A spark-point timer with high first-point positioning accuracy

Abstract

The invention provides an electric spark dotting timer with high accuracy in first point positioning, comprising a shell, wherein a power module, a single chip microcomputer, a functional partition potentiometer, an electric spark high voltage generator, an electromagnet and a boost adjustment module are also arranged inside the shell, a display screen is arranged outside the shell, the power module is electrically connected with the single chip microcomputer, the functional partition potentiometer, the electric spark high voltage generator, the electromagnet and the boost adjustment module through a circuit, the single chip microcomputer is provided with circuit pins, and is electrically connected with the display screen, the functional partition potentiometer, the electric spark high voltage generator and the electromagnet through the circuit pins, a computer control program is arranged inside the single chip microcomputer, high voltage driving is performed through the computer control program, and a discharge needle is driven by the electric spark high voltage generator to dot, the shell is also provided with a toner paper tray and a discharge needle, and the invention changes the high voltage by making the power supply voltage adjustable; and reduces the influence of residual magnetism on the first point positioning accuracy by using an electromagnet dual control circuit.

Description

Technical Field

[0001] The invention relates to the technical field of teaching instruments, in particular to an electric spark striking timer with high first point positioning accuracy. Background Art

[0002] At present, the middle school physics experiments use electric spark dot timers to study the movement of objects on mechanical tracks. The input power is 50Hz alternating current. The period of the electric spark generated by the timer is fixed at 20ms. It can be used to calculate the acceleration at higher speeds, but it will produce large errors for the acceleration calculation at lower speeds. There are many ways to improve the accuracy of the dot timer, such as using quartz crystal oscillation as the output pulse signal source; for example, by changing the data processing method such as using the least squares method for fitting calculations; for example, improving from the automation aspect; such as by changing the fixing method, such as replacing the often easily damaged toner paper with a fine and durable ink drum, and improving the use of the dot timer to improve accuracy. At present, there are also electric spark dot timers with adjustable frequency developed using single-chip microcomputers to solve the problem of acceleration calculation errors in low-speed motion, but the electric spark dot timer still cannot solve the problem of large positioning errors at the first point with an initial velocity of zero.

[0003] Based on the above series of problems, the following technical solutions are proposed. Summary of the invention

[0004] The purpose of the present invention is to provide an electric spark striking timer with high accuracy in first point positioning, which can change the high voltage by adjusting the power supply voltage; and reduce the influence of residual magnetism on the first point positioning accuracy by using an electromagnet dual control circuit.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a spark dotting timer with high accuracy in first point positioning, comprising a shell, wherein a power module, a single chip microcomputer, a functional partition potentiometer, a spark high voltage generator, an electromagnet and a boost adjustment module are also arranged inside the shell, a display screen is arranged outside the shell, the power module is electrically connected with the single chip microcomputer, the functional partition potentiometer, the spark high voltage generator, the electromagnet and the boost adjustment module through a circuit, the single chip microcomputer is provided with a circuit pin, and is electrically connected with the display screen, the functional partition potentiometer, the spark high voltage generator and the electromagnet through the circuit pin, a computer control program is arranged inside the single chip microcomputer, and high voltage driving is performed through the computer control program, and a discharge needle is driven to dot through the spark high voltage generator, and a toner paper tray and a discharge needle are also arranged on the shell, and when the dotting timer starts working, the paper tape is measured by the dots made by the toner paper tray and the discharge needle.

[0007] Furthermore, a residual magnetic control circuit is provided in the single chip microcomputer, and the residual magnetic control circuit is externally connected to an electromagnet, and the initial running speed of the trolley when the dot timer is running is controlled by the magnetic force of the electromagnet.

[0008] Furthermore, the shell is provided with a groove, a toner paper tray is placed on the groove, a discharge needle is provided in the middle of the toner paper tray, and the discharge needle performs discharge dotting under the drive of the electric spark high voltage generator.

[0009] Furthermore, a conductive sheet paper pressing strip is fixedly provided on one end of the shell, and the paper tape is pressed by the conductive sheet paper pressing strip.

