CN211262418U - Electronic scale circuit - Google Patents
Electronic scale circuit Download PDFInfo
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- CN211262418U CN211262418U CN201921857452.6U CN201921857452U CN211262418U CN 211262418 U CN211262418 U CN 211262418U CN 201921857452 U CN201921857452 U CN 201921857452U CN 211262418 U CN211262418 U CN 211262418U
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- operational amplifier
- electronic scale
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Abstract
The utility model discloses an electronic scale circuit, including power supply circuit, sensor circuit, amplifier circuit, analog-to-digital conversion circuit, singlechip circuit, display circuit, regulating circuit and filter circuit, wherein, the regulating circuit coupling is between amplifier circuit and filter circuit for carry out zero degree or full scale to amplifier circuit output signal and adjust, the filter circuit coupling is between regulating circuit and analog-to-digital conversion circuit, is used for carrying out the second order active filtering to regulator circuit output signal. The utility model discloses a weight of perception object converts weight to analog signal, then enlargies analog signal, suppresses external disturbance and noise at the amplification process.
Description
Technical Field
The embodiment of the utility model provides a relate to the electronic circuit field, particularly, relate to an electronic scale circuit.
Background
In the modern society with rapid economic development, goods transaction happens anytime and anywhere, and in many transaction occasions, the goods transaction can be carried out by using a tool called as a weight measuring tool of goods; with the development of social economy, people pay attention to how to quickly measure the weight of an article and realize the coordination between a buyer and a seller; with the rapid development of economy, the problems of overlong transaction time and the like occur in many goods transactions due to the lagging of weighing tools, so that the rapid weight measurement of the goods is realized to the maximum extent, and the weighing instrument is one of solutions for improving the transaction efficiency and developing the economy.
In view of the above phenomena, patent document CN205537911U discloses a digital electronic scale based on AT89C52 single chip microcomputer, which mainly includes AT89C52 single chip microcomputer minimum system, sensor module, amplification module, analog-to-digital conversion module, display module, and power supply module; when an object is placed on the sensor module, the resistance strain gauge in the sensor module deforms to generate weak bias voltage, the weak bias voltage is amplified by the amplifying module, then subjected to analog-to-digital conversion by the analog-to-digital conversion module, finally transmitted to the AT89C52 singlechip minimum system, and processed by the AT89C52 singlechip minimum system, and the weight of the placed object is displayed on the display module.
The above patent realizes fast measurement of the weight of the article, but only the high-precision instrument amplifier AD620 and the potentiometer are formed, so that the bias voltage related to the weight of the article is easily interfered by the outside when being amplified, and the noise brought by the amplifier in the amplifying process is inevitable.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to the above-mentioned defect among the prior art, provide an electronic scale circuit that can effectively restrain to external disturbance and noise.
In order to realize the purpose of the utility model, the utility model adopts the following technical scheme:
an electronic scale circuit comprises a power supply circuit, a sensor circuit, an amplifying circuit, an analog-to-digital conversion circuit, a single chip microcomputer circuit, a display circuit, an adjusting circuit and a filter circuit, wherein the adjusting circuit is coupled between the amplifying circuit and the filter circuit and used for carrying out zero degree or full degree adjustment on an output signal of the amplifying circuit, and the filter circuit is coupled between the adjusting circuit and the analog-to-digital conversion circuit and used for carrying out second-order active filtering on an output signal of the adjusting circuit.
Furthermore, the utility model discloses still provide following subsidiary technical scheme:
the adjusting circuit comprises a second operational amplifier and a peripheral circuit thereof, wherein the peripheral circuit comprises a first adjustable resistor and a second adjustable resistor, the first adjustable resistor is coupled between a power supply and a non-inverting input end of the second operational amplifier and used for full-scale adjustment, and the second adjustable resistor is coupled between an inverting input end and an output end of the second operational amplifier and used for zero-scale adjustment.
The model of the second operational amplifier is AD 8629.
The filter circuit comprises an in-phase proportional amplification circuit and two sections of RC filter circuits, the in-phase proportional amplification circuit comprises a third operational amplifier, and the two sections of RC filter circuits comprise a ninth resistor, a tenth resistor, a third capacitor and a fourth capacitor.
The model of the third operational amplifier is AD 8615.
The power circuit comprises a rectifier bridge, a voltage stabilizer and a third adjustable resistor, wherein the rectifier bridge is coupled between the power input end and the voltage stabilizer input end, the third adjustable resistor is coupled at the voltage stabilizer output end, and the voltage stabilizer outputs constant-current direct current.
The amplifying circuit comprises a first operational amplifier and a peripheral circuit thereof, and the model of the first operational amplifier is AD 8237.
The analog-to-digital conversion circuit comprises an analog-to-digital conversion chip with the model number of ADC 0832.
