CN214224217U

CN214224217U - Multi-channel environmental parameter monitoring circuit based on single chip microcomputer

Info

Publication number: CN214224217U
Application number: CN202120597363.3U
Authority: CN
Inventors: 吴慧芳
Original assignee: Guangxi Electrical Polytechnic Institute
Current assignee: Guangxi Electrical Polytechnic Institute
Priority date: 2021-03-24
Filing date: 2021-03-24
Publication date: 2021-09-17
Anticipated expiration: 2031-03-24

Abstract

The utility model discloses a multichannel environmental parameter monitoring circuit based on singlechip, including the I/V converter, the C/V converter, the singlechip, multichannel analog switch and signal processing circuit, wherein, the input of I/V converter is coupled current formula sensor, singlechip and multichannel analog switch are coupled to the output, capacitanc sensor is coupled to the input of C/V converter, singlechip and multichannel analog switch are coupled to the output, the singlechip is coupled to the accuse end of multichannel analog switch, signal processing circuit is coupled to the output, signal processing circuit's output is coupled the singlechip. When the single chip senses that a signal is sent out by a certain sensor, the multi-path analog switch is controlled to open a corresponding signal channel, so that the signal of the sensor enters the signal processing circuit, and the sensing signal after signal processing enters the single chip. The sensor signal acquisition monitoring device has the advantages that the sensor signals of various types acquired by various sensors in a single channel are acquired and monitored, and the use of a processor is reduced.

Description

Multi-channel environmental parameter monitoring circuit based on single chip microcomputer

Technical Field

The embodiment of the utility model provides a relate to the data acquisition field particularly, relate to a multichannel environmental parameter monitoring circuit based on singlechip.

Background

In an intelligent home, monitoring environmental parameters is the most important part, and the currently commonly used environmental parameters mainly include: temperature, humidity, smoke sensation, brightness, PM2.5, infrared, and the like. The necessary equipment for obtaining the environmental parameters is a sensor, and the sensor corresponding to the environmental parameters comprises: temperature sensors, humidity sensors, smoke sensors, brightness sensors, PM2.5 sensors, infrared sensors, and the like.

Various types and models of sensors are available on the market, and these sensors have various signal representations, such as a temperature sensor, a current output type and a voltage output type. There are of course other sensors for signal representation, such as capacitive. However, most signal acquisition devices are single-channel, only one type of output signal can be acquired, and a processor is required to be added for acquiring output signals of various types of sensors.

The use of a processor would be reduced if multiple different types of sensor output signals could also be acquired through a single channel.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the above-mentioned defect among the prior art, provide a multichannel environmental parameter monitoring circuit based on singlechip.

In order to realize the purpose of the utility model, the utility model adopts the following technical scheme: a multi-channel environmental parameter monitoring circuit based on a single chip microcomputer comprises an I/V converter, a C/V converter, the single chip microcomputer, a multi-channel analog switch and a signal processing circuit, wherein the input end of the I/V converter is coupled with a current type sensor, and the output end of the I/V converter is coupled with the single chip microcomputer and the input ends of the multi-channel analog switch and is used for converting a current signal output by the current type sensor into a voltage signal; the input end of the C/V converter is coupled with the capacitive sensor, and the output end of the C/V converter is coupled with the singlechip and the input ends of the multi-path analog switches and used for converting a capacitive signal output by the capacitive sensor into a voltage signal; the controlled end of the multi-path analog switch is coupled with the singlechip, and the output end of the multi-path analog switch is coupled with the input end of the signal processing circuit and is used for transmitting the converted voltage signal; the output end of the signal processing circuit is coupled with the singlechip and used for differentially amplifying, filtering and reversely amplifying the voltage signal.

Furthermore, the utility model discloses still provide following subsidiary technical scheme:

preferably, the I/V converter is of type MAX 472.

Preferably, the C/V converter is of the CAV424 type.

Preferably, the model of the singlechip is 89C 52.

Preferably, the multi-way analog switch is of a CD4051 type.

Preferably, the signal processing circuit includes an amplifying circuit and a filtering circuit; the amplifying circuit is a differential amplifying circuit, inputs a voltage signal output by the multi-path analog switch and amplifies the voltage signal; the filter circuit comprises a primary filter circuit, a secondary filter circuit and an inverting amplifying circuit which are connected in series, and the filter circuit inputs a voltage signal output by the amplifying circuit and filters and secondarily amplifies the voltage signal.

Compared with the prior art, the utility model discloses a multichannel environmental parameter monitoring circuit based on singlechip's advantage lies in: the multi-channel analog switch comprises an I/V converter, a C/V converter, a single chip microcomputer, a multi-channel analog switch and a signal processing circuit, wherein the input end of the I/V converter is coupled with a current type sensor, the output end of the I/V converter is coupled with the input ends of the single chip microcomputer and the multi-channel analog switch, the input end of the C/V converter is coupled with a capacitance type sensor, the output end of the C/V converter is coupled with the input ends of the single chip microcomputer and the multi-channel analog switch, the controlled end of the multi-channel analog switch is coupled with the single chip microcomputer. The single chip microcomputer is coupled with the sensors through the converter to sense whether sensing signals are sent out by the sensors or not, when sensing that signals are sent out by a certain sensor, the multi-path analog switch is controlled to open a corresponding signal channel, signals of the sensor can enter the signal processing circuit to carry out differential amplification, filtration and reversed phase amplification on voltage signals, and the sensing signals after signal processing enter the single chip microcomputer.

