ABSTRACT
With the rapid race of globalisation and an ever increasing global population, the agricultural field has great importance and the need to artificially create the perfect environmental conditions is very essential. Appropriate environmental conditions are necessary for optimum plant growth, improved crop yields and efficient use of water and other resources. Automating the data acquisition process of the soil conditions and various climatic parameters that govern plant growth allows information to be collected at high frequency and with less labour requirements.
We therefore need a system that is easy to install, simple to use. So we came up with a LabVIEW based monitoring system which can monitor and record temperature, humidity, soil moisture and sun light, which is constantly modified and can be controlled in future to optimize these resources so that the plant growth and yield is maximized. The use of easily available components reduces the manufacturing and maintenance costs. The ease of operation and use of the LabVIEW software makes it more suitable to this process.
TABLE OF CONTENTS
CHAPTERS CONTENTS PAGE NO
1. INTRODUCTION 1
2. BLOCK DIAGRAM 2
2.1 DESCRIPTION OF BLOCK DIAGRAM 3
2.1.1 Temperature sensor 3
2.1.2 Humidity sensor 4
2.1.3 Light sensor 7
2.1.4 Soil moisture sensor 9
2.2 SIGNAL CONDITIONING UNIT 11
3. LabVIEW SOFTWARE 12
3.1 DAQ 16
4. CENTERALISED MONITORING
SOFTWARE 18
5. RESULT 25
6. ADVANTAGES & DISADVANTAGES 26
7. FUTURE ENHANCEMENT OF THE
PROJECT 27
8. CONCLUSION 28
BIBLIOGRAPHY 29
APPENDIX 30
LIST OF FIGURES AND TABLES
Fig 2 BLOCK DIAGRAM OF WEATHER MONITORING 2
Fig 2.1.1(a) BASIC CENIGRADE TEMPERATURE SENSOR 4
Fig 2.1.1(b) PIN DIAGRAM OF LM35 4
Fig 2.1.2(a) SY-HS-220 HUMIDITY SENSOR 5
Fig 2.1.2(b) PIN CONFIGURATION OF SY-HS-220 6
Fig 2.1.2(c) RELATIVE HUMIDITY VS OUTPUT VOLTAGE 7
Fig 2.1.3(a) LIGHT DEPENDANT RESISTOR 8
Fig 2.1.3(b) LIGHT INTENSITY VS RESISTANCE 8
Fig 2.1.4 SOIL MOISTURE SENSOR 10
Fig 2.2 WHEATSTONE BRIDGE 11
Fig 3(a) LabVIEW SOFTWARE 12
Fig 3(b) FRONTPANEL OF LabVIEW SOFTWARE 14
Fig 3(c) BLOCK DIAGRAM OF LabVIEW SOFTWARE 15
Fig 3(d) ICON/CONNECTORS 15
Fig 3.1(a) NATIONAL INSTRUMENTS DAQ 16
Fig 3.1(b) PARTS OF DAQ 17
Fig 4(a) TAB CONTROL 18
Fig 4(b) FRONT PANEL OF GENERAL TAB 19
Fig 4(c) FRONT PANEL OF TEMPERATURE TAB 20
Fig 4(d) FRONT PANEL OF HUMIDITY TAB 21
Fig 4(e) FRONT PANEL OF LIGHT TAB 22
Fig 4(f) FRONT PANEL OF SOIL MOISTURE TAB 23
Table 2.1.2 STANDARD CHARACTERISTICS OF HUMIDITY 6
CHAPTER 1
INTRODUCTION
Weather is a state of atmosphere at a particular time and place. The elements of weather include temperature, light intensity and wind speed. Every new development was some way influenced by weather. Weather determined mans evolution, culture & fortune.
Our software has the ability to display the latest temperature, light intensity and humidity and soil moisture. The system is able to display weather condition, update its reading and display regularly on monitor. Weather values monitored by system are updated quickly. The monitor not only updates the values but give proper alarm when any of readings goes critical.
The system consists of four sensors for measuring temperature, light intensity, humidity and soil moisture. The sensors are connected to DAQ and thereby to PC.
