Coin based mobile charging using solar tracking system

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,

[email protected]

Dept. of E&C, SIT, Tumkur 1


CHAPTER 1

INTRODUCTION

Mobile 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 don’t 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 OBJECTIVE

The 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 REPORT

The report is divided into 5 chapters

Chapter 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 2

BLOCK 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 DESCRIPTION

3.1. HARDWARE IMPLEMENTATION

The 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 doesn’t 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

comparator. The converter’s digital outputs are positive true.

Here IN0, IN1, IN2, IN3 and IN4 are used as input pins where inputs are given

from five LDRs respectively. The outputs of ADC i.e. D0 to D7 is connected to Port2

of microcontroller as shown in Figure 3.1.

3.8. LIQUID CRYSTAL DISPLAY (LCD)

Figure 3.9: Pin diagram of 16X2 LCD.

The Figure 3.9 shows the pin diagram of 16X2 LCD display. In this LCD each

character is displayed in 5X7 pixel matrix. While Vcc and GND (Vss) are connected

to +5V and ground respectively, Vee is used for controlling contrast. In this project

LCD is used to display message for coin insertion and detection, mobile charging

initiation and completion.

RS ( Register select)



The register select pin of LCD is connected to P3.6 pin of microcontroller. The RS

pin is used for selecting the registers. If RS is low, command register is selected,

allowing the user to send commands such as clear display, cursor at home etc. If RS is

high, data register is selected, allowing the user to send data to be displayed on the

LCD.

R/W (read/write)

R/W input allows the user to write information to the LCD or read information

from it. When reading R/W=1; when writing R/W = 0.

EN (enable)

The enable pin is used by the LCD to latch information present on its data pins.

When data is supplied to data pins, a high to low pulse must be applied to this pin in

order for the LCD to latch the data present at the data pins. This pulse must have a

minimum width of 450ns. EN pin of LCD is connected to P3.7 pin of microcontroller.

DB0-DB7

The 8-bit data pins DB0-DB7, are used to send information to the LCD or read the

contents of the LCD’s internal registers. To display letters and numbers, ASCII codes

for the letters A-Z, a-z and numbers 0-9 are sent to these pins while making RS as

high. Here DB0 to DB7 pins of LCD are connected P1.0 to P1.7 of microcontroller.

3.9 RELAY

Relay is an electrically operated switch. Many relays use an electromagnet to

operate a switching mechanism mechanically. In this project HEJQC3FC relay with

maximum current and voltage rating of 7.5A,14V is used, to supply +5V to multi

charger connector when it receives enable signal from microcontroller.

3.10 REGULATOR( LM317 )

The LM317 series of adjustable 3-terminal positive voltage regulators is capable of

supplying in excess of 1.5A over 1.2V to 37V output range. The Figure 3.11 Circuit

design using LM317.



In this project LM317 is used to attain 5V and 12V output voltages. Here input

voltage must be greater than required output voltage and it is given from the batterty

of 12V and 1.5A which is charged using solar panel.

Figure 3.11: Circuit design using LM317.

3.11 MICROCONTROLLER

The P89V51RD2 is 80C51 microcontroller with 64KB flash and 4KB of data

RAM.

The flash program memory supports both parallel programming and in serial ISP.

Parallel programming mode offers gang-programming at high speed, reducing

programming costs and time to market. ISP allows a device to be reprogrammed in

the end product under software control. The capability to field/update the application

firmware makes a wide range of applications possible.

The microcontroller[4] P89V51RD2 is used to give the control signals to the

stepper motor driver in order to generate the necessary sequence required to

energize the winding of the stepper motor and to give enable input to initiate

charging for certain interval of time.

Unique features of the microcontroller are as follows:

1. 8051 Central Processing Unit.

2. 5 V Operating voltage from 0 to 40 MHz.

3. 64 KB of on-chip Flash program memory with ISP (In-System Programming).

5. SPI (Serial Peripheral Interface) and enhanced UART.

6. Four 8-bit I/O ports with three high-current Port 1 pins (16mA each).

7. Three 16-bit timers/counters with Programmable Watchdog timer (WDT).

8. Eight interrupt sources with four priority levels.

9. TTL- and CMOS-compatible logic levels.



CHAPTER 4

SOFTWARE IMPLEMENTATION

4.1 SOFTWARE REQUIRED

The software implementation of the project is described in this chapter. The

programs for interfacing the LCD, Stepper motor and ADC is written in C language

and burnt in microcontroller with the help of Keil software.

4.1.1 Introduction to Keil

Keil was found in 1986 in order to market the add-on products for the

development tools provided by the silicon vendors. Keil implemented the first C

compiler designed for the group-up specifically for 8051 microcontroller. Keil

software development tools for the 8051 microcontroller family supports every level

developer from beginners to the professional applications engineer.

