Weighing method of electronic scale and electronic scale

Abstract

This invention discloses a weighing method and an electronic scale. The electronic scale includes a tray and a weighing body. A permanent magnet is mounted on the tray. The weighing body includes a housing, a control circuit board, a display, an iron core with a coil wound around it, and a distance measuring module. The control circuit board integrates a microprocessor and a coil current control circuit. The microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil. The weighing method involves energizing the coil. The iron core with the coil wound around it generates a magnetic force, causing the tray with the permanent magnet to be mounted to levitate. The distance measuring module measures the distance signal between the tray and the weighing body and sends it to the microprocessor. The microprocessor calculates the weight of the object being weighed on the tray and displays it on the display. This invention eliminates the need for four scale feet with pressure strain gauges, simplifying the structure of the electronic scale, making assembly convenient, wiring simple, and manufacturing costs low.

Description

Technical Field

[0001] This invention relates to a weighing method for an electronic scale and an electronic scale. Background Technology

[0002] The basic structure of a traditional electronic scale includes several weighing feet (usually four) and a scale body. The four feet are installed at the four corners of the scale body, and each foot is equipped with a pressure strain gauge (pressure sensor), requiring a total of four pressure sensors. An LCD display and control buttons are located on the surface of the scale body. Inside the scale body is a circuit board integrating a weight detection circuit and a microprocessor. When an object is placed on the scale body, the pressure strain gauge deforms and generates an electrical signal. This signal is detected and amplified by the weight detection circuit and sent to the microprocessor. The microprocessor calculates the weight of the object and displays it on the LCD display. For a detailed description of the structure, see patent number CN202021280681, entitled "An Electronic Scale for Easy Assembly."

[0003] Traditional electronic scales have the following shortcomings: 1) Because pressure strain gauges need to be installed on each scale foot, each scale foot has a complex structure, making assembly troublesome and wiring complicated (because wires are needed to connect the pressure strain gauges of the four scale feet to the control circuit board). Electronic scales using pressure sensors of different shapes require independent re-molding of the scale feet, resulting in high manufacturing costs; 2) Due to the layout of the four scale feet, the shape design of the scale body is greatly limited. Generally, the scale body is mostly square, and there are also round ones, which prevents bold and innovative designs in appearance; 3) They do not encourage users to think about the weighing principle of the scale body and lack interest. Summary of the Invention

[0004] One objective of this invention is to provide a weighing method for an electronic scale that solves the technical problems of existing weighing methods that rely on the electrical signals generated by the deformation of the pressure strain gauges on the four scale feet under pressure, resulting in complex electronic scale structures, cumbersome assembly, complex wiring, and high manufacturing costs.

[0005] Another objective of this invention is to provide an electronic scale that solves the technical problems of traditional electronic scales in the prior art, which require the installation of pressure strain gauges on each scale foot, resulting in complex structure of each scale foot, troublesome assembly, complicated wiring, and high manufacturing costs.

[0006] The technical solution of this invention is implemented as follows:

[0007] A weighing method for an electronic scale, the electronic scale comprising a tray for holding the object to be weighed and a weighing body, wherein a permanent magnet is mounted on the tray, and the weighing body comprises a housing, a control circuit board, a display, an iron core wound with a coil, and a distance measuring module; the control circuit board integrates a microprocessor and a coil current control circuit, and the microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil; the weighing method is characterized in that: the coil is energized, the iron core wound with the coil generates magnetic force to levitate the tray on which the permanent magnet is mounted; the distance measuring module measures the distance signal between the tray and the weighing body and sends it to the microprocessor; the microprocessor calculates the weight of the object to be weighed on the tray based on the distance signal between the tray and the weighing body and displays it on the display; the current supplied to the coil by the microprocessor is a constant current.

[0008] The above method involves placing standard weights of different weights on a tray, measuring the distance H between the tray and the weighing body corresponding to different weights, and obtaining the equation for calculating the weight of the object being weighed in relation to the distance H.

