SOLAR PANEL POSITION CONTROL BY USING DC

MOTOR

TABLE OF CONTENTS

CHAPTER NO TITLE PAGE NO

Abstract

1 INTRODUCTION 1

1.1 Energy Scene 1

1.2 Solar Energy Options 2

1.3 General 3

1.4 Positioning System for Solar Panel 3

1.4.1 Single Access Positioning System 3

1.4.2 Dual Access Positioning System 3

1.4.3 Passive Positioning System 3

2 PRINCIPLE OF OPERATION OF SOLAR PHOTOVOLTICS

2.1 Photovoltaic Effect on Semiconductor 5

2.2 P-Type Semiconductor 6

2.3 N-Type Semiconductor 6

2.4 PN Junction Silicon Solar cell 6

2.5 Purification and Reformation into Wafers 7

2.6 Antireflective Coating 7

2.7 Block Diagram 10

3 COMPONENTS AND THERE FUNCTION

3.1 Sensor 11

3.2 ADC 11

3.3 Micro Controller 12

3.4 Solar Photovoltaic Array 13

3.5 Battery Bank 16

3.6 Charge Controller 17

3.7 Design and Fabrication 18

3.8 Conversion Efficiency and Power Output 20

4 DETAIL VIEW OF MICRO CONTROLLER AND IC’S

4.1 Block Diagram of AT89S52 22

4.2 Pin Description 23

4.2.1 Power on Reset Circuit 24

4.3 Oscillator Clock Circuit of AT89S52 26

4.4 Special Function Registers 26

4.5 Memory Organization 27

5. POWER SUPPLY UNIT

5.1 Power Supply Components 31

5.2 Working Principle 32

6. PCB DESIGN

6.1 Layout Preparation 39

6.2 Painting of PCB 39

6.3 Development of the Printed Circuit Diagram 39

6.4 Etching of PCB 40

6.5 Drilling of Holes

40

6.5.1 Advantages 40

6.5.2 Disadvantages 40

6.6 Material Required 41

7. DC MOTOR DIRECTION CONTROL CIRCUIT

7.1 DC Wiper motor Control Unit 43

7.2 CMOS Switch 43

7.3 DC Motor Direction Control Circuit Unit 43

8. SOLDERING 44

9. ADVANTAGES AND APPLICATIONS 45

10. PROGRAM

47

11. CONCLUSION 51

12. BIBLIOGRAPHY 52

ABSTRACT

This ‘solar position control and automatic power distribution system’ it is a most

advanced embedded based project. This is completely integrated ID program. In industrial

environment the power consumption is very important by using solar position system we can

save the power.

This project titled as” SOLAR PANEL POSITION CONTROL BY USING DC

MOTOR” to develop a system through which we can save the power. Till now in shopping

malls, theaters and House appliances and conference halls and at any another places they are

using the source like generators along with the main power supply, but they are expensive.

That’s why by using the solar power we can generate power economically and this is a natural

power so there is no reduction in the source of power production and also no power wastage in

this system.

In normal solar panel we can get the power only in one direction, so we are unable to

fully utilize the natural resource with this system. That’s why a system is developed through

which we can get the power in all directions on rotating the panel according to the sun position.

Through this system we can increase the output power than normal system. For this one stepper

motor is connected to solar panel. Sun light observers (LDRs) are connected in the circuit

according to change in position of the sun. When corresponding LDRs observe the sunlight. The

output of LDR is in analog form. Microcontroller accepts only digital form. In this we are

interfacing another device called Analog to Digital Converter to convert the generated analog

signal to digital form and to send it to microcontroller. Finally all LDRs value is compare and

selects the LDR of giving more brightness and dc motor will turn on and moves the solar panel

to the position of the corresponding LDR. By this process we can get the more power.

i

BLOCK DIAGRAM:

ii

CHAPTER NO: 1

INTRODUCTION

Sun is the primary source of Energy. The earth receives 16 x 1018 units of energy from

the sun annually, which is 20,000 times the requirement of mankind on the Earth. Some of the

Solar Energy causes evaporation of water, leading to rains and creation of rivers etc. Some of it

is utilized in photosynthesis which is essential for sustenance of life on earth. Man has tried from

time immemorial to harness this infinite source of energy. But has been able to tap only a

negligibly fraction of this energy till today.

