Experimental balance convenient for accurate reading

Abstract

An experimental balance facilitating accurate reading comprises a base, a supporting frame is fixed to the middle of the top end of the base, a fixing frame is rotatably connected to the top end of the supporting frame, trays are installed at the two ends of the fixing frame, a ruler is fixedly installed in the middle of the front wall of the fixing frame, and a rider sleeves the outer side of the ruler; the scale is a PCB, the front side of the scale is provided with scale marks, the back side of the scale is provided with a patch B and a patch A, the back side of the scale is provided with a fixing groove, and a carbon film resistor is printed in the fixing groove; the rider is connected with the carbon film resistor through the spring and the steel ball; the voltage division circuit is arranged on the scale, and the voltage division circuit is connected with the patch B and the patch A; the single chip microcomputer is connected with the voltage division circuit; according to the invention, the rider monitoring value of the experiment can be accurately and rapidly read without being influenced by the outside, and the experiment results of students can be better guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of measuring tools, and in particular to an experimental balance that is convenient for accurate reading and its application. Background Art

[0002] With the development of artificial intelligence technology and the deepening of educational informatization reform, intelligent experimental instruments have entered campus laboratories. The intelligence of teaching equipment has provided a safe and stable learning and examination environment for middle school physiology, chemistry and biology experiments.

[0003] Prior art CN206399513U discloses a high-precision physical balance, including a base, a column and a crossbeam, wherein the base is arranged at the lower end of the column, the crossbeam is arranged at the upper end of the column, the crossbeam is rotatably connected to the column, a fixed platform is arranged between the column and the base, the upper end of the fixed platform is fixedly connected to the column, the lower end of the fixed platform is fixedly connected to the base, a dial is fixedly arranged on the upper end of the fixed platform, the dial is arranged at the front end of the column, a laser pointer is fixedly arranged at the lower end of the crossbeam, a straight-line gap is arranged at the lower end of the laser pointer, trays are arranged at the left and right ends of the crossbeam, the upper end of the tray is rotatably connected to the crossbeam, a fixing rod is fixedly arranged at the lower end of the tray, and a fixing seat is arranged at the upper end of the base. The high-precision physical balance adopts a laser pointer as a pointer to avoid the pointer breaking and reading errors during use. In order to facilitate high-precision reading, the prior art only makes improvements on the pointer, and still needs to read the value manually. It is easy to have errors in the artificial reading of the value during the experiment. Because of the differences between people, the results are not unique, and the read values ​​are not accurate enough;

[0004] Therefore, there is an urgent need for an experimental balance that is easy to read accurately, can read the value of the sliding code accurately and quickly, and is not affected by external human factors. Summary of the invention

[0005] The purpose of the present invention is to provide an experimental balance that is easy to read accurately. By improving the traditional balance scale, the product is upgraded and the production cost is reduced. At the same time, accurate and fast reading of experimental values ​​is achieved, the error range is reduced, and the problems existing in the above-mentioned prior art are solved.

[0006] A laboratory balance for easy and accurate reading, comprising;

[0007] A base, a support frame is fixed in the middle of the top of the base, a fixing frame is rotatably connected to the top of the support frame, trays are installed at both ends of the fixing frame, a ruler is fixed in the middle of the front wall of the fixing frame, and a sliding weight is sleeved on the outside of the ruler;

[0008] The scale is a PCB board, the front of the scale is provided with scale lines, the back is provided with patch B and patch A, the back of the scale is provided with a fixing groove, the fixing groove is printed with a carbon film resistor, and the sliding weight sleeve is provided on the scale;

[0009] A cylindrical groove is provided on a surface of the sliding weight close to the back of the scale, a spring is fixed at the bottom of the groove, a steel ball is fixed at the top of the spring, and the steel ball is in contact with the carbon film resistor;

[0010] A voltage divider circuit, the voltage divider circuit is arranged on the scale, and the voltage divider circuit is connected to the patch B and the patch A;

[0011] A single chip microcomputer, wherein the single chip microcomputer is connected to the voltage divider circuit;

[0012] The single chip microcomputer, digital-to-analog conversion module, wireless module connection, and PC terminal are connected in sequence from left to right.