[0009] The equation for calculating the weight of the object being weighed and the distance H is a quadratic equation in one variable: G×G=H0-H; where G is the weight of the object being weighed, H0 is a constant, K1 is a coefficient, and H is the distance between the tray and the weighing body.

[0010] The microprocessor described above calculates the weight of the object being weighed on the tray based on the constant current supplied to the coil and the distance H between the tray and the weighing body, and then sends the result to the display.

[0011] An electronic scale includes a tray for holding an object to be weighed and a weighing body. The scale is characterized in that: a permanent magnet is mounted on the tray; the weighing body includes a housing, a control circuit board, a display, control buttons, an iron core with a coil wound around it, and a distance measuring module. The control circuit board is installed inside the housing, and the display and control buttons are mounted on the housing. The iron core with the coil wound around it is mounted on the housing. The control circuit board integrates a microprocessor and a coil current control circuit. The microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil. When the coil is energized, the iron core with the coil wound around it generates magnetic force, causing the tray with the permanent magnet to be mounted to levitate. The distance measuring module measures the distance signal between the tray and the weighing body and sends it to the microprocessor. The microprocessor calculates the weight of the object placed on the tray based on the current supplied to the coil and the distance signal between the tray and the weighing body, and displays the weight on the display. The current supplied to the coil by the microprocessor is a constant current.

[0012] The tray described above is pot-shaped, with permanent magnet blocks wrapped inside its bottom plate.

[0013] The aforementioned ranging module can be a laser ranging module, an ultrasonic ranging module, a CMOS displacement detection module, or an infrared ranging module. A battery is also installed inside the weighing body's housing to power the weighing body; the ranging module is located on the outside of the iron core.

[0014] The aforementioned iron cores wound with coils consist of four groups, evenly distributed circumferentially.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. The electronic scale of the present invention includes a tray for holding the object to be weighed and a weighing body. A permanent magnet is mounted on the tray. The weighing body includes a housing, a control circuit board, a display, an iron core wound with a coil, and a distance measuring module. The control circuit board integrates a microprocessor and a coil current control circuit. The microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil. The weighing method involves energizing the coil, causing the iron core wound with the coil to generate magnetic force, which magnetically levitates the tray with the permanent magnet. The distance measuring module measures the distance signal between the tray and the weighing body and sends it to the microprocessor. The microprocessor calculates the weight of the object placed on the tray based on the distance signal and displays it on the display. It omits four scale feet with pressure strain gauges, simplifying the structure of the electronic scale, making assembly convenient, wiring simple, and manufacturing costs low.

[0017] 2. Other advantages of the present invention are described in detail in the embodiments section of the specification. Attached Figure Description

[0018] Figure 1 This is a perspective view of the electronic scale provided in Embodiment 1 of the present invention;

[0019] Figure 2 This is an exploded view of the electronic scale provided in Embodiment 1 of the present invention;

[0020] Figure 3 This is a top view of the electronic scale provided in Embodiment 1 of the present invention;

[0021] Figure 4 for Figure 3 AA section solid;

[0022] Figure 5 This is a distribution diagram of the coil and iron core of the electronic scale provided in Embodiment 1 of the present invention;

[0023] Figure 6 This is a circuit block diagram of the electronic scale provided in Embodiment 1 of the present invention;

[0024] Figure 7 for Figure 6 The corresponding part of the circuit diagram;

[0025] Figure 8 This is a curve graph of the experimental data measured in Embodiment 2 of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Embodiment 1:

