WO2018068185A1

WO2018068185A1 - Water quality detection device and detection method therefor

Info

Publication number: WO2018068185A1
Application number: PCT/CN2016/101698
Authority: WO
Inventors: 付庆波; 孙东; 董旭毅
Original assignee: 深圳市比特原子科技有限公司
Priority date: 2016-10-10
Filing date: 2016-10-10
Publication date: 2018-04-19

Abstract

A water quality detection device and detection method therefor, the water quality detection device comprising: a plurality of monochromatic LED light sources (1) as well as a photodetector (2), a microcontroller (MCU) (3) and a temperature sensor (4), all having a one-to-one correspondence to each monochromatic LED light source (1); the photodetector (2) and the temperature sensor (4) are respectively connected to the MCU (3), and the MCU (3) is connected to the plurality of monochromatic LED light sources (1); the photodetector (2) is used for detecting original light intensity signals emitted by each corresponding monochromatic LED light source (1) which pass through a detected water sample, and sending the original light intensity signals to the MCU (3); the temperature sensor (4) is used for detecting the temperature of a detected water sample and sending the temperature of the detected water sample to the MCU (3); the MCU (3) is used for processing the received original light intensity signals and the temperature of the detected water sample so as to obtain a water quality parameter detection index of the detected water sample.

Description

Water quality detecting device and detecting method thereof

Technical field

The invention belongs to the technical field of multi-spectral detection, and particularly relates to a water quality detecting device and a detecting method thereof.

Background technique

Water is the source of life. As the problem of water pollution becomes more and more serious, people's attention to daily drinking water safety is gradually increasing. As a result, more and more homes have installed home reverse osmosis water purifiers. However, there is currently no effective method for evaluating the purification effect of water purifiers. This poses a problem in that the consumer cannot effectively evaluate the purification effect of the water purifier and cannot accurately determine the time required to replace the filter element.

At present, some high-end positioning water purifiers are equipped with water quality TDS (Total dissolved Solids, dissolved total solids) detectors are used to assess the purification effect of water quality. However, the TDS indicator reflects the concentration of ions ionized in water, and the number of these anions and cations does not directly reflect the quality of water. For example, the TDS of pure water is lower than that of mineral water, but it does not mean that the water quality of mineral water is Poor.

There are 106 indicators for water quality testing in the national standards, of which more than 30 are related to organic pollution in water bodies. Therefore, it is more practical to judge the quality of water quality by judging the indicators of water quality organic matter. TOC (total organic carbon) and COD (chemical oxygen demand) are two important indicators that reflect organic pollution in water. However, in the past, the electrochemical water quality monitoring technology was used in the water quality testing process. This method has a long cycle, complicated measurement, and requires a large amount of chemical raw materials.

In recent years, the application of UV-Vis spectroscopy in water quality monitoring has many advantages such as no secondary pollution, no chemical reagents and multi-parameter measurement. With the further development of information technology, water quality spectral data processing has been further developed. For the time being, UV-visible spectroscopy for water quality testing is mainly for TOC, COD, TURB (turbidity) And NO3-N The water quality parameters are monitored, and according to the specific detection methods, the parameters of the UV-visible spectrum water quality analysis include continuous spectrum analysis, multi-wavelength analysis, dual-wavelength analysis and single-wavelength analysis. At present, the use of ultraviolet spectroscopy method can achieve fast, multi-parameter water quality testing; however, the method is costly (tens of thousands of yuan), large in size, high in power consumption, and the equipment needs to be strictly corrected before being shipped. It cannot be installed in a household water purifier. .

technical problem

The technical problem to be solved by the present invention is to provide a water quality detecting device and a detecting method thereof, aiming to provide a water pipe which can be conveniently connected with a water purifier, and can directly detect and analyze the water purifying device for purifying drinking water in real time. Degree of water quality testing device.

