CN210689702U - Detection circuit, temperature and humidity detection device thereof and temperature and humidity detection system - Google Patents
Detection circuit, temperature and humidity detection device thereof and temperature and humidity detection system Download PDFInfo
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- CN210689702U CN210689702U CN201920749275.3U CN201920749275U CN210689702U CN 210689702 U CN210689702 U CN 210689702U CN 201920749275 U CN201920749275 U CN 201920749275U CN 210689702 U CN210689702 U CN 210689702U
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Abstract
The application discloses detection circuitry and temperature and humidity detection device, temperature and humidity measurement system thereof, this detection circuitry is applied to temperature and humidity detection device, and detection circuitry includes: the device comprises a thermistor, a control circuit, a first reference resistor and a second reference resistor; one end of the thermistor is connected with a power supply voltage, and the other end of the thermistor is connected with the control circuit; when the control circuit is in a first state, the input end of the control circuit is connected with a first reference resistor; when the control circuit is in the second state, the input end of the control circuit is connected with the second reference resistor. The detection circuit enables the thermistor to be always in a linear change area by accessing different reference resistors, and the sampling accuracy of the detection circuit is improved.
Description
Technical Field
The application relates to the technical field of temperature and humidity detection, in particular to a detection circuit, a temperature and humidity detection device and a temperature and humidity detection system.
Background
The internet of things is used as a new information technology, and informatization, remote management control and intellectualization between people and objects and between objects can be realized. The Internet of things in the prior art detects the temperature and humidity information of the environment through a temperature and humidity detection device.
However, the temperature and humidity information of the external environment cannot be always accurately obtained by the current temperature and humidity detection device due to the limitation of the thermistor property.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problems, the present application provides a detection circuit, a temperature and humidity detection device, and a temperature and humidity detection system thereof, which can solve the problem of inaccurate detection of the detection circuit in the prior art.
The technical scheme adopted by the application is as follows: the detection circuit is applied to a temperature and humidity detection device and comprises: the device comprises a thermistor, a control circuit, a first reference resistor and a second reference resistor; one end of the thermistor is connected with a power supply voltage, and the other end of the thermistor is connected with the control circuit; when the control circuit is in a first state, the input end of the control circuit is connected with the first reference resistor; when the control circuit is in a second state, the input end of the control circuit is connected with the second reference resistor.
Another technical scheme adopted by the application is as follows: provided is a temperature and humidity detection device, the temperature and humidity detection device at least including: a housing comprising at least a first cavity and a second cavity; the temperature and humidity sensor is arranged in the second cavity and used for collecting temperature and humidity information of the environment where the temperature and humidity detection device is located, and the temperature and humidity sensor is provided with the detection circuit; the processor is arranged in the first cavity, is electrically connected with the temperature and humidity sensor, and is used for receiving temperature and humidity information of the temperature and humidity sensor; a first partition plate is arranged between the first cavity and the second cavity, and a through hole is formed between the second cavity and the outside.
Another technical scheme adopted by the application is as follows: providing a temperature and humidity detection system, wherein the temperature and humidity detection system at least comprises a temperature and humidity detection device and a fixed shell, and the temperature and humidity detection device is the temperature and humidity detection device; the temperature and humidity detection device is also provided with a metal patch, the fixed shell is provided with a metal contact corresponding to the metal patch, and the metal contact is connected with a sensor; the fixed shell is provided with an accommodating space for accommodating the temperature and humidity detection device; when the temperature and humidity detection device is accommodated in the accommodating space. The metal patch is in contact with the metal contact so that the temperature and humidity detection device is electrically connected with the sensor.
The application provides a detection circuit includes: the device comprises a thermistor, a control circuit, a first reference resistor and a second reference resistor; one end of the thermistor is connected with a power supply voltage, and the other end of the thermistor is connected with the control circuit; when the control circuit is in a first state, the input end of the control circuit is connected with a first reference resistor; when the control circuit is in a second state, the input end of the control circuit is connected with a second reference resistor; the detection circuit enables the thermistor to be connected with the current reference resistor in series through the control circuit by accessing different reference resistors, so that the thermistor is always in a linear change area, and the sampling accuracy of the thermistor is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:
fig. 1 is a schematic structural diagram of an embodiment of a temperature and humidity detection device according to the present application;
FIG. 2 is an exploded view of the temperature and humidity sensing device of FIG. 1;
FIG. 3 is a schematic structural diagram of an embodiment of the fixing shell of the present application;
FIG. 4 is a schematic structural diagram of an embodiment of a temperature and humidity measurement system of the present application;
FIG. 5 is an exploded view of the temperature and humidity detection system of FIG. 4;
fig. 6 is a schematic structural diagram of an embodiment of a temperature and humidity sensor detection circuit according to the present application;
fig. 7 is a schematic structural diagram of another embodiment of a temperature and humidity sensor detection circuit according to the present application;
FIG. 8 is a schematic flow chart diagram illustrating an embodiment of a temperature/humidity sensor circuit control method according to the present application;
FIG. 9 is a schematic diagram of the circuit of FIG. 8;
FIG. 10 is a schematic flow chart diagram illustrating another exemplary embodiment of a method for controlling a temperature/humidity sensor circuit according to the present application;
fig. 11 is a schematic structural view of another embodiment of the temperature and humidity detecting device according to the present application;
FIG. 12 is a schematic structural diagram of an embodiment of a computer storage medium according to the present application.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be noted that the following examples are only illustrative of the present application, and do not limit the scope of the present application. Likewise, the following examples are only some examples and not all examples of the present application, and all other examples obtained by a person of ordinary skill in the art without any inventive step are within the scope of the present application.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the information so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Referring to fig. 1 and fig. 2, fig. 1 is a schematic structural diagram of an embodiment of a temperature and humidity detection device according to the present application, and fig. 2 is an exploded view of the temperature and humidity detection device in fig. 1. The temperature and humidity detection device 100 can be installed in a cold chain environment to acquire temperature information and/or humidity information of an object to be detected in the cold chain environment. Specifically, the temperature and humidity detection device 100 of the present application establishes a wireless channel connection with a wireless gateway (not shown in the figure) within a preset range, wherein one wireless gateway can be in communication connection with a plurality of temperature and humidity detection devices 100 provided by the present application, so as to implement one-to-many communication.