Creating HEX file:

Open Keil and start a new project.

Select device for target ‘Target 1’.

P89V51RD2 will be selected as target device.

Click on ‘Source Group’ and then click on ‘Add files to source group’.

Choose the file and add it to ‘Source group’.

Go to options for target ‘Target 1’, under output tab check the box ‘Generate

. Hex file’.

Dumping HEX file

Connect the programmer to the microcontroller board.

Select the device and choose the proper baud rate.

Erase the previous program on the device.

Select ‘Auto’ to dump the program.

4.2 FLOWCHART OF THE SYSTEM Dept. of E&C, SIT, Tumkur 15


The flowchart of the system is shown in Figure 4.1.

Figure 4.1: Flow chart of the system.

4.3 FLOW CHART OF ADC CALCULATION



The flowchart of ADC calculation is shown in Figure 4.2

Figure 4.2: Flow chart of ADC calculation.

4.4 FLOW CHART OF SOLAR TRACKINGDept. of E&C, SIT, Tumkur 17


The flowchart of Solar tracking system is shown in Figure 4.3.

Figure 4.3: Flow chart of Solar tracking

CHAPTER 5Dept. of E&C, SIT, Tumkur 18


RESULTS

This chapter includes the execution part of the project and the results obtained.

Figure 5.1 and 5.2 shows the snapshot of the project outer view and inner view

respectively.

Figure 5.1: Project Outer view.

Figure 5.2: Project inner view.

As soon as the system is switched on, the LCD displays to insert one rupee coin as

shown in Figure 5.3.



Figure 5.3: Indicates to insert one rupee coin.

After coin is inserted, LCD displays coin detected and mobile starts charging as

shown in Figure 5.4.

Figure 5.4: Indicates coin is detected.

As soon as the charging is initiated from microcontroller, LCD displays charging

started as shown in Figure 5.5.



Figure 5.5: Indicating the initiation of mobile charging.

If the light intensity on LDR0 is more, the stepper motor rotates to position as

shown in the Figure 5.6.

Figure 5.6: Indicating the Zeroth position of the solar system.

If the light intensity on LDR1 is more, the stepper motor rotates to position as shown

in the Figure 5.7.



Figure5.7: Indicating the First position of the solar system


in the Figure 5.8.

Figure5.8: Indicating the Second position of the solar system.


in the Figure 5.9.



Figure 5.9: Indicating the Third position of the solar system


in the Figure 5.10.

Figure 5.10: Indicating the Fourth position of the solar system

CHAPTER 6



CONCLUSION AND FUTURE ENHANCEMENT

6.1 CONCLUSION

In this project a novel method of charging mobile batteries of different

manufacturer using solar power has been designed for rural and remote areas

where the power supply is not at all available all the time. This project can be

implemented outside any premises where the user has to plug the mobile phone into

one of the suitable multi charge connector pin by inserting a coin in order to charge

the mobile. It is, of course, possible to continue charging by inserting more coins. In

the meanwhile continuous solar tracking is done.

6.2 ADVANTAGES:

1. The coin-based mobile battery charger can be quickly and easily installed

outside any business premises.

2. Low power consumption.

3. Simple and portable.

4. Cost effective.

5. Effectively receive maximum energy due to solar tracking system used.

6. No external source required.

7. Universal charger.

8. One time investment.

6.3 APPLICATIONS:

1. It can be installed in urban/rural areas where grid power is not

available for partial/full time.

2. It can be installed in public places like Hotels, conference centers, serviced

offices, leisure centers, retail outlets, in vehicles etc.

6.4 FUTURE ENHANCEMENT

This project can be enhanced by Implementing Image processing for coin

detection system.

BIBLIOGRAPHY



1. M.S. Varadarajan. “Coin Based Mobile Battery Charger” . Veltech Dr.RR and

Dr.SR Technical University Chennai, India Journal of Engineering

(IOSRJEN) ISSN: 2250-3021 Volume 2, Issue 6 (June 2012), PP 1433-1438.

2. David A. Bell, “Electronic Devices and Circuits”, 4th edition, Prentice-Hall of

India Private Limited, 2013.

3. Robert L. Boylestad and Louis Nashelsky, “Electronic Devices and Circuit

Theory”, 9th edition, Pearson Education, 2013.

4. Muhammed Ali Mazidi, Janice Gillispie Mazidi, Rolin.D.Mckinlay, “The

8051 microcontroller and embedded systems”, 2nd edition, Prentice-Hall of

India Private Limited, 2012 reprint.

5. Millman And Halkias, ”Integrated circuits”, 5th edition, Tata McGraw Hill

publications, Pune, 2012.



APPENDIX


Coin based mobile charging using solar tracking system

Science