CN111724580A

CN111724580A - Ultralow-power-consumption soil temperature and humidity acquisition equipment and method based on LoRa scattering communication

Info

Publication number: CN111724580A
Application number: CN202010696156.3A
Authority: CN
Inventors: 徐浪; 蔡红涛; 谢桂辉; 胡轶斯
Original assignee: Zhongshan Zhilian Future Technology Co ltd
Current assignee: Zhongshan Zhilian Future Technology Co ltd
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2020-09-29

Abstract

The invention provides ultralow-power-consumption soil temperature and humidity acquisition equipment and method based on LoRa scattering communication, wherein the equipment comprises a shell, a control circuit, a temperature sensing probe, a humidity sensor, an antenna and a button cell; the control circuit comprises a microcontroller connected with the temperature and humidity sensing circuit and used for completing temperature and humidity sensing data collection, processing and digital modulation; the radio frequency circuit is connected with a radio frequency circuit used for finishing wireless data receiving and sending, and comprises a radio frequency switch and an impedance matching network; and a wake-up receiver connected between the impedance matching network and the microcontroller for receiving and transmitting a wake-up instruction to the microcontroller. The method is that the lower end of the shell is inserted into the soil; after initialization, the wake-up receiver is started to monitor wake-up instructions, and after wake-up instructions sent by the upper computer are received, the temperature sensing probe and the humidity sensor are started to acquire temperature and humidity sensing data, and the temperature and humidity sensing data are modulated and then output to the radio frequency circuit to be sent to the upper computer.

Description

Ultralow-power-consumption soil temperature and humidity acquisition equipment and method based on LoRa scattering communication

Technical Field

The invention relates to ultralow-power-consumption soil temperature and humidity acquisition equipment and method based on LoRa scattering communication.

Background

The power supply in the current agricultural thing networking soil humiture collection scheme mostly adopts the mode of "solar charging panel + battery", and battery voltage 12V needs power supply conversion to supply power for the system, and the finished product communication equipment that communication module adopted mainly has Zigbee, NB-IOT, loRa etc. at present, and the antenna is inhaled to the external magnetism of adoption, and equipment uses the sensor interface, can the multiple different sensor of adaptation, mainly has soil temperature and humidity sensor. The problems existing in the prior art are as follows: 1) in order to ensure the service life of the equipment, a large-capacity storage battery and a high-power solar panel are used, and the storage battery and the solar panel are equipment occupying relatively large space, so that the appearance design of the product is relatively large; 2) the high-capacity storage battery and the high-power solar panel occupy large space, are expensive in price and save finished communication equipment purchased in a development period, so that the cost is high; 3) the prior art uses a sensor interface, which enhances the performance of adapting the device to various sensors, but leads to the need for separate installation of the device and the product, complicated installation, and possibly even professional installation.

Disclosure of Invention

In order to solve the problems of large volume, high cost and the like in the prior art, the invention provides ultralow-power-consumption soil temperature and humidity acquisition equipment and method based on LoRa scattering communication, and the equipment and method have the following specific technical contents:

the invention relates to ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication, which comprises a shell and a control circuit, wherein the lower end of the shell is provided with a temperature sensing probe and a humidity sensor, the upper end of the shell is provided with an antenna, and the control circuit and a button battery are arranged in the middle of the shell; the control circuit comprises a microcontroller which is connected with the temperature sensing probe and the humidity sensor and is used for completing data collection, processing and digital modulation; the radio frequency circuit is connected between the microcontroller and the antenna and used for completing wireless data receiving and sending, and the radio frequency circuit comprises a radio frequency switch and an impedance matching network; and a wake-up receiver connected between the impedance matching network and the microcontroller for receiving and transmitting a wake-up instruction to the microcontroller.

In one or more embodiments of the present invention, the housing is in a pen shape or a bamboo stick shape, and the temperature sensing probe, the humidity sensor, the control circuit, and the antenna are sequentially disposed from bottom to top.

In one or more embodiments of the present invention, the antenna is a retractable antenna.

In one or more embodiments of the present invention, the microcontroller is a low power consumption single chip microcomputer.

