WO2019023881A1

WO2019023881A1 - Human skin water and oil analysis circuit and skin testing instrument

Info

Publication number: WO2019023881A1
Application number: PCT/CN2017/095265
Authority: WO
Inventors: 何江波
Original assignee: 深圳和而泰智能控制股份有限公司
Priority date: 2017-07-31
Filing date: 2017-07-31
Publication date: 2019-02-07
Also published as: CN108700859A

Abstract

A human skin water and oil analysis circuit, the human skin water and oil analysis circuit comprising a water and oil detection module (110) and a single chip microcomputer (120). The water and oil detection module (110) is used to receive a square wave signal, and use the square wave signal as an excitation signal to detect the percentages of water and oil on the human skin, and obtain a voltage signal capable of reflecting data of the percentages on water and oil of the human skin; the single chip microcomputer (120) is used to perform analog-to-digital conversion on the voltage signal obtained by the water and oil detection module (110), and send the voltage signal that has been converted from analog to digital to an external data processing device such that the external data processing device performs data analysis on the voltage signal so as to detect the data of the percentages of water and oil on the human skin. A skin testing instrument, comprising the human skin water and oil analysis circuit. By means of the foregoing manner, the accuracy of tested data of the percentages of water and oil in the human skin test may be increased.

Description

Human skin water and oil analysis circuit and skin tester

Technical field

The embodiments of the present application relate to the field of human skin testing, and in particular to a human skin water and oil analysis circuit and a skin detector.

Background technique

With the development of science and technology, people are more and more concerned about health and beauty, and the detection of the body is particularly important. In the study of body composition, measuring the bioelectrical impedance value of the human body can obtain information about the health status of the human body such as moisture and fat. The monitoring of human health and the early diagnosis of diseases are of great significance, so more and more skin test products have emerged.

The existing skin test product tests the percentage of human skin water and oil through a differential amplification detection circuit, and the single chip transmits the test data to the mobile phone connected with the skin test product to analyze the water and oil characteristics of the human skin, and the method is performed on the human bioelectrical impedance. The single-frequency method is used for detection, that is, the measurement is performed by using a sine wave signal only at a fixed frequency, and generally only the mode of the electrical impedance is measured, so that the implementation is simple, and it is suitable for popularization on portable instruments. However, the accuracy of the single-frequency test data is low, and the test data deviation of the same part is even 10%, and the consistency is poor, which does not well represent the water-oil characteristics of human skin.

Summary of the invention

The technical problem mainly solved by the embodiment of the present application is to provide a human skin water and oil analysis circuit, which can improve the accuracy of the human skin water and oil percentage test data.

In order to solve the above technical problem, a technical solution adopted by the embodiment of the present application is to provide a human skin water and oil analysis circuit.

Wherein, the human skin water and oil analysis circuit comprises:

The water and oil detection module is configured to receive a square wave signal, and use the square wave signal as an excitation signal to detect a percentage of human skin water and oil, and obtain a voltage signal capable of reflecting a percentage of human skin water and oil data;

a single chip microcomputer for performing analog to digital conversion on a voltage signal obtained by the water oil detecting module And translating, and transmitting the analog-digital converted voltage signal to an external data processing device, so that the external data processing device performs data analysis on the voltage signal to detect human skin water and oil percentage data.

Preferably, the water oil detecting module comprises:

a voltage following unit, configured to receive the square wave signal, follow the square wave signal, and output a voltage following signal;

a first amplifying unit, configured to amplify the voltage following signal, and output a voltage amplifying signal;

The voltage amplification signal is subjected to a skin test to generate the skin voltage signal;

a differential unit configured to limit a sharp voltage signal generated after passing through the human skin in the skin voltage signal to smooth the sharp voltage signal;

a filtering unit, configured to filter the smoothed skin voltage signal and output a DC voltage signal;

And a second amplifying unit, configured to amplify the DC voltage signal, and output the amplified DC voltage signal to the single chip microcomputer.

Preferably, the voltage following unit includes a square wave signal receiving end, a first operational amplifier and a first resistor;

The non-inverting input terminal of the first operational amplifier is connected to the square wave signal receiving end via the first resistor, and the inverting input end of the first operational amplifier is connected to the output end of the first operational amplifier. An output of the first operational amplifier is coupled to the first amplifying unit.

Preferably, the first amplifying unit includes a second operational amplifier, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a voltage amplification signal output terminal;

One end of the second resistor is connected to the voltage follower unit, the other end of the second resistor is connected to the non-inverting input terminal of the second operational amplifier, and is grounded via the third resistor; the second operation An inverting input terminal of the amplifier is grounded via the fourth resistor, and is connected to an output end of the second operational amplifier via the fifth resistor, and an output end of the second operational amplifier is connected to the sixth resistor The output of the voltage amplification signal is connected.