Technical solution

The invention provides a water quality detecting device, comprising: a plurality of monochromatic LED light sources, a photodetector, an MCU and a temperature sensor corresponding to each of the monochromatic LED light sources; the photodetector and the temperature sensor Connected to the MCU respectively, the MCU is connected to the plurality of monochromatic LED light sources;

The photodetector is configured to detect a corresponding original light intensity signal emitted by each of the single-color LED light sources and transmitted through the detected water sample, and send the original light intensity signal to the MCU;

The temperature sensor is configured to detect a temperature of the detected water sample, and send the temperature of the detected water sample to the MCU;

The MCU is configured to process the received raw light intensity signal and the temperature of the detected water sample to obtain a water quality parameter detection index of the detected water sample.

Further, the plurality of monochromatic LED light sources comprise an infrared light LED light source, a visible light LED light source and an ultraviolet light LED light source, the photodetector comprising a first silicon based photodiode, a second silicon based photodiode and a gallium nitride material And a photodiode of the process; the infrared light LED light source, the visible light LED light source and the ultraviolet light LED light source and the first silicon-based photodiode, the second silicon-based photodiode, and a gallium nitride material and a photodiode of the process Correspondingly, an original light intensity signal for sensing a corresponding monochrome LED light source; the first silicon-based photodiode and the second silicon-based photodiode are used for sensing a light intensity signal of a visible light to a near-infrared wavelength range, The gallium nitride material and process photodiode are used to sense light intensity signals in the ultraviolet to deep ultraviolet range.

Further, the water quality detecting device further includes a current voltage conversion circuit, a filter amplification circuit, and an analog to digital conversion circuit, wherein the current voltage conversion circuit is connected to the photodetector at one end, and the filter amplifier circuit is connected to the other end. One end of the analog-to-digital conversion circuit is connected to the filter amplifying circuit, and the other end is connected to the MCU;

The current voltage conversion circuit is configured to convert a photocurrent signal detected by the photodetector into a voltage signal, and the filter amplifying circuit is configured to perform low pass filtering and amplification processing on the voltage signal, the analog to digital conversion The circuit is configured to perform analog-to-digital conversion of the processed signal to obtain an original infrared light spectrum, a visible light spectrum, and an ultraviolet light spectrum, and send the signal to the MCU.

Further, the water quality detecting device further includes: a constant current source circuit and a boosting circuit, wherein one end of the constant current source circuit is connected to the plurality of monochromatic LED light sources, and the other end is connected to the MCU, and the boosting circuit Connected to the constant current source circuit;

The constant current source circuit is configured to provide a specific constant current power source for the plurality of monochromatic LED light sources according to an instruction of the MCU, wherein the constant current power source is used to drive the plurality of monochromatic LED light sources to operate; A circuit is used to provide the voltage required to drive the plurality of monochromatic LED sources.

Further, the water quality detecting device further includes: a serial communication interface, the serial communication interface is connected to the MCU, and configured to receive a control command sent by the outside world to the MCU and send a detection result of the MCU.

Further, the original light intensity signal includes an acquired infrared light spectrum, a visible light spectrum, and an ultraviolet light spectrum transmitted through the current water sample, and the water quality parameter detection indicators include turbidity, chromaticity, TOC, COD, and temperature. The process of processing, by the MCU, the received raw light intensity signal and the temperature of the detected water sample is:

The infrared absorbance spectrum, the visible light absorbance spectrum and the ultraviolet absorbance spectrum were calculated by the absorbance formula A=logI0/I. Among them, I is the collected infrared light spectrum, visible light spectrum and ultraviolet light spectrum of the current water sample, I0 is Pre-stored background spectrum corresponding to each channel; temperature correction of the infrared light absorbance by using the temperature of the detected water sample to obtain corrected infrared light absorbance; according to the corrected infrared light absorbance, combined with the pre-calibrated turbidity standard Working curve, calculating the turbidity of the detected water sample; correcting the visible light absorbance by using the corrected infrared light absorbance to obtain the corrected visible light absorbance, the corrected external light absorbance, and combining the pre-calibrated chromaticity a standard working curve, calculating the chromaticity of the detected water sample; correcting the ultraviolet light absorbance by using the corrected infrared light absorbance, obtaining the corrected ultraviolet light absorbance, and adjusting the ultraviolet light absorbance, combined with pre-calibration The standard working curve of the TOC, the standard working curve of the COD, and the calculated Kind of TOC, COD.

