CHAPTER 3 PROJECT METHODOLOGY 3.1 Introduction This chapter will cover the details explanation of methodology that is being used to make this project complete and working well. Many methodology or findings from this field mainly generated into journal for others to take advantages and improve as upcoming studies. The method is use to achieve the objective of the project that will accomplish a perfect result. 3.2 Implementation Flow Chart Project List Choose The Project Gathering Information Analysis and Research Designing and Planning Project Implementation Circuit Analysis related Component Installation Test Circuit Combined and Testing Final Presentation Final Project Report 3.3 Planning of the project 3.3.1 List of measures work The systems development life cycle (SDLC) describes a set of steps that produces a Solar Powered Automatic Street Light Controller (Badie N. Farah.2004). The SDLC is a problem-solving process. Each step in the process delineates a number of activities. Performing these activities in the order prescribed by the SDLC will bring about a solution for a problem. The SDLC process consists of the following phases: I. Investigation process II. Generating process III. Synthesis process IV. Implementation process V. Analysis process I. Investigation process The first phase of the systems development life cycle is preliminary investigation. Due to limited resources an organization can undertake only those projects that are critical to its mission, goals, and objectives. Therefore, the goal of preliminary investigation is simply to identify and select a project for development from among all the projects that are under consideration. The preliminary-investigation phase sets the stage for gathering information about the current problem and the existing information system. This information is then used in studying the feasibility of possible information systems solutions. II. Generate process Generate is the second step after the investigation. Generate is an idea to produce a sketch before starting the project. Each given ideas we have reviewed the consent of all members of the group to get good results. Therefore cooperation between members of the group is very important for the success of product quality and desired. Prior to this project, sketches made in order to facilitate our work. In this project I have divided the work into 2 section which is mechanical section and electrical/electronic section, to complete this very important project with the work schedule so that what I have planned was going on well and it did prevent from problems to arise. MECHANICAL DIVISION Cutting the hard plastic Cutting plastic box Punch holes in plastic box Cutting the polystyrene to make prototype (High way) ELECTRICAL AND ELECTRONICS DIVISION III. Install components on the circuit board Install the power supply Install LDR sensors Small wiring for connection into 2 circuit board Soldering the components Synthesis process Synthesis process is the step in design where the person select component parts and how to interconnecting them to create his flowsheet (Naonori Nishida, 1981). A systematic framework for a process synthesis based on 2 way communication between lecturer and student or groupmates. In this process, I made a schematic diagram of battery charger circuit and sensor circuit by using NI Multisim software. Then I also draw another simple sketches from that schematic diagram to identify the component placement and also wire connection between those components. IV. Implementing process After did the schematic diagram using NI Multisim software, the process of produce project board circuit (PCB) was followed. Components The components for this project are based on the circuit diagram where all the components related have been ready at one of electronic component shop at Senawang, Negeri Sembilan. The costing for the components as stated at the buying receipt and can see at Appendix. Construction Checking After the parts of mounting the components at PCB finished, I need to check the continuity track of the circuit. This part of job is to ensure that the operation of this circuit will run smoothly. The tools related with the checking parts is multimeter and the continuity checking involve with every circuit tracks and the point of soldering. By using the buzzer multimeter, it’s will alert the failed continuity. The failed continuity will recover with the solder again the lake of components related. Testing The procedure of testing is beginning with charger circuit connected with 12V power supply. Turn on the power supply and check whether the LED ON of not to make sure charger circuit is working. V. Analysis process The analysis stage is the final stage in this methodology where the two points will be done. The analysis is based on the performance of the circuit related where the output must be performed well and successful and the second is identifying the conclusion. Analysed the circuit The