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  1. 1. Bharat Institute of Technology Meerut PROJECT REPORT ON Monitor and Control of Greenhouse Environment “The Project GreenBee”A Project report submitted in partial fulfillment of the requirement for the award of Bachelor of Engineering In Applied Electrical &Electronics Engineering Submitted by: Sumit Kumar Mohit Kumar Aswani Kumar Praneet Garg Under the guidance of Er. Vivek Pandey Dept. of Electrical & Elecronics Engineering Bharat Institute of Engineering Meerut. 1
  2. 2. 1. INTRODUCTIONWe live in a world where everythingstill a few important sectors in our cput to a full-fledged use, perhaps becfield is that of agriculture. Agricultuearly civilizations and even today mform an important part of the agriculused to grow plants under controlledgreenhouse envisages monitoring anindirectly govern the plant growth an 2industrial machinery and processes,
  3. 3. 1. INTRODUCTIONWe live in a world where everything can be controlled and operated automatically, but there arestill a few important sectors in our country where automation has not been adopted or not been 3
  4. 4. put to a full-fledged use, perhaps because of several reasons one such reason is cost. One suchfield is that of agriculture. Agriculture has been one of the primary occupations of man sinceearly civilizations and even today manual interventions in farming are inevitable. Greenhousesform an important part of the agriculture and horticulture sectors in our country as they can beused to grow plants under controlled climatic conditions for optimum produce. Automating agreenhouse envisages monitoring and controlling of the climatic parameters which directly orindirectly govern the plant growth and hence their produce. Automation is process control ofindustrial machinery and processes, thereby replacing human operators.1 .1 CURRENT SCENARIOGreenhouses in India are being deployed in the high-altitude regions where the sub-zerotemperature up to 4O0 C makes any kind of plantation almost impossible and in arid regionswhere conditions for plant growth are hostile. The existing set-ups primarily are:1.1.1 MANUAL SET-UP:This set-up involves visual inspection of the plant growth, manual irrigation of plants, turningON and OFF the temperature controllers, manual spraying of the fertilizers and pesticides. It istime consuming, vulnerable to human error and hence less accurate and unreliable.1.1.2. PARTIALLY AUTOMATED SET-UP:This set-up is a combination of manual supervision and partial automation and is similar tomanual set-up in most respects but it reduces the labor involved in terms of irrigating the set-up.1.1.3. FULLY- AUTOMATED:This is a sophisticated set-up which is well equipped to react to most of the climatic changesoccurring inside the greenhouse. It works on a feedback system which helps it to respond to theexternal stimuli efficiently. Although this set-up overcomes the problems caused due to humanerrors it is not completely automated and expensive.1.2. PROBLEM DEFINITIONA number of problems associated with the above mentioned systems are enumerated as below:1. Complexity involved in monitoring climatic parameters like humidity, soil moisture, 4
  5. 5. Illumination, soil pH, temperature, etc which directly or indirectly govern the plant growth.2. Investment in the automation process are high, as today’s greenhouse control systems aredesigned for only one parameter monitoring (as per GKVK research centre); to control more thanone parameter simultaneously there will be a need to buy more than one system.3. High maintenance and need for skilled technical labour. The modern proposed systems use themobile technology as the communication schemes and wireless data acquisition systems,providing global access to the information about one’s farms. But it suffers from variouslimitations like design complexity, inconvenient repairing and high price. Also the reliability ofthe system is relatively low, and when there are malfunctions in local devices, all local and teledata will be lost and hence the whole system collapses. More over farmers in India do not workunder such sophisticated environment and find no necessity of such an advanced system, andcannot afford the same. Keeping these issues in view, a microcontroller based monitoring andcontrol system is designed to find implementation in the near future that will help Indian farmers.1.3. PROPOSED MODEL FOR AUTOMATION OFGREENHOUSEThe proposed system is an embedded system which will closely monitor and control themicroclimatic parameters of a greenhouse on a regular basis round the clock for cultivation ofcrops or specific plant species which could maximize their production over the whole cropgrowth season and to eliminate the difficulties involved in the system by reducing humanintervention to the best possible extent. The system comprises of sensors, Analog