Preferably, the differential unit includes a sharp voltage signal input terminal, a third operational amplifier, a first capacitor, a seventh resistor, and an eighth resistor;

An inverting input terminal of the third operational amplifier is connected to the sharp voltage signal input terminal via the first capacitor, a non-inverting input terminal of the third operational amplifier is grounded, and an output end of the third operational amplifier is a filtering unit is connected; one end of the seventh resistor is connected to an inverting input end of the third operational amplifier, and the other end of the seventh resistor is connected to an output end of the third operational amplifier via the eighth resistor connection.

Preferably, the filtering unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a second capacitor, a third capacitor, and a fourth capacitor;

One end of the ninth resistor is connected to the differentiating unit, and the other end of the ninth resistor is grounded via the second capacitor; one end of the tenth resistor is opposite to the ninth resistor and the second capacitor a common connection point is connected, the other end of the tenth resistor is grounded via the third capacitor; one end of the eleventh resistor is connected to a common connection point of the tenth resistor and the third capacitor, The other end of the eleventh resistor is grounded via the fourth capacitor, and a common connection point of the eleventh resistor and the fourth capacitor is connected to the second amplifying unit.

Preferably, the second amplifying unit includes a fourth operational amplifier, a twelfth resistor, a thirteenth resistor, and a fifth capacitor;

The non-inverting input terminal of the fourth operational amplifier is connected to the filtering unit, the inverting input end of the fourth operational amplifier is grounded via the twelfth resistor, and the thirteenth resistor and the fourth The output of the operational amplifier is connected, the output of the fourth operational amplifier is grounded via the fifth capacitor, and the common connection point of the output of the fourth operational amplifier and the fifth capacitor is connected to the single chip microcomputer.

Preferably, the human skin water and oil analysis circuit further includes a signal transmitting module and a signal receiving module;

The signal transmitting module is configured to send a signal output by the single chip to the external data processing device, where the signal receiving module is configured to receive a signal sent by the external data processing device, and send the signal to the single chip microcomputer And establishing communication between the single chip microcomputer and the external data processing device.

Preferably, the signal transmitting module includes a first signal receiving end, a first signal transmitting end, a fourteenth resistor, a fifteenth resistor, a sixth capacitor and a seventh capacitor;

One end of the fourteenth resistor is connected to the single chip through the first signal receiving end Connecting, the other end of the fourteenth resistor is connected to one end of the sixth capacitor, and is grounded via the seventh capacitor; the other end of the sixth capacitor is grounded via the fifteenth resistor, the first A common connection point of the six capacitor and the fifteenth resistor and the first signal transmitting end, the first signal transmitting end is for transmitting a signal to an external data processing device.

Preferably, the signal receiving module comprises a second signal receiving end, a second signal transmitting end, a working power input end, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, and a twentieth resistor. , the twenty-first resistor, the twenty-second resistor, the twenty-third resistor, the twenty-fourth resistor, the twenty-fifth resistor, the eighth capacitor, the ninth capacitor, the tenth capacitor, the eleventh capacitor, the tenth Two capacitors and comparators;

The second signal receiving end is configured to receive a signal sent by an external data processing device, and one end of the sixteenth resistor is connected to the second signal receiving end, and the other end of the sixteenth resistor is opposite to the first One end of the eight capacitor is connected and grounded via the ninth capacitor; one end of the seventeenth resistor is connected to the working power input end, and the other end of the seventeenth resistor is sequentially connected via the eighteenth resistor, a nineteenth resistor is grounded; a common connection point of the seventeenth resistor and the eighteenth resistor is connected to the other end of the eighth capacitor, and is sequentially grounded via the tens resistor and the tenth capacitor;

One end of the twenty-first resistor is connected to the working power input end, and the other end of the twenty-first resistor is grounded via the second twelve resistor; an inverting input end of the comparator is a twenty-third resistor is connected to a common connection point of the twenty-first resistor and the twenty-second resistor, and is grounded via the eleventh capacitor, the non-inverting input of the comparator and the twentieth resistor Connected to a common connection point of the tenth capacitor, the power terminal of the comparator is connected to the working power input end, and the ground end of the comparator is grounded;

One end of the twelfth capacitor is connected to the working power input end, and the other end of the twelfth capacitor is grounded; one end of the twenty-fourth resistor is connected to the working power input end, and the second The other end of the fourteenth resistor is connected to one end of the twenty-fifth resistor, and a common connection point of the twenty-fourth resistor and the twenty-fifth resistor is connected to an output end of the comparator; The other end of the five resistors is connected to the single chip through the second signal transmitting end.

In order to solve the above technical problem, another technical solution adopted by the embodiment of the present application is to provide a skin detector.

Wherein, the skin detector comprises a human skin water and oil analysis circuit, and the human skin water and oil analysis circuit comprises:

a single chip microcomputer, configured to perform analog-to-digital conversion on the voltage signal obtained by the water-oil detecting module, and send the analog-digital converted voltage signal to an external data processing device, so that the external data processing device pairs the voltage signal Data analysis was performed to detect the percentage of human skin water and oil.