The singlechip circuit comprises a singlechip and a peripheral circuit thereof, and the type of the singlechip is AT89C 51.
The display circuit includes an LCD display of the type LCD 1602.
Compared with the prior art, the utility model has the advantages that: the weight of an object is sensed through the sensor circuit and converted into an analog signal, then the analog signal is amplified through the amplifying circuit, external interference and noise are suppressed in the amplifying process, and a stable and reliable analog signal is provided for subsequent data conversion.
Drawings
In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or related technologies will be briefly introduced below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention and are not limiting to the present invention.
Fig. 1 is a schematic circuit diagram of an electronic scale circuit according to a preferred embodiment of the present invention.
Fig. 2 is a circuit diagram of the power circuit, the sensor circuit, the amplifying circuit, the adjusting circuit and the filter circuit according to the preferred embodiment of the present invention.
Fig. 3 is a circuit diagram of an analog-to-digital conversion circuit according to a preferred embodiment of the present invention.
Fig. 4 is a circuit diagram of a single chip circuit according to a preferred embodiment of the present invention.
Fig. 5 is a circuit diagram of a display circuit according to a preferred embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the present invention, taken in conjunction with the accompanying drawings and the detailed description, is given in a non-limiting manner.
Referring to fig. 1, the electronic scale circuit comprises a power circuit, a sensor circuit, an amplifying circuit, a regulating circuit, a filter circuit, an analog-to-digital conversion circuit, a single chip circuit and a display circuit. The power supply circuit is used for outputting constant-current direct current to the sensor circuit; the sensor circuit is used for converting gravity into an analog signal; the amplifying circuit is used for amplifying the analog signal generated by the sensor circuit; the adjusting circuit is used for adjusting the zero degree or the full scale of the output signal of the amplifying circuit; the filter circuit is used for carrying out second-order active filtering on the output signal of the regulating circuit; the analog-to-digital conversion circuit is used for performing analog-to-digital conversion on the amplified analog signal; the singlechip is used for receiving the voltage signal converted by the analog-to-digital conversion circuit and feeding the voltage signal back to the display circuit; the display circuit is used for displaying the weight of the weighed object.
Referring to fig. 2, the power circuit includes a rectifier bridge D1, a regulator U6, a third adjustable resistor RP3, a first capacitor C1 and a second capacitor C2, the rectifier bridge D1 is coupled between the 5V dc power supply and the input terminal Vin of the regulator U6, and the 5V power supply may not distinguish between positive and negative when inputting because the rectifier bridge is connected. A first capacitor C1 is further coupled between the input terminal Vin and the common terminal GND of the regulator U6 for suppressing input ripple. An output end Vout of the voltage stabilizer U6 is coupled with a 1 st pin and a center end of a third adjustable resistor RP3, a 2 nd pin of the third adjustable resistor RP3 is coupled with a common end GND of the voltage stabilizer U6 and a sensor circuit, and the third adjustable resistor RP3 is coupled between the output end Vout of the voltage stabilizer U6 and the common end GND to form a fixed constant current source, and the current can be changed by adjusting the third adjustable resistor RP3 during operation. A second capacitor C2 is further coupled between the output terminal Vout of the regulator U6 and the common terminal GND, for improving the frequency stability of the regulator U6 and preventing output oscillation. In this embodiment, the first capacitor C1 and the second capacitor C2 are both capacitors of type 104, and the third adjustable resistor RP3 is a potentiometer of type 103.
The sensor circuit comprises resistance strain gauges which are respectively a first resistance strain gauge R1, a second resistance strain gauge R2, a third resistance strain gauge R3 and a fourth resistance strain gauge R4, the four resistance strain gauges form a Wheatstone bridge, the sensitivity of the Wheatstone bridge is high, the parameters of each arm are consistent, the influence of various interferences can be mutually offset, and the compensation problem of the weighing sensor can be conveniently solved. In the present embodiment, the resistance values of the first resistive strain gauge R1 and the third resistive strain gauge R3 are decreased with the increase of the force, the resistance values of the second resistive strain gauge R2 and the fourth resistive strain gauge R4 are increased with the increase of the force, and the excitation voltage thereof is set to be UiWhen subjected to a force, the resistance strain gauge has a variable Δ R, i.e.: when R1 and R3 decrease by Δ R and R2 and R4 increase by Δ R, respectively, it can be deduced that the output voltage U iso＝(ΔR/R)*UiThereby converting gravity into an analog electrical signal.
