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Coin based mobile charging using solar tracking system

Feb 08, 2017




Chapter 1

Coin Based Mobile Charger Using Solar Tracking System 2014-15

This project is done by Shashidhara T S ,S.I.T TUMKUR ,if you like the project idea and you want to implement it then contact :8892484273,


INTRODUCTIONMobile phones have become a major source of business/personal communication. The mobile phone business is currently worth billions of dollars, and supports millions of phones. The need to provide a public charging service is essential.1.1 MOTIVATION

Now a days students and many other people use the public transportation , people who are making very long journey in order attend business conventions, conferences, or for any private purpose dont know that their battery level is low and they often forget their charger at home or in hotel rooms. In rural areas there is no continuous power supply about 13-14 hours. Many times battery becomes flat in the middle of conversation particularly at inconvenient times when access to a standard charger isn't possible . Many critics argued that long distance traveling vehicles provides power points. Even though one or two power points are provided at a particular place in the vehicles it is not all sufficient for all the passengers, therefore need to provide a public charging service is essential and coin-based mobile battery chargers are designed to solve these problems. 1.2 OBJECTIVEThe main aim of the project is to build a coin based mobile battery charger which provides a unique service to both urban/rural public where grid power is not available for partial/full time and a source of revenue for site providers for installation. The coin-based mobile battery charger can be quickly and easily installed outside any business premises and Solar energy is one of the abundant source of energy which is freely available in the nature in this project solar tracking system is mainly used to harness that energy in order to use it as power supply for charging the mobile.

1.3 ORGANIZATION OF THE REPORTThe report is divided into 5 chaptersChapter 1: Introduction: Briefly describes the Motivation and the objectives.Chapter 2: Block diagram description: Presents the block diagram of coin based

mobile charger using solar tracking system with a brief description of

each component.Chapter 3: Hardware description: It encloses description of all the components,

their features with specifications. Chapter 4: Software implementation: It describes the algorithm using flowchart

and software used. Chapter 5: Results: This chapter includes the execution part of the project and the

results obtained.Chapter 6: Conclusion and Future enhancement: It Includes Conclusion, advantages ,applications and future enhancement. CHAPTER 2BLOCK DIAGRAM DESCRIPTION The block diagram of the project coin based mobile charger using solar tracking system is shown in Figure 2.1.

Figure 2.1: Block diagram of coin based mobile charger using solar tracking system. The mobile battery charger starts charging a mobile connected to it, when a coin is inserted at the insertion slot at the input stage. The type of coin will be displayed at the LCD display for the user, so as to ensure correct coin insertion, if the correct coin is inserted, the proximity sensor detects the coin and coin detection system sends a pulse to the control unit authorizing to start mobile battery charging by enabling relay where it acts as switch, regulator is used to supply the required voltage and current for charging mobile. Solar panel used to harness solar energy whereas five LDR and stepper motor is used to track the Sun to attain the maximum efficiency.CHAPTER 3

HARDWARE DESCRIPTION3.1. HARDWARE IMPLEMENTATIONThe hardware implementation mainly consists of three sections Coin detection, Solar tracking and mobile charging system. The implementation is shown in Figure 3.1.

Figure 3.1: Hardware Implementation Of Coin Based Mobile Charger Using Solar Tracking System.3.2. DESCRIPTION OF SOLAR TRACKING SYSTEM WITH BLOCK DIAGRAM Solar energy is one of abudantly available renewable source of energy. Presently this field is having more demand and is likely to become integrated into more and more aspects of every day life.Different mechanisms are applied to increase the efficiency of the solar cell. Solar tracking system is most appropriate technology to increase the output power of solar cell . The mechanical movement of the solar panel is controlled through the stepper motor, as shown in the Figure 3.2

Figure 3.2: Block diagram for solar tracking system.