The beneficial effects of the embodiments of the present application are: different from the prior art, the water-oil detection module uses the square wave signal as an excitation signal to detect the percentage of water and oil of the human skin, and obtains the data that can reflect the skin oil and water percentage of the human skin. The voltage signal is analog-to-digital converted by the single-chip microcomputer to the voltage signal obtained by the water-oil detecting module, and then sent to an external data processing device to analyze the voltage signal through an external data processing device to detect the percentage of human skin water and oil. data. The embodiment of the present application adopts a square wave signal as an excitation signal, has stable waveform, is easy to be combined with a digital circuit, and has a wide spectrum. Therefore, while preventing polarization of the measured unit, information of multiple frequency points can be obtained, thereby Improve the accuracy of the human skin water and oil percentage test data.

DRAWINGS

1 is a schematic block diagram of an embodiment of the body water and oil analysis circuit of the present applicant;

2 is a schematic block diagram of another embodiment of the body water and oil analysis circuit of the present applicant;

3 is a schematic diagram showing the circuit structure of an embodiment of a water and oil detecting module in the body skin water and oil analysis circuit of the applicant;

4 is a schematic diagram showing the circuit structure of an embodiment of a signal transmitting module in the body skin water and oil analysis circuit of the applicant;

Figure 5 is a diagram of an embodiment of a signal receiving module in the body water and oil analysis circuit of the applicant Road structure diagram.

Detailed ways

Referring to FIG. 1 , the human skin water and oil analysis circuit provided by the embodiment of the present application includes a water and oil detection module 110 and a single chip microcomputer 120 . The water and oil detection module 110 is configured to receive a square wave signal, and use the square wave signal as an excitation signal to detect a percentage of human skin water and oil, and obtain a voltage signal capable of reflecting a percentage of human skin water and oil data; the single chip 120 is used for water and oil The voltage signal obtained by the detection module is subjected to analog-to-digital conversion, and the analog-to-digital converted voltage signal is sent to an external data processing device, which may be a device capable of using the Internet for big data analysis, such as a mobile phone or a computer. The data of the voltage signal outputted by the single chip 120 is analyzed by the external data processing device to detect the water and oil percentage data of the human skin.

In this embodiment, the human skin water and oil analysis circuit receives the square wave signal, for example, a square wave signal of 4 KHz, by the water and oil detection module 110, and the square wave signal received by the water and oil detection module 110 may be provided by an external data processing device, or Provided by the microcontroller 120, it can also be provided by an external signal generator.

The water and oil detection module 110 detects the percentage of water and oil of the human skin using the square wave signal as an excitation signal, and obtains a voltage signal capable of reflecting the percentage data of the human body skin water and oil. The single chip microcomputer 120 collects the voltage signal detected by the water and oil detecting module 110, performs analog-to-digital conversion on the voltage signal, and transmits the analog-digital converted voltage signal to an external data processing device to pass the external data processing device to the human body. The skin water and oil percentage data were analyzed for data, and the human skin water and oil percentage data was detected to show the human skin characteristics.

Compared with the prior art, the body water and oil analysis circuit of the applicant detects the water and oil percentage of the human skin by using the square wave signal as an excitation signal by the water and oil detection module 110, and obtains a voltage signal capable of reflecting the percentage data of the human body skin water and oil, thereby detecting Percentage data of human skin water and oil. Since the square wave signal is used as the excitation signal, the waveform is stable, easy to be combined with the digital circuit, and has a wide spectrum, so that the polarization of the measured unit can be prevented, and the information of multiple frequency points can be obtained, thereby improving the information. The accuracy of the human skin water and oil percentage test data.

Referring again to FIG. 2, based on the human skin water and oil analysis circuit shown in FIG. 1, the method shown in FIG. The human skin water and oil analysis circuit further includes a signal transmitting module 130 and a signal receiving module 140. The signal transmitting module 130 is configured to send the signal output by the single chip microcomputer 120 to the external data processing device, and the signal receiving module 140 is configured to receive the signal sent by the external data processing device, and send the signal to the single chip microcomputer 120 to establish the single chip microcomputer 120 and the external device. Communication between data processing devices.

When the single chip microcomputer 120 establishes a connection with the external data processing device through the signal transmitting module 130 and the signal receiving module 140, the single chip microcomputer 120 transmits a signal of a certain frequency (such as 1.37 KHz) to the signal transmitting module 130, and the signal transmitting module 130 transmits the signal transmitted by the single chip microcomputer 120. The bias voltage is adjusted to a voltage range detectable by the external data processing device, and the signal after adjusting the bias voltage is sent to the external data processing device, so that the external data processing device can completely detect the signal transmitted by the single chip microcomputer 120; The signal receiving module 140 also adjusts the signal sent by the external data processing device, and outputs the signal after adjusting the bias voltage to the single chip microcomputer 120, so that the single chip microcomputer 120 can recognize the signal sent by the external data processing device. Thereby, stable communication between the single chip microcomputer 120 and the external data processing device is established.

