. The capacitance value is linearly converted into a corresponding frequency value according to a capacitance-to-frequency formula, wherein the capacitance-to-frequency formula is: f=k*C, where C represents the equivalent capacitance value of the RC oscillator circuit where the capacitance value is located, k is a constant, and f represents the frequency value;

[0015] S22. Convert the frequency value into a frequency characteristic quantity by sequentially outputting rising edges as frequency characteristics.

[0016] Furthermore, the step S3 specifically includes the steps of:

[0017] S31. Count the number of rising edges received to obtain the frequency characteristic;

[0018] S32. Calculate the number of paper pages corresponding to the measured frequency characteristic quantity according to the corresponding relationship between the frequency characteristic quantity and the number of paper pages.

[0019] The present invention also provides a paper page number detection system, corresponding to the above-mentioned paper page number detection method, comprising a power supply module, a capacitor-to-frequency circuit module, a frequency measurement module, a main control chip module and a display module connected in sequence;

[0020] The power supply module is used to provide a stable power supply for the capacitor-to-frequency circuit module;

[0021] The capacitance-to-frequency circuit module is used to collect the capacitance value of a stack of paper to be detected and convert the capacitance value into a frequency characteristic quantity;

[0022] The frequency measurement module is used to obtain the frequency characteristic value and send it to the main control chip module;

[0023] The main control chip module is used to convert the frequency characteristic quantity into the corresponding paper page number and display it through the display module.

[0024] Specifically, the capacitance-to-frequency circuit module is provided with two electrode plates for clamping the stack of paper to be detected, and is also provided with an RC oscillation circuit for converting the capacitance value into a corresponding irregular signal waveform; it is also provided with a comparator chip for converting the irregular signal waveform into a regular rectangular wave, and by sequentially outputting rising edges as frequency characteristics, the frequency value represented by the rectangular wave is converted into a frequency characteristic quantity and output to the frequency measurement module;

[0025] The comparator chip is provided with a rail-to-rail high-speed comparator with a shutdown function. Preferably, the frequency measurement module adopts an FPGA chip, which can count the frequency characteristic quantity by adding 1 every time a rising edge is received and send it to the main control chip module.

[0026] Preferably, the main control chip module adopts STM32F1 series chip; the power supply module adopts LM7805CT chip, and the output power supply is 5V; the display module adopts OLED liquid crystal display screen or LCD screen.

[0027] The present invention also provides a capacitance-to-frequency circuit, corresponding to the capacitance-to-frequency circuit module of the above-mentioned paper page number detection system, provided with a comparator chip, a first electrode plate, a second electrode plate, and further provided with a first capacitor, a second capacitor and a third capacitor connected in series in sequence between the reverse input terminal of the comparator chip and the ground, the first electrode plate is connected to the common connection terminal of the first capacitor and the second capacitor, and the second electrode plate is connected to the common connection terminal of the second capacitor and the third capacitor;

[0028] A voltage stabilizing filter circuit is also provided which is connected between the power supply and the same-direction input terminal of the comparator chip, and a first resistor is connected between the same-direction input terminal of the comparator chip and the frequency signal output terminal, and a second resistor is connected between the reverse input terminal of the comparator chip and the frequency signal output terminal;

[0029] The comparator chip is provided with a rail-to-rail high-speed comparator with a shutdown function.

[0030] Preferably, the comparator chip adopts TLV3501SO-8; the shutdown signal control terminal of the comparator chip is grounded, the positive power output terminal is connected to the power supply, the negative power input terminal is grounded, and a fourth capacitor is also connected between the positive power output terminal and the negative power input terminal.

[0031] The present invention provides a paper page number detection method, which measures the capacitance value of a stack of paper to be detected and converts it into a corresponding frequency characteristic value. Finally, the specific number of papers is obtained through the correspondence between the number of papers and the frequency characteristic value. The paper test result can be displayed within 2 seconds, which is simple and efficient.

