Design of Intelligent Farmland Environment Monitoring System Based on Wireless Sensor Network - IOPscience
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Journal of Physics: Conference Series
PAPER • OPEN ACCESS
Design of Intelligent Farmland Environment Monitoring System Based on
Wireless Sensor Network
To cite this article: Xiaokang Lou et al 2020 J. Phys.: Conf. Ser. 1635 012031
View the article online for updates and enhancements.
This content was downloaded from IP address 46.4.80.155 on 22/12/2020 at 00:30
IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
Design of Intelligent Farmland Environment Monitoring
System Based on Wireless Sensor Network
Lou Xiaokang1,a, Zhang Lixin1,b,*, Zhang Xueyuan1, Fan Jinjie1, Hu xue1, Li
Chunzhi1
1
College of Mechanical and Electrical Engineering, Shihezi University, Shihezi,
Xinjiang, China
a
louxiaokang@stu.shzu.edu.cn
a
18642861317@163.com
b,*
Zhlx2001730@126.com
Abstract—In view of the problems of waste of water resources, high labor intensity and
unscientific irrigation during farmland irrigation, and the shortcomings of ZigBee technology
in the water-saving irrigation system network, such as short transmission distance, complicated
network structure, and signals that are easily interfered during transmission. This paper designs
a farmland environment information collection and monitoring system based on NB-IoT. The
system consists of a terminal collection node, a wireless communication module and a host
computer. Farmland environment monitoring system based on wireless sensor network
includes wireless temperature and humidity sensor, wireless nitrogen, phosphorus and
potassium sensor, Arduino MEGA development board NB-IoT communication module,
gateway and Wasp mobile network, real-time collection, processing and wireless of farmland
moisture data Transmission function, using NI LabVIEW software to compile the monitoring
interface, real-time display of soil moisture in the form of waveform graph, and automatically
control the opening and closing of the valve according to the soil moisture information. The
system has flexible layout, long transmission distance, simple structure and integrated modules.
It can achieve the purpose of precise irrigation and water saving, and is suitable for field
planting, which has certain promotion significance.
1. INTRODUCTION
In the field of modern agriculture, "smart agriculture" can be realized by applying the Internet of Things
to agricultural precision irrigation. With the development of Internet of Things technology, the
agricultural Internet of Things will become an inevitable trend. It can monitor the soil temperature and
humidity information, soil nitrogen, phosphorus, potassium content, air temperature and humidity and
other environmental parameters in real time according to the user's requirements, and use wireless
transmission module to transmit data, switch or adjust the specified equipment. Agricultural Internet of
things provides scientific basis for realizing intelligent management of water-saving irrigation in
farmland. At present, the main irrigation method for farmland is drip irrigation. By manually
controlling the drip irrigation time and amount, it is not only time-consuming and laborious, but also
cannot reach the precision planting, which affects the crop yield. Therefore, it is very necessary to
monitor the soil moisture information in real time and maintain the moisture content in the field by
controlling the intelligent water valve.
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Published under licence by IOP Publishing Ltd 1IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
Wireless Sensor Network technology in the application of intelligent irrigation is the smart Sensor
according to the layout of the installation must be irrigated farmland, and then through the wireless
communication for real-time monitoring, environmental awareness and gathering Network coverage
area and monitoring object information, and then sent to the information collection station or irrigation
system set control center, to avoid the irrigation field wiring of all sorts of problems[1]. The farmland
environment monitoring system based on wireless sensor network includes real-time monitoring of soil
moisture information by terminal sensing node, wireless transmission of data information by NB-IOT
module and nest bee mobile network. The upper computer interface visually displays the soil
information, and the data information is stored in the SQL database in the form of data table. The
Arduino MEGA microcontroller controls the intelligent water valve by driving circuit to ensure the
moisture content of farmland soil. The system has the characteristics of long wireless transmission
distance, low cost, simple arrangement and fast response time. The system can be used to monitor soil
temperature and humidity information, nitrogen, phosphorus and potassium content information,
control valves and data management. Standardized and standardized irrigation can reduce the waste of
water resources, improve crop yield and promote the goal of increasing farmers' income. [2].