[0010] Furthermore, the power module is provided with a power button, which is connected to a household power voltage of 220V. When the dotting timer needs to be used, the power button of the dotting timer is pressed and connected to the household power voltage.

[0011] Furthermore, the computer control program is externally provided with a parallel interface, through which a pulse signal is output to a high-voltage drive circuit, the high-voltage drive circuit drives a high-voltage module, and the high-voltage module outputs a high-voltage arc to produce an electric spark.

[0012] Furthermore, the high-voltage module is provided with an N-channel MOS tube. When the power is turned on, the parallel interface outputs a high level, the base B of the transistor is pulled up by the power supply, the collector C of the transistor is at a low level, the gate of the MOS tube is at a low level, and the anode of the MOS tube is at a high level and cut off; when the parallel interface outputs a low level, the transistor is cut off, the gate of the MOS tube is at a high level, the anode of the MOS tube is at a low level and turned on, the current is turned on to the ground through the primary of the high-voltage coil, and the secondary high voltage is output to generate electric sparks.

[0013] Furthermore, when the high-level pulse signal from the parallel interface turns on the transistor, the C pole of the transistor outputs a low level, the gate of the MOS tube is at a low level, the anode of the MOS tube is at a high level and is cut off, and there is no high voltage output.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Adjustable spark

[0016] The spark pulse width is adjustable (5us~100us), the number of points is adjustable, the frequency is adjustable, and the high voltage is adjustable. The experimental parameters can be set according to different paper and climatic conditions, and the dotting mode (double pulse mode) can be adjusted to prevent the occurrence of leakage points.

[0017] 2. Improvement of electromagnet control circuit

[0018] A dual control circuit is used to reduce the influence of the residual magnetism of the electromagnet on the initial velocity of the car; a narrow pulse controlled by a single-chip microcomputer is used to determine the accuracy of the first point positioning of the paper tape.

[0019] 3. Innovation in data processing methods

[0020] The use of electromagnet dual control circuit can reduce the influence of electromagnet on the accuracy of first point positioning, so that a simpler calculation method can be added to the original difference method and simultaneous equation method when processing data. The calculation is carried out, and it is verified by experiments that the accuracy of the calculated acceleration can be improved.

[0021] 4. Innovation in control device migration method

[0022] From computer control technology research to the transfer of results to single-chip microcomputer control technology, an electric spark timer based on high-precision single-chip microcomputer control for first-point positioning was produced.

[0023] 5. Extend the service life of toner paper

[0024] The high voltage under the control of 14V power supply causes less damage to the toner paper and the dots on the paper tape are small and clear, which improves the measurement accuracy of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is the circuit topology diagram of the first point positioning high-precision electric spark timer;

[0027] Figure 2 It is a structural diagram of a first-point positioning high-precision electric spark timer;

[0028] Figure 3 This is a partial content diagram of the computer program of the present invention. Figure 1 ;

[0029] Figure 4 This is a partial content diagram of the computer program of the present invention. Figure 2 ;

[0030] Figure 5 This is a partial content diagram of the computer program of the present invention. Figure 3 ;

[0031] Figure 6 It is the schematic diagram of the high voltage spark circuit for debugging at the computer LPT port;

[0032] Figure 7It is a line chart of data processing by the old dot timer;

[0033] Figure 8 It is a line chart of data processing by the new dot timer;

[0034] In the figure: 1 power module; 2 single chip microcomputer; 3 functional partition potentiometer; 4 display screen; 5 electric spark high voltage generator; 6 electromagnet; 7 boost adjustment module; 8 paper tape; 9 conductive sheet pressure strip; 10 toner paper tray; 11 discharge needle DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0036] The present invention provides a first point positioning high-precision electric spark timer. Figure 1 to Figure 8 The technical solution provided by the present invention is described in more detail.