CHAPTER 2
BLOCK DIAGRAM
Fig 2: Block diagram of weather monitoring
2.1 DESCRIPTION OF BLOCK DIAGRAM
The different components in the block diagram are,
1. Temperature sensor
2. Humidity sensor
3. Light intensity sensor
4. Soil moisture sensor
5. Signal conditioning unit
6. DAQ
7. PC
2.1.1 TEMPERATURE SENSOR
We are using IC LM35 for temperature sensing. The LM35 series are precision integrated circuit temperature sensors, whose output voltage is linearly proportional to Celsius temperature. The LM35 has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain its equivalent centigrade scaling. The LM35 does not require any external calibration or trimming to provide accuracy of +/- 25 0C at room temperature. Low cost is assured by trimming and calibration at water level. The LM35 is low output impedance, linear output, and precise inherent calibration make interfacing to readout.
Features
· Calibrated directly in Celsius
· Linear =10.0 mv/c scale factor
· Suitable for remote application
· Low cost due to water level trimming
· Operation from 4 to 30 volts
· Low impedance output
Fig 2.1.1(a): Basic centigrade Temperature Sensor
Fig 2.1.1(b): Pin diagram of LM35
2.1.2 HUMIDITY SENSOR
A humidity sensor also called a hygrometer, measures and regularly reports the relative humidity in the air. This means that it measures both air temperature and moisture. Humidity sensor gives regular, ongoing readings of the relative humidity, so they are usually used for data collection in the weather stations.
The humidity sensor SY-HS-220 can operate upto the range of 95% RH(Relative Humidity). Humidity sensor module itself contain the signal conditioning unit and the voltage out can take out through the connectors.
Fig 2.1.2(a): SY-HS-220 Humidity sensor
We know that the level of humidity in the air is also a function of temperature. Excess humidity can cause growth of fungus. Too little humidity can cause static discharge or accumulation of unwanted dust, contributing to allergies.
Here we use a humidity sensor known as SY-HS-2 and the module is SY-HS-220 series which produces more accurate and linear voltage output. This is a polymer humidity sensor. The voltage output is directly amplified and given to the LabVIEW to monitor the value of humidity in the air. It is clear that the output voltage indicated is proportional to the intensity of atmospheric moisture content.
Features:
1. Humidity sensor module with voltage output
2. Wide temperature compensation range
3. High reliability and long term stability
4. Linear dc voltage output for humidity range
5. High sensitivity and low hysteresis
6. Compact size and cost effectiveness
This features of the sensor make it more applicable in the measurement field. One of the main advantage is that it has high sensitivity, so that it will respond to the slight change in humidity.
CONNECTOR PIN CONFIGURATION:
| T2 |
| V out |
| T1 |
| Vin |
| GND |
Fig 2.1.2(b): Pin configuration for SY-HS-220
Standard Characteristics:
| Sl. No. | %RH | Output voltage (V) |
| 1 | 20 | 0.66 |
| 2 | 30 | 0.99 |
| 3 | 40 | 1.32 |
| 4 | 50 | 1.65 |
| 5 | 60 | 1.98 |
| 6 | 70 | 2.31 |
| 7 | 80 | 2.64 |
| 8 | 90 | 2.97 |
| 9 | 95 | 3.14 |
Table 2.1.2: Standard characteristics of humidity
Measurement condition: - Temperature: 25 o C, Input Voltage: 5V DC
| Relative Humidity (%RH) |
Fig2.1.2(c): Relative humidity (%RH) Vs Output voltage (V) Characteristic Graph
2.1.3 LIGHT SENSOR
The light sensor is made using an LDR (Light Dependant Resistor). The resistance of the LDR varies according to the intensity of light falling on the surface. This change in resistance is connected with a whetstone’s bridge arrangement and the corresponding change in voltage is amplified and given to the PC with LabVIEW through DAQ to monitor it.
Fig2.1.3 (a): Light Dependent Resistor (LDR)
2.1.3(b): light intensity vs. resistance characteristics graph
Two Cadmium sulphide (CdS) photoconductive cells with spectral responses similar to that of the human eye. The cell resistance falls with increasing light intensity.
Features:
· Wide spectral response
· Low cost
· Wide ambient temperature range.
Applications:
· Smoke detection
· Automatic lighting control
· Batch counting
· Burglar alarm system
2.1.4 SOIL MOISTURE SENSOR
The existing mechanism to measure the soil moisture content is costly and difficult to use. So we turned to design a soil moisture sensor which is cheap and gives excellent performance. It is made up of two electrodes and a very little quantity of plaster of Paris.