In the cold chain process, the carrier storing the object to be measured is generally a refrigeration device or a cold chain box. The refrigeration equipment can be a refrigerator, an ice chest, a refrigerating chamber and the like, and is mainly used for storing medicines, vaccines or other articles needing cold chain transportation. For example, the temperature and humidity detecting device 100 may be installed inside or outside the refrigeration apparatus, and the temperature and humidity detecting device 100 is used to collect temperature information and/or humidity information of the internal environment or the external environment of the refrigeration apparatus. After temperature and humidity detection device 100 collects temperature information and/or humidity information of the internal environment or the external environment of the refrigeration equipment, the temperature information and/or humidity information is sent to a connected wireless gateway, so that the temperature information and/or humidity information is uploaded to a remote server through the wireless gateway.
Referring to fig. 1 and 2, the temperature/humidity detection apparatus 100 of the present embodiment includes a housing 11, a sensor 12, and a processor 13.
The housing 11 includes a first cavity 111 and at least one second cavity 112, and an accommodating space formed by the first cavity 111 is greater than or equal to an accommodating space formed by the second cavity 112. A first partition 1111 is disposed between the first cavity 111 and the second cavity 112, and a small hole (not shown) adapted to an electric wire is disposed on the first partition 1111.
A processor 13 is disposed within the first chamber 111, the processor 13 being configured to receive and process the temperature information and/or the humidity information. The sensor 12 is disposed in the second cavity 112, and the sensor 12 is configured to acquire temperature information and/or humidity information of an environment where the temperature and humidity detecting apparatus 100 is located. And a wire connecting the first cavity 111 and the second cavity 112 is arranged in the housing 11, one end of the wire is connected with the sensor 12, and the other end of the wire passes through the small hole in the first partition 1111 and is connected with the processor 13. The sensor 12 is electrically connected with the processor 13 through the electric wire, and the sensor 12 transmits the acquired temperature information and/or humidity information to the processor 13 through the electric wire. Further, the processor 13 may also be connected to a display screen and a charging interface (not shown) disposed on the first cavity 111.
Since the electronic devices such as the processor 13 and/or the circuit board need to be sealed, the first cavity 111 is not communicated with the external environment, so as to prevent the electronic devices such as the processor 13 from being damaged due to the contact of water vapor of the external environment. A closed space is formed in the first cavity 111, the second cavity 112 is provided with a first through hole 1121, and the sensor 12 in the second cavity 112 is in contact with the external environment through the first through hole 1121, so that temperature information and/or humidity information of the environment where the external temperature and humidity detection device 100 is located can be better detected. Specifically, the first through hole 1121 is disposed such that the temperature condition and the humidity condition in the second cavity 112 are consistent with the external temperature condition and the external humidity condition, so that the accuracy of the temperature information and/or the humidity information obtained by the sensor 12 is high.
Further, the sensor 12 may be disposed in the second cavity 112 corresponding to the first through hole 1121, for example, a detection chip of the sensor 12 is disposed corresponding to the first through hole 1121, so that the detection chip can better detect the temperature information and/or the humidity information.
The sensor 12 of the present embodiment may be a temperature and humidity sensor, a thermal sensor, a platinum resistance temperature sensor, or the like.
In this embodiment, the first through hole 1121 may include a plurality of openings spaced side by side, specifically refer to fig. 1 and fig. 2; the first through holes 1121 may also be lattice-shaped through holes or honeycomb-shaped through holes. In other embodiments, the first through hole 1121 may also be a through hole including the above structure, which is not described herein again.
The second cavity 112 may further include a second through hole 1122, the second through hole 1122 and the first through hole 1121 are oppositely disposed at two sides of the second cavity 112, and the sensor 12 is disposed at a position between the first through hole 1121 and the second through hole 1122. In other embodiments, the second through hole 1122 may also be disposed on an adjacent side of the first through hole 1121.