As shown in the Figure 3.2 LDRs will be placed on edges of the solar panel or on a separate platform, so according to the Sun light intensity LDR resistance will be varied. Whenever the Sun light intensity is more LDR offers less resistance the voltage across each LDR is given to ADC. According to this ADC shows the equivalent digital output. Based on the received values from ADC, microcontroller makes the decisions in accordance with the algorithm designed and rotates the stepper motor to required position.3.2.1 SOLAR PANEL

A major component of the solar tracking device will be the photovoltaic solar panel that collects the sunlight and translates that into useful form energy. Polycrystalline solar panels are economically feasible and are moderately efficient, so this project uses 5x5cm solar panel with voltage and current ratings of 4V,100mA respectively. A polycrystalline solar panel is as shown in Figure 3.3. This panel is mounted on the shaft of the stepper motor.

Figure 3.3: Polycrystalline solar panel.3.3 LIGHT DEPENDENT RESISTOR (LDR) It is an electronic component whose resistance decreases with increasing incident light intensity. This project uses LDR as the sensor to sense the position of the Sun. LDRs will be placed on edges of the solar panel or on a separate platform. A typical LDR is as shown in Figure 3.4.

Figure 3.4: Light Dependent Resistor (LDR).3.3.1 DESIGN OF LDR SENSOR CIRCUIT As the sunlight falls on the LDR, the resistance of LDR falls. This allows the current to easily pass through LDR thus voltage across LDR drops. But when no light falls on LDR, the resistance is maximum thus voltage drop across LDR is more. Figure 3.5 shows the complete sensor circuit.

Figure 3.5: Sensor circuit diagram.3.3.2. LDR SENSOR CIRCUIT ARRANGMENT LDR Sensor circuit consists of five LDR sensors and each LDR is covered using hollow tubes as shown in Figure 3.6. It can either fixed on the panel or on a separate platform.

Figure 3.6: LDR arrangement.3.4 STEPPER MOTOR DRIVER CIRCUIT

ULN2803 is a stepper motor driver. It is mainly used for interfacing between low logic level digital circuitry (such as TTL, CMOS or PMOS/NMOS) and the higher current/voltage requirements of Stepper motors. The phase inputs given to stepper motor from the microcontroller is in TTL logic (0 to 3.5V) which is not sufficient to drive the stepper motor, so ULN2803 is used as driver for stepper motor. 3.5 STEPPER MOTOR A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. The stepper motor is used for position controlling in the applications like disk drives, robotics and tracking systems. This project makes use of 12 volt,1A,1.8degree-per-step, 4 phase bipolar stepper motor since it provides heavy torque and commonly used to drive larger loads such as solar panels etc. Solar panel is mounted on shaft of the stepper motor where the direction and steps for rotation is received from microcontroller through ULN2803. 3.6 COIN DETECTION SYSTEM

Figure 3.7: Coin detection system. Coin accepted is based on the Proximity sensor, where diameter of the coin and whether it is a coin or not is checked by proximity sensor as shown in the Figure 3.7. If the inserted coin doesnt match required specification, microcontroller will not enable the charging system. If correct coin is inserted, invokes microcontroller along with LCD interface and initiates mobile charging system. 3.6.1 PROXIMITY SENSOR

A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact as shown in the Figure3.8. Figure 3.8: Proximity Sensor. A proximity sensor often emits an electromagnetic or electrostatic field, or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductiveproximity sensor requires a metal target. As shown in the Figure 3.8. This project uses 6 - 36V,200mA proximity sensor.3.7 ANALOG TO DIGITAL CONVERTER (ADC) It is an analog to digital converter. In this project ADC0809 with 8-channel single-ended analog signal multiplexer with three select lines is used. A particular input channel is selected by using the address decoder. Table 3.1 shows the input states for the address lines to select any channel. The address is latched into the decoder on the low-to-high transition of the address latch enable signal.Table 3.1: Address for input selection.

The converter is designed to give fast, accurate, and repeatable conversions over a wide range of analog voltage levels. The converter is partitioned into 3 major sections: the 256R ladder network, the successive approximation register and the