The invention also provides a detection method of the above water quality detecting device, comprising:

Step S1, the photodetector detects the original light intensity signal emitted by each of the corresponding single-color LED light sources and transmitted through the detected water sample, and transmits the original light intensity signal to the MCU;

Step S2, the MCU receives the original light intensity signal sent by the photodetector, and receives the temperature of the detected water sample detected by the temperature sensor;

Step S3, the MCU obtains a water quality parameter detection index of the detected water sample according to the original light intensity signal and the temperature of the detected water sample, and combined with a correlation algorithm.

Further, the step S1 is specifically: the photodetector detects the original light intensity signal emitted by the corresponding infrared light LED light source, the visible light LED light source and the ultraviolet light LED light source and transmitted through the detected water sample, and passes through the After processing by the voltage conversion circuit, the filter amplification circuit and the analog-to-digital conversion circuit, the original infrared light spectrum, visible light spectrum and ultraviolet light spectrum are obtained, and the original infrared light spectrum, visible light spectrum and ultraviolet light spectrum are sent to the MCU .

Further, before the step S1, the method further includes: step S0, correcting and calibrating the water quality detecting device;

The step of correcting is to set a target output voltage value of 2400 mV for each channel composed of each monochromatic LED light source and its corresponding photodetector, and set a default operating current of 20 mA for each channel, the detected water The pure water for configuring the standard solution is used, and the temperature of the purified water is 25 degrees Celsius; the voltage value under the default working current of each channel is collected, and the voltage values of the collected channels and the target output voltage values are respectively compared. Size; by changing the drive current value until the voltage value of the channel is closest to the target output voltage value; setting the current drive current value to the new operating current of the channel; collecting the new operating current for each channel a voltage value as a background spectrum of the channel, and storing the background spectrum in the MCU;

The voltage value of the default operating current of each channel is the actual AD sampling voltage of each channel minus the dark voltage value of the monochromatic LED light source corresponding to the channel;

The step of calibrating is to respectively configure four standard solutions of different concentrations of the concentration in the target detection range, and separately collect the original spectral values of the four standard solutions, and obtain corresponding four standard solutions according to the original spectral values. The standard working curve of the TOC, the standard working curve of the COD, the standard working curve of the chromaticity, and the standard working curve of the turbidity are stored in the flash of the MCU.

Further, the step S3 specifically includes:

In step S31, the infrared light absorbance spectrum, the visible light absorbance spectrum, and the ultraviolet absorbance spectrum are calculated by using the absorbance formula A=logI0/I.

Wherein, I is the collected infrared light spectrum, visible light spectrum and ultraviolet light spectrum of the currently tested water sample, and I0 is the background spectrum corresponding to each channel;

Step S32, performing temperature correction on the infrared light absorbance by using the temperature of the detected water sample to obtain the corrected infrared light absorbance;

Step S33, calculating the turbidity of the detected water sample according to the corrected infrared light absorbance and combining the standard working curve of the turbidity;

Step S34, correcting the visible light absorbance by using the corrected infrared light absorbance to obtain the corrected visible light absorbance, and calculating the detected water sample by using the corrected external light absorbance and combining the standard working curve of the chroma. Chromaticity

Using the corrected infrared light absorbance to correct the ultraviolet light absorbance, the corrected ultraviolet light absorbance is obtained, and the corrected ultraviolet light absorbance is combined with the TOC standard working curve and the COD standard working curve to calculate the Detect the TOC and COD of the water sample.

Compared with the prior art, the invention has the beneficial effects that the water quality detecting device and the detecting method thereof provided by the invention adopts a multi-spectral analysis method, and can quickly and automatically detect multiple parameter indexes of water online, thereby analyzing The water quality solves the problems of long time of inspection and high cost of traditional methods.