The housing 11 may further include a third cavity 113, and an area of a receiving space formed by the third cavity 113 may be the same as an area of a receiving space formed by the second cavity 112. In this embodiment, as shown in fig. 1, the first cavity 111 is disposed above the temperature and humidity detection device 100, the second cavity 112 is disposed at the left lower side of the temperature and humidity detection device 100, and the third cavity 113 is disposed at the right lower side of the temperature and humidity detection device 100. In other embodiments, the first cavity 111 may also be disposed in the middle of the temperature and humidity detecting device 100, the second cavity 112 and the third cavity 113 are disposed on two sides of the first cavity 111, respectively, and a technician may adjust the positions of the first cavity 111, the second cavity 112 and the third cavity 113 according to requirements.
The third cavity 113 may be used to accommodate a sound module (not shown), wherein the sound module may be a buzzer, a speaker, or a microphone. A second partition 1112 is arranged between the third cavity 113 and the first cavity 111, and the second partition 1112 is also provided with a small hole adapted to the electric wire. The housing 11 is provided with a wire connecting the first cavity 111 and the third cavity 113, one end of the wire is connected to the sound module, and the other end of the wire passes through the small hole on the second partition 1112 and is connected to the processor 13. The sound module and the processor 13 are electrically connected through the electric wire, and the processor 13 controls the sound module to play sound, wherein the sound can be alarm sound or temperature information and/or humidity information broadcast sound.
The third cavity 113 is provided with a third through hole (not shown in the figure) as the second cavity 112, and the sound module in the third cavity 113 can better transmit sound to the external environment through the third through hole.
Further, the third cavity 113 may further include a fourth through hole, and the structure and the arrangement manner of the third through hole and the fourth through hole may be the same as those of the first through hole 1121 and the second through hole 1122, and are not described herein again.
In this embodiment, the casing 11 of the temperature and humidity detecting apparatus 100 at least includes a first cavity 111 and a second cavity 112, wherein a closed space is formed in the first cavity 111 to protect the processor 13 in the first cavity 111. At least one first through hole 1121 is formed between the second cavity 112 and the outside, so that the temperature condition and the humidity condition in the second cavity 112 are consistent with the temperature condition and the humidity condition of the outside, and the detection accuracy of the sensor 12 is improved.
The present application further provides a fixing housing, specifically please refer to fig. 3, and fig. 3 is a schematic structural diagram of an embodiment of the fixing housing of the present application. The fixing shell 200 of the present embodiment may be used to accommodate the temperature and humidity detecting device 100 in the above embodiments, and further, the fixing shell 200 may also be adapted to various installation environments, so as to better accommodate the temperature and humidity detecting device 100.
As shown in fig. 3, the fixing case 200 of the present embodiment includes a case 21, and at least three ends of the case 21 are provided with bosses 211. The protrusion 211 extends in the opposite direction of the housing 21 and is bent toward the center of the housing 21 to form a limited space for fixing the temperature/humidity detection device 100 to the housing 21.
While the temperature and humidity detecting device 100 is fixed, the fixing shell 200 itself needs to be fixed in different installation environments, so that the temperature and humidity detecting device 100 collects temperature information and/or humidity information in different environments.
To meet the above requirements, the housing 21 is provided with screw holes 22 and a fixing structure 23. At least two screw holes 22 are formed on the housing 21, and as shown in fig. 3, one screw hole 22 is formed at each of four corners of the housing 21 to match the position of the fixing case 200. In other embodiments, the housing 21 may be provided with two corresponding screw holes 22 only at opposite corners.
The four corners of the housing 21 are respectively provided with a fixing structure 23, and when the fixing structures 23 are in the first state, the fixing structures 23 are used for fixing the position of the fixing shell 200; when the fixing structure 23 is in the second state, the fixing structure 23 releases the fixing case 200 to disengage the fixing case 200 from the original position.
Specifically, the fixing structure 23 at least includes an accommodating groove 231 and a magnetic sheet 232 disposed in the accommodating groove 231. When the magnetic sheet 232 has magnetism, the magnetic sheet 232 fixes the fixing case 200 on the metal case by magnetic adsorption; when the magnetic sheet 232 loses its magnetism, the fixing case 200 loses its magnetic attraction and is separated from the metal case.
As shown in fig. 3, the receiving grooves 231 may include a first receiving groove, a second receiving groove, a third receiving groove and a fourth receiving groove; the first receiving groove, the second receiving groove, the third receiving groove and the fourth receiving groove are respectively disposed at four corners of the housing 21, so as to achieve the best fixing effect.
