Temperature and humidity detection circuit

Abstract

The utility model discloses a temperature and humidity detection circuit. The temperature and humidity detection circuit comprises an MCU, a power supply circuit, a temperature and humidity acquisition circuit, an external relay group, a display module, a crystal oscillator circuit, a reset circuit and a wireless module. The temperature and humidity acquisition circuit is connected with the MCU through IIC communication to establish temperature and humidity signal transmission; the external relay group is connected with the MCU, and the MCU controls on and off of one or more relays of the external relay group according to the received temperature and humidity signals; the display module is connected with the MCU, and the crystal oscillation circuit is connected with the MCU; according to the temperature and humidity detection circuit, on-off of one or more peripheral electric appliances can be controlled under different temperature and humidity conditions, so that intelligent control of the electric appliances is realized. According to the temperature and humidity detection circuit, manual operation can be omitted, the labor cost is reduced, and the operation efficiency of the whole system circuit is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature and humidity detection, in particular to a temperature and humidity detection circuit. Background Art

[0002] With the rapid development of the Internet of Things, more and more sensors are used. The current temperature and humidity sensors such as GXHT3X and GXHTC3 are becoming more and more common. Therefore, many people have the need to test the sensors to compare their accuracy and quality.

[0003] The circuit accuracy and functions of ordinary thermometers and hygrometers are gradually unable to meet the needs of the market. They can only simply test temperature and humidity, which is difficult to meet the needs of today's people's market. Therefore, multifunctional thermometers and hygrometers are born.

[0004] However, since temperature and humidity chips such as GXHT3X use the IIC protocol for communication, after the detection is completed, it is sent to the main control unit, which prompts the back-end service personnel to turn on the humidifier or heater through an alarm.

[0005] As the market demand for the functions of thermometers and hygrometers becomes stronger and stronger, multifunctional thermometers and hygrometers have been continuously favored by the market instead of ordinary thermometers and hygrometers. Therefore, it is necessary to design a thermometer and hygrometer including temperature and humidity detection and external control functions to solve the above technical problems. Utility Model Content

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the utility model is to provide a temperature and humidity detection circuit. The purpose of designing the temperature and humidity detection circuit is: first, to improve the measurement accuracy, and second, to be able to intelligently open and close the humidifier or heater through signals under different temperature and humidity conditions.

[0007] In order to solve the above technical problems, the utility model is implemented by the following scheme: A temperature and humidity detection circuit of the utility model includes an MCU and a power supply circuit connected to the MCU, and also includes:

[0008] A temperature and humidity acquisition circuit is connected to the MCU via IIC communication to establish temperature and humidity signal transmission;

[0009] An external relay group is connected to the MCU, and the MCU controls one or more relays of the external relay group to turn on and off according to the received temperature and humidity signals;

[0010] A display module is connected to the MCU. The display module has a display control chip and a multi-digit digital tube connected to the display control chip. The display control chip obtains the temperature and humidity data of the MCU and transmits the data to the multi-digit digital tube through multiple pins of the display control chip, so that the multi-digit digital tube displays the temperature and humidity data digitally.

[0011] A crystal oscillator circuit, the crystal oscillator circuit is connected to the MCU;

[0012] A reset circuit connected to a RESET port of the MCU;

[0013] The wireless module is connected to the MCU.

[0014] Furthermore, the MCU used is a single chip microcomputer of the STM32F10 series.

[0015] Furthermore, the temperature and humidity acquisition circuit is connected to a temperature and humidity sensor.

[0016] Furthermore, the external relay group includes a plurality of relays connected in parallel and connected to a neutral line and a live line, and the output circuit of any relay includes a diode, a first transistor and a capacitor, the positive electrode of the diode is connected to the normally closed pin 1 of the output end of the relay, the negative electrode of the diode is connected to the normally closed pin 2 of the output end of the relay and the first voltage, the collector of the first transistor is connected to the positive electrode of the diode, the emitter of the first transistor is grounded, and the capacitor is connected between the base and the emitter of the first transistor;

[0017] The base of each first transistor is connected to the corresponding port of the MCU;

[0018] The emitters of the first triodes are connected to each other.

[0019] Furthermore, the first voltage is a +12V voltage output by the power supply circuit.

[0020] Furthermore, the display module also includes a plurality of optocoupler circuits connected to the display control chip.