The utility model discloses a multichannel environmental parameter monitoring circuit based on singlechip, simple structure to every module all has its functional effect that corresponds. The key point is that the sensor signals of various types collected by various sensors are collected and monitored in a single channel, and the use of a processor is reduced.

Drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or related technologies will be briefly introduced below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention and are not limiting to the present invention.

Fig. 1 is the circuit block diagram of the multi-channel environmental parameter monitoring circuit based on the single chip microcomputer.

Fig. 2 is a circuit connection diagram of the multi-way analog switch and the single chip microcomputer.

Fig. 3 is a circuit schematic of the signal processing circuit.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the present invention, taken in conjunction with the accompanying drawings and the detailed description, is given in a non-limiting manner.

Referring to fig. 1, the multi-channel environment parameter monitoring circuit based on the single chip microcomputer of the present embodiment mainly includes: the device comprises an I/V converter 1, a C/V converter 2, a multi-way analog switch 3, a signal processing circuit 4 and a singlechip 5.

In this embodiment, the I/V converter 1 is of a MAX472 type, an input terminal (NC terminal) thereof is coupled to the external current sensor, an output terminal (OUT terminal) thereof is coupled to the input terminal of the multi-channel analog switch 3 and the PO terminal of the single chip microcomputer 5, the UCC terminal is connected to the power supply, and RX1 and RX2 terminals are coupled to the external gain resistor, respectively. The I/V converter 1 is mainly used for converting a current signal output by the current sensor into a voltage signal and sending the voltage signal to the multi-path analog switch 3 and the single chip microcomputer 5.

In this embodiment, the C/V converter 2 is of a CAV424 type, and input terminals (CX1 and CX2 terminals) thereof are respectively coupled to the external capacitive sensor, an output terminal (LPOUT terminal) thereof is coupled to the input terminal of the multi-way analog switch 3 and the PO terminal of the single chip microcomputer 5, VCC terminal is connected to the power supply, and RCX1, RCX2 and RCOSC terminals are respectively coupled to the external gain resistor. The C/V converter 2 is mainly used for converting a capacitance signal output by the capacitance sensor into a voltage signal and sending the voltage signal to the multi-path analog switch 3 and the single chip microcomputer 5.

In this embodiment, the model of the multi-channel analog switch 3 is CD4051, the model of the single chip microcomputer 5 is 89C52, and the multi-channel analog switch 3 has eight channels. Referring to fig. 2, controlled terminals (

pins

9, 10, and 11) of the multi-path analog switch 3 are respectively coupled to I/O ports of the single chip, an output terminal (pin 3) is coupled to an input terminal of the signal processing circuit, and input terminals (

pins

1, 2, 4, 5, 12, 13, 14, and 15) are respectively coupled to at least one I/V converter 1, at least one C/V converter 2, or at least one external voltage type sensor. The multi-channel analog switch 3 is mainly used for being controlled by the singlechip 5, opening a corresponding signal channel and transmitting a signal (Vin1) on the signal channel to the signal processing circuit.

Referring to fig. 3, the signal processing circuit includes an amplifying circuit and a filtering circuit.

The amplifying circuit is a differential amplifying circuit for inputting the voltage signal output by the multi-path analog switch and amplifying the voltage signal. The amplifying circuit mainly includes: the circuit comprises a first operational amplifier U1, a reference voltage circuit, a resistor R1 (resistance value 10K), a resistor R2 (resistance value 40K), a resistor R3 (resistance value 10K) and a resistor R4 (resistance value 40K). The first operational amplifier U1 is model OP 07. One end of the resistor R1 is coupled to the output end of the multi-path analog switch 3, and the input signal (Vin1), and the other end is coupled to the non-inverting input end of the first operational amplifier U1. One end of the resistor R2 is coupled to the non-inverting input terminal of the first operational amplifier U1, and the other end is grounded. One end of the resistor R3 is coupled to the reference voltage circuit, and the other end is coupled to the inverting input terminal of the first operational amplifier U1. One end of the resistor R4 is coupled to the inverting input terminal of the first operational amplifier U1, and the other end is coupled to the output terminal of the first operational amplifier U1. The reference voltage circuit includes: a resistor R5 (resistance 1K), a resistor R6 (resistance 10K), a sliding resistor R7 (maximum resistance 50K) and a voltage regulator tube D1 (voltage 5V); one end of the resistor R5 is coupled to a power supply, the other end is coupled to one end of the resistor R6, the other end of the resistor R6 is coupled to one fixed end of the sliding resistor R7, the other fixed end of the sliding resistor R7 is grounded, and the sliding end of the sliding resistor R7 is coupled to the resistor R3; the cathode of the voltage regulator tube D1 is coupled to the connection point between the resistor R5 and the resistor R6, and the anode is grounded. By adjusting the sliding resistor R7, the output voltage value of the reference voltage circuit can be adjusted. In this embodiment, the reference voltage circuit outputs a 2.73V reference voltage.