We know that gypsum is a material which shows water absorbing property and are users in medicine packing fields to avoid the presence of humidity. Depending on the water content in the soil the absorbing rate varies. If we insert an electrode, the conduction through electrode varies with content of water absorbed by gypsum. Or in the words the resistance of conductor varies. But the problem is that gypsum is not a commonly available material. The plaster of Paris is a material which shows the same property and it’s derived from gypsum. When gypsum is heated to 150 0c, it’s converted into plaster of Paris. The absorbing is not changed while changing into this. And we can mould any shape using this plaster of Paris, which makes it more suitable for our use.
For the ease in use of the sensor we made it in a cylindrical shape. The construction of such a sensor is as follows. Two electrodes of stainless steel of size 6cm * 0.5cm * 0.05cm is selected. It is placed 15mm apart in a cylindrical tube. To avoid any kind of disturbances fix the electrodes together by using some adhesives. And it should be noted that there should not be any conduction through this contact. The adhesive used should be a non-conducting one. Now mix the plaster of Paris with water and make it to a paste form. For two table spoons of plaster of Paris, pour one table spoon of water. This paste is then poured into the cylindrical tube which contains the two electrodes attached together. Then it is allowed to get dried. Then remove the cylindrical cover and solder wires to the electrodes to take the output. Now the sensor is ready.
| Connection Leads |
Insert this sensor in the soil in which the soil level covers the whole plaster of Paris in the sensor. Before that, calibrate the sensor for dry and wet conditions of the soil. Then we can measure the change in resistance corresponding to the soil moisture content in the soil. This change in resistance is then connected to a whetstones bridge and the corresponding voltage output is amplified and given to the PC with LabVIEW software to monitor the water content in the soil.
| Electrodes |
| Plaster of Paris |
Fig 2.1.4: Soil moisture sensor
2.2 SIGNAL CONDITIONING UNIT
The sensors used to measure various parameters in the farm give their output in terms of change in resistance. We have to convert this change in resistance to a suitable form to connect with the LabVIEW through DAQ. The input voltage range of DAQ is from 0v to 10v.To convert the change in resistance values to voltage in this range we use a Wheatstone bridge circuit.
Wheatstone bridge is a very simple circuit usually used to convert impedance variation into voltage variation. One of advantage of bridge for this task is that it can be designed so the voltage produced varies around zero. This means that amplification can be used to increase the voltage level for increased sensitivity to variation impedance, initially the bridge was in balanced position. This is the resistance offered by input and output resistors will be same and thus there is no resistance no potential difference between input and output. Any change in one of the resistors will lead to imbalance to bridge and thus to change in voltage. Thus the change in resistance offered by sensors can be effectively measured.
Fig 2.2 Wheatstone bridge
CHAPTER 3
LabVIEW SOFTWARE
Fig.3 (a): labVIEW software
The expanded form of LabVIEW is Laboratory Virtual Instrumentation Engineering Workbench. Graphical programming language that Allows for instrument control, data acquisition, and pre/post processing of acquired data. The main feature of this program are easy to use, faster development time, graphical user interface graphical source code, easily modularized, application builder to create stand-alone executables, multi-platform compatibility(perform natural and migrate applications between platforms).The entire Measurement and Automated system can be controlled With LabVIEW locally, or over the Internet. LabVIEW can acquire data by using DAQ. LabVIEW includes the following tools analyze the data:
- Analysis Vis for differential equations, optimization, curve fitting, calculus, linear algebra, statistics, etc.
- Signal processing Vis for filtering, windowing transforms, peak detection, harmonic analysis, spectrum analysis etc.
LabVIEW version 7 has introduced a new concept in interfacing- the use of assistants. The idea behind the introduction is to provide a user interactive way for development of data acquisition, instrument interfacing and code analysis. thus the assistants provide a user friendly face to the somewhat complex task of interfacing, be it an instrument or a multifunction device. The DAQ assistant icon when placed on the diagram initializes itself and comes up with a display appropriate to the hardware installed.
LabVIEW relies on graphical symbols rather than textual language to describe programming actions. The principle of data flow, in which the functions execute only after receiving the following data, governs execution in straightforward manner. LabVIEW programs are called virtual instruments (VIs) because their appearance and operation imitate actual instruments. However they are analogous to main programs, functions and subroutines from popular languages like C, FORTRAN, and Pascal etc. In LabVIEW we can create or use “Virtual instruments” (VI) for data acquisition. A VI allows computer screen to act as an actual laboratory instrument with characteristics tailored to particular needs. We can also use build-in examples, or use standard templates for setting up your data acquisition input channels.
