Internet of Things monitoring system

Abstract

The utility model belongs to the field of Internet of Things, and provides an Internet of Things monitoring system, which comprises a detection module and a cloud module, the detection module comprises a sensor unit, a signal amplification and processing unit, a data processing unit and a communication unit, and the cloud module comprises a cloud server. The sensor unit is triggered by ambient air based on the photoelectric detector to generate a current signal; the signal amplifying and processing unit comprises a transimpedance amplifier and an inverting amplifier, the transimpedance amplifier is used for converting a current signal into a voltage signal, the inverting amplifier is used for amplifying and filtering the voltage signal, and the compensation capacitor and the first feedback resistor are connected to the transimpedance amplifier in parallel; the high-frequency noise of the trans-impedance amplifier is reduced and the frequency response is stabilized; the data processing unit is used for analog-to-digital conversion of the voltage signal into a digital signal. Through the combination of the trans-impedance amplifier and the multi-stage amplification structure, high-precision amplification of weak signals of the sensor is realized, and the concentration of trace pollutants in ambient air can be effectively detected.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of internet of things, especially relate to a kind of internet of things monitoring system. BACKGROUND

[0002] The concentration monitoring of trace pollutants (such as particulate matter, volatile organic compounds, nitrogen oxides, etc.) in the air has become an important research direction of environmental protection. To realize real-time detection and high-precision analysis of these pollutants, it is of great significance to develop high-sensitivity, low-noise detection equipment.

[0003] Traditional air quality detection instruments are mainly based on chemical analysis or optical measurement methods. These methods usually require complex pretreatment processes, expensive equipment and long response times, making it difficult to meet the needs of rapid, portable and on-site monitoring. In recent years, sensor technology based on electrical signal measurement has received widespread attention in environmental air detection. This technology generates weak electrical signals by detecting the interaction between gases or particulate matter and sensors, reflecting the concentration of target substances. However, such signals are often very weak and susceptible to noise interference, so high-performance signal amplification and processing modules are needed to improve detection accuracy and stability.

[0004] Existing signal amplification circuits mainly use multi-stage amplifier design, but it is difficult to balance between high gain and low noise, and oscillation and instability problems often occur in high frequency range. In addition, due to the extremely low concentration of pollutants in the environment air (especially when detecting trace components in background air), the dynamic range of sensor output signals is very small, which puts higher requirements on the sensitivity and reliability of signal processing circuits. Therefore, how to design a high-sensitivity, low-noise, stable signal amplification and processing circuit is a problem that needs to be solved in the field of environmental air detection. SUMMARY

[0005] In view of the above technical problems, the utility model provides an internet of things monitoring system.

[0006] Other features and advantages of the present disclosure will become apparent from the following detailed description, or will be learned by practice of the present disclosure.

[0007] The utility model discloses an internet of things monitoring system, the system includes detection module and cloud module, the detection module includes sensor unit, signal amplification and processing unit, data processing unit, communication unit, the cloud module includes cloud server, wherein:

[0008] The sensor unit generates a current signal based on a photodetector triggered by environmental air;

[0009] The signal amplification and processing unit comprises two-stage amplifiers, a compensation capacitor and a first feedback resistor, the two-stage amplifiers comprise a transimpedance amplifier and an inverting amplifier, the transimpedance amplifier is used to convert the current signal into a voltage signal, the inverting amplifier is used to amplify and filter the voltage signal, and the compensation capacitor and the first feedback resistor are connected in parallel to the transimpedance amplifier to reduce high-frequency noise and stabilize frequency response of the transimpedance amplifier.

[0010] The data processing unit is used to convert the voltage signal into a digital signal through analog-digital conversion.

[0011] The communication unit is used to transmit the digital signal to the cloud server.