In one or more embodiments of the present invention, the wake-up receiver includes an LNA amplifier, an envelope detection and amplification module, a baseband amplification module, and a comparator, which are connected in sequence, where one input end of the comparator is directly connected to an output end of the baseband amplification module, and the other input end of the comparator is connected to an output end of the baseband amplification module through an LPF filter.

In one or more embodiments of the present invention, the microcontroller has a low power consumption timer, and the low power consumption timer is used for connecting and controlling the wake-up receiver.

The ultralow-power-consumption soil temperature and humidity acquisition method based on LoRa scattering communication adopts the ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication to insert the lower end of a shell containing a temperature sensing probe and a humidity sensor into soil; the method comprises the following operation steps:

step S1, after the equipment is initialized, the awakening receiver is started to carry out awakening instruction monitoring, and the microcontroller, the temperature sensing probe and the humidity sensor enter a sleep state; after receiving a wake-up instruction sent by the upper computer, the step proceeds to step S2;

step S2, the microcontroller is awakened and judges whether the sun-calling instruction is matched; if the temperature and the humidity are matched, starting the temperature sensing probe and the humidity sensor to acquire temperature and humidity sensing data, and turning to the step S3; otherwise, the microcontroller enters a sleep state;

step S3, the microcontroller packages the collected temperature and humidity sensing data into a Lora frame format and carries out DDS digital modulation, and then outputs the data to the radio frequency circuit to be sent to the upper computer;

and then, the microcontroller, the temperature sensing probe and the humidity sensor enter a sleep state, and the receiver is awakened to continue to monitor the awakening instruction.

In one or more embodiments of the present invention, the microcontroller employs a DCW-MAC protocol, which starts the wake-up receiver to listen at a preset time duty cycle.

In one or more embodiments of the present invention, in step S1, after receiving the wake-up command, the wake-up command is sequentially amplified by low noise, envelope detection, and baseband amplification, and then divided into two paths of signals, where one path of signal is directly input to the positive terminal of the comparator, the other path of signal is subjected to low pass filtering to obtain a dc component thereof, and then the dc component is input to the negative terminal of the comparator as a comparison voltage, and finally a baseband square wave is obtained and output to the microcontroller.

In one or more embodiments of the present invention, when the rf switch is turned on, the antenna is connected to the impedance matching network, and the antenna is in a signal receiving state; when the radio frequency switch is turned off, the antenna is in a scattering state.

The invention has the beneficial effects that: 1) the circuit of the equipment is simple, and the equipment can be realized by only needing a few basic electronic components, so the equipment has small volume and low cost. 2) The power consumption of the scattering communication is ultra-low, so that a product can use a battery with smaller volume, lower capacity and lower cost, and a button battery can replace a solar panel and a storage battery in the traditional scheme, thereby greatly reducing the cost and the volume. 3) And a power conversion module is not needed, because most of the MCUs can work under the voltage of 1.8-3.6V, and the maximum voltage of the 3V button battery is about 3.2V, the power conversion module is omitted in the system. 4) Directly integrate temperature and humidity sensor in the product, the installation is very simple, in direct insertion soil can.

Drawings

FIG. 1 is a schematic diagram of the apparatus of the present invention.

Fig. 2 is a schematic block diagram of the apparatus of the present invention.

Fig. 3 is a schematic view of the installation layout of the apparatus of the present invention.

FIG. 4 is a flow chart of the method of the present invention.

Fig. 5 is a schematic diagram of a wake-up receiver of the present invention.

Fig. 6 is a scattering diagram of the present invention.

Fig. 7 is a diagram illustrating DDS data modulation of the present invention.

Fig. 8 shows the LoRa scattering modulation spectrum according to the present invention.

FIG. 9 is a schematic diagram of the DCW-MAC of the present invention.

Detailed Description

The scheme of the application is further described as follows:

referring to the attached drawings 1 and 2, the ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication comprises a shell 1 and a control circuit 2, wherein the shell is a waterproof and dustproof shell in a bamboo stick shape, and is sequentially provided with a temperature sensing probe 3, a humidity sensor 4, a post-button battery 5, the control circuit 2 and an antenna 6 from bottom to top; the control circuit 2 comprises a microcontroller 21 which is connected with the temperature sensing probe 3 and the humidity sensor 4 and is used for completing temperature and humidity sensing data collection, processing and digital modulation; the radio frequency circuit 22 is connected between the microcontroller 21 and the antenna 6 and used for completing wireless data transceiving, and the radio frequency circuit 22 comprises a radio frequency switch 221 and an impedance matching network 222; and a wake-up receiver 23 connected between the impedance matching network 222 and the microcontroller 21 for receiving and transmitting a wake-up command to the microcontroller 21, wherein the antenna 6 is a telescopic antenna.