The filter circuit comprises a primary filter circuit, a secondary filter circuit and an inverting amplifying circuit which are connected in series, and is used for inputting a voltage signal output by the amplifying circuit and filtering and amplifying the voltage signal twice. The primary filter circuit comprises a capacitor C1 (with the capacity of 100nF) and a resistor R8 (with the resistance of 100K) for performing first-order low-pass filtering, wherein the capacitor C1 and the resistor R8 are connected in series with each other and are also coupled to the output end of the first operational amplifier U1. The secondary filter circuit comprises a resistor R9 (with the resistance value of 1K) and a capacitor C2 (with the capacity of 20nF) and is used for carrying out first-order high-pass filtering, one end of the resistor R9 is coupled with the primary filter circuit, the other end of the resistor R9 is coupled with one end of the capacitor C2, and the other end of the capacitor C2 is grounded. The inverting amplifier circuit comprises a second operational amplifier U2, a resistor R10 (resistance value 1K) and a resistor R11 (resistance value 1K) and is used for inverting amplification. The model of the second operational amplifier U2 is OP07, the inverting input end of the second operational amplifier U is coupled with the connection point of R9 and a capacitor C2, the non-inverting input end of the second operational amplifier U is grounded after passing through a resistor R10, and the output end of the second operational amplifier U is coupled with the I/O port of the singlechip and outputs a signal (Vout 1). One end of the resistor R11 is coupled to the output terminal of the second operational amplifier U2, and the other end is coupled to the common-direction input terminal of the second operational amplifier U2.

When the single-chip microcomputer works, the single-chip microcomputer is coupled with an external current type sensor through the I/V converter 1, coupled with an external capacitance type sensor through the C/V converter 2 and directly coupled with an external voltage type sensor, when any external sensor is triggered to send out a sensing signal, the single-chip microcomputer receives the sensing signal (the signal is a trigger signal and cannot be used as a monitoring signal) at the first time, controls the multi-path analog switch 3 to open a signal channel where the sensor is located, and the sensing signal enters the signal processing circuit and is input into the single-chip microcomputer after differential amplification, first-order low-pass filtering, first-order high-pass filtering and reverse amplification. After that, the single chip microcomputer can send data to the PC 200 through the RS232 communication interface 100 or the remote communication module, thereby completing the terminal monitoring.

It should be noted that the above-mentioned preferred embodiments are only for illustrating the technical concepts and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the protection scope of the present invention cannot be limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides a multichannel environmental parameter monitoring circuit based on singlechip which characterized in that: comprises an I/V converter, a C/V converter, a singlechip, a multi-channel analog switch and a signal processing circuit, wherein,

the input end of the I/V converter is coupled with the current sensor, and the output end of the I/V converter is coupled with the single chip microcomputer and the input ends of the multi-path analog switches and used for converting current signals output by the current sensor into voltage signals;

the input end of the C/V converter is coupled with the capacitive sensor, and the output end of the C/V converter is coupled with the singlechip and the input ends of the multi-path analog switches and used for converting a capacitive signal output by the capacitive sensor into a voltage signal;

the controlled end of the multi-path analog switch is coupled with the singlechip, and the output end of the multi-path analog switch is coupled with the input end of the signal processing circuit and is used for transmitting the converted voltage signal;

the output end of the signal processing circuit is coupled with the singlechip and used for differentially amplifying, filtering and reversely amplifying the voltage signal.

2. The multi-channel environment parameter monitoring circuit based on the single chip microcomputer according to claim 1, wherein: the model of the I/V converter is MAX 472.

3. The multi-channel environment parameter monitoring circuit based on the single chip microcomputer according to claim 1, wherein: the model of the C/V converter is CAV 424.

4. The multi-channel environment parameter monitoring circuit based on the single chip microcomputer according to claim 1, wherein: the model of the single chip microcomputer is 89C 52.

5. The multi-channel environment parameter monitoring circuit based on the single chip microcomputer according to claim 1, wherein: the model of the multi-channel analog switch is CD 4051.

6. The multi-channel environment parameter monitoring circuit based on the single chip microcomputer according to claim 1, wherein: the signal processing circuit comprises an amplifying circuit and a filtering circuit; wherein the content of the first and second substances,

the amplifying circuit is a differential amplifying circuit, inputs the voltage signals output by the multi-path analog switch and amplifies the voltage signals;

the filter circuit comprises a primary filter circuit, a secondary filter circuit and an inverting amplifying circuit which are connected in series, and the filter circuit inputs a voltage signal output by the amplifying circuit and carries out filtering and secondary amplification on the voltage signal.