to DigitalConverter, microcontroller and actuators.When any of the above mentioned climatic parameters cross a safety threshold which has to bemaintained to protect the crops, the sensors sense the change and the microcontroller reads thisfrom the data at its input ports after being converted to a digital form by the ADC. Themicrocontroller then performs the needed actions by employing relays until the strayed-outparameter has been brought back to its optimum level. Since a microcontroller is used as theheart of the system, it makes the set-up low-cost and effective nevertheless. As the system alsoemploys an LCD display for continuously alerting the user about the condition inside thegreenhouse, the entire set-up becomes user friendly. Thus, this system eliminates the drawbacks 5
  6. 6. of the existing set-ups mentioned in the previous section and is designed as an easy to maintain,flexible and low cost solution.2.BASIC MODEL OF THE SYSTEM 6
  7. 7. Fig.2.1 Block diagram of the system2.1 PARTS/ COMPONENTS OF THE SYSTEM:• Sensors (Data acquisition system)• Temperature sensor (LM35)• Humidity sensor (HIH4000)• Light sensor (LDR)• Moisture sensor 7
  8. 8. • Analog to Digital Converter ( ADC 0808/0809)• Microcontroller (AT89S52)• Liquid Crystal Display (Hitachi’s HD44780)• Actuators — Relays• Devices controlled• Water Pump (simulated as a bulb)• Sprayer (simulated as a bulb)• Cooler (simulated as a fan)• Artificial Lights (simulated as 2 bulbs)• Buzzer2 .1.1 TRANSDUCERS (Data acquisition system):. A transducer is a device which measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. Monitoring and controlling of a greenhouse environment involves sensing the changes occurring inside it which can influence the rate of growth in plants. The parameters which are of importance are the temperature inside the greenhouse which affect the photosynthetic and transpiration processes are humidity, moisture content in the soil, the illumination etc. Since all these 8
  9. 9. parameters are interlinked, a closed loop (feedback) control system is employed inmonitoring it. The sensors used in this system are: 1. Soil Moisture Sensor(Transistor amplifier) 2. Light Sensor ( LDR (Light Dependent Resistor) ) 3. Humidity Sensor (HIH4000) 4. Temperature Sensor (LM35) MOISTURE SENSORFeatures of the Soil moisture sensor: 1. The circuit designed uses a 5V supply, fixed resistance of 100Ω, variable resistance of 10ΚΩ, two copper leads as the sensor probes, 2N222N transistor. 2. It gives a voltage output corresponding to the conductivity of the soil. 3. The conductivity of soil depends upon the amount of moisture present in it. It increases with increase in the water content of the soil. LIGHT SENSORLight Dependent Resistor (LDR) also known as photoconductor or photocell, is a devicewhich has a resistance which varies according to the amount of light falling on its surface.Since LDR is extremely sensitive in visible light range, it is well suited for the proposedapplication.Features of the light sensor: • The Light Dependent Resistor (LDR) is made using the semiconductor Cadmium Sulphide (CdS). • The light falling on the brown zigzag lines on the sensor causes the resistance of thedevice to fall. This is known as a negative co-efficient. There are some LDRs that work in the opposite way i.e. their resistance increases with light (called positive co- efficient). 9
  10. 10. • he resistance of the LDR decreases as the intensity of the light falling on it increases. Incident photons drive electrons from the valence band into the conduction band. HUMIDITY SENSOR The humidity sensor HIH4000, manufactured by Honeywell is used for sensing thehumidity. It delivers instrumentation quality RH (Relative Humidity) sensing performance ina low cost, solder able SIP (Single In-line Package). Relative humidity is a measure, inpercentage, of the vapour in the air compared to the total amount of vapour that could be heldin the air at a given temperature.Features: • Linear voltage output vs. %RH • Laser trimmed interchangeability • Low power design • High accuracy • Stable, low drift performance • Chemically resistant • The RH sensor is a laser trimmed, thermoset polymer capacitive sensing element with on-chip integrated signal conditioning. The sensing elements multilayer construction provides excellent resistance to most application hazards such as wetting, dust, dirt, oils and common environmental chemicals. TEMPERATURE SENSOR National Semiconductor’s LM35 IC has been used for sensing the temperature. It isan integrated circuit sensor that can be used to measure temperature with an electrical output oproportional to the temperature (in C). The temperature can be measured more accurately 2with it than using a thermistor. The sensor circuitry is sealed and not subject to oxidation, etc.Features: • Calibrated directly in ° Celsius (Centigrade) 10