Referring to FIG. 3, in the body water and oil analysis circuit of the applicant, the water and oil detection module 110 includes a voltage following unit 111, a first amplifying unit 112, a differentiating unit 113, a filtering unit 114, and a second amplifying unit 115.

The voltage follower unit 111 is configured to receive a square wave signal, follow the square wave signal, and output a voltage follower signal. The first amplifying unit 112 is configured to amplify the voltage follower signal output by the voltage follower unit 111 and output a voltage amplifying signal. The voltage amplified signal is skin tested after skin testing. The differentiation unit 113 is configured to limit the sharp voltage signal generated after the skin voltage signal passes through the human skin to smooth the sharp voltage signal. The filtering unit 114 is configured to filter the skin voltage signal after being smoothed by the differentiating unit 113, and output a DC voltage signal. The second amplifying unit 115 is configured to amplify the DC voltage signal output by the filtering unit 114, and output the amplified DC voltage signal to the MCU 120.

Specifically, as shown in FIG. 3, the voltage following unit 111 includes a square wave signal receiving terminal VPWM, a first operational amplifier U1, and a first resistor R1.

The non-inverting input of the first operational amplifier U1 is received via the first resistor R1 and the square wave signal The terminal VPWM is connected, the inverting input terminal of the first operational amplifier U1 is connected to the output terminal of the first operational amplifier U1, and the output terminal of the first operational amplifier U1 is connected to the first amplifying unit 112.

Specifically, as shown in FIG. 3, the first amplifying unit 112 includes a second operational amplifier U2, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a voltage amplification signal output. End VTX.

One end of the second resistor R2 is connected to the voltage follower unit 111, the other end of the second resistor R2 is connected to the non-inverting input terminal of the second operational amplifier U2, and is grounded via the third resistor R3; the inverting input terminal of the second operational amplifier U2 The ground is connected to the output terminal of the second operational amplifier U2 via the fifth resistor R5, and the output terminal of the second operational amplifier U2 is connected to the voltage amplified signal output terminal VTX via the sixth resistor R6.

Specifically, as shown in FIG. 3, the differentiation unit 113 includes a sharp voltage signal input terminal VRX, a third operational amplifier U3, a first capacitor C1, a seventh resistor R7, and an eighth resistor R8.

The inverting input terminal of the third operational amplifier U3 is connected to the sharp voltage signal input terminal VRX via the first capacitor C1, the non-inverting input terminal of the third operational amplifier U3 is grounded, the third operational amplifier U3 is connected to the filtering unit 114, and the seventh resistor R7 is connected. One end is connected to the inverting input terminal of the third operational amplifier U3, and the other end of the seventh resistor R7 is connected to the output terminal of the third operational amplifier U3 via the eighth resistor R8.

Specifically, as shown in FIG. 3, the filtering unit 114 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4.

One end of the ninth resistor R9 is connected to the differential unit 113, and the other end of the ninth resistor R9 is grounded via the second capacitor C2; one end of the tenth resistor R10 is connected to a common connection point of the ninth resistor R9 and the second capacitor C2, tenth The other end of the resistor R10 is grounded via a third capacitor C3; one end of the eleventh resistor R11 is connected to a common connection point of the tenth resistor R10 and the third capacitor C3, and the other end of the eleventh resistor R11 is grounded via the fourth capacitor C4. The common connection point of the eleventh resistor R11 and the fourth capacitor C4 is connected to the second amplifying unit 115.

In this embodiment, the voltage following unit 111 receives the square wave signal through the square wave signal receiving end VPWM, and follows the square wave signal to output a voltage following signal, and the voltage following signal output by the voltage following unit 111 and the received square wave signal. Equal in size, in the same phase, through The voltage following process improves the load carrying capacity of the square wave signal. The first amplifying unit 112 amplifies the voltage following signal outputted by the voltage following unit 111, and outputs a voltage amplifying signal, and the voltage amplifying signal generates a skin voltage signal after skin testing; the skin voltage signal is amplified by a signal to increase an output signal. The amplitude, that is, the amplitude of the signal passing through the human skin, enables the signal after the human skin to collect more amplitude information to ensure the accuracy of the human skin water and oil percentage test data.

It should be understood by those skilled in the art that the square wave signal will obtain a relatively sharp signal after passing through the skin of the human body, which is determined by the resistance characteristics of the human skin, and different skin moisture and oil have different resistance characteristics, thus obtaining There will also be a difference in the amplitude of the sharp voltage signal.

Therefore, the first amplifying unit 112 passes the voltage amplifying signal outputted by the voltage amplifying signal output terminal VTX, that is, the square wave signal after the voltage following and amplifying processing passes through the human skin and becomes a relatively sharp voltage signal, and the differential unit 113 passes the sharp voltage. The signal input terminal VRX receives the sharp voltage signal that the voltage amplification signal output by the first amplification unit 112 passes through the skin of the human body, and the differentiation unit 113 limits the amplitude of the sharp voltage signal in the skin voltage signal, thereby enabling The sharp voltage signal is smoothed to obtain a stable voltage signal, which can reflect the human skin water and oil percentage data. The filtering unit 114 performs three-stage filtering on the voltage signal output by the differentiating unit 113, and filters out the low frequency signal, the intermediate frequency signal and the high frequency signal in the voltage signal outputted by the differential unit 113, respectively, to obtain a stable DC voltage signal. The second amplifying unit 115 amplifies the DC voltage signal output by the filtering unit 114, and outputs the amplified DC voltage signal to the data collecting terminal DATA_AD of the single chip microcomputer 120.

