Data transmission circuit for classified detection of acid-producing bacteria based on Raman spectrum

Abstract

The utility model relates to the technical field of Raman spectrum classification detection, in particular to an acid-producing bacteria classification detection data transmission circuit based on Raman spectrum, which comprises a spectrum sensor, a microcontroller unit, a laser driving module, a signal conditioning module, a data compression transmission module and a laser diode. The microcontroller unit is respectively connected with the laser driving module and the data compression transmission module, and the laser driving module is connected with the laser diode; the signal conditioning module is connected with the spectrum sensor and the microcontroller unit and comprises a high-speed analog-to-digital converter, an operational amplifier, a reference voltage source and a filter capacitor; the data compression transmission module comprises a hardware encryption accelerator, a communication interface and a CRC check circuit, and the output end of the data compression transmission module is connected with an external interface. The circuit can accurately drive a laser diode, efficiently condition weak spectral signals, encrypt and verify data, guarantee the stability, accuracy and safety of classified detection data transmission of acid-producing bacteria, and improve the detection efficiency and reliability.

Description

Technical Field

[0001] This utility model relates to the field of Raman spectroscopy classification and detection technology, specifically to a data transmission circuit for the classification and detection of acid-producing bacteria based on Raman spectroscopy. Background Technology

[0002] Raman spectroscopy, as a powerful analytical tool, has shown great potential in the field of microbial detection, especially in the detection of acid-producing bacteria. It can rapidly and non-destructively acquire characteristic information of microorganisms, identifying and classifying different acid-producing bacteria by analyzing the characteristic peaks of Raman spectra. This is crucial for industries such as brewing and food fermentation, enabling real-time monitoring of the types and states of microorganisms during production, ensuring product quality and safety. At the single-cell level, Raman spectroscopy can also rapidly identify the metabolic functions of cells in a bacterial community without culture. Furthermore, combined with multivariate data analysis techniques, such as principal component analysis and partial least squares discriminant analysis, it can effectively distinguish between different bacterial species.

[0003] Currently, there are many problems with data transmission circuitry in the Raman spectroscopy detection of acid-producing bacteria. Regarding laser driving, lasers often operate at a fixed power. When faced with samples with large differences in bacterial concentration, high-concentration samples are prone to signal saturation, sample burn-out, or strong fluorescence background masking characteristic peaks due to excessively high laser power. Low-concentration samples, on the other hand, cannot obtain effective spectra due to insufficient power, affecting the accuracy of subsequent classification models. In signal conditioning, the processing of weak photocurrent signals output by the spectral sensor is inefficient, with significant noise interference leading to poor signal stability and hindering accurate analysis by the microcontroller. In the data transmission stage, traditional methods transmit complete spectral data indiscriminately, resulting in large data volumes and high power consumption. This is detrimental to equipment portability and cannot meet the needs of long-term on-site monitoring. Furthermore, the lack of effective data encryption and verification mechanisms makes it difficult to guarantee data security and integrity. Utility Model Content

[0004] The purpose of this invention is to provide a data transmission circuit for the classification and detection of acid-producing bacteria based on Raman spectroscopy, so as to solve the problems in the existing Raman spectroscopy detection of acid-producing bacteria, such as poor detection effect of samples with different concentrations due to fixed laser driving power, large amount of spectral data transmission and high power consumption.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model includes a spectral sensor, a microcontroller unit, a laser driving module, a signal conditioning module, a data compression and transmission module, and a laser diode.

[0006] The control signal output terminal of the microcontroller unit is electrically connected to the signal input terminal of the laser drive module, and its data communication terminal is electrically connected to the signal input terminal of the data compression and transmission module.

[0007] The output terminal of the laser driver module is connected to the positive terminal of the laser diode, and the negative terminal of the laser diode is grounded.

[0008] The input of the signal conditioning module is connected to the signal output of the spectral sensor, and its output is connected to the analog-to-digital converter input of the microcontroller unit.

[0009] The output of the data compression and transmission module is connected to an external communication interface.

[0010] The above-mentioned technical solution is adopted, in which the laser driving module includes a power MOSFET and a digital-to-analog converter;

[0011] The signal input terminal of the digital-to-analog converter is electrically connected to the control signal output terminal of the microcontroller unit, and its output terminal is electrically connected to the gate of the power MOSFET. It is used to receive the control signal from the microcontroller unit and output analog voltage. The source of the power MOSFET is grounded, and its drain is electrically connected to the positive terminal of the laser diode. It is used to adjust the conduction state of the power MOSFET according to the analog voltage, thereby regulating the current of the laser diode.