Further, the fixing structure 23 may further include a suction cup (not shown) disposed in the accommodating groove 231. The sucking disc of this embodiment can be vacuum chuck, utilizes inside and outside atmospheric pressure's difference, will fix the shell 200 and adsorb on the installation environment of difference. For example, when the fixing case 200 is required to fix a case having a rough surface, the vacuum chuck is pressed against the case to discharge air in the vacuum chuck, so that the fixing case 200 can be adsorbed on the case; when the fixing case 200 needs to be replaced or removed, air is introduced into the vacuum chuck, so that the atmospheric pressure inside and outside the vacuum chuck is balanced, and the fixing case 200 is separated from the housing. The vacuum chuck may be made of polyurethane, nitrile rubber, or vinyl containing polymers.
In other embodiments, the suction cup may also be an electromagnetic suction cup, which uses the electromagnetic principle to generate magnetic force by energizing the internal coil, and the casing contacting the surface of the electromagnetic suction cup is tightly sucked by the magnetic conductive panel, thereby fixing the fixing casing 200. In order to cooperate with the electromagnetic chuck, the fixing case 200 is further provided with a switch module, and the switch module is electrically connected with the electromagnetic chuck. When the switch module is in an on state, the electromagnetic chuck fixes the fixing shell 200 on the metal shell through magnetic adsorption; when the switch module is in the off state, the electromagnetic chuck releases the fixing case 200, so that the fixing case 200 is separated from the metal case.
In the embodiment, the casing 21 of the fixing casing 200 is at least provided with a screw hole 22 and a fixing structure 23, and when the fixing casing 200 needs to be installed on a metal shell or a casing with a rough surface, the fixing casing 200 is fixed by vacuum adsorption or magnetic adsorption through the fixing structure 23; when it is required to mount the set cover 200 on a non-metal case or a case having a smooth surface, the set cover 200 is fixed by the screw fitting screw hole 22; through the above structural design, the set casing 200 can be adapted to various installation environments, improving the universality of the set casing 200.
The present application further provides a temperature and humidity detecting system, referring to fig. 4 and fig. 5 specifically, fig. 4 is a schematic structural diagram of an embodiment of the temperature and humidity detecting system of the present application, and fig. 5 is an exploded view of the temperature and humidity detecting system of fig. 4.
The temperature and humidity detecting system 300 of this embodiment at least includes a temperature and humidity detecting device 31 and a fixing case 32, where the temperature and humidity detecting device 31 may be the temperature and humidity detecting device 100 in the above embodiment, and the fixing case 32 may be the fixing case 200 in the above embodiment, which is not described herein again. The fixing shell 32 is used for accommodating the temperature and humidity detection device 31, so that the temperature and humidity detection device 31 can collect temperature information and/or humidity information of the environment where the temperature and humidity detection system 300 is located.
The stationary housing 32 further includes a collection module 321, and the collection module 321 can be used to collect temperature information and/or humidity information. The collecting module 321 may include a temperature and humidity sensor 3211 and a connecting line 3212 connecting the temperature and humidity sensor 3211 and the fixing case 32.
Specifically, the bottom of the fixing shell 32 is provided with a metal contact 322, one end of the connecting wire 3212 is connected to the metal contact 322, and the other end is connected to the temperature and humidity sensor 3211. A metal patch (not shown) corresponding to the metal contact 322 is disposed at the bottom of the temperature and humidity detecting device 31, and when the metal patch contacts the metal contact 322, the temperature and humidity sensor 3211 is electrically connected to the temperature and humidity detecting device 31 through a connecting wire 3212.
When the temperature and humidity detection device 31 is accommodated in the fixing case 32, the metal contact 322 contacts with the metal patch, and the temperature and humidity detection device 31 can acquire temperature information and/or humidity information of an environment where the temperature and humidity detection device is located through the temperature and humidity sensor 3211.
For example, when the temperature and humidity detecting system 300 needs to detect temperature information and/or humidity information inside and outside the refrigerator, the fixing casing 32 may be fixed on an outer wall of the refrigerator, the temperature and humidity detecting device 31 is placed in the fixing casing 32, so that the metal contact 322 contacts with the metal patch 311, and the temperature and humidity sensor 3211 connected to the fixing casing 32 is placed in the refrigerator. At this time, the temperature and humidity detecting device 31 can collect temperature information and/or humidity information outside the refrigerator, and the temperature and humidity detecting device 31 collects temperature information and/or humidity information inside the refrigerator through the temperature and humidity sensor 3211 connected to the fixing case 32.
Therefore, the temperature and humidity detection system 300 can acquire the temperature information and/or the humidity information inside and outside the refrigerating box at the same time, and a better detection effect is achieved.
The fixing case 32 may further include a battery module (not shown), and the battery module may be a 3.6V-5V battery pack. The battery module is electrically connected with the metal contact 322, and when the metal patch 311 of the temperature and humidity detection device 31 contacts the metal contact 322, the battery module is used for supplying power to the temperature and humidity detection device 31 and the temperature and humidity sensor 3211.
For example, when the temperature and humidity detecting system 300 detects temperature information and/or humidity information inside and outside the refrigerator, the battery module provides power to the temperature and humidity sensor 3211, and if the temperature and humidity detecting device 31 is short of power or stops supplying power, the battery module provides power to the temperature and humidity detecting device 31 to maintain the normal operation of the temperature and humidity detecting system 300.