[0037] Before explaining the specific process of the present invention, the following specialized terms and concepts that may be mentioned in the present invention are first described:

[0038] parallel port

[0039] It is usually called a printer port or LPT port. Ordinary computers are generally equipped with a parallel port, which can obtain external signals, process them through programming languages, and control external devices through the closure of relays to achieve the purpose of automatic control. The parallel port has 25 pins. In a PC, the standard parallel port uses three 8-bit port registers, which are data, status, and control registers. The parallel port can be used for digital input and output. Digital output means that a certain switch point of a certain device is turned on or off when the program requires it. The parallel port can be used as a digital output port or a digital input port.

[0040] VB programming software

[0041] VB is the abbreviation of Visual Basic. It was developed by Microsoft Corporation in 1991. It is a structured, modular, object-oriented, and visual programming language that includes an event-driven mechanism to assist the development environment. It can be used to develop various applications under the Windows environment. It is simple, easy to learn, efficient, and powerful. In the Visual Basic environment, using event-driven programming mechanisms, novel and easy-to-use visual design tools, and using a wide range of application program interface (API) functions, dynamic link libraries (DLLs), object linking and embedding (OLE), open data connectivity (ODBC) and other technologies within Windows, you can efficiently and quickly develop powerful and graphically rich application software systems under the Windows environment, which is especially suitable for beginners to learn.

[0042] By applying VB programming software and independently developed computer parallel port controls and sensor controls, the communication between sensors and computers is directly and simply connected, extending directly from virtual experiments to the real world.

[0043] like Figure 1-2 As shown, a first-point positioning high-precision electric spark dotting timer includes a shell, wherein the shell is further provided with a power module 1, a single-chip microcomputer 2, a functional partition potentiometer 3, an electric spark high-voltage generator 5, an electromagnet 6 and a boost adjustment module 7, and the shell is provided with a display screen 4 outside. The power module 1 is electrically connected with the single-chip microcomputer 2, the functional partition potentiometer 3, the electric spark high-voltage generator 5, the electromagnet 6 and the boost adjustment module 7 through a circuit, the single-chip microcomputer 2 is provided with a circuit pin, and is electrically connected with the display screen 4, the functional partition potentiometer 3, the electric spark high-voltage generator 5, and the electromagnet 6 through the circuit pin, the single-chip microcomputer 2 is provided with a computer control program, and high-voltage driving is performed through the computer control program, and the discharge needle 11 is driven to dot through the electric spark high-voltage generator 5, and the shell is further provided with a toner paper tray 10 and a discharge needle 11, and when the dotting timer starts working, the paper tape 8 is measured by the dotting of the toner paper tray 10 and the discharge needle 11.

[0044] Preferably, the single chip microcomputer 2 is provided with a residual magnetic control circuit, and the residual magnetic control circuit is externally connected to an electromagnet 6, and the magnetic force of the electromagnet 6 is used to control the initial running speed of the trolley when the dotting timer is running.

[0045] Preferably, the housing is provided with a groove, a toner paper tray 10 is placed on the groove, a discharge needle 11 is provided in the middle of the toner paper tray 10, and the discharge needle 11 performs discharge dot-making under the drive of the electric spark high-voltage generator 5.

[0046] Preferably, a conductive sheet pressing strip 9 is fixedly provided on one end of the housing, and the paper tape 8 is pressed by the conductive sheet pressing strip 9 .

[0047] Preferably, the power module 1 is provided with a power button, and the power button is externally connected to a household power voltage of 220V. When the dotting timer needs to be used, the power button of the dotting timer is pressed and connected to the household power voltage.

[0048] Preferably, the computer control program is externally provided with a parallel interface, and a pulse signal is output to a high-voltage drive circuit through the parallel interface. The high-voltage drive circuit drives a high-voltage circuit module, and the high-voltage module outputs a high-voltage arc to produce an electric spark.