The broad categories of possible large scale applications of solar power are the heating

and cooling of residential and commercial buildings.

A. The chemical and Biological conversion of organic material to liquid solid and gaseous

fuels.

B. Conversion of solar energy to Electricity.

In this project we use the solar energy for the generation of electrical energy, by using

solar cells.

The solar cell receives the solar energy. The solar cells operate on the principle of

photovoltaic effect, by using solar cells. Basically the cells are placed in an open and fixed

manner.

1.1 ENERGY SCENERIO

Drastic changes in energy conversion system are anticipated due to shortage of

conventional fuels. Fuel deposit in the world will soon deplete by the end of 2020. Fossil fuel

scarcity will be maximum. The main reasons for the above are due to increasing demand for

electricity, rising population, rapid advance in technology.

It is worthwhile to mention here that indiscriminate use of commercial energy has lead to

serious environment problems like air and water pollutions. Man, when he is embarking on use

of alternate sources of energy should bear in mind, his environment. The creation of new source

of perennial environmentally acceptable, low cost electrical energy as a replacement for energy

from rapidly depleting resources of fossil fuels is the fundamental need for the survival of

mankind

1

1.2 SOLAR ENERGY OPTIONS

Solar energy has the greatest potential of all the sources of renewable energy and it will

be one of the most important sources of energy especially when other sources in the country have

depleted. Solar energy could supply all the present and future energy needs of the world on a

connecting basis. This makes it one of the most promising of the nonconventional energy

sources.

Solar Energy can be a major source of power. Its potential is 178 billion MW which is about

20,000 times the worlds demand. The energy radiated by the sun on a bright sunny day is

approximately 1kw/m2. The problem associated with the use of solar energy is that its

availability varies widely with time. The variations in availability occur daily, because of the

day-night cycle and also seasonally because of Earth’s orbit around the sun. In addition

variations occur at a specific location because of local weather conditions. Consequently the

energy collected with the sun is shining must be stored for use during periods when it is not

available.

Attempts have been made to make use of this energy in raising steam which may be used

in driving the prime movers for the purpose of generation of electrical energy. However due to

large space requirement and uncertainty of availability in constant rate this method becomes

ineffective.

Photovoltaic cell is an alternate device used for power generation which converts suns

radiation directly into electrical power. Thus power generated can be stored and utilized.

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1.3 GENERAL CONCEPT

In 1968 Dr. Peter Glaser in the U.S. Published an idea that centered on the fact that in

orbit close to earth, 1.43 KW of solar energy illuminates may one square meter which is

considerably greater and one more continuous than an anyone square meter on the Earth which,

even when perpendicular to the sun can receive only a maximum of 1 kw. His idea was,

converting sunlight to electricity to convert to a radio frequency signal and beamed down to the

earth carrying significant levels of energy. This electricity is by establishing a very large array of

solar cells in geostationary orbit. A receiving antenna station on the earth would convert this

radio frequency back into an alternate current which would be fed into a local grid.

1.4 Positioning systems for solar Panels

Various positioning structures of the PV panels can be built from a variety of materials and in a

variety of styles. Almost all designs can be made to be seasonally adjustable. All commercial

produced PV panels have a virtual and difficult seasonally adjustment because they are made to

work at a wide range of latitudes

1.4.1 Single-axis positioning systems These have a single axis for the rotation of the PV panel; the East-West motion.

This system is a little complicated it need only a simple motor and a control that turns the solar

array from East to West each day. This maintains the panel in a close proximity to the Sun.

1.4.2 Dual-axis positioning systems

These use both East-West and South-North axes for positioning the solar panel.

During a year, the dual axis system will produce the most amount of power, because one can

follow the changing of the Sun trajectory every season. At the same time, this structure is more

expensive, more complicated for being designed, constructed and maintained.