The fixing case 32 may further include a processing module (not shown), which is electrically connected to the battery module and the metal contact 322. The processing module can control the temperature and humidity sensor 3211 to collect temperature information and/or humidity information of the environment under the condition that the temperature and humidity detection device 31 is not in contact with the fixed shell 32.
For example, when the temperature and humidity detecting device 31 is not accommodated in the fixing case 32, the processing module controls the temperature and humidity sensor 3211 to collect temperature information and/or humidity information of the environment; after the temperature and humidity detecting device 31 is accommodated in the fixing shell 32, when the processing module detects that the temperature and humidity detecting device 31 is connected, the processing module sends the collected temperature information and/or humidity information to the temperature and humidity detecting device 31, and the temperature and humidity detecting device 31 controls the temperature and humidity sensor 3211 to continuously collect the temperature information and/or humidity information of the environment.
The present application further provides a detection circuit, please refer to fig. 6 and 7 specifically, in which fig. 6 is a schematic structural diagram of an embodiment of the detection circuit of the temperature and humidity sensor of the present application, and fig. 7 is a schematic structural diagram of another embodiment of the detection circuit of the temperature and humidity sensor of the present application. The detection circuit 400 of the present embodiment may be applied to the sensor 12 of the temperature and humidity detection apparatus 100 in fig. 1, and may also be applied to the temperature and humidity sensor 3211 connected to the fixing case 32 in fig. 4.
The detection circuit 400 may be specifically disposed on an FPC board of the temperature and humidity sensor, and the detection circuit 400 is disposed with a thermistor 41. The thermistor 41 is characterized by being sensitive to temperature, exhibiting different resistance values at different temperatures, and the thermistor 41 can be used to detect the ambient temperature according to the relationship between the thermistor 41 and the temperature. The thermistor 41 is classified into a positive temperature coefficient thermistor (PTC) and a negative temperature coefficient thermistor (NTC) according to the temperature coefficient, and the positive temperature coefficient thermistor has a larger resistance value at a higher temperature and the negative temperature coefficient thermistor has a smaller resistance value at a higher temperature. In the present embodiment, the thermistor 41 on the detection circuit 400 belongs to a negative temperature coefficient thermistor; in other embodiments, the thermistor 41 can also be a positive temperature coefficient thermistor, which is not described herein.
The detection circuit 400 is also provided with a control circuit 42, a reference resistor group and a calculation circuit 44. One end of the thermistor 41 is connected with a VCC power supply voltage, and the power supply voltage outputs 3.6V/5.0V direct current voltage; the other end of the thermistor 41 is connected to a control circuit 42. The input end of the control circuit 42 is connected to a certain reference resistor in the reference resistor group, specifically, the reference resistor group includes at least a first reference resistor 431 and a second reference resistor 432, and when the control circuit 42 is in the first state, the input end of the control circuit 42 is connected to the first reference resistor 431; when control circuit 42 is in the second state, the input of control circuit 42 is connected to second reference resistor 432.
The input end of the computing circuit 44 is connected to the thermistor 41, and is used for acquiring the temperature information of the environment according to the resistance value of the thermistor 41. The calculation circuit 44 may detect the resistance value of the thermistor 41 and then output the temperature information corresponding to the resistance value according to the temperature resistance value table corresponding to the thermistor 41.
As shown in fig. 7, the calculation circuit 44 may further include an ADC circuit 441 (digital-to-analog conversion circuit). The ADC circuit 441 is configured to convert a continuously varying analog signal, which may be a current signal or a voltage signal in this embodiment, into a discrete digital signal, and the ADC circuit 441 outputs a 12-bit AD value according to the current signal or the voltage signal of the thermistor 41.
Specifically, when the input terminal of the control circuit 42 is not connected to the first reference resistor 431 or the second reference resistor 432, the ADC circuit 441 outputs the first AD value; when the input terminal of the control circuit 42 is connected to the first reference resistor 431, the ADC circuit 441 outputs a second AD value; the ADC circuit 441 outputs the third AD value when the input terminal of the control circuit 42 is connected to the second reference resistor 432.
The calculating circuit 44 further compares the first AD value, the second AD value and the third AD value according to a preset rule, for example, compares a half value of the first AD value with the second AD value to obtain an absolute value of the first difference; and comparing the half value of the first AD value with the third AD value to obtain the absolute value of the second difference value. If the absolute value of the first difference is greater than the absolute value of the second difference, it indicates that the resistance of the thermistor 41 is closest to the resistance of the second reference resistor 432, and the control circuit 42 is set to the second state, i.e., connected to the second reference resistor 432 according to the comparison result. If the absolute value of the first difference is smaller than the absolute value of the second difference, it indicates that the resistance value of the thermistor 41 is closest to the resistance value of the first reference resistor 431 at this time, and the control circuit 42 is set to the first state, i.e., connected to the first reference resistor 431, according to the comparison result.