[0049] Preferably, the high-voltage circuit module is provided with an N-channel MOS tube. When the power is turned on, the parallel interface outputs a high level, the base B of the transistor is pulled up by the power supply, the collector C of the transistor is low level, the gate of the MOS tube is low level, and the anode high level of the MOS tube is cut off; when the parallel interface outputs a low level, the transistor is cut off, the gate of the MOS tube is high level, the anode low level of the MOS tube is turned on, the current is turned on to the ground through the primary of the high-voltage coil, and the secondary high voltage is output to generate electric sparks.

[0050] Preferably, when the high-level pulse signal from the parallel interface turns on the transistor, the C pole of the transistor outputs a low level, the gate of the MOS tube is at a low level, the anode of the MOS tube is at a high level and is cut off, and no high voltage is output.

[0051] like Figure 3-5 As shown, it is a schematic diagram of the contents of the computer control program of the present invention. Figure 3-5 The contents shown are used to control the operation of the microcontroller.

[0052] The technical solution of the present invention is to use computer control technology to study the influence of electric spark on the damage degree of printing toner paper and the clarity of paper tape under different power supply voltages, and transplant the research results to single chip 2. Using single chip 2 control technology, a frequency-adjustable electric spark control program is written to solve the problem of missing points caused by selecting multiple points for calculation using the difference method when the speed of the track trolley is too small; solve the problem of large errors in calculating the first few points using the formula S=at2 / 2 due to residual magnetism when the initial speed is zero when the electromagnet is used to control the first point dotting positioning; explore the influence of high voltage size and discharge port on dotting accuracy.

[0053] The specific operation process includes the following:

[0054] As we all know, the spark dot timer is a timing instrument that uses spark discharge to make toner dots on paper tape to show dot traces. Connect the spark dot timer to a 220V power supply, press the pulse output switch, and the pulse current emitted by the timer connects the positive discharge needle and the toner paper tray to the negative paper tray shaft, generating spark discharge, thus making a series of dots on the paper tape, and discharges once in each cycle of the alternating current, so the time interval between the dots of the spark dot timer is equal to the cycle of the alternating current. When the power frequency is 50 Hz, it makes a dot every 0.02S. It is a commonly used speed measuring instrument in high schools.

[0055] The present invention preferably adopts computer control program to make electric spark timer, first selects Figure 6 The high voltage module shown, such as Figure 6 The circuit principle shown is as follows:

[0056] IRF540 is an N-channel MOS tube, which is used in the range of 100V / 33A. It can be used as a PWM driver tube to drive solenoid valves or relays. The current flows from D to S, and the gate G is turned on at a high level.

[0057] When the power is turned on, the LPT port outputs a high level, the base B of the transistor is pulled up by the power supply, the collector C of the transistor is at a low level, the gate of the MOS tube is at a low level, and the high level of the anode of the MOS tube is cut off; when the LPT port outputs a low level, the transistor is cut off, the gate of the MOS tube is at a high level, the low level of the anode of the MOS tube is turned on, the current is turned on to the ground through the primary of the high-voltage coil, and the secondary high voltage is output to generate sparks; when the high-level pulse signal from the LPT port turns on the transistor, the C pole of the transistor outputs a low level, the gate of the MOS tube is at a low level, the high level of the anode of the MOS tube is cut off, and there is no high voltage output; in this way, the single-pulse electric spark dot after the modification is clear and round, without missing points and tailing.

[0058] A PTC resettable fuse is connected in series at the input end of the power supply. When the overcurrent and overheating fault caused by excessive current is eliminated, the resettable fuse element automatically recovers to a low resistance state to ensure that the IRF540MOS tube is not broken down. This avoids maintenance and replacement, and also avoids the continuous cycle of on and off states that may cause circuit damage. The reason why the resettable fuse has the dual functions of overcurrent and overheating protection and automatic recovery is due to its special manufacturing.

[0059] The boost adjustment module is used to change the output voltage of the high-voltage module. When the high-precision potentiometer rotates clockwise, the output voltage increases, and vice versa.

