CN213041771U

CN213041771U - Water sample pH value detector

Info

Publication number: CN213041771U
Application number: CN202021639710.6U
Authority: CN
Inventors: 刘万瑾; 林惠霞; 柯盛海; 武永华
Original assignee: Fujian Zhihengyou Water Technology Co ltd
Current assignee: Fujian Zhihengyou Water Technology Co ltd
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2021-04-23
Anticipated expiration: 2030-08-10

Abstract

The utility model provides a water sample PH value detector in the technical field of PH value detection, which comprises a PH composite electrode, a PH value sensor, a controller, a display screen, a reset circuit and a power module; the input end of the PH value sensor is connected with the output end of the PH composite electrode, and the output end of the PH value sensor is connected with the controller; the display screen and the reset circuit are connected with the controller; and the power supply module is respectively connected with the PH value sensor, the controller, the display screen and the reset circuit. The utility model has the advantages that: the PH value detection precision and the detection convenience are greatly improved, and the power consumption of the PH value detection is reduced.

Description

Water sample pH value detector

Technical Field

The utility model relates to a PH value detects technical field, indicates a water sample PH value detector very much.

Background

Acid rain is called acid wet sedimentation from the professional perspective, particularly acid precipitation with a pH value below 5.6, and the formation of the acid rain is mainly caused by acid gas generated by massive combustion of sulfur-containing fuel, automobile exhaust emission, straw burning and the like. The long-term harm of acid rain to the ecological environment and human body is huge, which not only harms soil and corrodes buildings, but also easily causes diseases of human respiratory system. In addition, a large amount of waste liquid is generated in industrial manufacturing, and some factory enterprises discharge the waste liquid at will, so that water environment pollution is easily caused. The pH value of the water is acidic or alkaline, which can damage the ecological environment and even threaten the health of human beings. Therefore, the pH value is an important parameter for measuring the health condition of water quality, and the detection of the pH value is essential.

However, most people still use the traditional pH test paper for detecting the pH value, so that the measurement accuracy is low, and although some pH testers exist in the market, the traditional pH test paper has the defects of large volume, high power consumption and the need of replacing batteries all the time.

Therefore, how to provide a water sample PH detector realizes promoting the accuracy of PH detection and the convenience of detection, reduces the power consumption of PH detection, and becomes a problem to be solved urgently.

Disclosure of Invention

The to-be-solved technical problem of the utility model lies in providing a water sample pH value detector, realizes promoting the precision that the pH value detected and the convenience that detects, reduces the consumption that the pH value detected.

The utility model provides a water sample PH value detector, which comprises a PH composite electrode, a PH value sensor, a controller, a display screen, a reset circuit and a power module;

the input end of the PH value sensor is connected with the output end of the PH composite electrode, and the output end of the PH value sensor is connected with the controller; the display screen and the reset circuit are connected with the controller; and the power supply module is respectively connected with the PH value sensor, the controller, the display screen and the reset circuit.

Further, the controller includes a passive crystal oscillator U1, a single chip microcomputer U2, an SPI memory U3, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a capacitor C20, an inductor L4, a resistor R1, and an antenna ANT 1;

pin 1 of the single chip microcomputer U2 is connected with a capacitor C9 and a power supply module, pin 2 is connected with a capacitor C14 and an inductor L4,

pins

3 and 4 are connected with a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13 and a power supply module, pin 9 is connected with a reset circuit, pin 13 is connected with a PH value sensor, pin 19 is connected with a capacitor C19 and the power supply module, pin 26 is connected with a capacitor C18 and the power supply module, pin 37 is connected with a capacitor C4 and the power supply module, pins 40 and 41 are connected with a display screen, and pins 43 and 46 are connected with a capacitor C3, a capacitor C20 and the power supply module; one end of the capacitor C16 is connected with 5 of the singlechip U2, and the other end of the capacitor C16 is connected with 6 of the singlechip U2; one end of the capacitor C17 is connected with 7 of the singlechip U2, and the other end of the capacitor C17 is connected with 8 of the singlechip U2; a pin 1 of the antenna ANT1 is connected with a capacitor C14 and a capacitor C15, and a pin 2 is grounded;

pins

1, 2, 3, 5, 6 and 7 of the SPI 3 are respectively connected with

pins

30, 32, 29, 33, 31 and 28 of a singlechip U2, pin 8 is connected with a power supply module, and pin 4 is grounded;

after the resistor R1 and the capacitor C6 are connected in parallel, one end of the resistor R1 is connected with the capacitor C5 and a pin 48 of the singlechip U2, and the other end of the resistor R1 is connected with a pin 47 of the singlechip U2;

pin 1 of the passive crystal oscillator U1 is connected with a capacitor C1 and a pin 45 of a singlechip U2,

pins

2 and 4 are grounded, and pin 3 is connected with a capacitor C2 and a pin 44 of a singlechip U2; the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C9, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the capacitor C15, the capacitor C18, the capacitor C19 and the capacitor C20 are all grounded.