2. SYSTEM DESIGN
2.1 The overall structural design of the system
The farmland environment monitoring system based on wireless sensor network includes hardware
system and software system. Hardware system consists of wireless temperature and humidity sensor,
NPK sensor, the Arduino MEGA development board, wireless electric valve, NB - IoT module, power
module, gateway and upper unit, it is mainly used for farmland water environment monitoring, data
processing and intelligent valve control switch, and the collected data through the NB - IoT wireless
communication module is sent to PC; Software system is mainly used for farmland environmental data
real-time monitoring and intelligent water valve switch control and the use of the Internet of things
platform, using LabVIEW based display in the form of oscillogram intuitive show soil NPK ratio,
moisture content and temperature, and the collected data and irrigation records in the SQL database,
data query and traceability. Basic functions of the system: real-time monitoring and display of n, P, K
ratio, moisture content and temperature, opening and closing of intelligent water valve, temperature and
humidity data and irrigation statistics [3]. The overall structure of farmland environment monitoring
system based on wireless sensor network is shown in Figure 1.
Figure 1. Overall system structure
2IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
It mainly includes three parts: terminal sensor node, NB-IoT gateway and host computer application.
The wireless terminal sensor node and NB-IoT gateway based on NB-IoT module realize data
transmission and communication. The sensor node and the NB-IoT gateway perform long-distance
wireless communication through the NB-IoT module, and the NB-IoT gateway and the host computer
perform long-distance data transmission through the China Mobile Internet of Things card built into the
gateway [4]. Wireless temperature and humidity sensors, nitrogen, phosphorus and potassium sensors
collect real-time temperature information of farmland soil moisture content and soil nitrogen,
phosphorus and potassium content, and Arduino MEGA single-chip microcomputer performs data
processing and control of intelligent water valve switches, and transmits information to the gateway
through the NB-IoT module. The terminal sensor node is powered by a solar cell module, and the
lithium battery stores electrical energy to complete the temperature information of farmland soil
moisture content and soil nitrogen, phosphorus, and potassium content monitoring. In order to make full
use of water resources and reduce resource waste, the lower limit of soil water content is set at 40%, the
upper limit is 75%, the lower limit of nitrogen content is 150mg/kg, the upper limit is 200 mg/kg, the
lower limit of phosphorus content is 60 mg/kg, and the upper limit is 100 mg/kg, the lower limit of
potassium content is 100 mg/kg, and the upper limit is 150 mg/kg. When the soil water content and
nitrogen, phosphorus, and potassium content are lower than the set lower limit, the single chip
computer controls the intelligent water valve to open through the drive circuit, when the water content
is high When the upper limit is set, the single-chip microcomputer controls the intelligent water valve to
close through the driving circuit, so as to realize the accurate control of the soil moisture content of the
cotton field[5].
3. DESIGN OF SENSOR NODES
3.1 Hardware selection
The main hardware of farmland environment monitoring system based on wireless sensor network
includes temperature and humidity sensor, nitrogen, phosphorus and potassium sensor, Arduino MEGA
single chip microcomputer, intelligent water valve, NB-IoT module, power module, NB-IoT gateway
and host computer. The information collected by the terminal node is very important for the monitoring
system of soil moisture in cotton fields. The temperature and humidity wireless sensor are selected in
this paper. This sensor has stable performance and high sensitivity. It is an important tool for observing
and studying the occurrence, evolution, improvement and water-salt dynamics of saline soil. By
measuring the dielectric constant of the soil, it can directly and stably reflect the true moisture content
of various soils. The volume percentage of soil moisture that can be measured is a method of measuring
soil moisture that complies with current international standards. The conductivity measurement
accuracy reaches ±3% within the range of 0-10000us/cm; the range is 0-20000us/cm, the temperature
measurement accuracy reaches ± 0.5 ℃ , the range is -40~80 ℃ ; the soil moisture parameter
measurement accuracy is 0-50 2% within %, 3% within 50-100%, and the range is 0-100%. It meets the
system acquisition requirements, and the module is based on digital sensing technology, which has the
advantages of low energy consumption, strong anti-interference ability and high stability. The selected
soil nitrogen, phosphorus, and potassium sensor is suitable for detecting the content of nitrogen,
phosphorus, and potassium in the soil. By detecting the content of nitrogen, phosphorus, and potassium
in the soil to determine the fertility of the soil, it is convenient for the customer to systematically assess
the soil condition. Its measuring range is 0-1999mg/kg, and its measuring accuracy is ±2%F.s. Some
hardware objects are shown in Figure 2 and Figure 3.
3IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
Figure 2. Temperature and humidity sensor
Figure 3. Soil NPK sensor
The NB-IoT module uses the NB-IoT BC26 module of Telecommunications. It is a high-
performance, low-power NB-IoT module that supports multi-band communication. Through the NB-
IoT radio communication protocol (3GPP Rel. 14). The BC26 module can establish communication
with the basic equipment of the network operator. The power supply design of the module is critical to
its performance. The BC26 can use an LDO with low quiescent current and output current capability of
0.8A as a power supply. It also supports lithium battery power supply; The power input voltage range
should be 3.1V~4.2V. When the module is in data transmission, it must ensure that the power supply
voltage drop is not lower than the module's minimum operating voltage of 3.1V. This article selects
Arduino MEGA microcontroller as the sensor node processor. Arduino Mega is a development board
based on ATmega2560. It is designed for the more complex ARDUINO development project. It has 54
digital input/output pins (of which 15 pins can be used for PWM output), 16 analog output pins, 4
USART hardware serial interfaces, 16 MHz crystal oscillator, 1 USB interface, and 1 power supply
4IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
Interface, support online serial programming and reset button. The signal collected by the sensor
module is directly transmitted to the single-chip microcomputer, after digital-to-analog conversion and
filtering of the single-chip microcomputer, it is wirelessly transmitted to the gateway through the NB-
IoT module. The data collected by the terminal node is uploaded to the ONE NET Internet of Things
cloud platform through the wireless transmission module [6]. Arduino MEGA pin description diagram
shown in Figure 4.
Figure 4. Arduino MEGA pin description diagram
3.2 Sensor node wireless network design
The wireless sensor network is composed of a large number of terminal sensor nodes and gateways and
host computers deployed in the field. It monitors soil temperature and humidity information, nitrogen,
phosphorus, and potassium content in real time, and intelligently controls the opening and closing of
water valves based on the collected data. The topological structure of the NB-IoT network of this
system adopts a star topology structure, and the two-way communication between each sensor node is a
self-healing and multi-hop organization network. It is a narrow-band IoT technology based on cellular
networks, focusing on low-power WAN, supporting cellular data connection of IoT devices in WAN,
can be directly deployed with LTE network, can reduce deployment costs and achieve smooth upgrades,
is a global A wide range of Internet of Things technology, its characteristics can be summarized as:
wide coverage, low power consumption, low cost, large connection and other characteristics. In the
wireless sensor network, in order to achieve the coverage of the wireless network while reducing the
energy consumption and number of sensor nodes as much as possible, a small number of sensor nodes
act as coordinator nodes, collect sensor node data, and send and receive data transmitted by other sensor
nodes, Most of the remaining sensor nodes are only responsible for data collection, and transmit the
data information to the nearest coordinator node to reduce the energy consumption of the terminal
sensor node The NB-IoT BC26 module uses the LwM2M network protocol to form a Mesh network[7].
All sensor node data information is finally sent to the gateway, and the NB-IoT gateway sends all data
information to the host computer through the cellular network at a long distance. Establish a wireless
network through the coordinator node and manage the network application requests and network
address allocation of other sensor terminal nodes, build a wireless sensor network, and realize data
collection, processing and bidirectional transmission of the entire system [8]. The flow chart of the
sensor node program is shown in Figure 5.
5IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
Figure 5. Flow chart of sensor node program
3.3 Wireless electric valve control
The intelligent water valve uses a wireless electric valve. The electric valve is driven by a DC low-
voltage motor, and the motor rotates to control the opening angle of the valve, thereby controlling the
flow rate of the water flow. The water valve is connected with the Arduino MEGA single chip
microcomputer, and the opening and closing of the water valve is controlled by the driving circuit, the
solar battery provides power, and the lithium battery serves as the energy storage unit. Set the lower
limit of the soil moisture content to 40%hr and the upper limit to 75%hr, and compare the humidity data
collected by the terminal node with the set value. When the moisture content monitored by the terminal
node reaches the lower limit threshold, the single-chip microcomputer controls the valve to open for
automatic irrigation. When the moisture content reaches the upper limit, the single-chip microcomputer
controls the valve to close, ensuring that the standardized and standardized farm irrigation can be
achieved under the conditions of crop growth. And then achieve the purpose of saving water resources.
