Digital titration analysis device based on Raspberry Pi

Abstract

A digital titrimetric analysis device based on Raspberry Pi comprises a microcomputer control unit, and a microcomputer comprises a USB interface, a GPIO interface, an HDMI interface and a power supply interface; the signal acquisition module comprises an electrode system, an electrode converter, a signal conversion board and an analog-to-digital conversion module, the electrode system is connected with the electrode converter, the signal conversion board is provided with a BNC interface, and the electrode converter is connected to the signal conversion board through the BNC interface so as to be used for amplifying analog signals; the analog signal is converted into a digital signal through the analog-to-digital conversion module, and then the digital signal is transmitted to the microcomputer control unit; the drop number detection module comprises an infrared photoelectric sensor, and the output end of the infrared photoelectric sensor is connected to a GPIO (General Purpose Input / Output) interface of the microcomputer control unit; and the digital display module comprises a display. According to the utility model, a titration curve is generated in real time by assembling a modularized construction device, and the device is low in cost, simple to operate, diversified in function and suitable for various types of titration analysis.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of chemical analysis instruments, in particular to a kind of digital titration analysis device based on raspberry pie. BACKGROUND

[0002] In the field of analytical chemistry, titration analysis is a classic and important quantitative analysis method, and plays a key role in the determination of the composition of matter. However, the traditional titration analysis relies on the color change of the indicator to determine the end point of titration. Although this method has accumulated a wealth of experience in chemical analysis, it still has some shortcomings: the determination of the end point of titration by the human eye is highly subjective, different operators have different sensitivities to color changes and different standards for judgment, and it is difficult to obtain accurate titration process information.

[0003] To address these issues, some automated and semi-automated titration devices have emerged, such as automatic potentiometric titrators that use mechanical structures to control the titration process of the burette. By monitoring certain physical properties of the solution and automatically stopping titration when the set threshold is reached. This instrument has reached a high level in terms of signal-to-noise ratio and stability, but also has some shortcomings, such as high equipment cost, complex operation, relatively single function, and difficulty in meeting the comprehensive needs of modern chemical analysis for dynamic monitoring, multi-functionality and convenience. Moreover, the existing technology is not perfect in data processing and visualization, making it difficult to present the data in the titration process in an intuitive and easy-to-understand manner to students, which is not conducive to data analysis and interpretation of the analysis results. SUMMARY

[0004] The technical problem to be solved by the utility model is to overcome the defects of the prior art that cannot meet the comprehensive needs of modern chemical analysis for dynamic monitoring, multi-functionality and convenience, and to provide a digital titration analysis device based on raspberry pie.

[0005] The technical solution adopted by the utility model to solve its technical problem is a digital titration analysis device based on raspberry pie, which includes a microcomputer control unit, including a USB interface, a GPIO interface, an HDMI interface and a power supply interface;

[0006] A signal acquisition module includes an electrode system, an electrode converter, a signal conversion board and an analog-to-digital conversion module. The electrodes of the electrode system are located in the beaker and connected to the electrode converter. The signal conversion board has a BNC interface. The electrode converter is connected to the signal conversion board through the BNC interface for amplifying analog signals, and the analog signals are converted into digital signals by the analog-to-digital conversion module and transmitted to the microcomputer control unit.

[0007] Drop detection module, including infrared photoelectric sensor, the infrared photoelectric sensor is located directly below the burette, and the infrared photoelectric sensor output end is connected to the GPIO interface of the microcomputer control unit, for real-time detection of titrant drop number and conversion into titration volume data;

[0008] Digital display module, including display, processing infrared photoelectric sensor and electrode system data through the microcomputer control unit, generating dynamic titration curve (E-V graph) on the display;

[0009] Interactive module, including mouse and keyboard, realizing man-machine interaction operation through connecting the USB interface.

[0010] Further, the microcomputer control unit adopts Raspberry Pi 4b or 5b.

[0011] Further, the analog-digital conversion module is MCP3008 chip, which communicates with the microcomputer control unit through SPI protocol, and discretizes continuous voltage signals into digital signals.

[0012] Further, the electrode system is modularly designed, and supports quick replacement of redox electrodes, ion selective electrodes or pH electrodes through the electrode converter, so as to meet different types of titration analysis requirements.