  11. 11. • Linear + 10.0 mV/°C scale factor • 0.5°C accuracy guaranteed (at +25°C) • Rated for full −55° to +150°C range • Suitable for remote applications • Low cost due to wafer-level trimming • Operates from 4 to 30 volts • Low self-heating, 0.08°C in still air2.1.2 ANALOG TO DIGITAL CONVERTER (ADC 0809)In physical world parameters such as temperature, pressure, humidity, and velocity areanalog signals. A physical quantity is converted into electrical signals. We need an analogto digital converter (ADC), which is an electronic circuit that converts continuoussignals into discrete form so that the microcontroller can read the data. Analog to digitalconvertersare the most widely used devices for data acquisition. The ADC0809 data acquisition component is a monolithic CMOS device with an8- bit analog-to-digital converter, 8-channel multiplexer and microprocessor compatiblecontrol logic. The 8-bit A/D converter uses successive approximation as the conversiontechnique. The converter features a high impedance chopper stabilized comparator, a256R voltage divider with analog switch tree and a successive approximation register. The8-channel multiplexer can directly access any of 8-single-ended analog signals. The design of the ADC0809 has been optimized by incorporating the most desirableaspects of several A/D conversion techniques. The device offers high speed, high accuracy,minimal temperature dependence, excellent long-term accuracy and repeatability, andconsumes minimal power. These features make it ideally suited for applications fromprocess and machine control to consumer and automotive applications. 11
  12. 12. 1. Easy interface to all microcontrollers.2. Operates ratiometrically or with 5 VDC or analog span adjusted voltage reference.3. No zero or full-scale adjust required.4. 8-channel multiplexer with address logic.5. Outputs meet TTL voltage level specifications.6. 28-pin molded chip carrier package. FIG.2.1.2ADC0809 12
  13. 13. 2.1.3.MICROCONTROLLER(AT89S52):The microcontroller is the heart of the proposed embedded system. It constantly monitors thedigitized parameters of the various sensors and verifies them with the predefined thresholdvalues and checks if any corrective action is to be taken for the condition at that instant of time.In case such a situation arises, it activates the actuators to perform a controlled operation. The 8051 family of microcontrollers is based on an architecture which is highlyoptimized for embedded control systems. It is used in a wide variety of applications from military equipment to automobiles to the keyboard. Second only to the Motorola 68HC11 in eight bit processors sales, the 8051 family of microcontrollers is available in a wide array of variations from manufacturers such as Intel, Philips, and Siemens. These manufacturers have added numerous features and peripherals to the 8051 such as I2C interfaces, analog to digital converters, watchdog timers, and pulse width modulated outputs. Variations of the 8051 with clock speeds up to 40MHz and voltage requirements down to 1.5 volts are available. This wide range of parts based on one core makes the 8051 family an excellent choice as the base architecture for a companys entire line of products since it can perform many functions and developers will only have to learn this one platform. The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry- standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost- 13
  14. 14. effective solution to many embedded control applications. In addition, the AT89S52 isdesigned with static logic for operation down to zero frequency and supports two softwareselectable power saving modes. The Idle Mode stops the CPU while allowing the RAM,timer/counters, serial port, and interrupt system to continue functioning. The Power-downmode saves the RAM con-tents but freezes the oscillator, disabling all other chip functionsuntil the next interrupt or hardware reset. The basic architecture of AT89C51 consists of the following features: • Compatible with MCS-51 Products • 8K Bytes of In-System Programmable (ISP) Flash Memory • 4.0V to 5.5V Operating Range • Fully Static Operation: 0 Hz to 33 MHz • 256 x 8-bit Internal RAM • Three 16-bit Timer/Counters • Eight Interrupt Sources • Full Duplex UART Serial Channel • Low-power Idle and Power-down Modes • Interrupt Recovery from Power-down Mode • Watchdog Timer • Fast Programming Time • Flexible ISP Programming (Byte and Page Mode) 14
  15. 15. DIAGRAM 15
  16. 16. FIG2.1.3MICROCONTROLLER(AT89S52) 16