Further, the type of the single chip microcomputer U2 is ESP32-DOWDQ 6.

Further, the reset circuit includes a reset chip U4, a resistor R2, and a resistor R3;

one end of the resistor R3 is connected with a pin 3 of a reset chip U4, and the other end of the resistor R3 is connected with the power supply module; pin 2 of the reset chip U4 is connected with the resistor R2 and the singlechip U2, and pin 1 is grounded; the resistor R2 is connected to ground.

Furthermore, the display screen is an HMI serial port screen.

Further, the PH sensor includes an operational amplifier Q1, an operational amplifier Q2, a reference voltage source P1, a connection terminal P2, a connection terminal P3, a potentiometer R12, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a capacitor C37, and a capacitor C38;

a pin 4 of the operational amplifier Q1 is grounded, a pin 5 is connected with a potentiometer R12, a capacitor C37 and a resistor R15, and

pins

6 and 7 are both connected with a pin 2 of a wiring terminal P2; the capacitor C37 is connected with the resistor R15 and is grounded; pin 1 of the operational amplifier Q2 is connected with a resistor R11 and a pin 5 of a wiring terminal P3, pin 2 is connected with a resistor R11 and a resistor R14, pin 3 is connected with pin 1 of a wiring terminal P2, and pin 8 is connected with a power module; the resistor R14 is grounded; pins S1, S2 and S3 of the wiring terminal P2 are respectively connected with

pins

1, 2 and 3 of a reference voltage source P1; the pin 8 of the reference voltage source P1 is connected with a resistor R13 and a capacitor C38; the capacitor C38 is connected with a pin 4 of a reference voltage source P1 and is grounded; the resistor R13 is connected with the power supply module;

pins

1 and 2 of the wiring terminal P2 are connected with a PH composite electrode; and a pin 5 of the wiring terminal P3 is connected with the controller.

Further, the operational amplifier Q1 and the operational amplifier Q2 are both TLC 4502.

The utility model has the advantages that:

by adopting the specially-made PH composite electrode, the PH value detection precision is greatly improved. Detect and show pH value through setting up PH combined electrode, pH value sensor, controller, display screen, reset circuit and power module, simple structure, the integrated level is high, and then very big promotion the convenience that detects. The controller is set to adopt the single chip microcomputer U2 with the model of ESP32-DOWDQ6, so that the two central processor cores can be independently controlled, a user can cut off the power supply of one processor, the detection is completed by using the low-power consumption coprocessor, the power consumption of the PH value detection is greatly reduced, and the battery is prevented from being frequently replaced.

Drawings

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

Fig. 1 is a schematic circuit diagram of a water sample PH detector according to the present invention.

Fig. 2 is a circuit diagram of the controller of the present invention.

Fig. 3 is a circuit diagram of the PH sensor of the present invention.

Fig. 4 is a circuit diagram of the reset circuit of the present invention.

Fig. 5 is a flow chart of the working principle of the present invention.

Detailed Description

The technical scheme in the embodiment of the application has the following general idea: and a specially-made PH composite electrode is utilized to improve the PH value detection precision. Through integrated PH combined electrode, PH value sensor, controller, display screen, reset circuit and power module in limited volume, simplified structure to promote the convenience that detects. The power consumption of PH value detection is reduced by adopting the singlechip U2 with the low-power consumption coprocessor.

Referring to fig. 1 to 5, a preferred embodiment of a PH detector for water samples of the present invention includes a PH composite electrode, a PH sensor, a controller, a display screen, a reset circuit and a power module;