[0013] Further, the trigger signal of the infrared photoelectric sensor is synchronously collected with the potential signal of the analog-digital conversion module, the drop number is converted into volume data through the preset calibration formula of the microcomputer control unit, and one-to-one correspondence between titration volume and potential is realized.

[0014] Further, the microcomputer control unit supports multi-channel expansion, connects multiple electrode systems and titration devices, and simultaneously realizes parallel titration analysis of multiple samples.

[0015] The utility model has the following beneficial technical effects:

[0016] 1. Precise monitoring and teaching innovation. By creatively integrating Raspberry Pi, various sensors and specific algorithms, comprehensive and high-precision data acquisition and real-time monitoring of the titration process are realized, and the titration jump is personified and visualized. In the teaching scene, this visualized presentation enables students to deeply understand the titration principle and process details, thereby enhancing the students' comprehensive ability of practical operation and data analysis, and effectively improving the teaching quality and learning efficiency.

[0017] 2. Economical and convenient to promote. With the unique modular design, take the low-cost and open-source easy-to-program Raspberry Pi as the core, combined with existing common sensors and analog-to-digital conversion modules to build the device. The hardware connection is simple and clear, and the software programming is based on easy-to-learn languages such as Python, and the operation process is simple and easy to understand. In terms of cost, compared with traditional complex professional titration analysis instruments, both the equipment procurement cost and the later maintenance cost are greatly reduced.

[0018] 3. Multi-adaptation. Based on the innovative architecture design, the device has strong function expansion and adaptability. The standardized and universal interface and signal processing module can easily adapt to various titration analysis such as oxidation-reduction, coordination, acid-base, etc., realize seamless connection and stable work, and realize one machine with multiple functions. Raspberry Pi as the core controller has strong processing capability and rich expansion interface, so that the device has higher flexibility and customizability in data processing, algorithm running and extended function development. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 is a device hardware structure schematic diagram of an embodiment of a digital titration analysis device based on Raspberry Pi of the utility model;

[0020] Fig. 2 is a hardware schematic diagram of an embodiment of a digital titration analysis device based on Raspberry Pi of the utility model;

[0021] Fig. 3 is a Raspberry Pi amplification schematic diagram of an embodiment of a digital titration analysis device based on Raspberry Pi of the utility model;

[0022] Fig. 4 is a signal conversion board and infrared photoelectric sensor amplification diagram of an embodiment of a digital titration analysis device based on Raspberry Pi of the utility model;

[0023] Fig. 5 is a digital experiment system design diagram of an embodiment of a digital titration analysis device based on Raspberry Pi of the utility model.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1, microcomputer control unit; 2, electrode system; 3, electrode converter; 4, signal conversion board; 5, analog-to-digital conversion module; 6, T-shaped board and breadboard; 7, magnetic stirrer; 8, display; 9, mouse; 10, keyboard; 11, infrared photoelectric sensor; 12, USB interface; 13, Ethernet interface; 14, GPIO interface; 15, HDMI interface; 16, power supply interface; 17, WiFi and Bluetooth module; 18, BNC interface. DETAILED DESCRIPTION

[0026] The utility model will be further explained in detail in connection with the drawings and examples.

[0027] Referring to Figs. 1 to 5 , embodiment 1 includes microcomputer control unit 1, signal acquisition module, drop detection module, digital display module and interactive module;

[0028] Microcomputer control unit 1 adopts raspberry pi 4b or 5b, and microcomputer control unit 1 is equipped with USB interface 12, ethernet interface 13, GPIO pin 14, HDMI interface 15, power supply interface 16 and WiFi and Bluetooth module 17.

[0029] Signal acquisition module includes electrode system 2, electrode converter 3, signal conversion board 4, analog-digital conversion module 5, and BNC interface 18 is arranged in signal conversion board 4, signal conversion board 4 is PH4502C, and analog-digital conversion module 5 adopts MCP3008 chip.

[0030] Digital display module includes display 8, and interactive module includes mouse 9, keyboard 10.In addition, it also includes T-shaped plate and breadboard 6 and magnetic stirrer 7.

[0031] Prepare microcomputer control unit 1, connect it with T-shaped plate and breadboard 6 through GPIO interface 14, to facilitate the connection with other chemical experiment devices.Meanwhile, ensure that the USB interface 12 of raspberry pi can be normally used, to be used for connecting mouse 9, keyboard 10 and other external equipment.