  17. 17. 2.1.4.DISPLAY UNIT: LIQUID CRYSTAL DISPLAY A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. Each pixel consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other. Many microcontroller devices use smart LCD displays to output visual information. LCD displays designed around Hitachis LCD HD44780 module, are inexpensive, easy to use, and it is even possible to produce a readout using the 8x80 pixels of the display. They have a standard ASCII set of characters and mathematical symbols. For an 8-bit data bus, the display requires a +5V supply plus 11 I/O lines. For a 4-bit data bus it only requires the supply lines plus seven extra lines. When the LCD display is not enabled, data lines are tri-state and they do not interfere with the operation of the microcontroller. Data can be placed at any location on the LCD. For 16×2 LCD, the address locations are:2.1.5.ACTUATORS:An array of actuators can be used in the system such as relays, contactors, and change overswitches etc. They are used to turn on AC devices such as motors, coolers, pumps, foggingmachines, sprayers. For the purpose of demonstration relays have been used to drive AC bulbs tosimulate actuators and AC devices. A complete working system can be realized by simplyreplacing these simulation devices by the actual devices. 17
  18. 18. A relay is an electrical switch that opens and closes under the control of anotherelectrical circuit. In the original form, the switch is operated by an electromagnet to open orclose one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relayis able to control an output circuit of higher power than the input circuit, it can be consideredto be, in a broad sense, a form of an electrical amplifier. Despite the speed of technological developments, some products prove so popularthat their key parameters and design features remain virtually unchanged for years. One suchproduct is the ‘sugar cube’ relay, shown in the figure above, which has proved useful tomany designers who needed to switch up to 10A, whilst using relatively little PCB area Since relays are switches, the terminology applied to switches is also applied torelays. A relay will switch one or more poles, each of whose contacts can be thrown byenergizing the coil in one of three ways:1.Normally - open (NO) contacts connect the circuit when the relay is activate d; the circuit is disconnected when the relay is inactive. It is also called a FORM A contact or “make” contact.2.Normally - closed (NC) contacts disconnect the circuit when the relay is activated ; the circuit is connected when relay is inactive. It is also called FORM B contact or” break” contact3.Change-over or double-throw contacts control two circuits ; one normally open contact and one normally –closed contact with a common terminal. It is also called a Form C “transfer “contact. 18
  19. 19. 2.2. STEPS FOLLOWED IN DESIGNING THE SYSTEM:Three general steps can be followed to appropriately select the control system:Step # 1: Identify measurable variables important to production.It is very important to correctly identify the parameters that are going to be measured by thecontroller’s data acquisition interface, and how they are to be measured. The set of variablestypically used in greenhouse control is shown below:An electronic sensor for measuring a variable must readily available, accurate, reliable and lowin cost. If a sensor is not available, the variable cannot be incorporated into the control system,even if it is very important. Many times variables that cannot be directly or continuouslymeasured can be controlled in a limited way by the system. For example, fertility levels innutrient solutions for greenhouse production are difficult to measure continuously.Step# 2: Investigate the control strategies.An important element in considering a control system is the control strategy that is to befollowed. The simplest strategy is to use threshold sensors that directly affect actuation ofdevices. For example, the temperature inside a greenhouse can be affected by controlling heaters,fans, or window openings once it exceeds the maximum allowable limit. The light intensity canbe controlled using four threshold levels. As the light intensity decreases one light may be turnedon. With a further decrease in its intensity a second light would be powered, and so on; thusensuring that the plants are not deprived of adequate sunlight even during the winter season or acloudy day. More complex control strategies are those based not only on the current values of thecontrolled variables, but also on the previous history of the system, including the rates at whichthe system variables are changing.SI. Variable to be Its Importance 19