[0012] Further, in the signal amplification and processing unit, the negative electrode of the transimpedance amplifier is connected to the output end of the photodetector, the positive electrode of the transimpedance amplifier is connected to a first external power supply, the compensation capacitor and the first feedback resistor are connected in parallel between the negative electrode and the output end of the transimpedance amplifier respectively, one end of a coupling capacitor is connected to the output end of the transimpedance amplifier, the other end of the coupling capacitor is connected to the negative electrode of the inverting amplifier, the positive electrode of the inverting amplifier is connected to a second external power supply, and the output end of the inverting amplifier outputs the voltage signal.

[0013] Further, a first capacitor is arranged between the coupling capacitor and the inverting amplifier, and two ends of the first capacitor are connected in parallel to a first resistor.

[0014] Further, a second feedback resistor and a feedback capacitor are connected in parallel between the negative electrode and the output end of the inverting amplifier.

[0015] The technical solution of the present disclosure has the following beneficial effects:

[0016] By combining the transimpedance amplifier and the multi-stage amplification structure, high-precision amplification of the weak signal of the sensor is realized, and the concentration of the trace pollutants in the ambient air can be effectively detected; by introducing the compensation capacitor into the feedback loop of the transimpedance amplifier and reasonably matching the components, high-frequency noise and self-oscillation of the circuit are effectively suppressed, the signal-to-noise ratio of the signal is improved, and the stability and reliability of the detection result are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 FIG. 1 is a structural block diagram of a monitoring system in an embodiment of the present disclosure;

[0018] Fig. 2 FIG. 2 is a circuit principle diagram of a signal amplification and processing unit in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] Example implementations will now be described more fully with reference to the accompanying drawings.

[0020] The accompanying drawings are only intended to schematically illustrate the present disclosure. The same reference signs in the drawings represent the same or similar parts, and thus repeated description thereof will be omitted. It can be understood that the ratio of each component in the drawings does not limit the present disclosure.

[0021] As Figs. 1-2 shown, the present specification embodiment provides an Internet of Things monitoring system, the system comprising a detection module 100 and a cloud module 200, the detection module 100 comprising a sensor unit 101, a signal amplification and processing unit 102, a data processing unit 103, a communication unit 104, the cloud module 200 comprising a cloud server, wherein:

[0022] The sensor unit 101 generates a current signal based on a photodetector triggered by ambient air; the photodetector can be a photodiode in particular;

[0023] The signal amplification and processing unit 102 comprises a two-stage amplifier, a compensation capacitor C8, and a first feedback resistor R6, the two-stage amplifier comprising a transimpedance amplifier OPA657 and an inverting amplifier OPA192, the transimpedance amplifier OPA657 being used to convert the current signal into a voltage signal, the inverting amplifier OPA192 being used to amplify and filter the voltage signal, the compensation capacitor C8 and the first feedback resistor R6 being connected in parallel to the transimpedance amplifier OPA657 to reduce the high-frequency noise and stabilize the frequency response of the transimpedance amplifier OPA657;

[0024] The data processing unit 103 is used to convert the voltage signal into a digital signal, and the data processing unit can comprise a microcontroller of model STM32F407 in particular, the integrated ADC of which can continuously monitor the conversion readings to evaluate whether the digital signal is within the protection range.

[0025] The communication unit 104 is used to transmit the digital signal to the cloud server.

[0026] In the signal amplification and processing unit 102, the negative electrode of the transimpedance amplifier OPA657 is connected to the output end of the photodetector, the positive electrode thereof is connected to a first external power supply, the compensation capacitor C8 and the first feedback resistor R6 are connected in parallel between the negative electrode and the output end of the transimpedance amplifier OPA657 respectively, the output end of the transimpedance amplifier OPA657 is further connected to one end of a coupling capacitor C13, the other end of the coupling capacitor C13 is connected to the negative electrode of the inverting amplifier OPA192, the positive electrode of the inverting amplifier OPA192 is connected to a second external power supply, and the output end thereof outputs a voltage signal. A first capacitor C14 is further arranged between the coupling capacitor C13 and the inverting amplifier OPA192, and the two ends of the first capacitor C14 are connected in parallel to a first resistor R10. A second feedback resistor R7 and a feedback capacitor C12 are connected in parallel between the negative electrode and the output end of the inverting amplifier OPA192.