Beneficial effect

The water quality detecting device uses a low-cost monochrome LED as a light source, and adopts multi-wavelength spectroscopy technology combined with the above-mentioned calibration method to eliminate the detection precision caused by poor LED consistency, thereby realizing the low cost of the device manufacturing; and the water quality The detection device can be conveniently connected with the water pipeline of the water purifier, realizing on-line online detection and analysis of the purifying degree of the water purifier for drinking water, and providing each household with a drinking water safety guarantee.

DRAWINGS

1 is a schematic diagram of a water quality detecting device according to an embodiment of the present invention;

2 is a flow chart showing a method of detecting the water quality detecting device provided in FIG. 1.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The main implementation idea of the present invention is: correcting and calibrating the water quality detecting device before detecting by using the water quality detecting device; and then detecting the water quality, specifically detecting the original light through the photodetector and the temperature sensor when detecting the water quality The strong signal and the water temperature of the detected water sample, and then the MCU analyzes the original light intensity signal and the water temperature according to the detected algorithm to obtain the TOC, COD, chromaticity and turbidity detection results of the detected water sample; The test results are sent out.

The water quality detecting device is first introduced as shown in FIG. 1 , and includes: a plurality of monochrome LED light sources 1 , a photodetector 2 , an MCU 3 , and a temperature sensor 4 corresponding to each of the single-color LED light sources; Photodetector 2 and said temperature sensor 4 are respectively connected to said MCU 3, said MCU 3 is connected to said plurality of monochromatic LED light sources 1; said photodetector 2 is for detecting each of said corresponding monochromatic LED light sources a raw light intensity signal emitted by the detected water sample and transmitted to the MCU 3; the temperature sensor 4 is configured to detect the temperature of the detected water sample, and The temperature of the detected water sample is sent to the MCU 3; the MCU 3 is configured to process the received raw light intensity signal and the temperature of the detected water sample to obtain a water quality parameter of the detected water sample. Detection Indicator.

Specifically, the LED light source circuit is in the form of a multi-wavelength combined LED, which is composed of LED light sources of different wavelengths such as deep ultraviolet, visible, near infrared, and infrared. In the embodiment of the present invention, a plurality of monochromatic LED light sources 1 are used to form an LED light source circuit. Specifically, the plurality of monochromatic LED light sources 1 include an infrared light LED light source, a visible light LED light source, and an ultraviolet light LED light source. In the future, LED light sources of different wavelengths can be added according to the needs of function expansion; in addition, laser diodes can be used instead of LED light sources to form laser light sources with better monochromatic performance to meet the detection of other water quality parameters.

Specifically, the photodetector uses two different semiconductor materials and process technologies, including a conventional first silicon-based photodiode, a second silicon-based photodiode, and a novel gallium nitride material and a photodiode of the process. . In addition, other photodetector components can be used for subsequent function expansion, including photodetectors such as infrared detectors, pyroelectric sensors, infrared thermopiles, CCDs, and CMOS image sensors.

Specifically, the first silicon-based photodiode and the second silicon-based photodiode are used to sense a light intensity signal of a visible to near-infrared wavelength, and the gallium nitride material and the photodiode of the process are used for sensing The light intensity signal of the ultraviolet to deep ultraviolet range wavelength; in the present invention, the first silicon-based photodiode is used to sense the original light intensity signal emitted by the infrared light LED light source, and the second silicon-based photodiode is used The raw light intensity signal emitted by the visible light LED light source is sensed, and the gallium nitride material and the photodiode of the process are used to sense the original light intensity signal emitted by the ultraviolet light LED light source.

Further, the water quality detecting device further includes: a current voltage conversion circuit 5, a filter amplifying circuit 6 and an analog to digital conversion circuit 7, one end of the current voltage conversion circuit 5 is connected to the photodetector 2, and the other end is The filter amplifying circuit 6 is connected, one end of the analog-to-digital conversion circuit 7 is connected to the filter amplifying circuit 6, and the other end is connected to the MCU 3; the current-voltage converting circuit 5 is used to detect the photodetector 2 The photocurrent signal is converted into a voltage signal required by the back-end analog-to-digital conversion circuit 7; the filter amplifying circuit 6 is configured to low-pass filter and amplify the voltage signal, and further process the analog signal to satisfy noise and The amplitude conversion circuit 6 is configured to perform analog-to-digital conversion on the processed signal to obtain an original infrared light spectrum, a visible light spectrum, and an ultraviolet light spectrum, and send the same to the MCU 3.