Specifically, as shown in FIG. 3, the second amplifying unit 115 includes a fourth operational amplifier U4, a twelfth resistor R12, a thirteenth resistor R13, and a fifth capacitor C5.

The non-inverting input terminal of the fourth operational amplifier U4 is connected to the filtering unit 114. The inverting input terminal of the fourth operational amplifier U4 is grounded via the twelfth resistor R12, and is connected to the output terminal of the fourth operational amplifier U4 via the thirteenth resistor R13. The output terminal of the fourth operational amplifier U4 is grounded via the fifth capacitor C5, and the common connection point of the output terminal of the fourth operational amplifier U4 and the fifth capacitor C5 is connected to the data acquisition terminal DATA_AD of the single chip microcomputer 120.

In the embodiment of the present application, preferably, the first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, and the fourth operational amplifier U4 are four operational amplifier integrated circuits, and the power supply pin of the first operational amplifier U1 is connected to the power supply VCC. The power supply VCC is grounded through the capacitor C0, and the ground pin of the first operational amplifier U1 is grounded.

Referring to FIG. 4, in the body water and oil analysis circuit of the applicant, the signal transmitting module 130 includes a first signal receiving end RX1, a first signal transmitting end TX1, a fourteenth resistor R14, a fifteenth resistor R15, and a sixth capacitor C6. And the seventh capacitor C7.

One end of the fourteenth resistor R14 is connected to the single chip 120 through the first signal receiving end RX1, the other end of the fourteenth resistor R14 is connected to one end of the sixth capacitor C6, and is grounded via the seventh capacitor C7; the other of the sixth capacitor C6 One end is grounded via a fifteenth resistor R15, a common connection point of the sixth capacitor C6 and the fifteenth resistor R15 is coupled to the first signal transmitting terminal TX1, and the first signal transmitting terminal TX1 is used to transmit a signal to an external data processing device.

Referring to FIG. 5, in the body water and oil analysis circuit of the applicant, the signal receiving module 140 includes a second signal receiving end RX2, a second signal transmitting end TX2, a working power input terminal VIN, a sixteenth resistor R16, and a seventeenth resistor. R17, the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, the twenty-fourth resistor R24, the second Fifteen resistor R25, eighth capacitor C8, ninth capacitor C9, tenth capacitor C10, eleventh capacitor C11, twelfth capacitor C12 and comparator U5.

The second signal receiving end RX2 is configured to receive a signal sent by the external data processing device, one end of the sixteenth resistor R16 is connected to the second signal receiving end RX2, and the other end of the sixteenth resistor R16 is connected to one end of the eighth capacitor C8. And is grounded via the ninth capacitor C9; one end of the seventeenth resistor R17 is connected to the working power input terminal VIN, and the other end of the seventeenth resistor R17 is grounded via the eighteenth resistor R18 and the nineteenth resistor R19 in sequence; The common connection point of the resistor R17 and the eighteenth resistor R18 is connected to the other end of the eighth capacitor C8, and is grounded via the tens ten resistor R20 and the tenth capacitor C10 in sequence.

One end of the twenty-first resistor R21 is connected to the working power input terminal VIN, and the other end of the twenty-first resistor R21 is grounded via the twenty-second resistor R22; the inverting input terminal of the comparator U5 is connected to the twenty-third resistor R23 The common connection point of the twenty-first resistor R21 and the twenty-second resistor R22 is connected, and is grounded via the eleventh capacitor C11, and the non-inverting input of the comparator U5 The terminal is connected to a common connection point of the twentieth resistor R20 and the tenth capacitor C10, the power terminal of the comparator U5 is connected to the working power input terminal VIN, and the ground terminal of the comparator U5 is grounded.

One end of the twelfth capacitor C12 is connected to the working power input terminal VIN, and the other end of the twelfth capacitor C12 is grounded; one end of the twenty-fourth resistor R24 is connected to the working power input terminal VIN, and the other end of the twenty-fourth resistor R24 is Connected to one end of the twenty-fifth resistor R25, the common connection point of the twenty-fourth resistor R24 and the twenty-fifth resistor R25 is connected to the output end of the comparator U5; the other end of the twenty-fifth resistor R25 passes the second signal The transmitting terminal TX2 is connected to the single chip microcomputer 120.