the PH composite electrode consists of a measuring electrode and a reference electrode, wherein the measuring electrode is made of a special glass film, namely, a glass electrode which selectively responds to H +, and the reference electrode is a silver chloride electrode. The bottom of the PH composite electrode is provided with a protective sleeve, a small amount of KCL solution is filled in the protective sleeve and used for protecting a glass ball membrane of the measuring electrode, the wetting of an electrode bulb is kept, the glass ball membrane is prevented from being damaged, the service life is prolonged, and meanwhile, the use is convenient. The core of the measuring electrode is a spherical melt-blown glass bubble, the lower half part of the spherical glass bubble is covered with a layer of glass film, and the glass film is sensitive to H + and has the characteristic of H + adsorption. When the measuring electrode is immersed in the solution to be measured, the glass film is contacted with the solution to be measured, the H + concentration on two sides of the glass film is different, concentration difference is formed, H + begins to migrate from the side with large concentration to the side with small concentration, the H + on two sides of the glass film accordingly establishes dynamic balance, the charge distribution is changed accordingly, and additional electromotive force is generated; while the potential of the reference electrode is constant and is not affected by the H + concentration. Thus, a potential difference is generated between the two electrodes, and the potential difference has a functional relation with the H + concentration in the solution to be measured, namely the pH value of the solution to be measured. Namely, the potential change Delta E of the PH composite electrode and the PH value of the solution to be detected meet the Nernst formula:

wherein E represents the measurement electrode potential; e₀Represents a reference electrode potential; r represents a gas constant (8.314570J. mol-1. K-1); t represents absolute temperature in kelvin; f represents a Faraday constant (96485.3383℃ mol-1);

the PH value sensor is used for sending the voltage analog signal collected by the PH composite electrode to the controller; the controller is used for converting the received voltage analog signal into a voltage digital signal, processing the voltage digital signal and outputting a PH value to be displayed on the display screen; the display screen is used for displaying the detection result; the reset circuit is used for carrying out system reset, kernel reset and CPU reset on the detector; the power supply module is used for providing power for the detector, and the power supply module capable of realizing the function is selected in specific implementation, and is not limited to any type;

The controller comprises a passive crystal oscillator U1, a singlechip U2, an SPI memory U3, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a capacitor C20, an inductor L4, a resistor R1 and an antenna ANT 1; the frequency of the passive crystal oscillator U1 is 40 MHz; the capacitance values of the capacitor C1 and the capacitor C2 are both 22 pF;

pins

1, 2, 3, 5, 6 and 7 of the SPI 3 are respectively connected with

pins

Pins

1, 3, 4, 43 and 46 of the singlechip U2 are input by an analog power supply; the clock chip power supply of ESP32-DOWDQ6 is pin 19, the CPU power supply input is pin 37, and the working voltage range of the digital power supply is 1.8V-3.6V. The output voltage of the pin 26(SDIO) of the singlechip U2 can be 1.8V or 3.3V. When the voltage is configured to be 1.8V, the maximum current which can be provided by the low-voltage drop linear voltage regulator in the ESP32-DOWDQ6 is 40mA, and the voltage output is in the range of 1650 mV-2000 mV; when the configuration is 3.3V, there will be a certain voltage difference between the

pins

26 and 19, so that a filter capacitor of 1 μ F, i.e. the capacitor C18, is externally connected to the pin 26.

The single chip microcomputer U2 is in an ESP 32-DOWNQ 6 model, integrates Wi-Fi and dual-mode Bluetooth, is extremely low in standby power consumption, rich in functions and wide in application scene, is suitable for tasks with extremely high requirements on low-power sensors and networks, such as voice recognition, multimedia communication and the like, has the characteristics of expandability and self-adaption, can realize independent control over two central processor cores, for example, a user can disconnect the power supply of a processor, and a low-power coprocessor is used for continuously monitoring state change of peripheral equipment or whether some analog quantity exceeds a threshold value. The sensor integrates a Hall sensor, a capacitive touch sensor, a low-noise sensing amplifier, an Ethernet interface, an SD card interface, a high-speed SDIO/SPI, a universal asynchronous transceiver transmitter, an I2C and the like, and the adjustable range of the internal clock frequency is 80MHz to 240 MHz. The most outstanding characteristic is that various elements are highly integrated in a tiny volume, and strong processing performance and wireless transmission function can be realized by only few peripheral devices, so as to meet various complex task requirements, for example, a PH value detected by Bluetooth is sent to a mobile phone for display.

The reset circuit comprises a reset chip U4, a resistor R2 and a resistor R3; the type of the reset chip U4 is preferably BL8509, and the reset chip U4 is used for generating a low-level signal for a period of time to trigger reset;

The display screen is an HMI serial port screen, is a human-computer interface product, has comprehensive functions and excellent performance, can be independently programmed and developed, and can be used for making a high-end human-computer interaction interface. The model is preferably TJC4024T032_011R of Taochi electronics, the resolution is 400 multiplied by 240, the system not only supports multiple communication interfaces such as TTL, RS232, RS485 and CAN, but also has a bidirectional I/O port, CAN configure 5 working modes, integrates a CPU processor, an RTC, a FLASH memory, a user data storage unit and the like, has multiple functions such as serial port communication, data storage, liquid crystal display and touch input, directly communicates with the single chip microcomputer U2 by using a character string instruction, and is higher in source code readability. An I/O port can be defined as either Input or Output; c language instructions are used, the data structure is simplified, and the assignment of the control attributes supports simple operation; the touch type of the screen is resistance touch, and the screen enters a working state immediately after being electrified without any initialization setting. The HMI serial port screen receives data through interruption, data packet loss and blocking are not easy to occur, and stability and high efficiency of the whole system are guaranteed.