circuit of Solar Powered Automatic Street Light Controller is a combination of a small electronic circuit, where in the working of small electronic circuit will perform the good result of automatically switched ON and OFF the street light. In this Solar Powered Automatic Street Light Controller, I have defined that the small electronic circuits, which stated as below: Solar Battery Charger Circuit This is the most simple and affordable solar battery charger that the hobbyist can make. It has a few drawbacks over other similar controls, but offers numerous advantages. It is intended for charging lead-acid batteries, but may also be used for charging any battery at a constant voltage. Voltage output is adjustable. Solar Battery Charger Circuit Principle Solar battery charger operated on the principle that the charge control circuit will produce the constant voltage. The charging current passes to LM317 voltage regulator through the diode D1. The output voltage and current are regulated by adjusting the adjust pin of LM317 voltage regulator. Battery is charged using the same current. Solar battery charger circuit diagram Figure 3. : Schematic diagram of Solar Battery Charger Circuit Advantages & Disadvantages of this solar charger + Simple, small & inexpensive + Uses commonly available components + Adjustable voltage + ZERO battery discharge when sun is not shining Solar battery charger specifications Solar panel rating: 20W (12V) or 10W (6V) Output voltage range: 5 to 14V (adjustable) (may be reduced further by shorting R2) Typical dropout voltage: 2 to 2.75V (depending upon load current) Maximum current: 1.5A (internally limits at about 2.2A) Voltage regulation: ±100mV (due to regulation of series rectifier) Battery discharge: 0mA (this control will not discharge the battery when the sun doesn’t shine) Solar Battery Charger Circuit Design Circuit must have adjustable voltage regulator, so Variable voltage regulator LM317 is selected. Here LM317 can produce a voltage from 1.25 to 37 volts maximum and maximum current of 1.5 Amps. Adjustable Voltage regulator has typical voltage drop of 2 V-2.5V .So Solar panel is selected such that it has more voltage than the load. Here I am selecting 17v/5w solar panel. Lead acid battery which is used here has specification of 12v/1.3Ah. In order to charge this battery following are required. Zener diode is used to protect the LM317 and panel from reverse voltage generated by the battery when it is not charging because it will blocks the current through it up to a certain voltage when reverse biased.. Any 3 A diode can be used here. For Charging 12V Battery Output voltage Set the output voltage to 14.5 volts (This voltage is specified on the battery as cycle use.) Charging current Charging current = Solar panel wattage/Solar Panel Voltage = 5 / 17 = 0.29A. Here LM317 can provide current upto 1.5A .So it is recommended to use high wattage panels if more current is required for your application. (But here my battery requires initial current less than 0.39Amps. This initial current is also mentioned on the battery). If the battery requires initial current more than 1.5A, it is not recommended to use LM317. Time taken for charging Time taken for charging = 1.3Ah/0.29A = 4.44hours. Power dissipation Here solar panel has 5Watts Power going into battery = 14.5*0.29 =4 watts Thus 1 watt of power going into regulator. Minimum Head Voltage This is also referred to “drop-out voltage.” The input voltage must exceed the output voltage by about 2.75V @ 1.5A. Fortunately, when the battery discharged, the output voltage is lower so the solar panel voltage will also be lower. When fully charged, the battery voltage will be high, but the current is very low— at this point, the drop-out voltage reduces to about 2V and the open circuit solar panel voltage also comes into play. The Zener diode was selected to reduce this head voltage requirement (Jim Keith, 2015). Zener diode will blocks the current through it up to a certain voltage when reverse biased. Beyond this reverse breakdown voltage, it allows the current to flow even when biased in the reverse. That makes this type of diode very useful for generating reference voltages, clamping signals to specific voltage levels or ranges and more generally acting as a voltage regulator. Zener diodes are manufactured to have their reverse breakdown voltage occur at specific, well-defined voltage levels. They are also able to operate continuously in the breakdown mode, without damage. Commonly, Zener diodes are available with breakdown voltage between 1.8 to 200 Volts (Andi, 2016). Current Limiting Current limiting is provided by the solar panel—it is not a commonly understood fact that the solar panel tends to be a constant current device. For this reason, a solar panel can withstand a short circuit. Therefore, the control does not need current limiting. The way to operate Solar Battery Charger 1. Give the connections according to the circuit diagram. 