[0021] Furthermore, the crystal oscillator circuit includes a capacitor C5 and a capacitor C6, the first end of the capacitor C5 and the first end of the capacitor C6 are interconnected and grounded, the second end of the capacitor C5 and the second end of the capacitor C6 are connected to the crystal oscillator X1, and the two ends of the crystal oscillator X1 are respectively connected to the OSCIN port of the MCU and the OSCOUT port of the MCU.

[0022] Furthermore, the reset circuit includes a resistor R25 and a capacitor C8, a first end of the resistor R25 and the capacitor C8 connected in series is grounded, and a second end of the resistor R25 and the capacitor C8 connected in series is connected to a second voltage.

[0023] Furthermore, the second voltage is a +3.3V voltage output by the power supply circuit.

[0024] Compared with the prior art, the beneficial effects of the utility model are:

[0025] 1. The temperature and humidity detection circuit of the present invention can control the on and off of one or more peripheral electrical appliances under different temperature and humidity conditions to achieve intelligent control of electrical appliances.

[0026] 2. The temperature and humidity detection circuit of the utility model can save manual operation, reduce labor costs, and improve the operating efficiency of the entire system circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a principle block diagram of the temperature and humidity detection circuit of the utility model.

[0028] Figure 2 This is the MCU circuit diagram of the utility model.

[0029] Figure 3 This is the circuit diagram of the external relay group of the utility model.

[0030] Figure 4 This is a circuit diagram of the display module of the utility model.

[0031] Figure 5 The utility model is a group of optocoupler circuit diagrams and a group of digital tube circuit diagrams.

[0032] Figure 6 This is the temperature and humidity detection circuit diagram of the utility model.

[0033] Figure 7 This is the circuit diagram of the clock module of the utility model.

[0034] Figure 8 This is the 485 communication circuit diagram of the utility model.

[0035] Fig. 9 This is the crystal oscillator circuit diagram of the utility model.

[0036] Fig.10 This is the reset circuit diagram of the utility model.

[0037] Fig.11 This is the circuit diagram of the wireless module of the utility model.

[0038] Markings in the attached figure: MCU1, peripheral relay group 2, display module 3, optocoupler circuit 4, temperature and humidity acquisition circuit 5, clock module circuit 6, 485 communication circuit 7, crystal oscillator circuit 8, reset circuit 9, wireless module 10. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model, so that the advantages and features of the utility model can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the protection scope of the utility model. Obviously, the embodiments described in the utility model are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0040] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] Embodiment 1: The specific structure of the utility model is as follows:

[0042] Please refer to the attached Figure 1-10 The utility model is a temperature and humidity detection circuit, comprising an MCU1 and a power supply circuit connected to the MCU1. The MCU1 adopts a single-chip microcomputer of the STM32F10 series, and specifically, the MCU1 adopts a single-chip microcomputer of the STM32F103C8T6 model. The power supply circuit outputs a first voltage of +12V, a second voltage of +3.3V, and a third voltage of +5V. The utility model drives the entire system through a crystal oscillator circuit connected to the MCU1, and a low-cost 4~16MHz crystal oscillator drives peripherals such as CPU and USB. The MCU1 of the utility model is also embedded with an 8MHz RC oscillator that is adjusted before leaving the factory, and the 8MHz RC oscillator can be used as a low-cost main clock source. The MCU1 of the utility model has a built-in power supply monitor, which reduces the requirements for external devices. The MCU1 of the utility model can also provide power-on reset, low voltage detection, and power-off detection functions.

[0043] The circuit of MCU1 is as follows:

[0044] Figure 2 In the embodiment, the 9th pin VDDA of MCU1 is connected to the first end of the capacitor C27 and the first end of the inductor L3, the second end of the capacitor C27 is grounded, and the second end of the inductor L3 is input with a +3.3V voltage.

[0045] A capacitor C18 is connected between the 47th pin VSS_3 of the MCU1 and the 48th pin VDD_3 of the MCU1. The 47th pin VSS_3 of the MCU1 is grounded, and the 48th pin VDD_3 of the MCU1 is connected to a +3.3V voltage.