Further, the water quality detecting device further includes: a constant current source circuit 8 and a boosting circuit 9, the one end of the constant current source circuit 8 is connected to the plurality of monochromatic LED light sources 1, and the other end is connected to the MCU3. The booster circuit 9 is connected to the constant current source circuit 8.

Specifically, the constant current source circuit 8 is configured to provide a stable constant current power source for driving the operation of the plurality of monochromatic LED light sources 1 according to an instruction of the MCU 3. Due to the difference of the detection parameters and the requirements of the correction algorithm, the current requirement for driving the plurality of monochromatic LED light sources 1 is controllable, so the part of the circuit is an adjustable constant current source circuit, and the output current can be programmed and adjusted by the MCU3. Moreover, the stepping accuracy of the current adjustment is high.

Specifically, the system uses a DC 3-5V supply, and the boost circuit is used to boost the higher voltage required to drive the plurality of monochromatic LED sources 1. This boost circuit can also be controlled to turn on and off through the MCU3 to achieve lower current consumption when the system is idle.

Specifically, the water quality detecting device further includes: a serial communication interface 10, the serial communication interface 10 is connected to the MCU, and configured to receive a control command sent by the outside world to the MCU3 and send the detection result of the MCU3. .

More specifically, the serial communication interface 10 is a serial communication interface 10 of the MCU 3, such as IIC/UART/SPI, etc., and communicates with an external circuit for receiving control commands and transmitting detection results.

More specifically, the Bluetooth module can be used instead of the serial communication interface 10, and the mobile phone APP can realize real-time viewing of the detection result on the user's mobile phone; again, by sending water quality and user data (ie, the registration information of the user on the APP, Such as mobile phone number, regional positioning, operation time, etc. to the cloud back-end system, you can record the water quality of users in different regions, and then draw a water quality map to provide more derivative services.

Specifically, the temperature sensor 4 is implemented by using an NTC thermistor for detecting the temperature of the detected water sample and performing temperature correction on the absorbance of the infrared spectrum.

Specifically, the MCU 3 undertakes processing of data, control of a circuit system, and collection of analog signals. The preferred choice of the microcontroller is ARM The 32-bit MCU of the Cortex-M0 core; depending on the amount of resources required by the internal algorithm, it can also be replaced by an 8-bit 51 MCU or a higher series of MCUs such as the ARM Cortex-M4.

Specifically, when the MCU3 receives the original light intensity signal and the temperature of the detected water sample, the processing process of the data is specifically:

The infrared light absorbance spectrum, the visible light absorbance spectrum, and the ultraviolet absorbance spectrum are calculated by using the absorbance formula A=logI0/I; wherein, I is the collected original light intensity signal passing through the current water sample, the original light intensity signal Including infrared light spectrum, visible light spectrum and ultraviolet light spectrum, I0 is a pre-stored background spectrum corresponding to each channel; using the temperature of the detected water sample to perform temperature correction on the infrared light absorbance to obtain corrected infrared light absorbance; Infrared light absorbance, combined with a standard working curve of pre-calibrated turbidity, calculating the turbidity of the detected water sample; correcting the visible light absorbance by using the corrected infrared light absorbance to obtain the corrected visible light absorbance, corrected by The remaining external light absorbance, combined with the standard working curve of the pre-calibrated chromaticity, calculates the chromaticity of the detected water sample; corrects the ultraviolet light absorbance by using the corrected infrared light absorbance to obtain the corrected ultraviolet light Absorbance, corrected by UV absorbance, combined with pre-calibrated TOC standards Line, COD of the standard curve, calculating the detected water sample TOC, COD.