A VI has three main parts:
1. The front panel: This is an interactive user interface of VI, so named because it can simulate the front panel of the physical instrument. Simply put, the front panel is the window through which the user interacts with the program. When we run VI we must have the front panel open such that we can input dada to the executing program. The front panel where you see your program’s output. The front panel is primarily the combination of controls and indicators. Components of the front panel are controls = inputs from the user = source terminals, indicators = outputs to the user = destinations.
Fig3 (b): Front Panel of labVIEW software
2. The block (or wiring) diagram: it is the Vis source code, constructed in LabVIEW’s graphical programming language: G. It is the actual executable program. Subroutine in the block diagram of VI. The block diagram window holds the graphical source code of a LabVIEW VI – it is the actual executable code.
You construct the block diagram by wiring together the objects that perform specific functions. The various components of a block diagrams are terminals, nodes, and wires.
Fig3(c): Block Diagram of labVIEW software
3. Icons/connectors: A LabVIEW VI is held together wires connecting nodes and terminals; they deliver data from one source terminals to one or more destination terminals.
Fig 3(d): Icons/connectors
3.1 DAQ
PC-Based Data Acquisition (DAQ):
DAQ is data acquisition. It is device which contains both ADC & DAC in it. It is interface between analog output of sensor and the PC. The data traditional experiments in it signal from sensors are sent to analog or digital domain, read by experimenter, and recorded by hand. In automated data acquisition systems the sensors transmit a voltage or current signal directly to a computer via data acquisition board. Software such as LabVIEW controls the acquisition and processing of such data. The benefits of automated systems are many:
· improved accuracy of recording
· increased frequency with which measurements can be taken
· potential to automate pre and post processing and built in quality control
Fig 3.1(a): National Instruments DAQ
CONFIGURATION CONSIDERATION
Here we have to consider the following properties of the input signal
1. Sampling Rate
2. Resolution
3. Range
4. Amplification
DEVICE RANGE
The device range can be as follows
Minimum and maximum voltages the ADC can digitize
DAQ devices often have different available ranges
· 0 to +10 volts
· -10 to +10 volts
Fig 3.1(b): Parts of DAQ
CHAPTER 4
CENTRALISED MONITORING SOFTWARE
The centralised farm monitoring system is developed by using LabVIEW. For making the monitoring and controlling more easier, each parameter is designed under different tab.
TAB Control:
Tab controls to overlap front panel controls and indicators in a smaller area. A tab control consists of pages and tabs. We can add front panel objects to the pages of the tab control and use the tab as the selector to display each page. A page is active when the tab for that page is flush with the page and the objects on the page are visible. Terminals for controls and indicators you add to the tab control appear as any other block diagram terminal.
| 1 |
| 3 |
| 5 |
| 4 |
| 2 |
Fig 4(a): TAB Control
1. GENERAL Tab
2. TEMPERATURE Tab
3. HUMIDITY Tab
4. LIGHT INTENSITY Tab
5. MOISTURE Tab
Each tab is designed in such a way to monitor the single parameter, but the GENERAL tab is the default tab and can monitor all the parameters at the same time.
1. GENERAL Tab:
Fig. 4(b): Front panel of GENERAL Tab
GENERAL Tab window consist of Waveform chart, process variable indicators and stop button. GENERAL Tab is the default tab which will run, when no other tab is selected to monitor the parameters. The process values of each parameter can be monitored using numerical indicators and waveform chart. This makes monitoring more accurate.
a) Waveform Chart
TEMPERATURE Vs TIME Chart is designed to plot graph for the different values of temperature. It is calibrated in terms in terms of degree Celsius.
HUMIDITY Vs TIME Chart is designed in such a way to display the variation in atmospheric humidity.
LIGHT INTENSITY Vs TIME Chart is designed to plot the graph proportional to the variation in the light intensity. Its unit is candela (Cd).
SOIL MOISTURE Vs TIME Chart indicates the presence of water content in the soil. Variation in soil moisture is plotted
b) Process variable indicators
Numerical indicators are used to display the process values of Temperature, Light intensity, Relative humidity and Soil moisture.
c) Stop button
Stop button is used to stop the execution of the program and thereby to stop the execution of the parameters.