[0046] A capacitor C24 is connected between the 35th pin VSS_2 of the MCU1 and the 36th pin VDD_2 of the MCU1. The 35th pin VSS_2 of the MCU1 is grounded, and the 36th pin VDD_2 of the MCU1 is connected to a +3.3V voltage.

[0047] A capacitor C39 is connected between the 23rd pin VSS_1 of the MCU1 and the 24th pin VDD_1 of the MCU1. The 23rd pin VSS_1 of the MCU1 is grounded, and the 24th pin VDD_1 of the MCU1 is connected to a +3.3V voltage.

[0048] The BOOT1 port of the MCU1 is connected to a resistor R68, and the other end of the resistor R68 is grounded.

[0049] Embodiment 2:

[0050] The temperature and humidity detection circuit of the present invention further includes a temperature and humidity acquisition circuit 5 , an external relay group 2 , a display module 3 , a crystal oscillator circuit 8 , a reset circuit 9 and a wireless module 10 .

[0051] The temperature and humidity acquisition circuit 5 is connected to the MCU1 through IIC communication to establish temperature and humidity signal transmission, and the temperature and humidity acquisition circuit 5 is connected to a temperature and humidity sensor. Figure 6 As shown, the temperature and humidity acquisition circuit 5 has two interfaces, namely, the sensor socket P1 and the sensor patch P2, and the sensor socket P1 and the sensor patch P2 are connected to the temperature and humidity sensor. The temperature and humidity sensor of the utility model uses the SHT35 thermistor, and the SHT35 thermistor collects temperature and humidity. The SHT35 thermistor can accurately collect data. The MCU1 obtains the temperature and humidity signal collected by the SHT35 thermistor through the IIC communication protocol. The MCU1 processes the data and generates a digital signal to send to the display module 3, and the display module 3 displays the corresponding digital temperature and digital humidity.

[0052] The sensor socket P1 has four pins. Pin 2 of the sensor socket P1 is connected to resistor R27, and pin 3 of the sensor socket P1 is connected to resistor R26. Pin 1 of the sensor socket P1 is connected to +5V voltage and capacitor C40. The other end of capacitor C40 is grounded and connected to pin 4 of the sensor socket P1. The other ends of resistors R26 and R27 are connected to each other and connected to pin 1 of the sensor socket P1. Resistors R26 and R27 are both 10K in size, and capacitor C40 uses a 104 capacitor. Pin 4 of the sensor socket P1 is connected to the SENSOR_SCL port of MCU1, and pin 3 of the sensor socket P1 is connected to the SENSOR_SDA port of MCU1.

[0053] The sensor patch P2 has four pins, and the four pins of the sensor patch P2 are connected one-to-one with the four pins of the sensor socket P1.

[0054] like Figure 3 As shown, Figure 3 The circuit diagram of the external relay group of the utility model is shown in FIG. The external relay group 2 is connected to the MCU1, and the MCU1 controls one or more relays of the external relay group 2 to turn on and off according to the received temperature and humidity signals. Figure 3 Four groups of relays are provided, and the four groups of relays are all connected to output circuits. The input ends of the four groups of relays connected in parallel are connected to the neutral line and the live line. The output circuit of any relay includes a diode, a transistor and a capacitor, the positive electrode of the diode is connected to the normally closed pin 1 of the output end of the relay, the negative electrode of the diode is connected to the normally closed pin 2 of the output end of the relay and the first voltage, the collector of the first transistor is connected to the positive electrode of the diode, the emitter of the first transistor is grounded, and the capacitor is connected between the base and the emitter of the first transistor;

[0055] The base of each first transistor is connected to the corresponding port of MCU1;

[0056] The emitters of the first triodes are connected to each other.

[0057] In the above peripheral relay group circuit, MCU1 will use the currently collected temperature and humidity to determine whether the collected temperature and humidity have reached the preset warning value and alarm value. When the collected temperature and humidity do not reach the warning value and alarm value, the relay will not work. When the collected temperature and humidity reach the warning value or alarm value, MCU1 will give a corresponding signal to control the corresponding relay to power on. After the relay is powered on, the heater or humidifier will work to make the ambient temperature and humidity reach the target value preset by MCU1.