2. Place the solar panel in sunlight. 3. Now set the output voltage by adjusting pot RV1 4. Check the battery voltage using digital multi meter. LDR Sensor Circuit Nowadays, lightening-up of highways is done through HID lamps but, the energy consumption of these lights is high as well as there is no particular mechanism to turn on/off the lights from sunrise to sunset. To overcome this problem, here is an alternative method using LEDs i.e. power conserving of intensity controlled street lights using LDR. An LDR or “Light Dependent Resistor” is a resistor where the resistance decreases with the strength of the light. Light Dependent Resistors Light Dependent Resistors (LDR) are also called photoresistors. They are made of high resistance semiconductor material. When light hits the device, the photons give electrons energy. This makes them jump into the conductive band and thereby conduct electricity. Light Dependent Resistor Circuit The circuit of LDR is an electronic circuit built with LDR, relay, Darlington pair, diode, & resistors shown in the below circuit diagram. Figure shows the schematic diagram of LDR sensor circuit. The circuit diagram present here is that of a street light that automatically switches ON when the night falls and turns OFF when the sun rises. The circuit uses a Light Dependent Resistor (LDR) to sense the light. When there is light, the resistance of LDR will be low. So the voltage drop across R3 will be high. This keeps the transistor QI ON. The collector of Q1 is coupled to base ofQ2. So Q2 will be OFF and so do the relay. The bulb will remain OFF. When night falls the resistance of LDR increases to make the voltage across the R3 to decrease below 0.6V. This makes transistor Q1 OFF which in turn makes Q2 ON. The relay will be energized and the bulb will glow. In addition, in the morning time, this sensor has a low resistance around 100Ω. Thus, the power supply flows through the LDR & ground through the variable resistor and resistor as shown in the above light sensor circuit. This is due to the resistance offered by the light dependent resistor in the daytime or when the light falls on the LDR, then it is less compared to the resistance of the remaining part of the sensor circuit. We are alert of the principle of current, that the flow of current always flow in the path of low resistance. Therefore, the relay coil does not get sufficient supplies to get strengthened. Hence, the light is switched off in the daylight. In the same way, during the night time, the resistance of the LDR increases to a high value (20MΩ). Thus, due to the high resistance of the resistor, the flow of current is low or almost zero. Now, the flow of current through the low-resistance lane such that it increases the base voltage of Darlington pair to reach more than 1.4v. As the Darlington pair transistor is triggered, the relay coil acquires enough supply to get energized, and hence, the light switches in the night time (Tarun Agaruvali, 2014). Applications of LDR Light dependent resistors are simple and low cost devices. These devices are used where there is a need to sense the presence and absence of light is necessary. These resistors are used as light sensors and the applications of LDR mainly include alarm locks, street lights, light intensity meters, burglar alarm circuits. For better understanding of this concept, here we have explained this project namely; Solar powered automatic street light controller using LDR. Conclusion As a conclusion, every project will have different methodologies that is being used to make the project successful and working well. Generally, the methodologies are divided into three parts, there are planning, implementing and analysis. In planning phase there are including with reading activity and some job of requirements of hardware and software to be used. In reading activity I do research through several sources such as text books, journal, paper references, the Internet and more sources due to get the information about the project related. While in the requirements of hardware and software to be use I was study and find out the functional and operational of the hardware and software related. Next step is implementing phase where in this part I did the appointment with third party because need help for component placement process. When the PCB was ready to mount the electronic components, the process of construction circuit is followed. The process of checking and testing are followed due to complete a part of implementing. Finally, in analysis phase, the project was come out with the operations of solar powered automatic street light controller system circuit. It was looking at the combination of battery charger circuit and LDR sensor circuit. The functions and the operations of the circuits related are very important to be analyzed. With appropriate steps and methodology, any process of completing the project can be managed wisely and will be make a good result.