1.4.3 Passive positioning system

These trackers follow the Sun without having any motors to drive them. The

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Trackers are carefully balanced. The tubes on each side of the tracker are filled with a gas. As the

Sun heats the gas on one side; the gas expands and flows into the other side of the tracker. This

Shifts the delicate balance, and the solar panels automatically tilt toward the Sun. The

Zomeworks tracker has no motor. It is a passive tracker in which the shifting weight of DuPont

Freon refrigerant tips the tracker to follow the Sun. The Freon moves to the cooler of two side

canisters, which because of the position of the shades, causes the rack to follow the Sun. This

simple yet elegant and cost-effective system demonstrates that even modest solar panel

installations can benefit from commercial Sun trackers, as long as the increased efficiencies

justify the added cost.

Passive positioning system

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CHAPTER NO: 2

PRINCIPLES OF OPERATION SOLAR PHOTOVOLTAICS

The solar energy can be directly converted into electrical energy by means of

photovoltaic effect, i.e. conversion of light into electricity. Generation of an electromotive force

due to absorption of ionizing radiation is known as photovoltaic effect.

The energy conversion devices which are used to convert sunlight to electricity by use of the

photovoltaic effect are called solar cells.

Photo voltaic energy conversion is one of the most popular nonconventional energy

source. The photovoltaic cell offers an existing potential for capturing solar energy in a way that

will provide clean, versatile, renewable energy. This simple device has no moving parts,

negligible maintenance costs, produces no pollution and has a lifetime equal to that of a

conventional fossil fuel.

Photovoltaic cells capture solar energy and convert it directly to electrical current by

separating electrons from their parent atoms and accelerating them across a one way.

2.1 Photo Voltaic Effect on Semiconductors

Semi conductors are materials which are neither conductors nor insulators. The photo

voltaic effect can be observed in nature in a variety of materials but semiconductors has shown

best performance. When photons from the sun are absorbed in a semiconductor they create for

electrons with higher energies than the electrons which provide the boarding in the base crystal.

Once these electrons are created, there must be an electric field to induce these higher energy

electrons to flow out of the semiconductor to do useful work. The electric field in most solar

cells is provided by a junction of materials which have different electrical properties.

To understand more about the functioning and properties of semiconductors, let us briefly

discuss. Semi conductors are classified into 1) Extrinsic semiconductor 2) Intrinsic

semiconductor. Semiconductors in its purest form are called intrinsic and when impurities are

added it is called extrinsic. Further extrinsic semiconductors are divided into p type and N type

semiconductor.

2.2 P-Type Semiconductor

When a small amount of pentavalent impurities (e.g. Gallium, Indium, Aluminum, and

Boron) are added to intrinsic semiconductor, it is called as p type semiconductor.

In p type semiconductor, when an electric potential is applied externally, the holes are

directed towards the negative electrode. Hence current is produced.

2.3 N- Type Semiconductors

When a small amount of pentavalent impurities (e.g. Antimony, Arsenic, Bismuth,

Phosphorus) are added to intrinsic semiconductors it is called N type semiconductor.

When an external electrical field is applied the free electrons are directed towards

positive electrode. Hence current is produced.

2.4 PN Junction Silicon Solar Cell

A PN junction is formed from a piece of semiconductor by diffusing p type materials to

one half side and N type materials to other half side.

It consists of both types of semiconductor materials. The N type layer is situated towards

the sunlight. As N type layer is thin, light can penetrate through it.

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The energy of the sunlight will create free electron in the N type material and holes in the p type

material. This condition built up the voltage within the crystal. Because the holes will travel to

the +ve region and the holes will travel to the –ve region. This conduction ability is one of the

main technical goals in fabricating solar cells.

2.5 Purification and Reformation into Wafers

The purification process basically entails high temperature melting of the sand and

simultaneous reduction in the presence of hydrogen. This results in a very pure polycrystalline

form of silicon.

The next step is to reform this silicon into a single crystal and then cut the crystal into a single

crystal and then cut the crystal into individual wafers. There are two methods namely czochralski

growth method and film fed growth. The former method produces single, cylindrical crystals and

later produces continuous ribbon of silicon crystals.

Then this cylindrical crystal and ribbon crystal is transformed into disc shaped cells and

rectangular cells by slicing. After that one side is doped by exposure to high temperature

phosphorus, forming a thin layer of N type material. Similarly p type is made. Electrical contacts

are applied to the two surfaces, an anti-reflection coating is added to the entire surface and the

entire cell is then sealed with protective skin.