It should be noted that, in Fig. 3 to Fig. 5, PWM1, PT1~PT10 are frequency test points, wherein PWM1 is the frequency test point of the received square wave signal, THP1 is the frequency test point before the signal passes through the human skin, and THP2 is the signal. After the frequency test point after the human skin, PT1 is the frequency test point of the output signal of the first operational amplifier U1, PT2 is the frequency test point of the signal after the second resistor R2 and the third resistor R3, and PT3 is the second operational amplifier U2 The frequency test point of the output signal, PT4 is the frequency test point of the output signal of the third operational amplifier U3, PT5 is the frequency test point of the signal filtered by the ninth resistor R9 and the second capacitor C2, and PT6 is the tenth resistor R10 and The frequency test point of the signal filtered by the third capacitor C3, PT7 is the frequency test point of the signal filtered by the eleventh resistor R11 and the fourth capacitor C4, and PT8 is the frequency test point of the output signal of the fourth operational amplifier U4, PT9 The frequency test point of the signal transmitted by the single chip 120 is filtered by the fourteenth resistor R14 and the seventh capacitor C7, and the PT10 is the frequency test point of the signal that enters the non-inverting input of the comparator U5.

As shown in FIG. 1 to FIG. 5, the working principle of the body water and oil analysis circuit of the applicant body is specifically described as follows:

When the single chip microcomputer 120 establishes a connection with the external data processing device, the single chip microcomputer 120 transmits a signal of a certain frequency (such as 1.37 KHz) to the signal transmitting module 130, and the signal transmitted by the single chip microcomputer 120 passes through the fourteenth resistor R14 and the fifteenth in the signal transmitting module 130. The voltage division of the resistor R15 and the charging and discharging of the seventh capacitor C7 cause the bias voltage of the signal waveform to be within the detection voltage range of the external data processing device, and the sixth capacitor C6 of the signal transmitting module 130 acts as a decoupling function. , acting as an anti-interference, enabling the signal transmitted by the single chip 120 to The integrity is transmitted to the external data processing device such that the external data processing device can fully detect the signal transmitted by the microcontroller 120, thereby enabling communication between the microcontroller 120 and the external data processing device.

At the same time, the external data processing device also sends a signal to the signal receiving module 140. In order to enable the single chip microcomputer 120 to recognize the signal sent by the external data processing device, in the signal receiving module 140, the power supply voltage Vdd input from the working power input terminal VIN passes through the seventeenth. The resistor R17, the eighteenth resistor R18 and the nineteenth resistor R19 are divided, so that the signal input to the non-inverting input terminal of the comparator U5 is a superimposed waveform based on the divided voltage, and the inverting input of the comparator U5 is input. The signal is a voltage divided by the twenty-first resistor R21 and the twenty-second resistor R22. In particular, the resistance of the twenty-first resistor R21 and the twenty-second resistor R22 are equal, so the comparison is performed. The voltage at the inverting input of U5 is 1/2 Vdd. According to the characteristics of the comparator U5, when the voltage of the non-inverting input terminal of the comparator U5 is greater than the voltage of the inverting input terminal of the comparator U5, the comparator U5 outputs a high level signal, and the output voltage of the comparator U5 is Vdd; When the voltage of the non-inverting input terminal of the comparator U5 is less than the voltage of the inverting input terminal of the comparator U5, the comparator U5 outputs a low-level signal, and the output voltage of the comparator U5 is 0V. Therefore, the signal output by the signal receiving module 140 through the second signal transmitting terminal TX2 is a high and low level signal based on the 1/2 Vdd bias. Since the power supply voltage of the single chip microcomputer 120 is also the power supply voltage Vdd input to the operating power input terminal VIN, the single chip microcomputer 120 Ability to identify signals from external data processing devices. The single chip microcomputer 120 can detect the signal sent from the external data processing device by detecting the high and low level signals received from the second signal transmitting terminal TX2 of the signal receiving module 140, thereby implementing communication between the single chip microcomputer 120 and the external data processing device.

The nineteenth resistor R19 in the signal receiving module 140 has a small resistance value, which can prevent the interference signal of the signal channel of the external data processing device from affecting the output of the comparator U5, and ensures the stability of the signal received by the single chip microcomputer 120 from the external data processing device.

After the single-chip microcomputer 120 establishes a communication connection with the external data processing device, the water-oil detecting module 110 receives the square wave signal. The embodiment of the present application is specifically a square wave signal of 4 KHz, and the square wave signal is input to the voltage following unit 111 via the first resistor R1. In the non-inverting input terminal of the first operational amplifier U1, the first operational amplifier U1 constitutes a voltage follower to follow the square wave signal, and outputs a voltage following signal having the same magnitude and phase as the square wave signal.

The voltage following signal outputted by the first operational amplifier U1 is divided by the second resistor R2 and the third resistor R3, and then input to the non-inverting input terminal of the second operational amplifier U2. The second operational amplifier U2 amplifies the input signal to increase the The amplitude of the signal of the human skin. According to the resistance characteristic of the human skin, the voltage amplification signal outputted by the second operational amplifier U2 is subjected to human skin test to generate the skin voltage signal, and the skin voltage signal becomes a relatively sharp voltage signal.