[0027] like Figures 1 to 7 As shown, this embodiment provides an electronic scale, including a tray 1 for holding an object to be weighed and a weighing body 2. The scale is characterized by: a permanent magnet block 11 mounted on the tray 1; and a housing 21, a control circuit board 22, a display 23, control buttons 24, an iron core 26 wound with a coil 25, and a distance measuring module 27. The control circuit board 22 is installed inside the housing 21, and the display 23 and control buttons 24 are mounted on the housing 21. The iron core 26 wound with the coil 25 is mounted on the housing 21. The control circuit board 22 integrates a microprocessor and a coil current control circuit. The microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil 25. When the coil 25 is energized, the iron core 26 wound with the coil 25 generates magnetic force, causing the tray 1 with the permanent magnet block 11 to be magnetically levitated. The distance measuring module 27 measures the distance signal between the tray 1 and the weighing body 2 and sends it to the microprocessor. The microprocessor calculates the weight of the object placed on the tray 1 based on the distance signal between the tray 1 and the weighing body 2 and sends it to the display 23 for display. The microprocessor controls the current supplied to coil 25 to be a constant current.

[0028] The aforementioned tray 1 is pot-shaped with an internal cavity 10. The object to be weighed is placed inside the cavity 10, and a permanent magnet block 11 is wrapped inside its base plate 12. The tray 1 is made of plastic, and the permanent magnet block 11 is sealed inside the base plate 12, resulting in a simpler structure and a more aesthetically pleasing design.

[0029] The housing 21 includes a front shell 21a and a bottom shell 21b. The front shell 21 is mounted on the bottom shell 21b and forms a sealed cavity 20. The control circuit board 22, display 23, and control buttons 24 are installed in the sealed cavity 20. A boss 3 is provided in the middle of the front shell 21a. The top and bottom ends of the boss 3 protrude from the front shell 21a. The iron core 26 with the coil 25 is wrapped and sealed in plastic inside the boss 3. This layout makes the product more integrated and reasonable, avoiding direct placement on the circuit board, which would make the circuit board too large and increase costs. A hollow cavity 29 is provided in the bottom shell 21b. The part of the boss 3 protruding below the front shell 21a is embedded in the hollow cavity 29. A ring support ring 291 is provided around the hollow cavity 29 to support the bottom surface of the front shell 21a, which can strengthen the structural strength because the part of the boss 3 is relatively heavy.

[0030] The aforementioned ranging module 27 can be a laser ranging module, an ultrasonic ranging module, a CMOS displacement detection module, or an infrared ranging module. For example, the ranging module 27 can also use a B5W-DB diffuse reflective sensor, an Omron ultra-small long-range diffuse reflective sensor, which is not limited by the installation position and is not easily affected by light interference. Alternatively, the ranging module 27 can also use the sensopart short-range laser ranging sensor sold by Shanghai Gellerk International Trade Co., Ltd. These can be found in the market or online and will not be described further here. The housing 21 of the weighing body 2 also houses a battery 28, which powers the weighing body 2; the ranging module 27 is located next to the outside of the iron core 26.

[0031] like Figure 5 As shown, the iron core 26 of the present invention, which is wound with coil 25, has 4 groups and is evenly distributed along the circumference to generate a uniformly distributed magnetic levitation force.

[0032] like Figure 6 , Figure 7As shown, the coil current control circuit of this invention includes an electronic resistor R1, resistors R2, R3, and R4, a transistor Q1, an optocoupler G, and a unidirectional thyristor D1. The electronic resistor R1 and transistor Q1 form the driving circuit for the optocoupler G. One end of the electronic resistor R1 is connected to the base of the transistor Q1. The I / O port of the microprocessor MCU outputs a signal to the other end of the electronic resistor R1. The collector of the transistor Q1 is connected to pin 2 of the optocoupler G. The emitter of the transistor Q1 is grounded to GND. Pin 1 of the optocoupler G is connected to the power supply V. Pin 3 of the optocoupler G is connected to the power supply V through resistor R2. Pin 4 of the coupling is connected to the control terminal of the unidirectional thyristor D1. The unidirectional thyristor D1, coil 25, and resistor R4 are connected in series between the power supply V and ground GND. Resistor R4 detects the current flowing through coil 25 and sends the signal to the A / D port of the microprocessor MCU. The I / O port output signal of the microprocessor MCU is a PWM signal. The PWM signal is used to control the conduction angle of the unidirectional thyristor D1 to control the current flowing through coil 25. Resistor R4 feeds back the current flowing through coil 25 and sends it to the microprocessor MCU, forming a closed-loop control to achieve the purpose of coil current control.