2.6 Antireflective Coating

Antireflective coating (arc) is an important part of a solar cell since the bare silicon has a

reflection coefficient of 0.33 to 0.54 in the spectral range of 0.35 to 1.1 cm. The arc not only

reduces the reflection losses but also lowers the surface recombination velocity. A single optimal

layer of ARC can reduce the reflection to 10 percent and two layers can reduce the reflection up

to 3 percent in desired range of wavelengths.

Generally, Arc’s are produced on the solar cell by vacuum evaporation process and the coatings

which are tried are SiO2, SiO, Al2O3, TiO2, Ta2O5 and Si3N4. Other methods of deposition are

sputtering, spin-on, spray-on or screen printing. Only the vacuum evaporation sputtering give

good results but are expensive.

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air The average reflection can be further reduced by using two antireflective coatings instead of

one where the outside (exposed side) coating has an index of refraction 1.3 to 1.6 and the second

layer between silicon and the first layer has an index of refraction 2.2 to 2.6. This two layer ARC

gives a better impedance match between the index of silicon and the index of air.

Fig 2.1 reflective coating

8

Fig 2.2

Fig 2.3

9

2.7 BLOCK DIAGRAM

Fig2.4

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CHAPTER NO: 3

COMPONENTS AND THEIR FUNCTION

The major components of this system are as follows.

1) Input photo transducer (LDR).

2) Analog to digital converter.

3) Microcontroller.

4) Tracking software.

5) Output mechanical transducer (dc motor).

3.1Sensor:

The system consists of two sensors, each composed of LDR. One unit is made up of four

LDRs. These are placed at the four corners of the solar panel. The intensity of sunlight is sensed

by the LDR and the output is sent to the controller. The control unit analyzes it and decides the

direction in which the panel has to be rotated, so that it gets maximum intensity of light.

The other unit of sensor is also composed of LDRs which is meant for the

control of a lighting load.

3.2ADC:

It is a converter which converts analog signal to digital signal. ADC device that

converts a continuous quatity to a discrete time digital representation. An ADC may also provide

an isolated measurement. The reverse operation is performed by a digital to analog converter

(DAC).

Typically, an ADC is an electronic device that converts an input analog voltage or

current to a digital number proportional to the magnitude of the voltage or current

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3.3 Micro controller:

It is the major part of the system. The microcontroller controls all the operations. The solar panel

is aligned according to the intensity of sunlight under the control of the microcontroller.A

microcontroller is a single chip that contains the processor (the CPU), non-volatile memory

for,the program (ROM or flash), volatile memory for input and output (RAM), a clock and an

I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs)

are embedded each year in a myriad of products from toys to appliances to automobiles. For

example, a single vehicle can use 70 or more microcontrollers. The following picture describes a

general block diagram of microcontroller.

AT89S52:

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 pro-grammer. 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-effective

solution to many, embedded control applications. The AT89S52 provides the following standard

features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers,

three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port,

on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for

operation down to zero frequency and supports two software selectable 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-down mode saves the RAM con-tents but freezes the

oscillator, disabling all other chip functions until the next interrupt.

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3.4 solar photovoltaic array

The solar photovoltaic array consists of an appropriate number of solar cells connected in

series and or parallel to provide the required current and voltage. The array is so oriented as to

collect the maximum solar radiation throughout the year.

There may be tracking arrays or modules or fixed arrays. A tracking array is defined as

one which is always kept mechanically perpendicular to the sun array line so that all times it

intercepts the maximum isolation. Such arrays must be physically movable by a suitable prime

mover and are generally considerably more complex than fixed arrays. A fixed array is usually

oriented east west and tilted up at an angle approximately equal to the latitude of the site. Thus

the array design falls into two broad classes:

(I)Flat Plate Arrays

Where in solar cells are attached with a suitable adhesive to some kind of substrate

structure usually semi rigid to prevent cells being cracked.This technology springs from the

space related photovoltaic technology and many such arrays have been built in various power

sizes.

(II) Concentrating Arrays

Where in suitable optics, e.g. Fresnel lenses, parabolic mirrors are combined with

photovoltaic cells in an array fashion. This technology is relatively new to photovoltaic in terms

of hardware development and comparatively fewer such arrays have actually been built.