[0032] Take the indicating electrode and reference electrode of electrode system 2, one end is placed in beaker, and the other end is connected with electrode converter 3 respectively, electrode converter 3 is connected with signal conversion board 4 through BNC interface 18, realizes the amplification processing of weak analog signal, to facilitate raspberry pi reading.

[0033] The output end of signal conversion board 4 is connected with the input end of analog-digital conversion module 5, and then the amplified analog signal is converted into digital signal.MCP3008 module communicates with raspberry pi through SPI interface (including CS, MISO, MOSI, SCLK), realizes the reading and processing of data, and wiring needs to be strictly carried out according to SPI protocol specification in the connection process, to avoid signal interference.The role of analog-digital conversion module 5 is to divide continuous voltage signal into 1024 discrete potential levels, and each level corresponds to a specific ten binary value, that is, digital signal, and the value is received by raspberry pi to draw an image.

[0034] The infrared photoelectric sensor 11 is located below the burette, and the titrated liquid passes through the detection port. The input end of the infrared photoelectric sensor 11 is directly connected to the GPIO interface 14 of the Raspberry Pi, so that in the experiment process, when the liquid drop passes through the detection port of the infrared photoelectric sensor 11, the photoelectric switch can be triggered, and the output control signal is recognized and recorded by the Raspberry Pi and converted into volume through a preset calibration formula.

[0035] The access power supply interface 16 provides stable power for the entire device. The Raspberry Pi is connected to the display 8 through the HDMI interface 15 for displaying the titration curve in the experiment process, and the USB interface 12 is connected to the mouse 9 and the keyboard 10 to realize human-computer interaction. The Ternius remote terminal software of the notebook computer can be used to remotely control the Raspberry Pi.

[0036] In the data processing process, from the original analog signal to the digital signal that can be used to draw the image, it has gone through multiple steps such as amplification by the electrode converter 3, conversion and discretization by the signal conversion board 4, etc., to ensure the accuracy and usability of the data. Among them, the Raspberry Pi is used to write Python programs to set the GPIO pin mode, and various libraries are used to process communication protocols and visualize sensor data. In the program, functions for reading analog signals by MCP3008 and functions for triggering drop sensors are defined, and through these functions, accurate collection and processing of sensor data are realized. In the experiment process, the infrared photoelectric sensor 11 obtains drop data and transmits it to the Raspberry Pi, which converts it into titration volume through a calibration formula, while the Raspberry Pi reads the real-time potential signal, realizes one-to-one correspondence between titration volume and potential signal, makes real-time E-V graph, and judges the endpoint according to the curve jump.

[0037] Taking the determination experiment of calcium content in water sample as an example:

[0038] (1) Weigh the EDTA solid reagent and prepare a solution for standby;

[0039] (2) Prepare a zinc ion solution with a known concentration, and titrate a certain volume of zinc ion solution with EDTA solution to calibrate the concentration of EDTA solution;

[0040] (3) Take a certain volume of solution to be titrated in a beaker, and add ammonia buffer solution, ion strength regulator and appropriate amount of chrome black T indicator. Note the amount of reagent to avoid uneven mixing of the solution or precipitation problems;

[0041] (4) Fill the calibrated EDTA solution in the 50.00 mL acid burette;

[0042] (5) To the beaker containing the solution to be tested, add a stirrer, and place it on a magnetic stirring device; fix the infrared photoelectric sensor 11 and the burette on the iron stand, so that the liquid drops pass through the infrared photoelectric sensor detection port and then drop into the beaker; immerse the activated calcium ion selective electrode and the reference electrode into the liquid surface, and connect them to the electrode converter 3 respectively;

[0043] (6) Connect the infrared photoelectric sensor 11, the electrode converter 3 and the display 8 to the Raspberry Pi respectively, start the power supply, open the titration program, and a "E-V" curve interface is presented;

[0044] (7) Adjust the burette knob so that the liquid drops are not continuous, and slowly titrate at a slow drop rate before the titration end point, that is, after the potential is stable, drop one drop of titrant;

[0045] (8) During the titration process, the maximum potential change corresponding to the single drop of titrant is observed, and then the burette knob is closed, the image generation is paused by entering "P" in the Raspberry Pi, and the titration data is saved by entering "S".