[0012] The above technical solution includes a current-limiting resistor in the laser driving module. The current-limiting resistor is connected in series between the drain of the power MOSFET and the positive terminal of the laser diode to limit the current and prevent excessive current from damaging the laser diode.

[0013] The above technical solution is adopted, and the signal conditioning module in this solution includes a high-speed analog-to-digital converter, a high-speed operational amplifier, and a reference voltage source;

[0014] The input terminal of the high-speed operational amplifier is electrically connected to the signal output terminal of the spectral sensor, and its signal output terminal is electrically connected to the signal input terminal of the high-speed analog-to-digital converter, used to convert the weak photocurrent output by the spectral sensor into a voltage signal; the voltage output terminal of the reference voltage source is electrically connected to the reference voltage input terminal of the high-speed operational amplifier; the output terminal of the high-speed analog-to-digital converter is electrically connected to the analog-to-digital conversion input terminal of the microcontroller unit, used to convert the voltage signal into a digital signal and transmit it to the microcontroller unit.

[0015] The above technical solution includes a signal conditioning module that also includes a filter capacitor connected in parallel between the signal output terminal of the high-speed operational amplifier and the ground line. This filter capacitor is used to filter out high-frequency noise in the output voltage signal of the high-speed operational amplifier and improve signal stability.

[0016] The above technical solution includes a data compression and transmission module comprising a hardware encryption accelerator and a communication interface. The input of the hardware encryption accelerator is electrically connected to the data communication terminal of the microcontroller unit, and its output is electrically connected to the signal input terminal of the communication interface, for encrypting the spectral data transmitted by the microcontroller unit. The signal output terminal of the communication interface is connected to an external communication interface for electrical connection with an external host computer or cloud device.

[0017] The above technical solution includes a data compression and transmission module that further includes a CRC check circuit. The signal input of the CRC check circuit is electrically connected to the signal output of the hardware encryption accelerator, and its output is electrically connected to the input of the communication interface. This circuit is used to add a check code to the processed spectral data to ensure the integrity and accuracy of the data transmission process.

[0018] By adopting the above-mentioned technical solution, the technological advancements achieved by this utility model compared to the prior art are as follows:

[0019] This technical solution achieves multi-dimensional breakthroughs in the circuit design of Raman spectroscopy for detecting acid-producing bacteria, resulting in significant technological advancements. In the laser driving stage, it abandons the traditional fixed-power mode and constructs a dynamically adjustable laser driving circuit through the coordinated connection of a microcontroller unit, a digital-to-analog converter, and a power MOSFET. This allows for precise adjustment of the laser diode current based on the actual detection requirements of the sample, overcoming the technical limitation that fixed power cannot adapt to samples of different concentrations. The signal conditioning module innovatively integrates a high-speed operational amplifier, filter capacitors, and a reference voltage source, optimizing the conversion and noise reduction path of weak photocurrent signals and solving the problems of high noise interference and poor signal stability in traditional conditioning circuits. In the data transmission section, it integrates a hardware encryption accelerator, a CRC check circuit, and a communication interface, overcoming the technical bottleneck of large data volume and low security in traditional indiscriminate data transmission, achieving hardware-level data processing and transmission optimization.

[0020] The application of this technical solution brings multiple practical benefits to the Raman detection of acid-producing bacteria. In terms of detection quality, dynamic laser power adjustment ensures no signal saturation in high-concentration samples and sufficient signal-to-noise ratio in low-concentration samples. Combined with stable signal conditioning, this significantly improves the accuracy of spectral data, providing reliable data support for subsequent acid-producing bacteria classification and assisting industries such as brewing and food fermentation in accurately controlling the microbial state. Regarding equipment performance, the data compression and transmission design significantly reduces data transmission volume, lowers overall circuit power consumption, and extends the battery life of portable detection devices, making them more suitable for long-term on-site monitoring scenarios. Simultaneously, hardware encryption and CRC verification mechanisms ensure the security and integrity of data transmission, preventing detection errors caused by data leakage or damage, further enhancing the reliability and practicality of the detection system. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to this utility model.

[0023] Figure 2 This is a flowchart illustrating the dynamic adjustment of laser power according to this utility model;

[0024] Figure 3 This is a flowchart of the spectral signal acquisition process of this utility model.