[0060] The following is the process of conducting a specific experiment using the timer designed according to the present invention:

[0061] 1. Effect of power supply change on paper tape dotting

[0062] sheet:

[0063]

[0064] In single pulse mode, when the voltage is small (less than 16V), no dots visible to the naked eye can be produced. When the voltage is slightly larger (greater than 16V), dots can be produced, but there is a phenomenon of missing dots, which will not disappear until about 20V. In single pulse mode, when the voltage is small, no dots visible to the naked eye can be produced. The larger the voltage, the clearer and larger the dots, and the less likely it is to have missing dots.

[0065] In the dual pulse mode, when the voltage is 12V to 16V, the damage to the toner paper is small, but the dots are blurred and there will be missing dots. When the voltage is above 17V, the dots are clear but the radius is large, and the damage to the toner paper is greater. Therefore, in the dual pulse mode, the higher the voltage, the clearer the dots, the larger the dot size, the less likely it is to have missing dots, and the greater the damage to the toner paper.

[0066] In the three-pulse mode, when the voltage is low (12V~16V), the dots printed are clearer, but when the voltage is 12V or 13V, there will be missing dots and some damage to the toner paper; when the voltage is 17V~20V, the dots printed are darker in color and the damage to the toner paper is relatively large. Therefore, in the three-pulse mode, the higher the voltage, the darker the color of the dots, the larger the size, the less likely it is to have missing dots, and the greater the damage to the toner paper.

[0067] 2. Explore the effect of pulse width on the dotting effect of paper tape (double-dot pulse)

[0068]

[0069] In the dual pulse mode, at a voltage of 14V, the dots printed are relatively clear without any missed dots. The larger the pulse width, the larger the printed dots and the greater the damage to the toner paper.

[0070] In the dual pulse mode, at a voltage of 15V, the dots printed are relatively clear without missing dots. The larger the pulse width, the larger the printed dots, causing more damage to the toner paper. The dots are larger than at a voltage of 14V, causing more damage to the toner paper.

[0071] In the dual pulse mode, at a voltage of 16V, the dots printed are relatively clear without missing dots. The larger the pulse width, the larger the printed dots, which causes more damage to the toner paper. The dots are larger than at a voltage of 15V, which causes more damage to the toner paper.

[0072] 3. Explore the dotting effect of different power supply voltages on paper tape with pulse width below 5us (double dot pulse)

[0073]

[0074] When the voltage is 14V and the pulse width is below 5us, the larger the pulse width, the clearer the printed dots are and the greater the damage to the toner paper is, but there is still a phenomenon of missing dots.

[0075] When the voltage is 15V and the pulse width is below 5us, the larger the pulse width, the clearer the dots are, the greater the damage to the toner paper is, and the leakage phenomenon is less obvious than when the voltage is 14V, but the damage to the toner paper is greater.

[0076] When the voltage is 16V and the pulse width is below 5us, the larger the pulse width, the clearer the dots are and the greater the damage to the toner paper. However, there is no leakage at this time and the damage to the toner paper is greater than at 15V.

[0077] 4. Explore the dotting effect of different dot numbers on paper tape under 14 V voltage and 4us pulse width (double dot pulse)

[0078] Under the condition of 14V voltage and 4us pulse width, the more dots are punched at the same position, the greater the damage to the toner paper.

[0079] 5. Summary of experimental results

[0080] Through experiments, it is found that the dots formed by the narrow pulse of 4us hitting the toner paper are difficult to distinguish with the naked eye, while the dots on the paper tape are clearly visible. It can be inferred that the dots formed on the paper tape are formed by the toner being adsorbed onto the paper tape due to the discharge effect. The difference in the leakage of dots between the analysis of the experimental power supply change on the dotting effect of the paper tape and the experimental exploration of the pulse width on the dotting effect of the paper tape may be due to insufficient experience in the first experiment. The toner paper experiment lasted too long, causing the toner paper to be punctured and empty, resulting in leakage points; in the following experiments, the toner paper was changed every time to retain clear printing damage points; based on the above 4 groups of experiments, it is concluded that under the high voltage generated by 14V voltage and 4us pulse width, the damage to the toner paper is minimal and the print dots printed on the paper tape are small and clearly visible. After dragging the paper tape, no leakage phenomenon was found. Therefore, we will proceed to the design of the next microcontroller product and apply the above experimental results to the production of the work of the microcontroller-controlled electric spark dotting timer.