[0027] The signal amplification and processing unit 102 amplifies the very weak electrical signal detected by the sensor and reduces noise interference to ensure stable output signal; the main task of the transimpedance amplifier OPA657 is to convert the current signal output by the sensor unit into a voltage signal. The OPA657 chip is used in the circuit, which is a high-performance operational amplifier very suitable for processing weak signals. Through the combination design of a feedback resistor R6 and a compensation capacitor C8, the transimpedance amplifier OPA657 not only amplifies the signal, but also ensures the stability of the circuit in the high frequency range. This design effectively reduces the interference problem caused by high frequency noise and improves the sensitivity of the circuit. Among them, in the circuit, the first resistor R10 and the first capacitor C14 element form a filter network, which can accurately select the frequency range of the target signal and further improve the signal quality. In order to make the signal stronger and the processing more accurate, the circuit adds an inverting amplifier OPA192 as the second stage of amplification after filtering, which is completed by the OPA192 operational amplifier chip. By setting appropriate gain parameters, the amplitude of the signal is further enhanced while maintaining low noise characteristics.

[0028] Advantages:

[0029] Through the combination of the transimpedance amplifier OPA657 and the multi-stage amplification structure, high-precision amplification of the weak signal of the sensor is realized, and the concentration of trace pollutants in the ambient air can be effectively detected; by introducing a compensation capacitor in the feedback loop of the transimpedance amplifier OPA657 and reasonably matching the elements, high-frequency noise and circuit self-oscillation are effectively suppressed, the signal-to-noise ratio is improved, and the stability and reliability of the detection results are ensured.

[0030] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed here. This application is intended to cover any variations, uses or adaptive changes of this disclosure that follow the general principles of this disclosure and include known or customary practices in the art of this disclosure not expressly disclosed.

Claims

1. An Internet of Things monitoring system, characterized by, The system comprises a detection module and a cloud module, the detection module comprises a sensor unit, a signal amplification and processing unit, a data processing unit, a communication unit, the cloud module comprises a cloud server, wherein: The sensor unit generates a current signal based on a photodetector triggered by ambient air; The signal amplification and processing unit comprises a two-stage amplifier, a compensation capacitor and a first feedback resistor, the two-stage amplifier comprises a transimpedance amplifier and an inverting amplifier, the transimpedance amplifier is used to convert the current signal into a voltage signal, the inverting amplifier is used to amplify and filter the voltage signal, the compensation capacitor and the first feedback resistor are connected in parallel to the transimpedance amplifier to reduce the high-frequency noise and stabilize the frequency response of the transimpedance amplifier; The data processing unit is used to convert the voltage signal into a digital signal through analog-to-digital conversion; The communication unit is used to transmit the digital signal to the cloud server.

2. The IoT monitoring system of claim 1, wherein, In the signal amplification and processing unit, the negative electrode of the transimpedance amplifier is connected to the output end of the photodetector, the positive electrode is connected to a first external power supply, the compensation capacitor and the first feedback resistor are connected in parallel between the negative electrode and the output end of the transimpedance amplifier, respectively, the output end of the transimpedance amplifier is also connected to one end of a coupling capacitor, the other end of the coupling capacitor is connected to the negative electrode of the inverting amplifier, the positive electrode of the inverting amplifier is connected to a second external power supply, and the output end outputs the voltage signal.

3. The IoT monitoring system of claim 2, wherein, A first capacitor is further arranged between the coupling capacitor and the inverting amplifier, and the two ends of the first capacitor are connected in parallel to a first resistor.

4. The IoT monitoring system of claim 2, wherein, A second feedback resistor and a feedback capacitor are connected in parallel between the negative electrode and the output end of the inverting amplifier.

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