The system adopts a low power consumption design. When the detection enters the idle state, the MCU 3 turns off the peripheral circuit by controlling the voltage switch of the boosting circuit 9 and the analog circuit part, that is, the current voltage conversion circuit 5, and enters the low power sleep mode. This mode allows the external control circuit to wake up the MCU3 through the serial communication interface.

The following describes the detection method based on the above water quality detecting device, as shown in FIG. 2, including:

Step S0, correcting and calibrating the water quality detecting device;

Specifically, the water quality detecting device needs to perform factory calibration (hardware correction) and calibration two processes before the user application.

Among them, the factory calibration is necessary for each instrument to be shipped from the factory. At the time of shipment (hardware installation), a calibration process must be performed; the purpose of calibration is to ensure the maximum consistency of the batch hardware and reduce the original spectral data. The difference between the stations improves the precision of detection in mass production quality control.

Specifically, before the calibration, after the water quality detecting device is assembled for the first time, and the inside of the pipeline is clean, the purified water for the standard solution is added, and the water temperature of the purified water is room temperature (the room temperature is 25 degrees Celsius). There is no bubble; the target output voltage value of each channel composed of each monochromatic LED light source and its corresponding photodetector is set to 2400mV, and the default operating current of each channel is set to 20mA. The specific correction step is to collect the voltage values under the default working current of each channel, and compare the voltage values of the collected channels and the target output voltage values respectively; increase or decrease the driving current value by the minimum step. Until the voltage value of the channel is closest to the target output voltage value; setting and saving the current driving current value as the new working current of the channel, that is, completing the setting of the working current of each channel; collecting the new The voltage value of each channel under the operating current is used as the background spectrum of the channel, and the background spectrum is stored in the NVM of the MCU (Non Volatile Memory, fixed memory, non-volatile memory).

Specifically, the voltage value of the default operating current of each channel is the actual AD sampling voltage of each channel minus the dark voltage value of the monochromatic LED light source corresponding to the channel;

Specifically, the calibration process is performed in the laboratory after the water quality detecting device completes the factory calibration, and the purpose is to obtain a standard working curve of different detection parameters, and the work only needs to be performed once in the entire product development. The obtained work curve parameters are solidified in the FLASH of the detector MCU by the firmware program.

The step of calibrating is specifically, for the four detection indexes of TOC, COD, chromaticity and turbidity, respectively configuring four standard solutions of different concentrations in the target detection range, and then separately collecting the four standard solutions. The original spectral value is finally obtained, and the standard working curve of the TOC corresponding to the four standard solutions, the standard working curve of the COD, the standard working curve of the chromaticity, and the standard working curve of the turbidity are obtained and stored in the FLASH of the MCU.

Specifically, the MCU controls the constant current source circuit to provide a stable constant current power source for driving the plurality of monochromatic LED light sources; the plurality of monochromatic LED light sources emit a series of different wavelengths of infrared light, visible light, and ultraviolet light. The photodetector corresponding to each monochromatic LED light source detects the original light intensity signal, and after processing by the current voltage conversion circuit, the filter amplification circuit and the analog to digital conversion circuit, the original infrared light is processed. Spectral, visible, and ultraviolet spectra are sent to the MCU.

Specifically, the step S3 includes:

The invention provides a water quality detecting device and a detecting method thereof, which adopts a multi-spectral analysis method, can quickly and accurately detect the TOC, COD, TURB (turbidity) and chromaticity parameter indexes of water, thereby analyzing water quality. It solves the problems of long-time inspection and high cost of the traditional method. The water quality detecting device uses a low-cost monochrome LED as a light source, and adopts multi-wavelength spectroscopy technology to realize the low cost of the device, and the water quality detecting device can be conveniently connected with the water pipe of the water purifier, realizing online in real time. To detect and analyze the purifier's purpose of purifying drinking water, and provide each household with a safe drinking water.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A water quality detecting device, comprising: a plurality of monochromatic LED light sources, a photodetector, an MCU, a temperature sensor corresponding to each of the monochromatic LED light sources; the photodetector and the temperature sensor Connected to the MCU respectively, the MCU is connected to the plurality of monochromatic LED light sources;