[0058] The utility model external relay group circuit obtains the signal of MCU1 through the pin of the transistor, and the relay is operated through the characteristics of the transistor. When the switch is turned on, the corresponding external interface will receive the user-defined signal. The user can connect the corresponding device according to this signal. For example, if the temperature is too high and reaches the alarm upper limit, the corresponding relay connected to the humidifier is turned on. Then the externally connected humidifier starts working after obtaining the signal. If the normal temperature range is reached, the relay is turned off. This greatly saves manpower.

[0059] Embodiment 3:

[0060] The display module 3 is connected to the MCU1, and has a display control chip and a multi-digit digital tube connected to the display control chip. The display control chip obtains the temperature and humidity data of the MCU1, and transmits it to the multi-digit digital tube through multiple pins of the display control chip, so that the multi-digit digital tube displays the temperature and humidity data digitally. The display module 3 also includes multiple optocoupler circuits 4 connected to the display control chip.

[0061] like Figure 4-5 As shown, Figure 4 This is the circuit diagram of the display module of the utility model. Figure 5 The display control chip of the utility model adopts the TM1640 chip. Figure 4 The chip IC1 in the circuit has its 7-pin DIN connected to the TM1640 DIN port of MCU1, and its 8-pin SCLK connected to the TM1640 SCLK port of MCU1.

[0062] The 6-pin VSS of the chip IC1 is grounded, and the 7-pin DIN is respectively connected to the first end of the resistor R18 and the first end of the capacitor C4. The 8-pin SCLK of the chip IC1 is respectively connected to the first end of the resistor R17 and the first end of the capacitor C3. The second end of the resistor R18 and the second end of the resistor R17 are mutually connected and connected to the +5V voltage. The second end of the capacitor C3 and the second end of the capacitor C4 are mutually connected and grounded. The capacitors C1 and C2 are also connected in parallel between the second end of the resistor R17 and the second end of the capacitor C3.

[0063] The optical coupler circuit 4 of the utility model is provided with 8 groups. Taking one group of optical coupler circuits 4 as an example for explanation, the optical coupler circuit 4 includes an optical coupler U11, a resistor R43, a resistor R44, a resistor R46, a resistor R45 and a transistor Q11. The positive electrode of the light-emitting end of the optical coupler U11 is connected to the SEG G port of the chip IC1, the negative electrode of the light-emitting end of the optical coupler U11 is connected to the resistor R43, and the other end of the resistor R43 is grounded. The collector of the light-receiving end of the optical coupler U11 is connected to the resistor R44, and the other end of the resistor R44 is connected to the +12V voltage. The emitter of the light-receiving end of the optical coupler U11 is respectively connected to one end of the resistor R46 and the base of the transistor Q11, the other end of the resistor R46 is grounded, the collector of the transistor Q11 is connected to one end of the resistor R45, the other end of the resistor R45 is connected to the +12V voltage, and the emitter of the transistor Q11 is connected to the corresponding LED indicator circuit.

[0064] The display module of the utility model can perform multi-digit digital tube display control, and its chip IC1 obtains the data transmission of MCU1 from DIN and SCLK. In the chip IC1, SEG1 to SEG8 are the display pins of the digital tube. The corresponding digital display will be performed according to the temperature and humidity data transmitted by the chip IC1. For example, if the third digital tube needs to be lit, GR3 will become a high level, and the rest will be a low level.

[0065] Embodiment 4:

[0066] The crystal oscillator circuit 8 of the utility model is connected to the MCU1; the crystal oscillator circuit 8 includes a capacitor C5 and a capacitor C6, the first end of the capacitor C5 and the first end of the capacitor C6 are interconnected and grounded, the second end of the capacitor C5 and the second end of the capacitor C6 are connected to the crystal oscillator X1, and the two ends of the crystal oscillator X1 are respectively connected to the OSCIN port of the MCU1 and the OSCOUT port of the MCU1.

[0067] The reset circuit 9 is connected to the RESET port of the MCU1, and the reset circuit 9 controls the reset of the entire circuit system through the MCU1. The reset circuit 9 includes a resistor R25 and a capacitor C8, wherein the first end of the resistor R25 and the capacitor C8 connected in series is grounded, and the second end of the resistor R25 and the capacitor C8 connected in series is connected to a second voltage.