2. TEMPERATURE Tab:
` Fig 4(c): Front panel for TEMPERATURE Tab
a) Waveform Chart
TEMPERATURE Vs TIME Chart is calibrated in such a way to plot the atmospheric temperature in terms of degree Celsius.
b) Thermometer
Thermometer is calibrated and arranged in such a way to indicate the temperature in degree Celsius as similar to the temperature indicated by mercury in thermometer.
c) Control Parameters panel
Control Parameters panel is designed and arranged in such a way to set the Set point temperature and to display the process variable and manipulated variable.
d) HIGH and LOW indicators
Indicators are used to indicate HIGH when the temperature (process variable) rises above the set point value and indicate LOW when the temperature decreases below the set point value.
| Fig4(d): Front panel of HUMIDITY Tab |
3. HUMIDITY Tab:
a) Waveform Chart
RELATIVE HUMIDITY Vs TIME Chart is calibrated in such a way to plot the atmospheric humidity in terms of RH %.
b) Control Parameters panel
Control Parameters panel is designed and arranged in such a way to set the Set point humidity and to display the process variable and manipulated variable.
c) HIGH and LOW indicators
Indicators are used to indicate HIGH when the Relative humidity (process variable) rises above the set point value and indicate LOW when the Relative humidity decreases below the set point value.
d) Humidity meter
Humidity meter is used to indicate the relative humidity in a calibrated scale using a needle or pointer.
4. LIGHT Tab:
| Fig 4(e): Front panel of LIGHT INTENSITY Tab |
a) Waveform Chart
LIGHT INTENSITY Vs TIME Chart is calibrated in such a way to plot the variation in the light intensity with respect to time.
b) Control Parameters panel
Control Parameters panel is designed and arranged in such a way to set the Set point value of light intensity and to display the process variable and manipulated variable.
c) HIGH and LOW indicators
Indicators are used to indicate HIGH when the light intensity (process variable) rises above the set point value and indicate LOW when the light intensity decreases below the set point value.
5. MOISTURE Tab:
Fig 4(f): Front panel of MOISTURE Tab
a) Waveform Chart
SOIL MOISTURE Vs TIME Chart is calibrated in such a way to plot the variation in the soil moisture with respect to time.
b) Control Parameters panel
Control Parameters panel is designed and arranged in such a way to set the Set point value of soil moisture and to display the process variable and manipulated variable.
c) HIGH and LOW indicators
Indicators are used to indicate HIGH when the soil moisture (process variable) rises above the set point value and indicate LOW when the soil moisture decreases below the set point value
CHAPTER 5
RESULT
A system to effectively monitor the agricultural farm weather condition using LabVIEW is setup. The system can monitor the farm weather parameters such as temperature, humidity, and light and soil moisture content. The main advantage of system using labVIEW is that it has high accuracy. Since the system has simple front panel, the user can easily monitor the atmospheric condition.Moreover, the system is very simple as compared to other microcontroller system.
CHAPTER 6
ADVANTAGES AND DISADVANTAGES
ADVANTAGES
- LabVIEW is user friendly.
- Use of LabVIEW software reduces wired circuit
- Hardware failure is very rare compared to embedded system.
- Monitoring the farm parameter through LabVIEW is very easy task.
- For further control of parameter, the LabVIEW software is helpful.
- It gives continuous display.
DISADVANTAGE
- The cost of LabVIEW is more compared to embedded system.
CHAPTER 7
FUTURE ENHANCEMENT OF THE PROJECT
· The importance of agricultural field is getting more relevant during these recent days. It will rise also in the future. So the system can be enhanced for controlling the atmospheric condition.
· It can be implemented in any variety of plantations.
· Centralised monitoring can be done effectively in the case of a wide area plantation.
· This system can be installed in place where any of the parameters such as light, humidity, temperature, soil moisture is controlled.
CHAPTER 8
CONCLUSION
A throughout study has been made about LabVIEW. Using this project atmospheric temperature, relative humidity, light and soil moisture presence can be detected & monitored. This Centralized farm monitoring system which automatically monitors the farm is done as our mini project is a better development in the field of agriculture because it has wide application which is relevant in the modern society.
It can be produced in the market in wide range with high accuracy. By doing this project what we have tried to do is to make just a demo of it. The most difficult part of the project was to calibrate the sensor output. It is done in maximum possible extend. With this we are concluding this mini project.
APPENDIX