The hardware is driven by a set of program instructions, or software. Once familiar with

hardware and software, the user can then apply the microcontroller to the problems easily.  

13

The pin diagram of the 8051 shows all of the input/output pins unique to microcontrollers:

The following are some of the capabilities of 8051 microcontroller.

Internal ROM and RAM

I/O ports with programmable pins

Timers and counters

Serial data communication

The 8051 architecture consists of these specific features:

16 bit PC &data pointer (DPTR)

8 bit program status word (PSW)

8 bit stack pointer (SP)

Internal ROM 4k

Internal RAM of 128 bytes.

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4 register banks, each containing 8 registers

80 bits of general purpose data memory

32 input/output pins arranged as four 8 bit ports: P0-P3

Two 16 bit timer/counters: T0-T1

Two external and three internal interrupt sources Oscillator and clock circuits.

PIN DIAGRAM OF AT89S52

It is similar to micro controller 8051, and the pins are also the same.

Features

Compatible with MCS®-51 Products

8K Bytes of In-System Programmable (ISP) Flash Memory – Endurance: 10,000

Write/Erase Cycles

15

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

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

Dual Data Pointer

Power-off flag

3.5 Battery Bank

In most alone PV power systems, storage batteries with charge regulators have to be

incorporated to provide a backup power source during periods of low solar irradiance and night.

Several types of accumulator are available in the market for use in PV power systems. The main

requirements to be met by an accumulator for solar power system are,

Ability to withstand several charge/discharge cycle.

A low self discharge rate

Little or no need for maintenance

16

The capacity of a battery is the total amount of electricity that can be drawn from a fully

charged battery at a fixed discharge rate and electrolyte temperature until the voltage falls to a

specified minimum. It is expressed in ampere hour. The capacity of the battery also depends

upon the temperature and age of battery.

The batteries in most PV systems are of lead acid type consisting of one or more 2v cells.

Each cell has a positive plate of lead peroxide and a negative plate of sponge lead. The

electrolyte is dilute sulphuric acid. During discharging when current is drawn from it, the

material of both plates’ changes to lead sulphate and water content in the electrolyte increases

thereby reducing its specific gravity.

When the battery is charged by passing electric current through it in the opposite

direction, the reverse chemical reaction takes place. The cell voltages are typically 2.4v and 1.9v

for fully charged and deeply discharged battery respectively. Lead acid batteries self discharge

slowly when not in use.

3.6 Charge Controller

Overcharging of some batteries results in loss of electrolytic, corrosion, plate growth and

loss of active material from the plates, causing reduction in battery life. Also, the repeated failure

to reach full charge also leads to stratification of electrolyte.

Thus, there is a need of charge regulators to optimize the battery life. Most charge

regulators start the charging process with a high current and reduce it to a very low level when a

certain battery voltage is reached. A digital based charge regulator monitors the battery current,

and voltage computes the level of charge and regulates the input and output currents so as to

avoid both overcharging and excessive discharging

Load

For continuous operation, we use solar cells for charging DC lamp.

17

3.7Design and Fabrication

The design and fabrication of a typical solar powered fan can be explained with the help

of a block diagram. The block diagram describes a simple solar powered fan with a manual. Let

us study the block diagram in detail by classifying it into three sections.

I) Input Section

a) Photovoltaic array

II) Storage Section

a) Battery bank

III) Output Section

a) Charge controller

b) Dc Bulb

c) Connecting wires

I) Input Section

The input section includes photovoltaic arrays consisting of solar cells. The solar cells are

connected in parallel to get the maximum current.

The characteristics of the solar cell array are as below:

Type of semi conductor used for cell : silicon

Number of arrays : 2

Power : 36 watt x 2 = 72 watt

Open circuit voltage : 21v

Short circuit current : 3.6 ampere

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II) Storage Section

The storage section includes a battery.

The characteristics of the battery are as below:

Type : Lead acid tubular battery

Ampere hour efficiency : 90 to 95%

Watt hour efficiency : 70 to 80%

Capacity: 40 AH, 12V.