[0025] In the diagram: 1. Spectral sensor; 2. Microcontroller unit; 3. Laser driver module; 4. Signal conditioning module; 5. Data compression and transmission module; 6. Laser diode. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to embodiments:

[0027] Example 1

[0028] like Figures 1-3 As shown, this utility model provides a data transmission circuit for the classification and detection of acid-producing bacteria based on Raman spectroscopy, including a spectral sensor 1, a microcontroller unit 2, a laser driving module 3, a signal conditioning module 4, a data compression and transmission module 5, and a laser diode 6.

[0029] The spectral sensor 1 uses a Hamamatsu S13360-3050CS silicon photomultiplier tube with a response wavelength range of 300-900nm, capable of capturing weak Raman scattered light signals. Other alternative models with the same technical parameters can also achieve this solution. The anode of the sensor is connected to the input of the high-speed operational amplifier of the signal conditioning module 4 via a 50Ω coaxial cable, with the cable shield grounded. The cathode of the sensor is connected to a 28V bias power supply, with a 100Ω current-limiting resistor and a 10μF tantalum capacitor connected in series at the bias power supply terminal to achieve overcurrent protection and low-frequency filtering, respectively. The GND pin of the sensor is directly connected to the analog ground plane, consistent with the grounding of the signal conditioning module 4.

[0030] Microcontroller unit 2 uses an STM32H743VIT6 microcontroller as the core control unit, which supports a 16-bit high-speed ADC and multi-interface communication to meet the requirements of spectral data processing and real-time control.

[0031] The STM32's VDD pin is grounded via two 100nF ceramic capacitors and draws power from the 12V system supply through a 3.3V low-dropout regulator. A 2.2Ω / 1W current-limiting resistor is connected in series at the LDO output to prevent damage from power-on inrush current. The STM32's PA0 pin serves as the control signal output for the digital-to-analog converter (DAC), connected to the DAC input of the laser driver module 3 via a 1kΩ pull-up resistor, outputting a PWM control signal. The PB10 pin is configured as an I2C communication interface for data exchange with the hardware encryption accelerator of the data compression and transmission module 5. Each pin is connected in series with a 22Ω matching resistor to suppress signal reflection. The PC0-PC7 pins serve as the data receivers for the high-speed DAC, with a 10nF filter capacitor connected in parallel to ground on each pin to reduce digital noise interference.

[0032] The laser drive module 3 includes a power MOSFET, a digital-to-analog converter, and a current-limiting resistor. It receives control signals from the microcontroller unit 2, outputs an analog voltage, and adjusts the conduction state of the power MOSFET based on the analog voltage to regulate the current of the laser diode 6. The current-limiting resistor is connected in series between the drain of the power MOSFET and the anode of the laser diode 6 to limit the current and prevent excessive current from damaging the laser diode 6.

[0033] The digital-to-analog converter (DAC) uses the AD5686RBRMZ-516-bit DAC, which supports a single 5V power supply and has an output voltage range of 0-5V, meeting the requirements for fine adjustment of laser power. The DAC's SCLK and DIN pins are connected to the STM32's PB13 and PB14 pins, respectively, to receive control commands; the SYNC pin is grounded through a 10kΩ pull-down resistor to ensure it is at a low level when idle; the DAC's OUT pin is connected to the gate of the power MOSFET after passing through an RC filter circuit to filter out high-frequency ripple in the DAC output.

[0034] The power MOSFET selected is the IRF740NN channel MOSFET, with a maximum drain current of 10A and a withstand voltage of 400V, suitable for driving the laser diode 6. The gate (G) pin of the MOSFET is connected to the output signal filtered by the DAC, and a 10kΩ pull-down resistor is connected in parallel to analog ground to prevent false turn-on due to gate floating. The drain (D) pin of the MOSFET is connected in series with a 1Ω / 5W precision sampling resistor, which is then connected to a current-limiting resistor. The source (S) pin is directly connected to analog ground, and a 0.1μF capacitor is connected in parallel across the sampling resistor for current signal sampling and filtering.

[0035] The current-limiting resistor is an RX24-5W-2.2Ω metal film resistor, connected in series between the drain of the MOSFET and the positive terminal of the laser diode 6, with a rated current of 2.27A, to ensure that the operating current of the laser diode 6 does not exceed the rated value.

[0036] The signal conditioning module 4 includes a high-speed analog-to-digital converter, a high-speed operational amplifier, a reference voltage source, and a filter capacitor. It is used to convert the weak photocurrent output by the spectral sensor 1 into a voltage signal, and then convert the voltage signal into a digital signal before transmitting it to the microcontroller unit 2. The filter capacitor is used to filter out high-frequency noise in the output voltage signal of the high-speed operational amplifier, improving signal stability.

