Automated irrigation system using solar power Main Project Report 2014

1. INTRODUCTION The continuously increasing demand of the food necessitates the rapid improvement in food production technology. In most of the developing countries such as Bangladesh, national economy mainly depends on the Agriculture. But these countries do not able to make proper use of agricultural resources due to the high dependency on rain . Nowadays different irrigation systems are used to reduce the dependency of rain and mostly the existing irrigation systems are driven by electrical power and manually ON/OFF scheduling controlled . Farmers usually control the electric motors observing the soil, crop and weather conditions by visiting the sites . These manually controlled irrigation systems cannot ensure a proper level of water in the site . Due to the lack of electricity and mismanagement in the manually controlling systems, sometimes their fields become dry and sometimes flooded with excess water. These unplanned and manually controlled irrigation systems also cause a significant amount of water waste. Automatic irrigation system is usually designed for ensuring the proper level of water for growing up the plants all through the season. Even when the farmers are away,these automatic irrigation systems always ensure the proper level of water in the sites . In addition, it provides maximum water usage efficiency by monitoring soil moistures at optimum level. Several research works have reputed aspects of development of automated irrigation system. With the development of technology in water saving irrigation and automation, automatic irrigation is going to be more popular in the farms. For example, a GSM based automatic irrigation water control is proposed. A mobile irrigation system has been developed which improves water efficiency by saving the water. Artificial Neural Network (ANN) based intelligent control system is proposed for effective irrigation scheduling in paddy fields . In the past, most of the proposed irrigation models are driven by electricity and their corresponding automated hardware are fixed rate. And these models are highly expensive as those were made of expensive devices. Thus, due to higher cost, the general farmers cannot buy it for their use; usually these models are used in the farms only for experiment or demonstration funded by government or any private organization. On the other hand, the variable rate automated controlling approach improves the overall irrigation system reducing the total cost and increases the production of crop yield.

Therefore, low price, alternative source of electricity and variable rate automated operation are the key concerns in the design of an irrigation system for the common farmers. In this paper, we propose a solar power controlled automated irrigation system. Sensors collect the information about the water level of paddy fields and update the farmer as well as the microcontroller. The farmer can switch ON and OFF the motor based on the water level even from distant places using a cell phone. However, if the water level reaches to the danger level, then the motor will automatically start to ensure the proper water level in the paddy field.

2. BLOCK DIAGRAM

Fig No:1

2.1 WORKING The area of paddy field usually may cover up several hundreds of hectares; to cover the whole area we need to place different sensors in the paddy field like humidity densor,tempersture sensor and water level sensor.The water sensors is simply a metal electrode. We are using such 3 electrodes made up of steel for sensing 3 levels. These 3 electrodes are connected to CD 4001 amplifier circuit. When water molecules come into contact with these terminals, Cd 4001 senses it and amplifies the signals to give a measurable output.It will always sense the water level of the field and will send a message to the users cell phone to inform the condition of irrigation. Farmer will control the motor sending assigned code to the microcontroller through a cell phone and a gsm module. Microcontroller is used as interface between the cell phone and sensor, it is through the microcontroller which cell phone interface and sensor sends singals and messages upon sensing the water level and feedback from the farmer. Here we use a pic type microcontroller PIC1673. Here we use a gsm module G300 as cell phone interface,gsm module is used for sending message to the cell phone upon receving singal from microprocessor and sens back singal from cell phone to microprocessor. A Photo Voltaic (PV) cell is the only source of energy to drive this type microcontroller pinproposed system. The energy will be stored in the DC Battery through power supply. The sensors, microcontroller and cell phone interface are driven by DC power. However, pump is driven by AC power; inverter is used to convert DC to AC power, and AC power interface ensures the proper AC power supply to the pump. A dc centrifugal pump is used to water the field by receiving assigned code to the microprocessor through gsm module. Pump is operated through a relay controlled by the microprocessor ,relay work as a switching device allowing turn on and turn off of pump by receiving signal from gsm module triggering microcontroller. The energy from pv cell is stored in a dc 12v battery which is inverted using an inverter and powers the whole system.