The amplifying circuit comprises a first operational amplifier U1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7. The 3 feet of the first operational amplifier U1 are coupled between the third resistive strain gauge R3 and the fourth resistive strain gauge R4 of the sensor circuit, the 2 feet are coupled between the first resistive strain gauge R1 and the second resistive strain gauge R2 of the sensor circuit, the fifth resistor R5 is coupled between the 8 feet and the 7 feet, the sixth resistor R6 is coupled between the 6 feet and the 7 feet, and the 8 feet are further coupled with the adjusting circuit through the seventh resistor R7. The first operational amplifier U1 receives the analog signal generated by the sensor circuit, amplifies the received signal and outputs the amplified signal to the regulating circuit. In this embodiment, the model of the first operational amplifier U1 is AD8237, the resistance of the fifth resistor R5 is 470, the resistance of the sixth resistor R6 is 330, and the resistance of the seventh resistor R7 is 2K.
The adjusting circuit comprises a second operational amplifier U2A, a first adjustable resistor RP1, a second adjustable resistor RP2 and an eighth resistor R8, wherein the inverting input end of the second operational amplifier U2A is coupled with the output end of the amplifying circuit, and is also coupled with the output end of the amplifying circuit through an eighth resistor R8 and a second adjustable resistor RP2 which are connected in series, and zero degree adjustment can be carried out by adjusting the second adjustable resistor RP 2. The non-inverting input terminal of the second operational amplifier U2A is coupled to the center terminal of the first adjustable resistor RP1, the 1 st pin of the first adjustable resistor RP1 is connected to the VCC, the 2 nd pin is grounded, and zero degree adjustment can be performed by adjusting the first adjustable resistor RP 1. The output of the second op-amp U2A is coupled to a filter circuit. The adjusting circuit is used for adjusting the full scale of the signal output by the amplifying circuit and then outputting the signal to the filter circuit. In this embodiment, the model of the second operational amplifier U2A is AD8629, the resistance of the eighth resistor R8 is 1K, and both the first potentiometer RP1 and the second potentiometer RP2 are 103 potentiometers.
The filter circuit comprises a third operational amplifier U3, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third capacitor C3 and a fourth capacitor C4. The non-inverting input terminal of the third operational amplifier U3 is coupled to the output terminal of the second operational amplifier U2A of the regulator circuit through a tenth resistor R10 and a ninth resistor R9 connected in series in sequence, and the non-inverting input terminal of the third operational amplifier U3 is grounded through a fourth capacitor C4. One end of the third capacitor C3 is coupled between the ninth resistor R9 and the tenth resistor R10, and the other end is coupled to the output end of the third operational amplifier U3. The ninth resistor R9, the tenth resistor R10, the third capacitor C3 and the fourth capacitor C4 form a filter circuit for filtering interference and providing stable and reliable analog signals for subsequent data acquisition. The ninth resistor R9 and the third capacitor C3 are a filter circuit, and the tenth resistor R10 and the fourth capacitor C4 are a filter circuit. The inverting input of the third op-amp U3 is coupled back to its output, forming negative feedback. The output terminal of the third operational amplifier U3 is connected to ground through an eleventh resistor R11. The output end of the third operational amplifier is also connected with an analog-to-digital conversion circuit. In this embodiment, the model of the third operational amplifier U3 is AD8615, the resistance of the ninth resistor R9 is 1K, the resistance of the tenth resistor R10 is 470, the resistance of the eleventh resistor R11 is 560, the third capacitor C3 is a capacitor of model 104, and the fourth capacitor C4 is a capacitor of model 103.
Referring to fig. 3, the analog-to-digital conversion circuit adopts an ADC0832 analog-to-digital conversion chip, an analog signal input terminal CH1 of the analog-to-digital conversion chip is coupled to an output terminal of a second operational amplifier U3 of the amplification circuit, a chip selection terminal is coupled to a P2.0 port of a single chip microcomputer U5, a serial clock input terminal CLK is coupled to a P2.1 port of the single chip microcomputer U5, and an analog-to-digital conversion result serial output terminal DO and two analog input selection input terminals DI are coupled to a P2.2 port of a single chip microcomputer U539. The amplifier circuit is used for receiving the analog signal output by the amplifying circuit and converting the analog signal into a digital signal.
Referring to fig. 4, the model of the single chip microcomputer U5 is 89C51, and a thirteenth resistor R13, a reset circuit and a crystal oscillator circuit are coupled to the periphery of the single chip microcomputer U5. The thirteenth resistor R13 is coupled to pins P0.0-P0.7 of the MCU U5 and is a pull-up resistor. The reset circuit comprises a fifth capacitor C5 and a twelfth resistor R12, one end of the fifth capacitor C5 is coupled with a power supply, the other end of the fifth capacitor C5 is coupled with a RST port of the singlechip U5 and one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is grounded. The crystal oscillator circuit comprises a crystal oscillator Y1 with the crystal oscillator frequency of 12MHz, a sixth capacitor C6 and a seventh capacitor C7, wherein the crystal oscillator Y1 is coupled between an XTAL1 port and an XTAL2 port of the single chip microcomputer U1, the sixth capacitor C6 is coupled between a pin 2 of the crystal oscillator Y1 and the ground, and the seventh capacitor C7 is coupled between a pin 1 of the crystal oscillator Y1 and the ground.