[0068] The wireless module 10 is connected to the MCU1. The wireless module 10 uses a DRF 1609H chip U2. The TX pin 5 of the chip U2 is connected to a resistor R23. The TX pin 6 of the chip U2 is connected to a resistor R12. The other end of the resistor R23 is connected to the USART1 TX port of the MCU1. The other end of the resistor R12 is connected to the USART1 RX port of the MCU1. The two LED pins of the chip U2 are connected one-to-one with LED light-emitting diodes.

[0069] Embodiment 5:

[0070] Figure 7 The clock module circuit 6 of the present utility model adopts the chip U7 of DS1302 model.

[0071] Figure 8 This is the 485 communication circuit diagram of the utility model. The 485 communication circuit 7 of the utility model adopts the chip U20 of the MAX485ESA model.

[0072] The temperature and humidity detection circuit of the utility model is also provided with a key circuit, a storage module circuit, an alarm circuit, a buzzer circuit and a burning circuit connected to the MCU1. Among them, the key circuit includes a setting key circuit and a wireless module key circuit.

[0073] In summary, the temperature and humidity detection circuit of the utility model can control the on and off of one or more peripheral electrical appliances under different temperature and humidity conditions to realize intelligent control of electrical appliances. The temperature and humidity detection circuit of the utility model can save manual operation, reduce labor costs, and improve the operating efficiency of the entire system circuit.

[0074] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A temperature and humidity detection circuit, comprising an MCU (1) and a power supply circuit connected to the MCU (1), characterized in that: Also includes: A temperature and humidity acquisition circuit (5) is connected to the MCU (1) via IIC communication to establish temperature and humidity signal transmission; An external relay group (2) is connected to the MCU (1), and the MCU (1) controls one or more relays of the external relay group (2) to turn on or off according to the received temperature and humidity signals; A display module (3) is connected to the MCU (1), the display module (3) comprising a display control chip and a multi-digit digital tube connected to the display control chip, the display control chip acquiring temperature and humidity data from the MCU (1) and transmitting the data to the multi-digit digital tube via a plurality of pins of the display control chip, so that the multi-digit digital tube displays the temperature and humidity data in digital form; A crystal oscillator circuit (8), the crystal oscillator circuit (8) being connected to the MCU (1); A reset circuit (9) connected to a RESET port of the MCU (1); A wireless module (10) connected to the MCU (1); The external relay group (2) comprises a plurality of relays connected in parallel and connected to a neutral line and a live line, the output end circuit of any relay comprises a first diode, a first transistor and a capacitor, the positive electrode of the diode is connected to the normally closed pin 1 of the output end of the relay, the negative electrode of the diode is connected to the normally closed pin 2 of the output end of the relay and a first voltage, the collector of the first transistor is connected to the positive electrode of the diode, the emitter of the first transistor is grounded, and the capacitor is connected between the base and the emitter of the first transistor; The base of each first transistor is connected to a corresponding port of the MCU (1); The emitters of the first triodes are connected to each other.

2. The temperature and humidity detection circuit according to claim 1, characterized in that: The MCU (1) is a single-chip microcomputer of the STM32F10 series.

3. The temperature and humidity detection circuit according to claim 2, characterized in that: The temperature and humidity acquisition circuit (5) is connected to a temperature and humidity sensor.

4. The temperature and humidity detection circuit according to claim 2, characterized in that: The first voltage is a +12V voltage output by the power supply circuit.

5. The temperature and humidity detection circuit according to claim 2, characterized in that: The display module (3) also includes a plurality of optical coupling circuits (4) connected to the display control chip.

6. The temperature and humidity detection circuit according to claim 2, characterized in that: The crystal oscillator circuit (8) comprises a capacitor C5 and a capacitor C6, wherein the first end of the capacitor C5 and the first end of the capacitor C6 are connected to each other and to ground, the second end of the capacitor C5 and the second end of the capacitor C6 are connected to a crystal oscillator X1, and the two ends of the crystal oscillator X1 are respectively connected to an OSCIN port of the MCU (1) and an OSCOUT port of the MCU (1).

7. The temperature and humidity detection circuit according to claim 2, characterized in that: The reset circuit (9) comprises a resistor R25 and a capacitor C8, wherein a first end of the resistor R25 and the capacitor C8 connected in series is grounded, and a second end of the resistor R25 and the capacitor C8 connected in series is connected to a second voltage.

8. The temperature and humidity detection circuit according to claim 7, characterized in that: The second voltage is a +3.3V voltage output by the power supply circuit.

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