[0033] The working principle of this invention is as follows: When the coil is energized, the iron core wound with the coil generates magnetic force, causing the tray with the permanent magnet block installed to be magnetically levitated. The distance measuring module measures the distance signal between the tray and the weighing body and sends it to the microprocessor. The microprocessor calculates the weight of the object being weighed on the tray based on the distance signal and sends it to the display. It eliminates the four scale feet with pressure strain gauges found in traditional electronic scales, simplifying the structure of the electronic scale, making assembly convenient, wiring simple, and manufacturing costs low.

[0034] Example 2:

[0035] like Figures 1 to 7 As shown, a weighing method for an electronic scale includes a tray 1 for holding the object to be weighed and a weighing body 2. A permanent magnet block 11 is installed on the tray 1. The weighing body 2 includes a housing 21, a control circuit board 22, a display 23, an iron core 26 wound with a coil 25, and a distance measuring module 27. The control circuit board 22 integrates a microprocessor and a coil current control circuit. The microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil 25. The weighing method involves energizing the coil 25, causing the iron core 26 wound with the coil 25 to generate magnetic force, suspending the tray 1 with the permanent magnet block 11. The distance measuring module 27 measures the distance signal between the tray 1 and the weighing body 2 and sends it to the microprocessor. The microprocessor calculates the weight of the object placed on the tray 1 based on the distance signal between the tray 1 and the weighing body 2 and displays it on the display 23.

[0036] The microprocessor described above supplies a constant current to the coil 25.

[0037] The above method uses standard weights of different weights placed on tray 1, and measures the distance H between tray 1 and weighing body 2 corresponding to different weights. The calculation equations for the weight of the object being weighed and the distance H between tray 1 and weighing body are obtained, as shown in Table 1 below.

[0038]

[0039] Plot points on the graph to fit the above data, such as... Figure 8 As shown, the equation for calculating the weight of the object being weighed and the distance H can be a quadratic equation in one variable: K1×G×G=H0-H; where G is the weight of the object being weighed, H0 is a constant, K1 is a coefficient, and H is the distance between tray 1 and weighing body 2. Using the data in Table 1 above, we can find that H0=23 and K1=-52.

[0040] In addition, to increase the weighing range of the electronic scale, the current supplied to the coil 25 can be increased. By placing standard weights of different weights on the tray 1, the distance H between the tray 1 and the weighing body 2 corresponding to different weights can be measured. The calculation equation for the weight of the object being weighed and the distance H between the tray 1 and the weighing body is obtained, as shown in Table 2.

[0041]

[0042] By plotting the above data on a graph and fitting the points, we can also obtain the equation for calculating the weight of the object being weighed and the distance H.

[0043] The microprocessor calculates the weight of the object being weighed on the tray 1 based on the constant current supplied to the coil 25 and the distance H between the tray 1 and the weighing body 2, and sends the result to the display 23 for display.

[0044] The weighing method of this invention involves energizing a coil, which generates magnetic force in the iron core around which the coil is wound, causing a tray with a permanent magnet block mounted on it to levitate magnetically. A distance measuring module measures the distance signal between the tray and the weighing body and sends it to a microprocessor. The microprocessor calculates the weight G of the object being weighed on the tray based on the distance H between the tray and the weighing body and a calculation formula derived from experimental data simulation (such as K1×G×G=H0-H mentioned above), and displays the result on a screen. This method omits four scale feet with pressure strain gauges, simplifying the structure of the electronic scale, making assembly convenient, wiring simple, and manufacturing costs low.

[0045] This type of electronic scale is very attractive to users or students because it uses magnetic levitation for weighing, thus stimulating their interest in learning.