[0037] The high-speed operational amplifier uses the AD8066ARZ dual op-amp. The non-inverting input of the op-amp is connected to the anode output of the spectral sensor 1 and to the coaxial cable through a 50Ω matching resistor. The inverting input is connected to the output of the op-amp through a 10kΩ feedback resistor, forming a non-inverting amplifier circuit. The V+ pin of the op-amp is connected to a 5V power supply, and the V- pin is grounded. The reference voltage source outputs a 2.5V reference voltage, which is connected to the inverting input of the op-amp through a 1kΩ resistor to ensure stable DC bias of the output signal. A 100pF ceramic capacitor is connected in parallel to the output of the op-amp to analog ground to filter out high-frequency noise above 100MHz.

[0038] The high-speed analog-to-digital converter uses the AD9226BCPZ-6512-bit ADC with a sampling rate of 65MSPS. The ADC's VIN+ pin is connected to the operational amplifier output, and the VIN- pin is connected to the 2.5V reference voltage source output, forming a differential input to improve anti-interference capability. The ADC's D0-D11 pins are connected to the STM32's PC0-PC11 pins respectively to output digital spectral data; the CLK pin is connected to the STM32's PA8 pin to receive a 65MHz sampling clock.

[0039] The filter capacitor is a 100nFX7R capacitor, which is connected in parallel between the output of the high-speed operational amplifier and the analog ground. The capacitance error is ±10%. It filters out high-frequency noise from the amplifier output and ensures that the signal-to-noise ratio of the ADC sampling signal is ≥60dB.

[0040] The data compression and transmission module 5 includes a hardware encryption accelerator, a communication interface, and a CRC check circuit; it is used to encrypt the spectral data transmitted by the microcontroller unit 2 and electrically connect to an external host computer or cloud device. The CRC check circuit adds a checksum to the processed spectral data to ensure the integrity and accuracy of data transmission.

[0041] The hardware encryption accelerator uses an AES-256 encryption chip. The accelerator's SPI interface pins are connected to the PB3, PB5, and PB4 pins of the STM32 to receive the spectral data to be encrypted. The accelerator's CS pin is connected to the PB2 pin of the STM32 to achieve chip select control. The VCC pin is connected to a 3.3V power supply.

[0042] The CRC check circuit uses a 74HC280N 9-bit parity check chip, which is suitable for CRC-8 check requirements with an 8-bit data width. The AH pin of the check circuit is connected to the DATA0-DATA7 pins of the encryption accelerator to receive the encrypted data; the EVEN and ODD pins of the check circuit are connected to 3.3V through two 1kΩ pull-up resistors, and the check result is output to the DATA_CHECK pin of the communication interface.

[0043] The communication interface uses the MAX3485CPARS485 transceiver. The DI pin of the transceiver is connected to the output pin of the encryption accelerator, and the RO pin is connected to the PB9 pin of the STM32 for receiving feedback signals. The RE and DE pins are shorted and connected to the PB8 pin of the STM32 to realize the switching of the transmit and receive modes.

[0044] Laser diode 6 is an HL6320G 635nm red laser diode with an adjustable output power of 0-50mW, suitable for the excitation requirements of Raman spectroscopy for acid-producing bacteria. The positive terminal of laser diode 6 is connected to the output terminal of the current-limiting resistor via a φ1.2mm tin-plated copper wire, with the copper wire insulated by a heat-shrink tubing. The negative terminal is directly connected to analog ground via a wire, and a 10nF ceramic capacitor is connected in parallel to ground to absorb reverse voltage spikes and protect laser diode 6.

[0045] The working principle of this data transmission circuit is as follows:

[0046] After the circuit is powered on, the STM32 completes the reset and clock initialization, and then configures peripherals such as DAC, ADC, and encryption accelerator. The laser driver module 3 outputs low power (5mW) by default, the power indicator light is always on, and the working light starts to flash.

[0047] The STM32 outputs control commands to the DAC based on the concentration of the acid-producing bacteria sample to be tested. The DAC converts the digital signal into a 0-5V analog voltage, adjusts the MOSFET gate voltage, and thus changes the current of the laser diode 6, achieving dynamic adjustment of the output power from 0-50mW.