The circuit principle of the control circuit 42 connecting the first reference resistor 431 or the second reference resistor 432 according to the comparison result is as follows: the resistance value of the thermistor 41 has a significant nonlinearity with temperature change, and when the voltage value of the thermistor 41 approaches half of the voltage value of the power supply voltage output, the change in the resistance value of the thermistor 41 most closely approaches a linear change. For example, when the power supply voltage outputs a voltage of 3.6V, the voltage value range corresponding to the linear variation region of the thermistor 41 is 1.6V to 2.0V; when the power voltage is 5.0V, the voltage value corresponding to the linear change region of the thermistor 41 is 1.6V to 2.0V. Therefore, the detection circuit 400 of the present embodiment requires a reference resistor with a similar resistance value to be connected in series with the thermistor 41.
Specifically, reference resistors with different ranges are arranged in the reference resistor group, for example, the reference resistor group may further include a third reference resistor 433 and a fourth reference resistor 434. The resistance of the first reference resistor 431 is 10K Ω, the resistance of the second reference resistor 432 is 100K Ω, the resistance of the third reference resistor 433 is 1000K Ω, and the resistance of the fourth reference resistor 434 is 10000K Ω. In other embodiments, the reference resistors with different ranges in the reference resistor group may have resistors with other resistance values, which are not described herein again.
The control circuit 42 at least includes a single-pole four-throw switch 422, one end of the single-pole four-throw switch 422 is connected to the thermistor 41, and the other end is connected to the first reference resistor 431, the second reference resistor 432, the third reference resistor 433 or the fourth reference resistor 434 in a floating manner.
In this embodiment, the detection circuit 400 detects whether the voltage value of the thermistor 41 is close to half of the voltage value output by the power supply voltage when different reference resistors are connected; if yes, the control circuit 42 adjusts the state, so that the thermistor 41 is connected in series with the current reference resistor through the control circuit 42, so that the thermistor 41 is always in the linear change region, and the sampling accuracy of the thermistor 41 is improved.
The sampling accuracy of the thermistor 41 is improved by hardware in the above embodiment, and similarly, the sampling accuracy of the thermistor 41 can also be improved by software control in the present embodiment. Referring to fig. 8 and 9, fig. 8 is a schematic flowchart of an embodiment of a method for controlling a temperature/humidity sensor circuit according to the present application, and fig. 9 is a schematic structural diagram of the circuit in fig. 8.
The detection circuit 500 of the present embodiment at least includes a thermistor 51, an ADC circuit 52, a control circuit 53, a first reference resistor 541, and a second reference resistor 542; one end of the thermistor 51 is connected to the ADC circuit 52, and the other end is connected to the control circuit 53.
The control method of the present embodiment is to connect a reference resistor with a suitable resistance value in series with the thermistor 51, so that the voltage value of the thermistor 51 can be kept within a preset voltage value range of half of the output voltage value of the power supply voltage; within the preset voltage range, the thermistor 51 has better sampling accuracy, and the detection circuit 500 can detect accurate temperature information.
As shown in fig. 8, the control method of the present embodiment specifically includes the following steps:
s601: the control circuit is connected to the first reference resistor and obtains a first detection value of the ADC circuit.
The detection circuit 500 controls the control circuit 53 to access the first reference resistor 541, and at this time, one end of the thermistor 51 is connected to the power supply voltage, and the other end is connected to the first reference resistor 541, that is, the first reference resistor 541 is connected in series with the thermistor 51. The ADC circuit 52 converts the continuously varying analog signal passing through the thermistor 51 into a discrete digital signal, and in this embodiment, the continuously varying analog signal may be a current signal or a voltage signal, and the ADC circuit 52 outputs a first detection value of 12 bits according to the current signal or the voltage signal of the thermistor 51.
S602: and the control circuit is connected to the second reference resistor and acquires a second detection value of the ADC circuit.
Step S602 is similar to step 601, and is not described herein again. A second detection value corresponding to the second reference resistance 542 is acquired through step S602.
S603: and judging whether the difference value of the first detection value and the preset detection value is smaller than the difference value of the second detection value and the preset detection value.
And comparing the preset detection value with the first detection value and the second detection value obtained in the step according to a preset rule. It is determined whether the difference between the first detected value and a preset detected value is smaller than the difference between the second detected value and the preset detected value, wherein the preset detected value is set according to the property of the thermistor 51, for example, the preset detected value may be half of the voltage value corresponding to the center point of the thermistor 51 in the linear variation region.
The difference value is an absolute value of a difference between the first detection value or the second detection value and a preset detection value.
Further, the preset detection value can be determined by the following method: when the control circuit 53 is not connected to the first reference resistor 541 or the second reference resistor 542, that is, the thermistor 51 is not connected to the series reference resistor, the ADC circuit 52 outputs a fifth detection value according to the current signal or the voltage signal of the thermistor 51, and sets half of the fifth detection value as the preset detection value. If the control circuit 53 is a single-pole multi-throw switch, the single-pole multi-throw switch is in a floating state.