[0046] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited thereto. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention are equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A weighing method for an electronic scale, the electronic scale comprising a tray (1) for holding the object to be weighed and a weighing body (2), wherein a permanent magnet block (11) is mounted on the tray (1), and the weighing body (2) comprises a housing (21), a control circuit board (22), a display (23), an iron core (26) wound with a coil (25), and a distance measuring module (27), wherein the control circuit board (22) integrates a microprocessor and a coil current control circuit, and the microprocessor outputs a signal to control the coil current control circuit to control the current supplied to the coil (25); characterized in that: The weighing method involves energizing the coil (25), and the iron core (26) with the coil (25) wound around it generates a magnetic force that causes the tray (1) with the permanent magnet block (11) installed to levitate. The distance measuring module (27) measures the distance signal between the tray (1) and the weighing body (2) and sends it to the microprocessor. The microprocessor calculates the weight of the object to be weighed on the tray (1) based on the distance signal between the tray (1) and the weighing body (2) and sends it to the display (23) for display. The microprocessor controls the current supplied to the coil (25) to be a constant current.

2. The weighing method of an electronic scale according to claim 1, characterized in that: By placing standard weights of different weights on the tray (1), the distance H between the tray (1) and the weighing body (2) corresponding to different weights is measured, and the calculation equation of the weight of the object being weighed and the distance H between the tray (1) and the weighing body is obtained.

3. The weighing method of an electronic scale according to claim 2, characterized in that: The equation for calculating the weight of the object being weighed and the distance H is a quadratic equation in one variable: K1×G×G=H0-H; Where G is the weight of the object being weighed, H0 is a constant, K1 is a coefficient, and H is the distance between the tray (1) and the weighing body (2).

4. The weighing method of an electronic scale according to claim 1, characterized in that: The microprocessor controls the current supplied to the coil (25) to be a constant current of different magnitudes. The microprocessor calculates the weight of the object to be weighed on the tray (1) based on the current supplied to the coil (25) and the distance H between the tray (1) and the weighing body (2), and sends it to the display (23) for display.

5. An electronic scale, comprising a tray (1) for holding an object to be weighed and a weighing body (2), characterized in that: The tray (1) is equipped with a permanent magnet block (11). The weighing body (2) includes a housing (21), a control circuit board (22), a display (23), control buttons (24), an iron core (26) with a coil (25) wound around it, and a ranging module (27). The control circuit board (22) is installed inside the housing (21). The display (23) and control buttons (24) are installed on the housing (21). The iron core (26) with a coil (25) wound around it is installed on the housing (21). The control circuit board (22) integrates a microprocessor and a coil current control circuit. The microprocessor outputs signals. The control coil current control circuit controls the current supplied to the coil (25). When the coil (25) is energized, the iron core (26) with the coil (25) wound around it generates a magnetic force that causes the tray (1) with the permanent magnet block (11) installed to levitate. The distance measuring module (27) measures the distance signal between the tray (1) and the weighing body (2) and sends it to the microprocessor. The microprocessor calculates the weight of the object to be weighed on the tray (1) based on the distance signal between the tray (1) and the weighing body (2) and sends it to the display (23) for display. The microprocessor controls the current supplied to the coil (25) to be a constant current.

6. An electronic scale according to claim 5, characterized in that: The tray (1) is pot-shaped, with a permanent magnet block (11) wrapped inside its bottom plate (12).

7. An electronic scale according to claim 6, characterized in that: The ranging module (27) is a laser ranging module, an ultrasonic ranging module, a CMOS displacement detection module, or an infrared ranging module.

8. An electronic scale according to claim 5, 6, or 7, characterized in that: A battery (28) is installed inside the shell (21) of the weighing body (2), which powers the weighing body (2); the ranging module (27) is located next to the outside of the iron core (26).

9. An electronic scale according to claim 8, characterized in that: There are 4 groups of iron cores (26) with coils (25) wound around them, and they are evenly distributed along the circumference.

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