The photodetector is configured to detect a corresponding original light intensity signal emitted by each of the single-color LED light sources and transmitted through the detected water sample, and send the original light intensity signal to the MCU;

The temperature sensor is configured to detect a temperature of the detected water sample, and send the temperature of the detected water sample to the MCU;

The MCU is configured to process the received raw light intensity signal and the temperature of the detected water sample to obtain a water quality parameter detection index of the detected water sample.
The water quality detecting device according to claim 1, wherein the plurality of monochromatic LED light sources comprise an infrared light LED light source, a visible light LED light source, and an ultraviolet light LED light source, wherein the photodetector comprises a first silicon-based photodiode, a second silicon-based photodiode and a gallium nitride material and a photodiode of the process; the infrared light LED light source, the visible light LED light source, and the ultraviolet light LED light source and the first silicon-based photodiode, the second silicon-based photodiode, and a gallium nitride material and a photodiode of the process are in one-to-one correspondence for sensing an original light intensity signal of a corresponding monochromatic LED light source; the first silicon-based photodiode and the second silicon-based photodiode are used for sensing A light intensity signal of visible light to a near-infrared wavelength is measured, and the gallium nitride material and the photodiode of the process are used to sense a light intensity signal in the ultraviolet to deep ultraviolet range.
The water quality detecting device according to claim 2, wherein the water quality detecting device further comprises a current voltage converting circuit, a filter amplifying circuit and an analog to digital converting circuit, wherein one end of the current voltage converting circuit is connected to the photodetector The other end is connected to the filter amplifying circuit, one end of the analog-to-digital conversion circuit is connected to the filter amplifying circuit, and the other end is connected to the MCU;

The current voltage conversion circuit is configured to convert a photocurrent signal detected by the photodetector into a voltage signal, and the filter amplifying circuit is configured to perform low pass filtering and amplification processing on the voltage signal, the analog to digital conversion The circuit is configured to perform analog-to-digital conversion of the processed signal to obtain an original infrared light spectrum, a visible light spectrum, and an ultraviolet light spectrum, and send the signal to the MCU.
The water quality detecting device according to claim 3, wherein the water quality detecting device further comprises: a constant current source circuit and a boosting circuit, wherein one end of the constant current source circuit is connected to the plurality of monochromatic LED light sources, and One end is connected to the MCU, and the boosting circuit is connected to the constant current source circuit;

The constant current source circuit is configured to provide a specific constant current power source for the plurality of monochromatic LED light sources according to an instruction of the MCU, wherein the constant current power source is used to drive the plurality of monochromatic LED light sources to operate; A circuit is used to provide the voltage required to drive the plurality of monochromatic LED sources.
The water quality detecting device according to claim 4, wherein the water quality detecting device further comprises: a serial communication interface, wherein the serial communication interface is connected to the MCU, and is configured to receive a control command sent by the outside world Describe the MCU and the detection result of transmitting the MCU.
The detecting device according to claim 5, wherein the original light intensity signal comprises an acquired infrared light spectrum, a visible light spectrum, and an ultraviolet light spectrum of the current water sample to be tested, wherein the water quality parameter detection index comprises Turbidity, chromaticity, TOC, COD and temperature; the process by which the MCU processes the received raw light intensity signal and the temperature of the detected water sample is specifically:

The infrared absorbance spectrum, the visible light absorbance spectrum, and the ultraviolet absorbance spectrum are calculated by the absorbance formula A=logI0/I, where I is the collected infrared light spectrum, visible light spectrum and ultraviolet light spectrum of the current water sample. I0 is a background spectrum corresponding to each pre-stored channel; temperature correction of the infrared light absorbance is performed by using the temperature of the detected water sample to obtain a corrected infrared light absorbance; and according to the corrected infrared light absorbance, combined with the pre-calibrated turbidity a standard working curve for calculating the turbidity of the water sample to be tested; correcting the visible light absorbance by using the corrected infrared light absorbance, obtaining the corrected visible light absorbance, and adjusting the absorbable external light absorbance, combined with the pre-calibrated a standard working curve of chromaticity, calculating the chromaticity of the detected water sample; correcting the ultraviolet light absorbance by using the corrected infrared light absorbance, obtaining the corrected ultraviolet light absorbance, and adjusting the absorbance of the ultraviolet light, and combining Pre-calibrated TOC standard working curve, COD standard working curve, calculate the Of water measured TOC, COD.
A method for detecting a water quality detecting device according to any one of claims 1 to 6, comprising:

Step S1, the photodetector detects the original light intensity signal emitted by each of the corresponding single-color LED light sources and transmitted through the detected water sample, and transmits the original light intensity signal to the MCU;

Step S2, the MCU receives the original light intensity signal sent by the photodetector, and receives the temperature of the detected water sample detected by the temperature sensor;

Step S3, the MCU obtains a water quality parameter detection index of the detected water sample according to the original light intensity signal and the temperature of the detected water sample, and combined with a correlation algorithm.
The detecting method according to claim 7, wherein the step S1 is specifically: the photodetector detects the corresponding infrared light LED light source, the visible light LED light source and the ultraviolet light LED light source and transmits the detected water. The original light intensity signal is processed by the voltage conversion circuit, the filter amplification circuit and the analog-to-digital conversion circuit to obtain the original infrared light spectrum, visible light spectrum and ultraviolet light spectrum, and the original infrared light spectrum, The visible light spectrum and the ultraviolet light spectrum are sent to the MCU.
The detecting method according to claim 8, wherein the step S1 further comprises: step S0, correcting and calibrating the water quality detecting device;

The step of correcting is to set a target output voltage value of 2400 mV for each channel composed of each monochromatic LED light source and its corresponding photodetector, and set a default operating current of 20 mA for each channel, the detected water The pure water for configuring the standard solution is used, and the temperature of the purified water is 25 degrees Celsius; the voltage value under the default working current of each channel is collected, and the voltage values of the collected channels and the target output voltage values are respectively compared. Size; by changing the drive current value until the voltage value of the channel is closest to the target output voltage value; setting the current drive current value to the new operating current of the channel; collecting the new operating current for each channel a voltage value as a background spectrum of the channel, and storing the background spectrum in the MCU;

The voltage value of the default operating current of each channel is the actual AD sampling voltage of each channel minus the dark voltage value of the monochromatic LED light source corresponding to the channel;

The step of calibrating is to respectively configure four standard solutions of different concentrations of the concentration in the target detection range, and separately collect the original spectral values of the four standard solutions, and obtain corresponding four standard solutions according to the original spectral values. The standard working curve of the TOC, the standard working curve of the COD, the standard working curve of the chromaticity, and the standard working curve of the turbidity are stored in the flash of the MCU.
The detecting method according to claim 9, wherein the step S3 specifically comprises:

In step S31, the infrared light absorbance spectrum, the visible light absorbance spectrum, and the ultraviolet absorbance spectrum are calculated by using the absorbance formula A=logI0/I.

Wherein, I is the collected infrared light spectrum, visible light spectrum and ultraviolet light spectrum of the currently tested water sample, and I0 is the background spectrum corresponding to each channel;

Step S32, performing temperature correction on the infrared light absorbance by using the temperature of the detected water sample to obtain the corrected infrared light absorbance;

Step S33, calculating the turbidity of the detected water sample according to the corrected infrared light absorbance and combining the standard working curve of the turbidity;

Step S34, correcting the visible light absorbance by using the corrected infrared light absorbance to obtain the corrected visible light absorbance, and calculating the detected water sample by using the corrected external light absorbance and combining the standard working curve of the chroma. Chromaticity

Using the corrected infrared light absorbance to correct the ultraviolet light absorbance, the corrected ultraviolet light absorbance is obtained, and the corrected ultraviolet light absorbance is combined with the TOC standard working curve and the COD standard working curve to calculate the Detect the TOC and COD of the water sample.