If the difference between the first detection value and the preset detection value is smaller than the difference between the second detection value and the preset detection value, go to step S604; if the difference between the first detection value and the preset detection value is greater than or equal to the difference between the second detection value and the preset detection value, the process goes to step S605.
The circuit principle of the control circuit 53 connecting the first reference resistor 541 or the second reference resistor 542 according to the comparison result is as follows: the resistance value of the thermistor 51 has a significant nonlinearity with temperature change, and when the voltage value of the thermistor 51 is close to half of the voltage value of the power supply voltage output, the change in the resistance value of the thermistor 51 is closest to a linear change. For example, when the power supply voltage outputs a voltage of 3.6V, the voltage value corresponding to the linear variation region of the thermistor 51 ranges from 1.6V to 2.0V; when the power voltage is 5.0V, the voltage value corresponding to the linear variation region of the thermistor 51 is 1.6V to 2.0V. Therefore, the detection circuit 500 of the present embodiment requires a reference resistor with a similar resistance value to be connected in series with the thermistor 51.
S604: the control circuit is connected with the first reference resistor.
The control circuit 53 is connected to the first reference resistor 541, so that the thermistor 51 is connected in series with the first reference resistor 541.
S605: the control circuit is connected with the second reference resistor.
The control circuit 53 is connected to the second reference resistor 542, so that the thermistor 51 is connected in series with the second reference resistor 542.
By the control method of the present embodiment, a reference resistor satisfying the above conditions is selected to be connected in series with the thermistor 51, so that the thermistor 51 is always in the linear variation region, and the sampling accuracy of the thermistor 51 is improved.
The detection circuit 500 may further include a third reference resistor 543 and a fourth reference resistor 544, wherein the first reference resistor 541, the second reference resistor 542, the third reference resistor 543, and the fourth reference resistor 544 have resistance values with different ranges. For example, the first reference resistor 541 has a resistance value of 10K Ω, the second reference resistor 542 has a resistance value of 100K Ω, the third reference resistor 543 has a resistance value of 1000K Ω, and the fourth reference resistor 544 has a resistance value of 10000K Ω. In other embodiments, the reference resistor with different ranges may have resistors with other resistance values, and will not be described herein.
In the present application, it is also necessary to consider whether the thermistor 51 is in a linear change region after the thermistor 51 is connected in series with a reference resistor having a certain resistance value. To solve the above problem, before step 603 of the above embodiment, the present application further provides another control method based on a temperature and humidity sensor circuit, specifically please refer to fig. 10, where fig. 10 is a schematic flow chart of another embodiment of the temperature and humidity sensor circuit control method of the present application.
As shown in fig. 10, the control method of the present embodiment specifically includes the following steps:
s701: and judging whether the difference value of the first detection value and the preset detection value and the difference value of the second detection value and the preset detection value are both larger than the preset value.
If the difference between the first detection value and the preset detection value is greater than the preset value, it indicates that the thermistor 51 is in a region outside the linear change region when the thermistor 51 is connected in series with the first reference resistor 541; at this time, the sampling accuracy of the thermistor 51 cannot be improved. If both the first detected value and the second detected value satisfy the above condition, it indicates that the sampling accuracy of the thermistor 51 cannot be improved by accessing either the first reference resistor 541 or the second reference resistor 542, and the process proceeds to step S702.
S702: the control circuit is not connected to the first reference resistor or the second reference resistor.
The control circuit 53 is not connected to the first reference resistor 541 or the second reference resistor 542; if the control circuit 53 is a single-pole multi-throw switch, the single-pole multi-throw switch is in a floating state.
To implement the control method of the foregoing embodiment, the present application further provides another temperature and humidity detecting device, and please refer to fig. 11 specifically, where fig. 11 is a schematic structural diagram of another embodiment of the temperature and humidity detecting device of the present application.
As shown in fig. 11, the temperature and humidity detecting apparatus 800 includes a processor 81 and a memory 82; the memory 82 stores therein a computer program, and the processor 81 is configured to execute the computer program to implement the steps of the control method according to the above-described embodiment.
In the aspect of a computer program, if it is sold or used as a stand-alone software product, it may be stored in a computer storage medium, and thus the present application proposes a computer storage medium. Referring to fig. 12, fig. 12 is a schematic structural diagram of an embodiment of a computer storage medium according to the present application, in which a computer program 91 is stored in a computer storage medium 900, and when the computer program 91 is executed by a processor, the control method of the embodiment is implemented.
The computer storage medium 900 may be a medium that can store a computer program, such as a usb disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, or may be a server that stores the computer program, and the server may send the stored computer program to another device for running or may run the stored computer program by itself. The computer storage medium 900 may be a combination of a plurality of entities from a physical point of view, for example, a plurality of servers, a server plus a memory, or a memory plus a removable hard disk.
The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.