[0048] Spectral signal acquisition: After the sample of acid-producing bacteria is irradiated by laser, the Raman scattered light generated is captured by the spectral sensor 1 and converted into a weak photocurrent; after the signal is amplified by the high-speed operational amplifier, it is converted into a 12-bit digital signal by the high-speed ADC at a sampling rate of 65MSPS and transmitted to the STM32.

[0049] After preprocessing the digital spectral data, the STM32 sends it to a hardware encryption accelerator for AES-256 encryption. The encrypted data is then added with a checksum by a CRC check circuit and transmitted to a host computer or cloud device via an RS485 communication interface at a transmission rate of 115200bps to ensure data integrity. Retransmission is triggered if the check fails.

[0050] If the operating current of laser diode 6 exceeds 2.2A, the STM32 will immediately control the DAC to output 0V and turn off the MOSFET. If the data transmission fails to verify three times in a row, the fault light will remain on, and the MCU will store the fault code (e.g., 0x01 indicates laser overcurrent, 0x02 indicates transmission error), waiting for the host computer to instruct it to resume operation.

[0051] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.

Claims

1. A data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy, characterized in that, It includes a spectral sensor (1), a microcontroller unit (2), a laser driving module (3), a signal conditioning module (4), a data compression and transmission module (5), and a laser diode (6). The control signal output terminal of the microcontroller unit (2) is electrically connected to the signal input terminal of the laser drive module (3), and its data communication terminal is electrically connected to the signal input terminal of the data compression and transmission module (5). The output terminal of the laser driving module (3) is connected to the positive terminal of the laser diode (6), and the negative terminal of the laser diode (6) is grounded; The input terminal of the signal conditioning module (4) is connected to the signal output terminal of the spectral sensor (1), and its output terminal is connected to the analog-to-digital converter input terminal of the microcontroller unit (2). The output of the data compression and transmission module (5) is connected to an external communication interface.

2. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 1, characterized in that: The laser driving module (3) includes a power field-effect transistor and a digital-to-analog converter; The signal input terminal of the digital-to-analog converter is electrically connected to the control signal output terminal of the microcontroller unit (2), and its output terminal is electrically connected to the gate of the power MOSFET, for receiving the control signal of the microcontroller unit (2) and outputting an analog voltage; the source of the power MOSFET is grounded, and its drain is electrically connected to the positive terminal of the laser diode (6), for adjusting the conduction state of the power MOSFET according to the analog voltage, thereby regulating the current of the laser diode (6).

3. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 2, characterized in that: The laser driving module (3) also includes a current-limiting resistor, which is connected in series between the drain of the power MOSFET and the positive terminal of the laser diode (6) to limit the current and prevent excessive current from damaging the laser diode (6).

4. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 1, characterized in that: The signal conditioning module (4) includes a high-speed analog-to-digital converter, a high-speed operational amplifier, and a reference voltage source; The input terminal of the high-speed operational amplifier is electrically connected to the signal output terminal of the spectral sensor (1), and its signal output terminal is electrically connected to the signal input terminal of the high-speed analog-to-digital converter, for converting the weak photocurrent output by the spectral sensor (1) into a voltage signal; the voltage output terminal of the reference voltage source is electrically connected to the reference voltage input terminal of the high-speed operational amplifier; the output terminal of the high-speed analog-to-digital converter is electrically connected to the analog-to-digital conversion input terminal of the microcontroller unit (2), for converting the voltage signal into a digital signal and transmitting it to the microcontroller unit (2).

5. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 4, characterized in that: The signal conditioning module (4) also includes a filter capacitor, which is connected in parallel between the signal output terminal of the high-speed operational amplifier and the ground line to filter out high-frequency noise in the output voltage signal of the high-speed operational amplifier and improve signal stability.

6. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 1, characterized in that: The data compression and transmission module (5) includes a hardware encryption accelerator and a communication interface; the input end of the hardware encryption accelerator is electrically connected to the data communication end of the microcontroller unit (2), and its output end is electrically connected to the signal input end of the communication interface, for encrypting the spectral data transmitted by the microcontroller unit (2); the signal output end of the communication interface is connected to an external communication interface for electrical connection with an external host computer or cloud device.

7. The data transmission circuit for classifying and detecting acid-producing bacteria based on Raman spectroscopy according to claim 6, characterized in that: The data compression and transmission module (5) further includes a CRC check circuit. The signal input terminal of the CRC check circuit is electrically connected to the signal output terminal of the hardware encryption accelerator, and its output terminal is electrically connected to the input terminal of the communication interface. It is used to add a check code to the processed spectral data to ensure the integrity and accuracy of the data transmission process.

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