[0081] The following is a comparison of the test results of the traditional dotting timer and the new dotting timer:

[0082] 1. Data processing of the timer of old works

[0083] The old product dot timer can be used because the first point is available, so the formula can be used Perform data processing.

[0084] The following is the formula Experimental data for data processing

[0085] 2. Data processing of the new work timer

[0086] Figure 8 This is the image drawn using the above data

[0087] 3. Summary of experimental results

[0088] The difference between the experimental power supply change on the dotting effect of the paper tape and the experimental exploration of the pulse width on the dotting effect of the paper tape in terms of leakage may be due to insufficient experience in the first experiment. The printing toner paper experiment lasted too long, causing the toner paper to be punctured and causing leakage. In the following experiments, the printing toner paper was changed every time to retain clear printing damage points. Combining the above 4 groups of experiments, it is concluded that under the high voltage generated by 14V voltage and 4us pulse width, the damage to the printing toner paper is minimal and the print dots printed on the paper tape are small and clearly visible. After dragging the paper tape, no leakage phenomenon was found. Therefore, we will proceed to the next step of the single-chip microcomputer product design work and apply the above experimental results to the production of the single-chip microcomputer controlled electric spark dotting timer.

[0089] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A spark timer with high first point positioning accuracy, comprising a housing, characterized in that: A power module, a single-chip microcomputer, a functional partition potentiometer, an electric spark high-voltage generator, an electromagnet and a boost adjustment module are also arranged inside the shell, a display screen is arranged outside the shell, the power module is electrically connected with the single-chip microcomputer, the functional partition potentiometer, the electric spark high-voltage generator, the electromagnet and the boost adjustment module through a circuit, the single-chip microcomputer is provided with a circuit pin, and is electrically connected with the display screen, the functional partition potentiometer, the electric spark high-voltage generator and the electromagnet through the circuit pin, a computer control program is arranged inside the single-chip microcomputer, a high-voltage drive is performed through the computer control program, and a discharge needle is driven to perform dotting through the electric spark high-voltage generator, a toner paper tray and a discharge needle are also arranged on the shell, and when the dotting timer starts working, the paper tape is measured through the dotting of the toner paper tray and the discharge needle; The boost adjustment module is used to change the output voltage of the high-voltage module. When the high-precision potentiometer rotates clockwise, the output voltage increases, and vice versa. The computer control program is externally provided with a parallel interface, through which a pulse signal is output to a high-voltage drive circuit, the high-voltage drive circuit drives a high-voltage module, and the high-voltage module outputs a high-voltage arc to produce an electric spark.

2. The first point positioning high-precision electric spark timer as claimed in claim 1, characterized in that: The single chip microcomputer is provided with a residual magnetic control circuit, and the residual magnetic control circuit is externally connected to an electromagnet, and the initial running speed of the trolley when the dot timer is running is controlled by the magnetic force of the electromagnet.

3. The first point positioning high-precision electric spark striking timer as claimed in claim 1, characterized in that: The shell is provided with a groove, a toner paper tray is placed on the groove, a discharge needle is provided in the middle of the toner paper tray, and the discharge needle performs discharge dotting under the drive of an electric spark high voltage generator.

4. The first point positioning high-precision electric spark striking timer as claimed in claim 1, characterized in that: A conductive sheet paper pressing strip is fixedly provided on one end of the shell, and the paper tape is pressed by the conductive sheet paper pressing strip.

5. The first point positioning high-precision electric spark striking timer as claimed in claim 1, characterized in that: The power module is provided with a power button, which is connected to a household power supply voltage of 220V. When the dotting timer needs to be used, the power button of the dotting timer is pressed and connected to the household power supply voltage.

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