[0032] The present invention provides a paper page number detection system, which measures the capacitance value of the paper to be tested between two electrode plates through a capacitance-to-frequency circuit module, then converts the capacitance value into a frequency characteristic quantity, and then detects the frequency characteristic quantity through a frequency measurement module, and finally calculates the frequency characteristic quantity through a main control chip module to obtain a specific number of paper pages, and displays it through a display module, so that the tester can obtain the test result in time. When using this system, the tester only needs to place the paper to be tested between the two electrode plates and clamp it, and the test result can be obtained within 2 seconds using the above method. Various integrated chips used within the test range can ensure that the test speed is not affected by the number of papers. The capacitance value is determined by converting capacitance and frequency based on an RC oscillation circuit and a high-speed comparator chip instead of directly using a capacitance sensor. When the environment changes greatly, it can also work stably, is less affected by the environment, and has high system reliability. In addition, this system is built with conventional components, which is low in cost and easy to implement.

[0033] The present invention provides a capacitance-to-frequency circuit, which has a capacitance sensing sensitivity of the picofarad (pf) level and a high conversion accuracy, and can help the above-mentioned detection system and method to obtain accurate detection results; the capacitance value is determined by converting capacitance and frequency based on an RC oscillation circuit and a high-speed comparator chip instead of directly using a capacitance sensor, and can work stably even when the environment changes greatly, is less affected by the environment, and has a high circuit reliability; and the circuit is constructed using conventional components, which is low in cost and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the steps of a method for detecting the number of paper pages provided by an embodiment of the present invention;

[0035] Figure 2 It is a module structure diagram of a paper page number detection system provided by an embodiment of the present invention;

[0036] Figure 3 A capacitor-to-frequency circuit (also Figure 2 A circuit diagram of an implementation of a capacitor-to-frequency circuit module 2;

[0037] Figure 4 Detailed description of the invention The invention is a circuit diagram of a power supply module 1 in a paper number detection system provided in an embodiment of the present invention.

[0038] Figure 2 , 3 Labels in: first electrode plate A, second electrode plate B, power supply module 1, capacitor-to-frequency circuit module 2, frequency measurement module 3, main control chip module 4, display module 5; comparator chip U1, first to seventh capacitors C1 to C7, first to fifth resistors R1 to R5, voltage stabilizing filter circuit 21, RC oscillation circuit 22. DETAILED DESCRIPTION

[0039] The following is a detailed explanation of the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided only for illustrative purposes and cannot be understood as limitations on the present invention. The selection and value sizes of components and the accompanying drawings are only preferred embodiments and are only for reference and illustration purposes. They do not constitute limitations on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0040] An embodiment of the present invention provides a method for detecting the number of paper pages, such as Figure 1 The step flow chart shown includes the steps of:

[0041] S1. Collect the capacitance value of a stack of paper to be tested;

[0042] S2. Converting the capacitance value into a frequency characteristic;

[0043] S3. Convert the frequency feature into the corresponding number of paper pages.

[0044] Furthermore, the step S1 specifically includes the steps of:

[0045] S11. The paper to be tested is placed between two electrode plates and clamped;

[0046] S12. Obtain the capacitance value detected by the two electrode plates.

[0047] Furthermore, the step S2 specifically includes the steps of:

[0048] S21. The capacitance value is linearly converted into a corresponding frequency value according to a capacitance-to-frequency formula, wherein the capacitance-to-frequency formula is: f=k*C, where C represents the equivalent capacitance value of the RC oscillator circuit where the capacitance value is located, k is a constant, and f represents the frequency value;

[0049] S22. Convert the frequency value into a frequency characteristic quantity by sequentially outputting rising edges as frequency characteristics.

[0050] Furthermore, the step S3 specifically includes the steps of:

[0051] S31. Count the number of rising edges received to obtain the frequency characteristic;

[0052] S32. Calculate the number of paper pages corresponding to the measured frequency characteristic quantity according to the corresponding relationship between the frequency characteristic quantity and the number of paper pages.