Preferably, the microcontroller 21 is a low-power consumption single chip microcomputer of a model such as MSP430, STM8L, and has a low-power consumption timer 211, and the low-power consumption timer 211 is used for connecting and controlling the wake-up receiver 23. The microcontroller 21 employs three major parts, namely, a LoRa protocol, a DDS (Direct Digital Synthesis, Direct Digital frequency Synthesis) algorithm, and a DCW-MAC (Duty Cycle Wake-up-Media Access Control).

The LoRa protocol realizes Hamming coding, scrambling, interleaving, Gray coding, CRC check and other coding of LoRa and encapsulation of frame head and frame tail addition into a LoRa frame format.

Referring to fig. 7, the DDS algorithm is used to implement digital modulation of LoRa. The original baseband signal of LoRa is a Chirp signal with linearly increasing frequency, which is simplified to a waveform as shown in fig. 7 for analysis convenience, and the LoRa analog modulation is to perform cyclic phase shift on the signal. The DDS algorithm maps the part of the signal greater than 0 to 1, and the part less than 0 to 0, and creates a ROM table, as shown in the b waveform of fig. 7, and the digital modulation of LoRa is output after cyclic shift of the ROM table, the square wave acts on the rf switch, and the frequency spectrum of the generated output signal is as shown in fig. 8, where the frequency spectrum at the center frequency of 433M is the LoRa signal, and the others are higher harmonics.

Referring to fig. 9, the DCW-MAC is a low power consumption MAC protocol, which is generally used in conjunction with WuRx hardware, and starts WuRx listening at a certain time duty cycle, as shown in the figure, W represents a wake-up signal, a represents a wait reply signal, and DATA represents DATA exchange; the duty ratio is set by setting timer parameters through MCU software, and a sending end can continuously send a wake-up signal before communication until receiving a response signal and then start data exchange.

Referring to fig. 5, the wake-up receiver 23 may be an improvement over existing scatter communication techniques. The prior scattering communication technology does not solve media access conflict, and only one-to-one is used in practice, the invention introduces the wake-up receiver 23, so that the wake-up receiver can receive wake-up instructions, the wake-up receiver comprises an LNA (low-noise amplifier) 231, an envelope detection and amplification module 232, a baseband amplification module 233 and a comparator 234 which are connected in sequence, one input end of the comparator 234 is directly connected with the output end of the baseband amplification module 233, and the other input end of the comparator is connected with the output end of the baseband amplification module 233 through an LPF (low-pass filter) 235.

Referring to fig. 3 and 4, an ultralow power consumption soil temperature and humidity acquisition method based on LoRa scattering communication is characterized in that the ultralow power consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication is adopted, and the lower end of a shell 1 containing a temperature sensing probe 3 and a humidity sensor 4 is inserted into soil; the method comprises the following operation steps:

step S1, after the equipment is initialized, the awakening receiver 23 is started to carry out awakening instruction monitoring, and the microcontroller 21, the temperature sensing probe 3 and the humidity sensor 4 enter a sleep state; the microcontroller 21 adopts a DCW-MAC protocol, starts the wake-up receiver 23 to monitor at a preset time duty ratio, and after receiving a wake-up command sent by an upper computer, the wake-up command is divided into two paths of signals after sequentially passing through low-noise amplification, envelope detection and baseband amplification, wherein one path of signals is directly input to the positive end of the comparator, the other path of signals obtains direct current components thereof through low-pass filtering and then is input to the negative end of the comparator as comparison voltage, finally baseband square waves are obtained and output to the microcontroller 21, and the process is switched to step S2;

step S2, the microcontroller 21 is awakened and determines whether the insolation command matches; if the temperature and humidity sensing data are matched with the temperature and humidity sensing data, starting the temperature sensing probe 3 and the humidity sensor 4 to acquire temperature and humidity sensing data, and turning to the step S3; otherwise, the micro controller 21 enters a sleep state;

step S3, the microcontroller 21 packages the collected temperature and humidity sensing data into a Lora frame format and carries out DDS digital modulation, and then outputs the data to the radio frequency circuit 22 to be sent to an upper computer;

subsequently, the microcontroller 21, the temperature sensing probe 3 and the humidity sensor 4 enter a sleep state, and the wake-up receiver 23 continues to perform wake-up instruction monitoring.