[0013] Preferably, in the voltage divider circuit, pin 1 of H4 is connected to the power supply, pin 2 of H4 is grounded through resistor R24, pin 2 of H4 is grounded through capacitor C27, resistor R24 ​​and capacitor C27 are connected in parallel, pin 2 of H4 is connected to the ADC channel, pin 1 of H4 is connected to patch B through a cable; pin 2 of H4 is connected to patch A through a cable, and the single-chip microcomputer is connected to the ADC channel.

[0014] Preferably, the cable is 36AWG Teflon wire.

[0015] Preferably, the resistance range of the resistor R24 ​​is 900-1000 ohms.

[0016] Preferably, the capacitance is 80-120 nanofarads.

[0017] Preferably, the resistance value of the coating resistor is 800-1200 kilo-ohms.

[0018] Preferably, a dividing plate is fixedly mounted in the middle of the top of the base, a pointer is fixedly mounted in the middle of the top of the fixing frame, and balance nuts are fixedly connected at both ends of the fixing frame.

[0019] Preferably, a non-slip pad is fixed to the bottom end of the base.

[0020] Preferably, the ruler is a PCB board manufactured by an immersion gold process.

[0021] The present invention discloses the following technical effects:

[0022] The invention discloses an experimental balance that is convenient for accurate reading. By designing a voltage divider circuit, a slider moves on a scale and forms an adjustable resistance structure with a carbon film resistor through a steel ball and a spring. When the slider is at different positions on the scale, its resistance value is constantly changing, generating different sampling values. The current slider voltage on the scale is obtained according to a median filtering algorithm of the sampling values. A computer program analyzes the current slider scale position according to a self-made scale data table algorithm to achieve accurate reading. Compared with a traditional balance scale, the slider acquisition value of the invention is more accurate and the error range is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 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 labor.

[0024] Figure 1 : A schematic diagram of the structure of an experimental balance that is convenient for accurate readings of the present invention;

[0025] Figure 2 : Schematic diagram of the voltage divider circuit of the present invention;

[0026] Figure 3 : A schematic diagram of the front structure of the ruler of the present invention;

[0027] Figure 4 : Schematic diagram of the back structure of the ruler of the present invention;

[0028] Figure 5 : A cross-sectional view of the swimming code of the present invention;

[0029] Figure 6 : Schematic diagram of the data conversion structure of the present invention;

[0030] Figure 7 : The present invention's swimming code collects numerical diagrams;

[0031] Among them, 1 is the base, 2 is the support frame, 3 is the fixed frame, 4 is the tray, 5 is the ruler, 6 is the sliding weight, 61 is the groove, 62 is the steel ball, 63 is the spring, 7 is the dividing plate, 8 is the pointer, 9 is the balance nut, 10 is the fixed slot, 11 is the carbon film resistor, 12 is the patch B, 13 is the patch A, 14 is the vertical frame, 15 is the sliding rod, and 16 is the support. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The invention discloses an experimental balance which is convenient for accurate reading, comprising:

[0035] Base 1, a support frame 2 is fixed to the middle of the top of the base 1, a fixed frame 3 is rotatably connected to the top of the support frame 2, vertical frames 14 are symmetrically arranged at both ends of the fixed frame 3 with the support frame 2 as the symmetry axis, the vertical frame 14 is rotatably connected to the fixed frame 3, a tray 4 is fixed to the top of the vertical frame 14, a slide groove is opened at the bottom of the vertical frame 14, a support 16 is fixed to the top of the base 1 relative to the bottom of the vertical frame 14, a slide rod 15 is fixed on the support 16, the top of the slide rod 15 is slidably connected to the slide groove, a ruler 5 is fixedly installed in the middle of the front wall of the fixed frame 3, and a sliding code 6 is sleeved on the outer side of the ruler 5;

[0036] The scale 5 is a PCB board, with scale lines on the front side, patches B12 and A13 on the back side, a fixing groove 10 on the back side, a carbon film resistor 11 printed in the fixing groove 10, and a sliding weight 6 set on the scale 5;

[0037] A cylindrical groove 61 is provided on one side of the sliding weight 6 close to the back side of the scale 5 . A spring 63 is fixed to the bottom of the groove 61 . A steel ball 62 is fixed to the top of the spring 63 . The steel ball 62 is in contact with the carbon film resistor 11 .