[0053] Among them, in step S32, the corresponding relationship between the frequency feature quantity and the number of paper pages is a curve relationship fitted by the system through numerous tests. Through the test, Table 1 shows the frequency values ​​corresponding to the number of pages of different papers (A4 paper purchased on the market) obtained by the test. The frequency values ​​are averaged and then plotted and fitted with the number of papers to obtain Figure 2 The results are shown. The results are the frequency values ​​corresponding to the 0th to 30th sheets, respectively, repeated 3 times. From this result, it can be found that there is a fixed polynomial relationship between the number of sheets and the frequency, and the repeatability is good. Based on the test results, piecewise linear fitting or n-order polynomial fitting can be performed, and the prior calculation formula (that is, the corresponding relationship between the frequency characteristic quantity and the number of sheets of paper) can be obtained by fitting. Based on the obtained prior formula, the number of sheets of paper can be calculated according to the frequency value obtained by the test.

[0054] Table 1

[0055]

[0056]

[0057] A paper page number detection method provided by an embodiment of the present invention measures the capacitance value of a stack of paper to be detected and converts it into a corresponding frequency characteristic value. Finally, the specific number of papers is obtained through the correspondence between the number of papers and the frequency characteristic value. The paper test result can be displayed within 2 seconds. The method is simple and efficient.

[0058] The embodiment of the present invention further provides a paper page number detection system, corresponding to the above-mentioned paper page number detection method, such as Figure 2 As shown in the module structure diagram, the system includes a power supply module 1, a capacitor-to-frequency circuit module 2, a frequency measurement module 3, a main control chip module 4 and a display module 5 which are connected in sequence.

[0059] The power supply module 1 is used to provide a stable power supply for the capacitance-to-frequency circuit module 2; the capacitance-to-frequency circuit module 2 is used to collect the capacitance value of a stack of paper to be detected and convert the capacitance value into a frequency characteristic quantity; the frequency measurement module 3 is used to obtain the frequency characteristic quantity and send it to the main control chip module 4; the main control chip module 4 is used to convert the frequency characteristic quantity into the corresponding number of paper pages and display it through the display module 5.

[0060] Specifically, the capacitance-to-frequency circuit module 2 is provided with two electrode plates for clamping the stack of paper to be detected; it is also provided with an RC oscillator circuit 22 for converting the capacitance value into a corresponding irregular signal waveform; it is also provided with a comparator chip for converting the irregular signal waveform into a regular rectangular wave, and by sequentially outputting rising edges as frequency characteristics, the frequency value represented by the rectangular wave is converted into a frequency characteristic quantity and output to the frequency measurement module 3. The capacitance-to-frequency circuit module 2 can be used as follows Figure 3 The circuit shown is mainly composed of a comparator chip U1, a first plate (A), a second plate (B), a capacitor and a resistor, etc., wherein the two plates A and B are two metal conductive sheets (such as copper sheets, etc.), with a typical area of ​​5cm*5cm and a typical thickness of 1cm*1cm. The RC oscillator circuit 22 is composed of Figure 3 The second resistor R2 and the first to third capacitors C1 to C3 are composed.

[0061] Preferably, the main control chip module 4 adopts STM32F1 series chip, which can analyze the obtained frequency characteristic quantity, convert it into the number of paper sheets through an algorithm, and then display the number of paper sheets on the display screen. The power supply module 1 adopts LM7805CT chip, and the output power supply is 5V. Figure 4 shown.

[0062] The display module 5 uses an OLED liquid crystal display screen or an LCD screen. The frequency measurement module 3 uses an FPGA chip, which can count the frequency characteristic quantity and send it to the main control chip module 4 by adding 1 to the count every time a rising edge is received.

[0063] It should be noted that the specific circuit structure of the present application can preferably adopt the above structure, but is not limited to this. It is well known that in the field of electrical engineering, there are many chips and circuits that can achieve the same function. Based on this, as long as other circuit modules can realize the relevant circuit modules of the present application, they are also within the protection scope of the present application.