4. SYSTEM CONTROLLED TEST
4.1 Test design
The accuracy of the data collected by the terminal directly affects the irrigation decision. In order to
verify the accuracy of the wireless sensor collection and the reliability of the system communication,
the overall performance of the system is tested. The test plan is to design 12 sensor nodes to be
6IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
regularly deployed in the irrigation test area with an equilateral shape, of which 6 sensors are nitrogen,
phosphorus and potassium sensors, 6 sensors are temperature and humidity sensors, and 2 sensor
nodes are selected as coordinator nodes, the rest 10 are terminal sensor nodes. According to the
maximum root length density of the crop at 20-30cm, bury the wireless sensor under the soil greater
than 20cm, place the Internet of Things gateway in the center of the hexagon, and set up a wireless
sensor network to achieve soil water content, nitrogen, phosphorus and potassium content Monitor and
send the collected data information to the upper computer remotely through the GPRS network,
display in real time and visual display in graphical form through the interface display, and store the
data into the database through LabSQL module in the form of table. Collect a small amount of soil
samples at this moment, and measure the temperature, humidity, and content of nitrogen, phosphorus,
and potassium with a portable temperature detector and a nitrogen, phosphorus, and potassium
sampler.
4.2 Experimental results
Table 1 is a comparison table of humidity test data. Table 2 is a comparison table of temperature test
data. Table 3 is a comparison table of test data of nitrogen content. Can be seen from Table 1. The
maximum absolute ratio between the measured humidity value and the standard value obtained by the
farmland environmental monitoring system based on the wireless sensor network designed in this
paper does not exceed 1.1%RH, and the maximum absolute ratio between the measured temperature
value and the standard value does not exceed 0.4℃ , The absolute ratio between the measured value of
nitrogen and the standard value is 2.8%mg/kg. In line with the practical requirements of the field, it
can provide accurate monitoring data for irrigation decision-making and ensure that the soil
information of the farmland is within a range suitable for crop growth.
TABLE I. THE HUMIDITY EXPERIMENTAL DATA OF SOIL (UNIT:RH)
number Measured value Standard value relative value
1 33.3% 33.1% 0.6%
2 32.5% 32.4% 0.3%
3 31.8% 31.5% 0.9%
4 33.2% 33.5% 0.9%
5 34.1% 34.5% 1.1%
6 32.8% 33.1% 0.9%
TABLE II. SOIL TEMPERATURE TEST DATA (UNIT: ℃)
number Measured value Standard value relative value
1 23.2 23.5 0.3
2 22.5 22.3 0.2
3 21.8 22.2 0.4
4 22.3 22.1 0.2
5 22.4 22.3 0.1
6 23.5 23.2 0.3
TABLE III. SOILNMEASUREMENT DATA(UNIT:MG/KG)
number Measured value Standard value relative value
1 175 172 1.7%
2 168 173 2.8%
3 180 178 1.1%
4 184 182 1%
5 176 175 0.5%
6 173 171 1.1%
7IFEMMT 2020 IOP Publishing
Journal of Physics: Conference Series 1635 (2020) 012031 doi:10.1088/1742-6596/1635/1/012031
5. CONCLUSION
This paper designs a farmland environment monitoring system based on a wireless sensor network. It
uses wireless temperature and humidity sensors, nitrogen, phosphorus, and potassium sensors and
Arduino MEGA to monitor soil information in real time, and uses NB-IoT module and Wasp mobile
network to collect data and host computers. The two-way communication of order realizes the real-time
monitoring of farmland soil moisture information. Set appropriate upper and lower thresholds for
farmland moisture content, and control the opening and closing of wireless electric valves to provide a
suitable growth environment for crop growth, and achieve the purposes of saving water, increasing crop
yield, and precision agriculture. The system software part uses the Arduino language as a development
platform to program the Arduino MEGA microcontroller chip, and uses software such as NI LabVIEW
2016 and SQL SEVER 2008 to visually and directly display the monitored data information in the form
of waveform charts on the monitoring interface. The data table is stored in the SQL database, which
provides convenience for users to query farmland information and irrigation records. The accuracy and
applicability of the system are verified by the accuracy test of wireless temperature and humidity sensor
and wireless nitrogen, phosphorus and potassium sensor.
Acknowledgments
Fund Project: National Natural Science Foundation Project (51365048)
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