In the differentiating unit 113, the third operational amplifier U3 limits the amplitude of the sharp voltage signal in the skin voltage signal, so that the sharp voltage signal is smoothed, and a stable voltage signal is obtained, which can reflect the skin moisture of the human body. Information that reflects the percentage of human skin water and oil.

In the filtering unit 114, the ninth resistor R9 and the second capacitor C2 filter the first time filtering of the voltage signal output by the third operational amplifier U3, filtering out the low frequency signal in the voltage signal, the tenth resistor R10 and the third capacitor C3 The filter performs a second filtering on the voltage signal after filtering the low frequency, and filters out the intermediate frequency signal in the voltage signal, and the eleventh resistor R11 and the fourth capacitor C4 perform the third filtering on the voltage signal after filtering the low frequency and the intermediate frequency. The high frequency signal in the voltage signal is filtered to obtain a stable DC voltage signal.

In the second amplifying unit 115, the fourth operational amplifier U4 amplifies the DC voltage signal output by the filtering unit 114, and outputs the amplified DC voltage signal to the data collecting terminal DATA_AD of the single chip microcomputer 120. When the single chip microcomputer 120 collects the DC voltage signal outputted by the fourth operational amplifier U4, the analog voltage conversion of the DC voltage signal, that is, AD conversion, obtains a fixed AD value, and the AD value reflects the human skin moisture value, so that the single chip microcomputer 120 When the AD value is sent to external data processing, the external data processing device can perform big data analysis on the Internet, and calculate the percentage of water and oil of the human skin combined with the comprehensive factors such as geography, air quality, and weather change, thereby testing the percentage of water and oil of the human skin. The data is displayed to show the characteristics of the human skin and to test the percentage of water and oil in the human skin, that is, the characteristics of the human skin. The embodiment of the present application improves the accuracy of the human skin water and oil percentage test data by improving the hardware circuit structure of the water oil detecting module 110.

The embodiment of the present application further provides a skin detector including a human skin The skin water oil analysis circuit, the circuit structure, the working principle and the beneficial effects of the human skin water and oil analysis circuit are all referred to the above embodiments, and are not described herein again.

In practical applications, the communication interface between the skin detector and the external data processing device can be connected to establish a communication connection between the single chip and the external data processing device in the human skin water and oil analysis circuit. It should be noted that the external data processing device may be a device such as a mobile phone or a computer that can perform big data analysis using the Internet, and the communication interface may be an interface such as a headphone interface or a USB interface.

The above description is only the embodiment of the present application, and thus does not limit the scope of the patent application, and the equivalent structure or equivalent process transformation of the specification and the drawings of the present application, or directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of this application.

Claims

A human skin water and oil analysis circuit, characterized in that it comprises:

The water and oil detection module is configured to receive a square wave signal, and use the square wave signal as an excitation signal to detect a percentage of human skin water and oil, and obtain a skin voltage signal capable of reflecting a percentage of human skin water and oil data;

a single chip microcomputer, configured to perform analog-to-digital conversion on the voltage signal obtained by the water-oil detecting module, and send the analog-digital converted voltage signal to an external data processing device, so that the external data processing device pairs the voltage signal Data analysis was performed to detect the percentage of human skin water and oil.
The human skin water and oil analysis circuit according to claim 1, wherein the water oil detecting module comprises:

a voltage following unit, configured to receive the square wave signal, follow the square wave signal, and output a voltage following signal;

a first amplifying unit, configured to amplify the voltage following signal, and output a voltage amplifying signal, wherein the voltage amplifying signal generates a skin voltage signal after being tested by a skin;

a differential unit configured to limit a sharp voltage signal generated after passing through the human skin in the skin voltage signal to smooth the sharp voltage signal;

a filtering unit, configured to filter the smoothed skin voltage signal and output a DC voltage signal;

And a second amplifying unit, configured to amplify the DC voltage signal, and output the amplified DC voltage signal to the single chip microcomputer.
The human skin water and oil analysis circuit according to claim 2, wherein the voltage following unit comprises a square wave signal receiving end, a first operational amplifier and a first resistor;

The non-inverting input terminal of the first operational amplifier is connected to the square wave signal receiving end via the first resistor, and the inverting input end of the first operational amplifier is connected to the output end of the first operational amplifier. An output of the first operational amplifier and the first amplifying unit connection.
The human skin water and oil analysis circuit according to claim 2, wherein the first amplifying unit comprises a second operational amplifier, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and Voltage amplification signal output terminal;

One end of the second resistor is connected to the voltage follower unit, the other end of the second resistor is connected to the non-inverting input terminal of the second operational amplifier, and is grounded via the third resistor; the second operation An inverting input terminal of the amplifier is grounded via the fourth resistor, and is connected to an output end of the second operational amplifier via the fifth resistor, and an output end of the second operational amplifier is connected to the sixth resistor The output of the voltage amplification signal is connected.
The human skin water and oil analysis circuit according to claim 2, wherein the differential unit comprises a sharp voltage signal input terminal, a third operational amplifier, a first capacitor, a seventh resistor, and an eighth resistor;