The PH value sensor comprises an operational amplifier Q1, an operational amplifier Q2, a reference voltage source P1, a connecting terminal P2, a connecting terminal P3, a potentiometer R12, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a capacitor C37 and a capacitor C38;

a pin 4 of the operational amplifier Q1 is grounded, a pin 5 is connected with a potentiometer R12, a capacitor C37 and a resistor R15, and pins 6 and 7 are both connected with a pin 2 of a wiring terminal P2; the capacitor C37 is connected with the resistor R15 and is grounded; pin 1 of the operational amplifier Q2 is connected with a resistor R11 and a pin 5 of a wiring terminal P3, pin 2 is connected with a resistor R11 and a resistor R14, pin 3 is connected with pin 1 of a wiring terminal P2, and pin 8 is connected with a power module; the resistor R14 is grounded; pins S1, S2 and S3 of the wiring terminal P2 are respectively connected with

pins

1, 2 and 3 of a reference voltage source P1; the pin 8 of the reference voltage source P1 is connected with a resistor R13 and a capacitor C38; the capacitor C38 is connected with a pin 4 of a reference voltage source P1 and is grounded; the resistor R13 is connected with the power supply module; pins 1 and 2 of the wiring terminal P2 are connected with a PH composite electrode; and a pin 5 of the wiring terminal P3 is connected with the controller.

The PH value sensor adopts a +5V single power supply for power supply, is connected with the PH composite electrode through the wiring terminal P2, and outputs a voltage analog signal through a pin 5 of the wiring terminal P3. Because the internal resistance of the PH composite electrode generally reaches 1012 omega, an accurate voltage value can be measured only by realizing high-impedance input, a high-performance self-calibration precise double-path operational amplifier TLC4502 is adopted, the open-loop gain of the operational amplifier TLC4502 is higher than 120dB, the requirement of high-impedance input is met, low input offset voltage drift and high output driving capability are achieved, and the offset voltage can be automatically calibrated to be zero after power-on. When measuring a neutral solution with a pH equal to about 7, the voltage analog signal output by the pH sensor is equal to the voltage of the reference electrode (which can be adjusted by the potentiometer R12). The voltage of the ESP32-DOWDQ6 pin is known to be 3.3V, i.e. the maximum value of the theoretical effective voltage measurement of the ADC channel analog pin is 3.3V, so that the measuring electrode needs to be put into a neutral solution, and the potentiometer R12 of the PH sensor is adjusted so that the output voltage is about 1.6V.

The models of the operational amplifier Q1 and the operational amplifier Q2 are TLC 4502.

The working principle of the utility model comprises the following steps:

step S10, setting the sampling frequency and the sampling times of a PH value sensor through a controller, and sending the sampling frequency and the sampling times to the PH value sensor; before detection, a controller, a PH value sensor and a display screen need to be initialized; the sampling times are preferably 40 times;

step S20, the PH value sensor collects voltage analog signals of the PH composite electrode based on the received sampling frequency and sampling times, and sends the voltage analog signals to the controller;

step S30, after converting the received voltage analog signals into voltage digital signals, the controller sorts the voltage digital signals according to the numerical value, and after eliminating the maximum value and the minimum value, the controller calculates the arithmetic mean value of the rest voltage digital signals to obtain the PH value; filtering by using a median filtering method, in order to reduce errors caused by noise interference and accidental factors and improve the accuracy of the measured PH value, and finally obtaining a relatively accurate digital quantity;

s40, adjusting the resistance value of a potentiometer R12 in the PH value sensor to enable the PH value sensor to work under different voltages and measure the PH values under different voltages;

and S50, fitting the PH values under different voltages by using a linear fitting method to obtain a PH curve of which the PH value changes along with the voltage, and sending the PH curve to a display screen for displaying in real time. The linear fitting method is preferably a least squares method.

To sum up, the utility model has the advantages that:

Although specific embodiments of the present invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the claims appended hereto.