3. CIRCUIT DIAGRAM

Fig No:2

3.1 WORKING In this section, different circuit components of proposed model are illustrated. Normally, sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer/ instrument. In this paper, we propose a model of designing sensor as presented . Two metal plates such as A and B are used to form a sensor; at where 5V DC power is attached with plate A, and plate B is connected with a microcontroller. Normally plate A and plate B are isolated from each other and no voltage signal passes to the microcontroller. When the water fills the gap, the metal plates A and B gets connection and voltage signal passes to the microcontroller. According to our design model, if the water level reaches to 0cm, the microcontroller will automatically start the pump through AC interface according to the command of the pin RA4 as depicted . The farmer will be confirmed by a message; for example, PUMP STARTED. AC interface usually consists of a relay which is operated by the microcontroller and used to control the pump as presented . The pump will remain switched ON until the water level reaches to the secured level 10cm. When the sensors sense the water level is above 10cm, microcontroller will make the pump to be switched OFF; as it is receiving the status of water level from the sensors. At the secure level (10cm) the microcontroller will not operate. However, if the water level goes down to mid level (3cm) the sensors will send a signal to the microcontroller through the pin 12 (RB6) as depicted. After receiving the signal the microcontroller will send a message (for example, WATER LEVEL LOW) to the users cell phone through the cell phone interface. The cell phone interface usually consists of an optocoupler which is connected with the keypad of the cell phone as depicted. The microcontroller will seek the decision from the farmer through a message; whether he wants to start the pump or not. In our propose model, an individual code is assigned for each user. If the farmer wants to start the pump, he will send a message with the assigned code to the microcontroller through the DTMF decoder. The circuit detail of a balanced-line mode DTMF is illustrated. To reject the common-mode noise signals,a balanced differential amplifier input is used. The circuit also provides an excellent bridging interface across a properly terminated telephone line.

Whenever the farmer presses any key on his mobile phone keypad, the delayed steering (Std) output of the IC (Integrated Circuit) goes high on receiving the tone-pair, and glow the LED15 (connect with pin15 of IC via resistor R15) for a duration depending on the value of capacitor and resistor connected with pins 16 and 17. The LEDs connected with resistors R11-R14 at pins 11-14, indicate the output of the IC. The tone pair of DTMF generated by pressing the telephone button is converted into binary values internally in the IC.3.2 PCB LAYOUT

Fig No: 3

Aprinted circuit board (PCB)mechanically supports and electrically connectselectronic componentsusingconductivetracks, pads and other featuresetchedfrom copper sheetslaminatedonto a non-conductivesubstrate. PCB's can besingle sided(one copper layer),double sided(two copper layers) ormulti-layer. Conductor on different layers are connected with plated-through holes calledvias. Advanced PCB's may contain components - capacitors, resistors or active devices - embedded in the substrate. Printed circuit boards are used in all but the simplest electronic products. Alternatives to PCBs includewire wrapandpoint-to-point construction. PCBs are more costly to design but allow automated manufacturing and assembly. Products are then faster and cheaper to manufacture, and potentially more reliable.Much of the electronics industry's PCB design, assembly, and quality control follows standards published by theIPCorganization. When the board has only copper connections and no embedded components it is more correctly called aprinted wiring board(PWB) oretched wiring board. Although more accurate, the term printed wiring board has fallen into disuse. A PCB populated with electronic components is called aprinted circuit assembly(PCA),printed circuit board assemblyorPCB assembly(PCBA). The IPC preferred term for assembled boards iscircuit card assembly(CCA), for assembledbackplanesit isbackplane assemblies. The term PCB is used informally both for bare and assembled boards.Printed circuit board artwork generation was initially a fully manual process done on clear mylar sheets at a scale of usually 2 or 4 times the desired size. The schematic diagram was first converted into a layout of components pin pads, then traces were routed to provide the required interconnections. Pre-printed non-reproducing mylar grids assisted in layout, and rub-ondry transfersof common arrangements of circuit elements (pads, contact fingers, integrated circuit profiles, and so on) helped standardize the layout. Traces between devices were made with self-adhesive tape. The finished layout "artwork" was then photographically reproduced on the resist layers of the blank coated copper-clad boards.

4. COMPONENTS4.1 TEMPERATURE SENSOR LM 35 Temperature sensors are used in diverse applications such as food processing, HVAC environmental control, medical devices, chemical handling and automotive under the hood monitoring (e.g., coolant, air intake, cylinder head temperatures, etc.). Temperature sensors tend to measure heat to ensure that a process is either; staying within a certain range, providing safe use of that application, or meeting a mandatory condition when dealing with extreme heat, hazards, or inaccessible measuring points.There are two main flavors: contact and noncontact temperature sensors. Contact sensors include thermocouples and thermistors that touch the object they are to measure, and noncontact sensors measure the thermal radiation a heat source releases to determine its temperature. The latter group measures temperature from a distance and often are used in hazardous environments. The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.Since it has Linear + 10.0 mV/C scale factor it is very easy to calculate temperature value.