  20. 20. No. monitored1 Temperature Affects all plant metabolic functions.2 Humidity Affects transpiration rate and plant’s thermal control mechanisms3 Soil moisture Affects salinity, and pH of irrigation water Affects photosynthetic rate, responsible for most thermal load4 Solar Radiation during warm periods.Step #3: Identify the software and the hardware to be used.It is very important that control system functions are specified before deciding what software andhardware system to purchase. The model chosen must have the ability to:1. Expand the number of measured variables (input subsystem) and controlled2. Devices (output subsystem) so that growth and changing needs of the3. Production operation can be satisfied in the future.4. Provide a flexible and easy to use interface.5. It must ensure high precision measurement and must have the ability resist6. Noise.Hardware must always follow the selection of software, with the hardware required beingsupported by the software selected. In addition to functional capabilities, the selection of thecontrol hardware should include factors such as reliability, support, previous experiences withthe equipment (successes and failures), and cost. 20
  23. 23. 5. ADVANTAGES AND DISADVANTAGES5.1 ADVANTAGES1. Sensors used have high sensitivity and are easy to handle.2. Low cost system, providing maximum automation.3. Closed loop design prevents any chances of disturbing the greenhouse environment.4. User is indicated for changes in actuator state thereby giving an option for manual override.5. Low maintenance and low power consumption.6. The system is more compact compared to the existing ones, hence is easily portable.7. Can be used for different plant species by making minor changes in the ambient environmentalparameters.8. Can be easily modified for improving the setup and adding new features.9. Labour saving.10. Provides a user-friendly interface hence will have a greater acceptance by the technologicallyunskilled workers.11. In response to the sensors, the system will adjust the heating, fans, lighting, irrigation,irnmediately, hence protect greenhouse from damage.12. Malfunctioning of single sensor will not affect the whole system.13. Natural resource like water saved to a great extent.5.2 DISADVANTAGES1. Complete automation in terms of pest and insect detection and eradication cannot be achieved.2. No self-test system to detect malfunction of sensors.3. Requires uninterrupted power supply.4. Facility to remotely monitor the greenhouse is not possible. 23
  24. 24. 6. SCOPE FOR FURTHER DEVELOPMENT1) The performance of the system can be further improved in terms of the operating speed,memory capacity, instruction cycle period of the microcontroller by using other controllers suchas AVRs and PICs. The number of channels can be increased to interface more number ofsensors which is possible by using advanced versions of microcontrollers.2) The system can be modified with the use of a data logger and a graphical LCDpanel showing the measured sensor data over a period of time.3) A speaking voice alarm could be used instead of the normal buzzer.4) This system can be connected to communication devices such as modems, cellular phones orsatellite terminal to enable the remote collection of recorded data or alarming of certainparameters.5) The device can be made to perform better by providing the power supply with the help ofbattery source which can be rechargeable or non-rechargeable, to reduce the requirement of mainAC power.6) Time bound administration of fertilizers, insecticides and pesticides can be introduced.7) A multi-controller system can be developed that will enable a master controller along with itsslave controllers to automate multiple greenhouses simultaneously. 24
  25. 25. 7.CONCLUSION A step-by-step approach in designing the microcontroller based system formeasurement and control of the four essential parameters for plant growth, i.e. temperature,humidity, soil moisture, and light intensity, has been followed. The results obtained from themeasurement have shown that the system performance is quite reliable and accurate. The system has successfully overcome quite a few shortcomings of the existingsystems by reducing the power consumption, maintenance and complexity, at the same timeproviding a flexible and precise form of maintaining the environment. The continuously decreasing costs of hardware and software, the wider acceptance ofelectronic systems in agriculture, and an emerging agricultural control system industry in severalareas of agricultural production, will result in reliable control systems that will addressseveral aspects of quality and quantity of production. Further improvements will be made as lessexpensive and more reliable sensors are developed for use in agricultural production. Although the enhancements mentioned in the previous chapter may seem far in the future,the required technology and components are available, many such systems have beenindependently developed, or are at least tested at a prototype level. Also, integration of allthese technologies is not a daunting task and can be successfully carried out. 25
  26. 26. 7.1REFERENCES:1. Muhammad All Mazidi, The 8051 Microcontroller & Embedded Systems2. Kenneth J Ayala, The 8051 Microcontroller Architecture3. Ramakant Gayalcwa, Operational Amplifiers Linear Integrated Circuits7.2.ONLINE REFERENCES:1. www.wikipedia.org2. www.805 1 26