Claims

1. The utility model provides a water sample pH value detector which characterized in that: comprises a PH composite electrode, a PH value sensor, a controller, a display screen, a reset circuit and a power module;

the input end of the PH value sensor is connected with the output end of the PH composite electrode, and the output end of the PH value sensor is connected with the controller; the display screen and the reset circuit are connected with the controller; the power supply module is respectively connected with the PH value sensor, the controller, the display screen and the reset circuit;

the PH composite electrode is provided with a measuring electrode and a reference electrode; the measuring electrode and the reference electrode are both connected with the PH value sensor; the measuring electrode is a glass electrode which selectively responds to H +; the reference electrode is a silver chloride electrode.

2. A water sample PH detector as claimed in claim 1, wherein: the controller comprises a passive crystal oscillator U1, a singlechip U2, an SPI memory U3, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a capacitor C17, a capacitor C18, a capacitor C19, a capacitor C20, an inductor L4, a resistor R1 and an antenna ANT 1;

pin 1 of the single chip microcomputer U2 is connected with a capacitor C9 and a power supply module, pin 2 is connected with a capacitor C14 and an inductor L4, pins 3 and 4 are connected with a capacitor C10, a capacitor C11, a capacitor C12, a capacitor C13 and a power supply module, pin 9 is connected with a reset circuit, pin 13 is connected with a PH value sensor, pin 19 is connected with a capacitor C19 and the power supply module, pin 26 is connected with a capacitor C18 and the power supply module, pin 37 is connected with a capacitor C4 and the power supply module, pins 40 and 41 are connected with a display screen, and pins 43 and 46 are connected with a capacitor C3, a capacitor C20 and the power supply module; one end of the capacitor C16 is connected with 5 of the singlechip U2, and the other end of the capacitor C16 is connected with 6 of the singlechip U2; one end of the capacitor C17 is connected with 7 of the singlechip U2, and the other end of the capacitor C17 is connected with 8 of the singlechip U2; a pin 1 of the antenna ANT1 is connected with a capacitor C14 and a capacitor C15, and a pin 2 is grounded;

pins 1, 2, 3, 5, 6 and 7 of the SPI 3 are respectively connected with pins 30, 32, 29, 33, 31 and 28 of a singlechip U2, pin 8 is connected with a power supply module, and pin 4 is grounded;

pin 1 of the passive crystal oscillator U1 is connected with a capacitor C1 and a pin 45 of a singlechip U2, pins 2 and 4 are grounded, and pin 3 is connected with a capacitor C2 and a pin 44 of a singlechip U2; the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C9, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, the capacitor C14, the capacitor C15, the capacitor C18, the capacitor C19 and the capacitor C20 are all grounded.

3. A water sample PH detector as claimed in claim 2, wherein: the model of the single chip microcomputer U2 is ESP32-DOWDQ 6.

4. A water sample PH detector as claimed in claim 1, wherein: the reset circuit comprises a reset chip U4, a resistor R2 and a resistor R3;

5. A water sample PH detector as claimed in claim 1, wherein: the display screen is an HMI serial port screen.

6. A water sample PH detector as claimed in claim 1, wherein: the PH value sensor comprises an operational amplifier Q1, an operational amplifier Q2, a reference voltage source P1, a connecting terminal P2, a connecting terminal P3, a potentiometer R12, a resistor R11, a resistor R13, a resistor R14, a resistor R15, a capacitor C37 and a capacitor C38;

a pin 4 of the operational amplifier Q1 is grounded, a pin 5 is connected with a potentiometer R12, a capacitor C37 and a resistor R15, and pins 6 and 7 are both connected with a pin 2 of a wiring terminal P2; the capacitor C37 is connected with the resistor R15 and is grounded; pin 1 of the operational amplifier Q2 is connected with a resistor R11 and a pin 5 of a wiring terminal P3, pin 2 is connected with a resistor R11 and a resistor R14, pin 3 is connected with pin 1 of a wiring terminal P2, and pin 8 is connected with a power module; the resistor R14 is grounded; pins S1, S2 and S3 of the wiring terminal P2 are respectively connected with pins 1, 2 and 3 of a reference voltage source P1; the pin 8 of the reference voltage source P1 is connected with a resistor R13 and a capacitor C38; the capacitor C38 is connected with a pin 4 of a reference voltage source P1 and is grounded; the resistor R13 is connected with the power supply module; pins 1 and 2 of the wiring terminal P2 are connected with a PH composite electrode; and a pin 5 of the wiring terminal P3 is connected with the controller.

7. A water sample pH sensor as claimed in claim 6 wherein: the models of the operational amplifier Q1 and the operational amplifier Q2 are TLC 4502.