[0064] The embodiment of the present invention provides a paper page number detection system, which measures the capacitance value of the paper to be tested between two electrode plates through a capacitance-to-frequency circuit module 2, then converts the capacitance value into a frequency characteristic quantity, and then detects the frequency characteristic quantity through a frequency measurement module 3, and finally calculates the frequency characteristic quantity through a main control chip module 4 to obtain a specific number of paper pages, and displays it through a display module 5, so that the tester can obtain the test result in time. When using this system, the tester only needs to place the paper to be tested between the two electrode plates and clamp it, and the test result can be obtained within 2 seconds using the above method. Various integrated chips used within the test range can ensure that the test speed is not affected by the number of papers. The capacitance value is determined by converting capacitance and frequency based on an RC oscillation circuit and a high-speed comparator chip instead of directly using a capacitance sensor. When the environment changes greatly, it can also work stably, is less affected by the environment, and has high system reliability. In addition, this system is built with conventional components, which is low in cost and easy to implement.

[0065] The embodiment of the present invention further provides a capacitance-to-frequency circuit, corresponding to the capacitance-to-frequency circuit module 2 of the above-mentioned paper page number detection system, such as Figure 3 As shown, a comparator chip U1, a first electrode plate (A), a second electrode plate (B), and a first capacitor C1, a second capacitor C2, and a third capacitor C3 are sequentially connected in series between the reverse input terminal (PIN2, PIN represents a pin, the same below) of the comparator chip U1 and the ground, the first electrode plate (A) is connected to the common connection terminal of the first capacitor C1 and the second capacitor C2, and the second electrode plate (B) is connected to the common connection terminal of the second capacitor C2 and the third capacitor C3;

[0066] A voltage stabilizing filter circuit 21 connected between a power supply (5V) and the same-direction input terminal (PIN3) of the comparator chip U1, a first resistor R1 connected between the same-direction input terminal (PIN3) of the comparator chip U1 and the frequency signal output terminal (PIN6), and a second resistor R2 connected between the reverse input terminal (PIN2) of the comparator chip U1 and the frequency signal output terminal (PIN6);

[0067] The comparator chip U1 is provided with a rail-to-rail high-speed comparator with a shutdown function.

[0068] Preferably, the comparator chip U1 adopts TLV3501SO-8; the shutdown signal control terminal (PIN8) of the comparator chip U1 is grounded, the positive power output terminal (PIN7) is connected to the power supply (5V), the negative power input terminal (PIN4) is grounded, and a fourth capacitor C4 is also connected between the positive power output terminal (PIN7) and the negative power input terminal (PIN4).

[0069] As an implementation method, Figure 3 As shown, the voltage stabilizing filter circuit 21 includes a third resistor R3 and a fourth resistor R4 connected in series between the power supply (5V) and the same-direction input terminal (PIN3) of the comparator chip U1, and also includes a fifth resistor R5 connected between the same-direction input terminal (PIN3) and the ground, and also includes a fifth capacitor C5 (electrolytic capacitor, the positive pole is connected to the 5V power supply) connected between the power supply (5V) and the ground, and a sixth capacitor C6 and a seventh capacitor C7 connected in parallel between the common connection terminal of the third resistor R3 and the fourth resistor R4 and the ground. The voltage stabilizing filter circuit 21 has the function of voltage stabilizing filtering. In other embodiments, other circuit structures used to achieve the same function are also within the protection scope of this application.

[0070] It should also be noted that in step S21 of the above detection method, the RC oscillator circuit 22 is composed of Figure 3 The second resistor R2 and the first to third capacitors C1 to C3 are composed, and the typical value of R2 is 100K ohms; the equivalent capacitance value C in the formula f=k*C is calculated by connecting C1, C2, C3 and the capacitance values ​​between the first and second plates A and B in parallel, and the typical capacitance values ​​of C1, C2 and C3 are 30pf.

[0071] A capacitance-to-frequency circuit provided in an embodiment of the present invention has a capacitance sensing sensitivity of the picofarad (pf) level and a high conversion accuracy, which can help the above-mentioned detection system and method to obtain accurate detection results. The capacitance value is determined by converting capacitance and frequency based on an RC oscillator circuit and a high-speed comparator chip instead of directly using a capacitance sensor. The circuit can work stably even when the environment changes greatly, is less affected by the environment, and has a high circuit reliability. In addition, the circuit is constructed using conventional components, which is low in cost and easy to implement.