[0046] In another embodiment, the design architecture of the equipment has high flexibility and universality. In terms of electrode system 2 adaptation, the interface and signal processing module can conveniently replace the electrode according to the connection mode of embodiment 1, so as to meet different types of titration analysis requirements. For example, in redox titration, a redox electrode can be connected, which can accurately respond to the potential fluctuation caused by the concentration change of oxidized and reduced substances in the solution; in the coordination titration scene, various ion selective electrodes such as calcium ion selective electrode are adapted, which can monitor the coordination reaction process by virtue of the high selectivity response to specific metal ions; for acid-base titration, a pH electrode can be selected to accurately measure the change of solution acidity. Through the replaceable design of the electrode, the application range of the electrode in the field of chemical analysis is greatly widened, and a unified and efficient digital solution is provided for different types of chemical quantitative analysis.

[0047] In another embodiment, a multi-channel titration analysis system can be built based on Raspberry Pi. Multiple electrode systems 2 and corresponding titration devices are connected on the Raspberry Pi, so that multiple samples can be titrated and analyzed at the same time, improving the experimental efficiency. The hardware connection and setting of each channel are basically the same as those of embodiment 1, and the program of the Raspberry Pi is optimized for multi-channel data acquisition and processing.

[0048] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application. In the description, the same parts are denoted by the same reference numerals. It should be noted that the words "front", "back", "left", "right", "up" and "down" in the following description refer to the directions in the drawings, and the words "in" and "out" refer to the directions towards or away from the geometric center of a particular part.

[0049] Equivalent changes made in structure, shape, principle of the present utility model should be covered in the protection scope of the present utility model.

Claims

1. A Raspberry Pi based digital titration analysis device, characterized in that, The microcomputer control unit (1) comprises a USB interface (12), a GPIO interface (14), an HDMI interface (15), and a power supply interface (16); The signal acquisition module comprises an electrode system (2), an electrode converter (3), a signal conversion board (4), and an analog-to-digital conversion module (5). The electrodes of the electrode system (2) are located in a beaker and are connected to the electrode converter (3). The signal conversion board (4) has a BNC interface (18). The electrode converter (3) is connected to the signal conversion board (4) through the BNC interface (18) for amplifying analog signals. After the analog signals are converted into digital signals by the analog-to-digital conversion module (5), the digital signals are transmitted to the microcomputer control unit (1); The drop detection module comprises an infrared photoelectric sensor (11) located directly below the burette. The output end of the infrared photoelectric sensor (11) is connected to the GPIO interface (14) of the microcomputer control unit (1) for real-time detection of the number of drops of titrant and conversion into titration volume data. The digital display module comprises a display (8). The microcomputer control unit (1) processes the data of the infrared photoelectric sensor (11) and the electrode system (2) to generate a dynamic titration curve on the display (8). The interactive module comprises a mouse (9) and a keyboard (10) connected to the USB interface (12) for human-computer interaction.

2. A Raspberry Pi based digital titration analysis device as claimed in claim 1, wherein, The microcomputer control unit (1) uses Raspberry Pi 4b or 5b.

3. The Raspberry Pi based digital titration analysis device as claimed in claim 1, wherein, The analog-to-digital conversion module (5) is an MCP3008 chip that communicates with the microcomputer control unit (1) through the SPI protocol to discretize continuous voltage signals into digital signals.

4. The Raspberry Pi based digital titration analysis device as claimed in claim 1, wherein, The electrode system (2) is modularly designed to support quick replacement of redox electrodes, ion-selective electrodes, or pH electrodes through the electrode converter (3) to meet different types of titration analysis requirements.

5. The Raspberry Pi based digital titration analysis device as claimed in claim 1, wherein, The trigger signal of the infrared photoelectric sensor (11) is synchronously collected with the potential signal of the analog-to-digital conversion module (5). The microcomputer control unit (1) uses a preset calibration formula to convert the number of drops into volume data, realizing one-to-one correspondence between titration volume and potential.

6. The Raspberry Pi based digital titration analysis device as claimed in claim 1, wherein, The microcomputer control unit (1) supports multi-channel expansion, connecting multiple electrode systems (2) and titration devices for parallel titration analysis of multiple samples.

Images