Fig no: 4 Full-Range Centigrade Temperature Sensor

The LM35 thus 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 convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of 14C at room temperature and 34C over a full 55 to +150C temperature range. Low cost is assured by trimming and calibration at the wafer level. The LM35s low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus supplies. As it draws only 60 A from its supply, it has very low self-heating, less than 0.1C in still air. The LM35 is applied easily in the same way as other integrated-circuit temperature sensors. Glue or cement the device to a surface and the temperature should be within about 0.01C of the surface temperature.This presumes that the ambient air temperature is almost the same as the surface temperature. If the air temperature were much higher or lower than the surface temperature, the actual temperature of the LM35 die would be at an intermediate temperature between the surface temperature and the air temperature, which is especially true for the TO-92 plastic package where the copper leads are the principal thermal path to carry heat into the device, so its temperature might be closer to the air temperature than to the surface temperature.To minimize this problem, ensure that the wiring to the LM35, as it leaves the device, is held at the same temperature as the surface of interest. The easiest way to do this is to cover up these wires with a bead of epoxy which will insure that the leads and wires are all at the same temperature as the surface, and that the temperature of the LM35 die is not affected by the air temperature.The TO-46 metal package can also be soldered to a metal surface or pipe without damage. Of course, in that case the V terminal of the circuit will be grounded to that metal. Alternatively, mount the LM35 inside a sealedend metal tube, and then dip into a bath or screw into a threaded hole in a tank. As with any IC, the LM35 and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may operate at cold temperatures where condensation can occur. Printed-circuit coatings and varnishes such as Humiseal and epoxy paints or dips are often used to insure that moisture cannot corrode the LM35 or its connections.These devices are sometimes soldered to a small light-weight heat fin to decrease the thermal time constant and speed up the response in slowly-moving air. On the other hand,

a small thermal mass may be added to the sensor, to give the steadiest reading despite small deviations in the air temperature.

TEMPERATURE SENSOR LM 35 Fig no:5 4.1.1 Features Calibrated directly in Celsius (Centigrade) Linear + 10.0 mV/C scale factor 0.5C accuracy guaranteeable (at +25C) Rated for full 55 to +150C range Suitable for remote applications Low cost due to wafer-level trimming Operates from 4 to 30 volts Less than 60 A current drain Low self-heating, 0.08C in still air Nonlinearity only 14C typical Low impedance output, 0.1 W for 1 mA load 4.2 HUMIDITY SENSOR SY HS 220 Humidity sensors relying on this principle consists of a hygroscopic dielectric material sandwiched between a pair of electrodes forming a small capacitor. Most capacitive sensors use a plastic or polymer as the dielectric material, with a typical dielectric constant ranging from 2 to 15. In absence of moisture, the dielectric constant of the hygroscopic dielectric material and the sensor geometry determine the value of capacitance.At normal room temperature, the dielectric constant of water vapor has a value of about 80, a value much larger than the constant of the sensor dielectric material. Therefore, absorption of water vapor by the sensor results in an increase in sensor capacitance. At equilibrium conditions, the amount of moisture present in a hygroscopic material depends on both the ambient temperature and the ambient water vapor pressure. This is true also for the hygroscopic dielectric material used on the sensor.

By definition, relative humidity is a function of both the ambient temperature and water vapor pressure. Therefore there is a relationship between relative humidity, the amount of moisture present in the sensor, and sensor capacitance. This relationship governs the operation of a capacitive humidity instrument. Humidity is the presence of water in air. The amount of water vapor in air can affect human comfort as well as many manufacturing processes in industries. The presence of water vapor also influences various physical, chemical, and biological processes.Humidity measurement in industries is critical because it may affect the business cost of the product and the health and safety of the personnel. Hence,humidity sensingis very important, especially in the control systems for industrial processes and human comfort. Controlling or monitoring humidity is of paramount importance in many industrial & domestic applications. In semiconductor industry, humidityor moisture levels needs to be properly controlled & monitored during wafer processing. In medical applications, humidity control is required for respiratory equipments, sterilizers, incubators, pharmaceutical processing, and biological products. Humidity control is also necessary in chemical gas purification, dryers, ovens, film desiccation, paper and textile production, and food processing. In agriculture, measurement of humidity is important for plantation protection

(dew prevention), soil moisture monitoring, etc. For domestic applications, humidity control is required for living environment in buildings, cooking control for microwave ovens, etc. In all such applications and many others,humidity sensorsare employed to provide an indication of the moisture levels in the environment. These module convert the relative humidity to the outputvoltage.This sensor module converts relative humidity(30-90%RH) to voltage and can be used in weather monitoring application. Most commonly used units for humidity measurement are Relative Humidity (RH), Dew/Frost point (D/F PT) and Parts Per Million (PPM). RH is a function of temperature, and thus it is a relative measurement. Dew/Frost point is a function of the pressure of the gas but is independent of temperature and is therefore defined as absolute humidity measurement. PPM is also an absolute measurement. Dew points and frost points are often used when the dryness of the gas is important. Dew point is also used as an indicator of water vapor in high temperature processes, such as industrial drying.Mixing ratios, volume percent, and specific humidity are usually used when water vapor is either an impurity or a defined component of a process gas mixture used in manufacturing.

Basic structure of capacitive type humidity sensor is shown below:

Fig No: 6 Humidity Sensor SY HS 220

4.2.1 Specifications:RATED VOLTAGEDC 5.0V

CURRENT CONSUMTION