Referring to fig. 5, the display circuit includes a display chip and a fourth potentiometer RP4 coupled to the display chip, and the display chip employs an LCD1602 chip. The center end of the fourth potentiometer RP4 is coupled with the 3 pins of the display chip, the head end and the tail end are respectively coupled with the power supply and the ground, the 6 pins of the display chip are coupled with the P2.7 port of the singlechip U5, and the 7 pins-14 pins are coupled with the P0.0-P0.7 ports of the singlechip U5.
The utility model discloses a theory of operation is:
the direct current 5V power supply is input at an A, B end, a constant current source is formed by a voltage stabilizer U6 and peripheral elements, the constant current source is output to a sensor circuit, when a resistance strain gage of the sensor circuit senses the change of force, the voltage output by a Wheatstone bridge connected by the resistance strain gage changes immediately, a signal is amplified by a first operational amplifier U1, the amplified signal is input to a second operational amplifier U2A for full degree adjustment, the amplified signal is transmitted to an analog-to-digital conversion chip U4 for analog-to-digital conversion after passing through a filter circuit formed by a third operational amplifier U3 and the peripheral circuits, then the analog-to-digital conversion chip is connected to a single chip microcomputer for processing, and finally the weight of a measured object is displayed by a display chip of a display circuit.
It should be noted that the above-mentioned preferred embodiments are only for illustrating the technical concepts and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the protection scope of the present invention cannot be limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.
Claims (10)
1. An electronic scale circuit comprises a power supply circuit, a sensor circuit, an amplifying circuit, an analog-to-digital conversion circuit, a single chip circuit and a display circuit, and is characterized in that: the device also comprises a regulating circuit and a filter circuit, wherein the regulating circuit is coupled between the amplifying circuit and the filter circuit and used for carrying out zero degree or full degree regulation on the output signal of the amplifying circuit, and the filter circuit is coupled between the regulating circuit and the analog-to-digital conversion circuit and used for carrying out second-order active filtering on the output signal of the regulating circuit.
2. The electronic scale circuit according to claim 1, characterized in that: the adjusting circuit comprises a second operational amplifier and a peripheral circuit thereof, wherein the peripheral circuit comprises a first adjustable resistor and a second adjustable resistor, the first adjustable resistor is coupled between a power supply and a non-inverting input end of the second operational amplifier and used for full-scale adjustment, and the second adjustable resistor is coupled between an inverting input end and an output end of the second operational amplifier and used for zero-scale adjustment.
3. The electronic scale circuit according to claim 2, characterized in that: the model of the second operational amplifier is AD 8629.
4. The electronic scale circuit according to claim 1, characterized in that: the filter circuit comprises an in-phase proportional amplification circuit and two sections of RC filter circuits, the in-phase proportional amplification circuit comprises a third operational amplifier, and the two sections of RC filter circuits comprise a ninth resistor, a tenth resistor, a third capacitor and a fourth capacitor.
5. The electronic scale circuit according to claim 4, characterized in that: the model of the third operational amplifier is AD 8615.
6. The electronic scale circuit according to claim 1, characterized in that: the power supply circuit comprises a rectifier bridge, a voltage stabilizer and a third adjustable resistor, wherein the rectifier bridge is coupled between the input end of the power supply and the input end of the voltage stabilizer, the third adjustable resistor is coupled at the output end of the voltage stabilizer, and the voltage stabilizer outputs constant-current direct current.
7. The electronic scale circuit according to claim 1, characterized in that: the amplifying circuit comprises a first operational amplifier and a peripheral circuit thereof, and the model of the first operational amplifier is AD 8237.
8. The electronic scale circuit according to claim 1, characterized in that: the analog-to-digital conversion circuit comprises an analog-to-digital conversion chip with the type of ADC 0832.
9. The electronic scale circuit according to claim 1, characterized in that: the single chip microcomputer circuit comprises a single chip microcomputer and a peripheral circuit thereof, and the type of the single chip microcomputer is AT89C 51.
10. The electronic scale circuit according to claim 1, characterized in that: the display circuit comprises an LCD display of the type LCD 1602.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921857452.6U CN211262418U (en) | 2019-10-31 | 2019-10-31 | Electronic scale circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921857452.6U CN211262418U (en) | 2019-10-31 | 2019-10-31 | Electronic scale circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211262418U true CN211262418U (en) | 2020-08-14 |
Family
ID=71958010
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921857452.6U Expired - Fee Related CN211262418U (en) | 2019-10-31 | 2019-10-31 | Electronic scale circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211262418U (en) |
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2019
- 2019-10-31 CN CN201921857452.6U patent/CN211262418U/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200814 Termination date: 20211031 |