Referring to fig. 6, when the rf switch 221 is turned on, the antenna 6 is connected to the impedance matching network 222, and the antenna 6 is in a signal receiving state; when the radio frequency switch 221 is open, the antenna 6 is in a scattering state.

The above preferred embodiments should be considered as examples of the embodiments of the present application, and technical deductions, substitutions, improvements and the like similar to, similar to or based on the embodiments of the present application should be considered as the protection scope of the present patent.

Claims

1. The utility model provides an ultra-low power consumption soil humiture collection equipment based on loRa scattering communication, includes shell and control circuit, its characterized in that: the lower end of the shell is provided with a temperature sensing probe and a humidity sensor, the upper end of the shell is provided with an antenna, and the middle part of the shell is internally provided with the control circuit and the button cell; the control circuit comprises a microcontroller which is connected with the temperature sensing probe and the humidity sensor and is used for completing data collection, processing and digital modulation; the radio frequency circuit is connected between the microcontroller and the antenna and used for completing wireless data receiving and sending, and the radio frequency circuit comprises a radio frequency switch and an impedance matching network; and a wake-up receiver connected between the impedance matching network and the microcontroller for receiving and transmitting a wake-up instruction to the microcontroller.

2. The ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication according to claim 1, characterized in that: the shell is in a pen shape or a bamboo stick shape, and the temperature sensing probe, the humidity sensor, the control circuit and the antenna are sequentially distributed from bottom to top.

3. The ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication according to claim 1, characterized in that: the antenna is a telescopic antenna.

4. The ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication according to claim 1, characterized in that: the micro controller is a low-power consumption singlechip.

5. The ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication according to claim 1, characterized in that: the awakening receiver comprises an LNA (low-noise amplifier), an envelope detection amplification module, a baseband amplification module and a comparator which are sequentially connected, wherein one input end of the comparator is directly connected with the output end of the baseband amplification module, and the other input end of the comparator is connected with the output end of the baseband amplification module through an LPF (low-pass filter).

6. The ultralow-power-consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication according to claim 1, characterized in that: the microcontroller is provided with a low-power consumption timer which is used for connecting and controlling the awakening receiver.

7. An ultralow-power-consumption soil temperature and humidity acquisition method based on LoRa scattering communication is characterized by comprising the following steps: the ultra-low power consumption soil temperature and humidity acquisition equipment based on LoRa scattering communication as claimed in claim 1 is adopted, the lower end of a shell containing a temperature sensing probe and a humidity sensor is inserted into soil; the method comprises the following operation steps:

8. The ultralow-power-consumption soil temperature and humidity acquisition method based on LoRa scattering communication according to claim 7, characterized in that: the microcontroller employs the DCW-MAC protocol which starts the wake-up receiver at a preset time duty cycle for listening.

9. The ultralow-power-consumption soil temperature and humidity acquisition method based on LoRa scattering communication according to claim 7, characterized in that: in step S1, after receiving the wake-up command, the baseband amplifier, the low noise amplifier, the envelope detection, and the low noise amplifier are sequentially performed to divide the wake-up command into two signals, wherein one signal is directly input to the positive terminal of the comparator, the other signal is subjected to low pass filtering to obtain a dc component thereof, and then the dc component is input to the negative terminal of the comparator as a comparison voltage, and finally a baseband square wave is obtained and output to the microcontroller.

10. The ultralow-power-consumption soil temperature and humidity acquisition method based on LoRa scattering communication according to claim 7, characterized in that: when the radio frequency switch is conducted, the antenna is connected with the impedance matching network, and the antenna is in a signal receiving state at the moment; when the radio frequency switch is turned off, the antenna is in a scattering state.