Claims (10)
1. The utility model provides a detection circuitry, its characterized in that, detection circuitry is applied to temperature and humidity detection device, detection circuitry includes: the device comprises a thermistor, a control circuit, a first reference resistor and a second reference resistor;
one end of the thermistor is connected with a power supply voltage, and the other end of the thermistor is connected with the control circuit; when the control circuit is in a first state, the input end of the control circuit is connected with the first reference resistor; when the control circuit is in a second state, the input end of the control circuit is connected with the second reference resistor.
2. The detection circuit according to claim 1, further comprising a calculation circuit, wherein an input terminal of the calculation circuit is connected to the thermistor, and is configured to obtain temperature information of an environment according to a resistance value of the thermistor.
3. The detection circuit of claim 2, wherein the computation circuit further comprises an ADC circuit;
when the input end of the control circuit is not connected with the first reference resistor or the second reference resistor, the ADC circuit outputs a first detection signal;
when the input end of the control circuit is connected with the first reference resistor, the ADC circuit outputs a second detection signal;
when the input end of the control circuit is connected with the second reference resistor, the ADC circuit outputs a third detection signal;
the calculation circuit compares the first detection signal, the second detection signal and the third detection signal according to a preset rule and outputs a control signal to a control circuit, so that the control circuit is connected with the first reference resistor or the second reference resistor according to the control signal.
4. The detection circuit of claim 3, further comprising a third reference resistance and a fourth reference resistance;
the resistance value of the first reference resistor is 10K omega, the resistance value of the second reference resistor is 100K omega, the resistance value of the third reference resistor is 1000K omega, and the resistance value of the fourth reference resistor is 10000K omega;
when the control circuit is in a third state, the input end of the control circuit is connected with the third reference resistor; when the control circuit is in a fourth state, the input end of the control circuit is connected with the fourth reference resistor.
5. The detection circuit of claim 4, wherein the control circuit comprises at least a single-pole, four-throw switch having one end connected to the thermistor and the other end connected to the first reference resistor, the second reference resistor, the third reference resistor, or the fourth reference resistor.
6. A temperature and humidity detection device, characterized in that, temperature and humidity detection device includes at least:
a housing comprising at least a first cavity and a second cavity;
the temperature and humidity sensor is arranged in the second cavity and used for collecting temperature and humidity information of the environment where the temperature and humidity detection device is located, and the temperature and humidity sensor is provided with the detection circuit of any one of claims 1-5;
the processor is arranged in the first cavity, is electrically connected with the temperature and humidity sensor, and is used for receiving temperature and humidity information of the temperature and humidity sensor;
a first partition plate is arranged between the first cavity and the second cavity, and a through hole is formed between the second cavity and the outside.
7. The temperature and humidity detection device according to claim 6, wherein the through holes at least comprise a first through hole and a second through hole, and the first through hole and the second through hole are oppositely arranged on two sides of the second cavity;
the temperature and humidity sensor is arranged between the first through hole and the second through hole.
8. The temperature and humidity detecting device according to claim 6, wherein the through holes include a plurality of openings spaced side by side, or the through holes are mesh-shaped through holes or honeycomb-shaped through holes.
9. A temperature and humidity detection system is characterized by at least comprising a temperature and humidity detection device and a fixed shell, wherein the temperature and humidity detection device is the temperature and humidity detection device according to any one of claims 6-8;
the temperature and humidity detection device is also provided with a metal patch, the fixed shell is provided with a metal contact corresponding to the metal patch, and the metal contact is connected with a sensor; the fixed shell is provided with an accommodating space for accommodating the temperature and humidity detection device;
when the temperature and humidity detection device is accommodated in the accommodating space, the metal patch is in contact with the metal contact, so that the temperature and humidity detection device is electrically connected with the sensor.
10. The temperature and humidity detection system according to claim 9, wherein the fixing case includes a front surface and a back surface, at least three ends of the front surface of the fixing case are provided with protrusions for fixing the temperature and humidity detection device; the back of the fixed shell is provided with:
the screw hole is used for matching with a screw to fix the position of the fixed shell;
the fixing structure is arranged in the accommodating groove and used for fixing the position of the fixing shell when the fixing structure is in a first state; when the fixed structure is in the second state, the fixed structure is placed on the fixed shell.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920749275.3U CN210689702U (en) | 2019-05-21 | 2019-05-21 | Detection circuit, temperature and humidity detection device thereof and temperature and humidity detection system |
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| CN201920749275.3U CN210689702U (en) | 2019-05-21 | 2019-05-21 | Detection circuit, temperature and humidity detection device thereof and temperature and humidity detection system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110118579A (en) * | 2019-05-21 | 2019-08-13 | 深圳洲斯移动物联网技术有限公司 | A kind of detection circuit and its temperature-humidity detecting device, temperature/humiditydetection detection system |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110118579A (en) * | 2019-05-21 | 2019-08-13 | 深圳洲斯移动物联网技术有限公司 | A kind of detection circuit and its temperature-humidity detecting device, temperature/humiditydetection detection system |
| CN110118579B (en) * | 2019-05-21 | 2024-10-18 | 深圳洲斯移动物联网技术有限公司 | Detection circuit, temperature and humidity detection device and temperature and humidity detection system thereof |
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