An inverting input terminal of the third operational amplifier is connected to the sharp voltage signal input terminal via the first capacitor, a non-inverting input terminal of the third operational amplifier is grounded, and an output end of the third operational amplifier is a filtering unit is connected; one end of the seventh resistor is connected to an inverting input end of the third operational amplifier, and the other end of the seventh resistor is connected to an output end of the third operational amplifier via the eighth resistor connection.
The human skin water and oil analysis circuit according to claim 2, wherein the filtering unit comprises a ninth resistor, a tenth resistor, an eleventh resistor, a second capacitor, a third capacitor, and a fourth capacitor;

One end of the ninth resistor is connected to the differentiating unit, and the other end of the ninth resistor is grounded via the second capacitor; one end of the tenth resistor is opposite to the ninth resistor and the second capacitor a common connection point is connected, the other end of the tenth resistor is grounded via the third capacitor; one end of the eleventh resistor is connected to a common connection point of the tenth resistor and the third capacitor, The other end of the eleventh resistor is grounded via the fourth capacitor, and a common connection point of the eleventh resistor and the fourth capacitor is connected to the second amplifying unit.
The human skin water and oil analysis circuit according to any one of claims 2 to 6, wherein The second amplifying unit includes a fourth operational amplifier, a twelfth resistor, a thirteenth resistor, and a fifth capacitor;

The non-inverting input terminal of the fourth operational amplifier is connected to the filtering unit, the inverting input end of the fourth operational amplifier is grounded via the twelfth resistor, and the thirteenth resistor and the fourth The output of the operational amplifier is connected, the output of the fourth operational amplifier is grounded via the fifth capacitor, and the common connection point of the output of the fourth operational amplifier and the fifth capacitor is connected to the single chip microcomputer.
The human skin water and oil analysis circuit according to claim 1, wherein the human skin water and oil analysis circuit further comprises a signal transmitting module and a signal receiving module;

The signal transmitting module is configured to send a signal output by the single chip to the external data processing device, where the signal receiving module is configured to receive a signal sent by the external data processing device, and send the signal to the single chip microcomputer And establishing communication between the single chip microcomputer and the external data processing device.
The human skin water and oil analysis circuit according to claim 8, wherein the signal transmitting module comprises a first signal receiving end, a first signal transmitting end, a fourteenth resistor, a fifteenth resistor, a sixth capacitor, and Seventh capacitor

One end of the fourteenth resistor is connected to the single chip through the first signal receiving end, and the other end of the fourteenth resistor is connected to one end of the sixth capacitor, and is grounded via the seventh capacitor; The other end of the sixth capacitor is grounded via the fifteenth resistor, a common connection point of the sixth capacitor and the fifteenth resistor is opposite to the first signal transmitting end, and the first signal transmitting end is used The signal is transmitted to an external data processing device.
The human skin water and oil analysis circuit according to claim 8 or 9, wherein the signal receiving module comprises a second signal receiving end, a second signal transmitting end, a working power input end, a sixteenth resistor, and a tenth Seven resistance, eighteenth resistance, nineteenth resistance, twentieth resistance, twenty-first resistance, twenty-second resistance, twenty-third resistance, twenty-fourth resistance, twenty-fifth resistance, eighth Capacitor, ninth capacitor, tenth capacitor, eleventh capacitor, twelfth capacitor and comparator;

The second signal receiving end is configured to receive a signal sent by an external data processing device, and one end of the sixteenth resistor is connected to the second signal receiving end, and the other end of the sixteenth resistor is opposite to the first One end of the eight capacitor is connected and grounded via the ninth capacitor; one end of the seventeenth resistor is connected to the working power input end, and the other end of the seventeenth resistor is sequentially connected via the eighteenth resistor, a nineteenth resistor is grounded; a common connection point of the seventeenth resistor and the eighteenth resistor is connected to the other end of the eighth capacitor, and is sequentially grounded via the tens resistor and the tenth capacitor;

One end of the twenty-first resistor is connected to the working power input end, and the other end of the twenty-first resistor is grounded via the second twelve resistor; an inverting input end of the comparator is a twenty-third resistor is connected to a common connection point of the twenty-first resistor and the twenty-second resistor, and is grounded via the eleventh capacitor, the non-inverting input of the comparator and the twentieth resistor Connected to a common connection point of the tenth capacitor, the power terminal of the comparator is connected to the working power input end, and the ground end of the comparator is grounded;

One end of the twelfth capacitor is connected to the working power input end, and the other end of the twelfth capacitor is grounded; one end of the twenty-fourth resistor is connected to the working power input end, and the second The other end of the fourteenth resistor is connected to one end of the twenty-fifth resistor, and a common connection point of the twenty-fourth resistor and the twenty-fifth resistor is connected to an output end of the comparator; The other end of the five resistors is connected to the single chip through the second signal transmitting end.
A skin tester comprising the human skin water and oil analysis circuit according to any one of claims 1 to 10.