[0072] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for detecting the number of paper pages, characterized in that: Includes steps: S1. Collect the capacitance value of a stack of paper to be tested; S2. Converting the capacitance value into a frequency characteristic; S3. Converting the frequency characteristic into the corresponding number of paper pages; Step S1 specifically includes the following steps: S11. The paper to be tested is placed between two electrode plates and clamped; S12. Obtaining the capacitance value detected by the two electrode plates; The step S2 specifically includes the following steps: S21. The capacitance value is linearly converted into a corresponding frequency value according to a capacitance-to-frequency formula, wherein the capacitance-to-frequency formula is: f=k*C, where C represents the equivalent capacitance value of the RC oscillator circuit where the capacitance value is located, k is a constant, and f represents the frequency value; S22. First, convert the capacitance value into a corresponding irregular signal waveform, then convert the irregular signal waveform into a regular rectangular wave, and then convert the frequency value represented by the rectangular wave into a frequency characteristic by sequentially outputting rising edges as frequency characteristics; The step S3 specifically comprises the following steps: S31. Count the number of rising edges received to obtain the frequency characteristic; S32. Calculate the number of paper pages corresponding to the measured frequency characteristic quantity according to the corresponding relationship between the frequency characteristic quantity and the number of paper pages.

2. A paper page number detection system, characterized in that: It includes a power supply module, a capacitor-to-frequency circuit module, a frequency measurement module, a main control chip module and a display module connected in sequence; The power supply module is used to provide a stable power supply for the capacitor-to-frequency circuit module; The capacitance-to-frequency circuit module is used to collect the capacitance value of a stack of paper to be detected and convert the capacitance value into a frequency characteristic quantity; The frequency measurement module is used to obtain the frequency characteristic value and send it to the main control chip module; The main control chip module is used to convert the frequency characteristic quantity into the corresponding paper page number and display it through the display module; The capacitance-to-frequency circuit module is provided with two electrode plates for clamping the stack of paper to be detected; it is also provided with an RC oscillation circuit for converting the capacitance value into a corresponding irregular signal waveform; it is also provided with a comparator chip for converting the irregular signal waveform into a regular rectangular wave, and by sequentially outputting rising edges as frequency characteristics, converting the frequency value represented by the rectangular wave into a frequency characteristic quantity and outputting it to the frequency measurement module; The comparator chip is provided with a rail-to-rail high-speed comparator with a shutdown function; The frequency measurement module adopts an FPGA chip, which can count the frequency characteristic quantity by adding 1 every time a rising edge is received and send it to the main control chip module; The capacitor-to-frequency circuit module is characterized by: a comparator chip, a first electrode plate, a second electrode plate, and a first capacitor, a second capacitor, and a third capacitor connected in series between the reverse input terminal of the comparator chip and the ground, wherein the first electrode plate is connected to the common connection terminal of the first capacitor and the second capacitor, and the second electrode plate is connected to the common connection terminal of the second capacitor and the third capacitor; A voltage stabilizing filter circuit is also provided which is connected between the power supply and the same-direction input terminal of the comparator chip, and a first resistor is connected between the same-direction input terminal of the comparator chip and the frequency signal output terminal, and a second resistor is connected between the reverse input terminal of the comparator chip and the frequency signal output terminal; The comparator chip is provided with a rail-to-rail high-speed comparator with a shutdown function; The shutdown signal control terminal of the comparator chip is grounded, the positive power output terminal is connected to the power supply, the negative power input terminal is grounded, and a fourth capacitor is further connected between the positive power output terminal and the negative power input terminal; The power supply output by the power supply module is 5V; The display module adopts an OLED liquid crystal display screen or an LCD screen.

3. A paper page number detection system as claimed in claim 2, characterized in that: The main control chip module adopts STM32F1 series chip; the power supply module adopts LM7805CT chip.

4. A capacitance-to-frequency circuit as claimed in claim 2, characterized in that: The comparator chip adopts TLV3501 SO-8.

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