[0038] A voltage divider circuit, the voltage divider circuit is arranged on the scale 5, and the voltage divider circuit is connected to the patch B12 and the patch A13;

[0039] A single chip microcomputer is connected with a voltage divider circuit;

[0040] The single-chip microcomputer, digital-to-analog conversion module, wireless module connection, and PC terminal are connected from left to right.

[0041] In this embodiment, the side of the scale 5 away from the fixing frame 3 is the front side, and the side close to the fixing frame 3 is the back side.

[0042] In this embodiment, the front side of the scale 5 is provided with scale marks of 0-5g.

[0043] In this embodiment, pin 1 of H4 in the voltage divider circuit is connected to the power supply, pin 2 of H4 is grounded through resistor R24, pin 2 of H4 is grounded through capacitor C27, resistor R24 ​​and capacitor C27 are connected in parallel, pin 2 of H4 is connected to the ADC channel, pin 1 of H4 is connected to patch B12 through a cable; pin 2 of H4 is connected to patch A13 through a cable, and the microcontroller is connected to the ADC channel.

[0044] According to the schematic diagram Figure 2 It can be seen that pin 1 of H4 is connected to a 3.3V power supply and is connected to point B of the ruler through a cable. The current flows as follows: point B of the ruler --> back of the ruler --> slider --> spring --> steel ball --> carbon film resistor --> point A of the ruler; point A is connected to pin 2 of H4 through a cable, and the current enters the reference ground after passing through resistor R24 ​​to form a loop. When the slider moves from 0g to 5g on the ruler, the carbon film resistor changes from large to small, and the collected voltages at points A and B change from small to large.

[0045] In this embodiment, the cable is a 36AWG Teflon wire.

[0046] In this embodiment, the resistance range of the resistor R24 ​​is 1000 ohms.

[0047] In this embodiment, the capacitance is 100 nanofarads.

[0048] In this embodiment, the resistance value of the coating resistor is 10 kilo-ohms.

[0049] In this embodiment, a dividing plate 7 is fixedly installed at the middle of the top of the base 1, a pointer 8 is fixedly installed at the middle of the top of the fixing frame 3, and balance nuts 9 are fixedly connected at both ends of the fixing frame 3.

[0050] In this embodiment, an anti-skid pad is fixed to the bottom end of the base 1 .

[0051] In this embodiment, the scale 5 is a PCB board manufactured by using an immersion gold process.

[0052] The solution for detecting the numerical value of the sliding weight of a tray balance of the present invention is as follows: an object to be weighed is placed in the tray on the left side of the balance, and a corresponding weight is placed in the tray on the right side of the balance, the position of the balance pointer is observed, and the sliding weight is moved for leveling; the sliding weight of the balance moves on the scale and is converted into a corresponding numerical value through a voltage divider circuit, and the numerical value is collected by a single chip microcomputer for digital-to-analog conversion and then sent to the PC terminal software through a wireless module.

[0053] The specific experimental process is as follows:

[0054] Experiment 1:

[0055] Experimental requirements: Students return the sliding weight on the balance scale to zero, and the microcontroller reads the sliding weight to collect the numerical value.

[0056] Intelligent judgment function: the sliding weight is reset to zero and debugged until the balance is balanced.

[0057] Implementation plan: Students move the cursor to the 0 scale line of the balance scale and observe whether the balance pointer 8 of the balance is centered. When the balance pointer 8 deviates to one side, use the balance nut 9 on that side to level it until the balance pointer 8 is centered. The microcontroller selects DMA to collect the register value through ADC channel 1, and then uses the median filter algorithm to obtain the current cursor voltage on the scale. The program parses the scale position of the current cursor according to the self-made scale data table algorithm.

[0058] Experiment 2:

[0059] Experimental requirements: When testing the mass of an object, the microcontroller reads the sliding code to collect the value.

[0060] Intelligent judgment function: move the sliding weight on the ruler until the balance is balanced.

[0061] Implementation plan: Students place the object to be measured on the left tray of the balance, use tweezers to select the appropriate weight and place it on the right tray, and then move the cursor 6 on the ruler to level it. When the pointer 8 of the balance is centered, the cursor 6 position is no longer adjusted. The microcontroller reads the current cursor 6 acquisition value and the right tray weight value, and then calculates and uploads them to the computer through the wireless device.

[0062] The working principle of the experimental balance for accurate reading of the present invention is as follows: the steel ball 62 contacts the carbon film resistor 11. When the slider 6 moves on the scale 5 according to the mass of the object, the steel ball 62 contacts different positions of the carbon film resistor 11 as the slider 6 moves, so that a variable resistor is formed. The slider 6, the spring 63, the steel ball 62 and the carbon film resistor 11 constitute an adjustable resistor principle, so that different scales correspond to different collection voltages.

[0063] The working principle of the resistor divider can be described by the following formula: Vout = Vin×(R2 / (R1+R2)), where Vout represents the output voltage, Vin represents the input voltage, and R1 and R2 represent the resistance values ​​of two series resistors respectively.

[0064] According to the above principle, pin 1 of H4 is connected to point B on the back of the ruler through a 36AWG Teflon wire; pin 2 of H4 is connected to point A on the back of the ruler in the same way; the adjustable resistance principle is realized by moving the steel ball of the sliding code on the carbon film resistor; R1 is the adjustable resistor, R2 is R24, and the formula is Vout=Vin×(R24 / (Radjustable+R24)); when the steel ball of the sliding code moves from 0g to 5g, the resistance value of the adjustable resistor becomes smaller, and the voltage division acquisition value Vout gradually increases; when the steel ball of the sliding code moves from 5g to 0g, the resistance value of the adjustable resistor becomes larger, and the voltage division acquisition value Vout gradually decreases; by changing the size of the resistance, different sampling voltages are achieved at different scale positions, thereby realizing the judgment of the sliding code quality reading based on the collected data.

[0065] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0066] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A laboratory balance that facilitates accurate readings, characterized in that: include A base, a support frame is fixed in the middle of the top of the base, a fixing frame is rotatably connected to the top of the support frame, trays are installed at both ends of the fixing frame, a ruler is fixed in the middle of the front wall of the fixing frame, and a sliding weight is sleeved on the outside of the ruler; The scale is a PCB board, the front of the scale is provided with scale lines, the back is provided with patch B and patch A, the back of the scale is provided with a fixing groove, the fixing groove is printed with a carbon film resistor, and the sliding weight is set on the scale; A cylindrical groove is provided on a surface of the sliding weight close to the back of the scale, a spring is fixed at the bottom of the groove, a steel ball is fixed at the top of the spring, and the steel ball is in contact with the carbon film resistor; The swimming weight is connected to the carbon film resistor via a spring and a steel ball; A voltage divider circuit, the voltage divider circuit is arranged on the scale, and the voltage divider circuit is connected to the patch B and the patch A; A single chip microcomputer, wherein the single chip microcomputer is connected to the voltage dividing circuit; The single chip microcomputer, digital-to-analog conversion module, wireless module connection, and PC terminal are connected in sequence from left to right.

2. A laboratory balance for accurate reading according to claim 1, characterized in that: In the voltage divider circuit, pin 1 of H4 is connected to the power supply, pin 2 of H4 is grounded through resistor R24, pin 2 of H4 is grounded through capacitor C27, resistor R24 ​​and capacitor C27 are connected in parallel, pin 2 of H4 is connected to the ADC channel, pin 1 of H4 is connected to patch B through a cable; pin 2 of H4 is connected to patch A through a cable, and the single-chip microcomputer is connected to the ADC channel.

3. A laboratory balance for accurate reading according to claim 2, characterized in that: The cable is 36AWG Teflon wire.

4. A laboratory balance for accurate reading according to claim 2, characterized in that: The resistance range of the resistor R24 ​​is 900-1100 ohms.

5. The laboratory balance for accurate reading according to claim 2, characterized in that: The capacitance is 80-120 nanofarads.

6. The laboratory balance for accurate reading according to claim 1, characterized in that: The resistance value of the carbon film resistor is 800-1200 kilo-ohms.

7. The laboratory balance for accurate reading according to claim 1, characterized in that: A dividing plate is fixedly installed at the middle of the top of the base, a pointer is fixedly installed at the middle of the top of the fixing frame, and both ends of the fixing frame are fixedly connected with balance nuts.

8. The laboratory balance for accurate reading according to claim 1, characterized in that: An anti-skid pad is fixed at the bottom end of the base.

9. The laboratory balance for accurate reading according to claim 1, characterized in that: The scale is a PCB board made by using the immersion gold process.

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