The characteristics of controller are as below:

Low voltage cut off

Over charge disconnect

Operating current : 10 ampere

III) Output Section

Output system includes various devices and equipments used for the distribution of the

power.

Switch

* Manual ON/OFF

Wires

* Type: 2 core with sleeve

* Quantity: 10 meters

* High copper rich 10amp wire for minimum power loss.

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3.8 Conversion Efficiency and Power Output

For both practical and theoretical reasons, not all of the solar radiation energy falling on a

solar cell can be converted into electrical energy. A specific amount of energy is required to

produce a free electron and a hole in a semiconductor. Consequently infrared radiation of longer

wavelength has no photovoltaic effect and energy radiation with shorter wavelength cannot be

completely utilized.

The maximum energy in radiation that is capable of producing free electrons and holes in

silicon is only about 45%. The maximum practical efficiency for conversion of solar energy into

electrical energy in a silicon solar cell is estimated to be about 10%

Amount of electricity produced

Conversion Efficiency = --------------------------------------------

Total input of solar energy radiation

The power output of any generator of electricity, including a photovoltaic cell is equal to

the product of the voltage and current.

Theoretically, a silicon solar cell should have a voltage of 1.1 volts, from 1.1 electron volts

energy of the free electrons produced. In practice, however, the maximum voltage is about 0.6

volt and this occurs on open circuit, when no power is produced.

The maximum power of a silicon solar cell occurs at an output voltage of approximately

0.45 volt. In full sunlight, the current from a commercial cell is then roughly 270 amperes per

sq.m of exposed surface. The power is thus about 0.45x270 = 120 watts. The electric power

output of a photovoltaic cell is roughly proportional to the rate at which solar radiation falls on

its surface.

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Most of the solar energy that is not converted into electricity in a photovoltaic cell is absorbed as

heat. In commercial single crystal silicon cell, with a conversion efficiency of about 12 percent,

more than 80 per cent of the incident solar energy appears as heat in cell. High conversion

efficiencies have been reported with cells made from combination of gallium aluminum and

gallium arsenide.

The following specifications are noted down:

Solar isolation = 800 w/m2

Ambient temperature = 34oc

Open circuit voltage = 21V

Short circuit current = 3.42 ampere

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CHAPTER NO: 4

DETAILED VIEW OF MICRO CONTROLLERS & IC’S

4.1 block diagram of AT89S52

  4.1.1 Block diagram of micro controller

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4.2 PIN DESCRIPTION: VCC: Supply voltageGND: Ground.Port 0:

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pincan sink

eight TTL inputs. When 1s are written to port 0 pins, the pins can be used ashigh-impedance

inputs. Port 0 can also be configured to be the multiplexed low-orderaddress/data bus during

accesses to external program and data memory.

Port 1:

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins,they are pulled high

by the internal pull-ups and can be used as inputs. As inputs, Port1 pins that are externally being

pulled low will source current (IIL) because of the internal   pull-ups. In addition, P1.0 and P1.1

can be configured to be the timer/counter2 externalcount input (P1.0/T2) and the timer/counter 2

trigger input (P1.1/T2EX), respectively.

Port 2:

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2output buffers

can sink/source four TTL inputs. When 1s are written to Port 2 pins,they are pulled high by

the internal pull-ups and can be used as inputs. As inputs, Port2pins that are externally

being pulled low will source current (IIL) because of the internalpull-ups. Port 2 emits the

high-order address byte during fetchesfromexternal programmemory and

during accesses to external data memory that use 16- bit addresses(MOVX @ DPTR). In this

application, Port 2 uses strong internal pull- ups when emitting1s. During accesses to external

data memory that uses 8-bit addresses (MOVX @ RI),Port 2 emits the contents of the P2

Special Function register.

23Port 3:

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3output buffers can

sink/source four TTL inputs. When 1s are written to Port 3 pins,they are pulled high by the

internal pull-ups and can be used as inputs. As inputs, Port3pins that are externally being pulled

low will source current (IIL) because of the pull-ups. Port 3 receives some control signals for

Flash programming and verification. Port 3also serves the functions of various special features of

the AT89S52, as shown in the following table

P.3 BIT FUNCTION PIN P3.0 RXD 1.0 P3.1 TXD 1.1 P3.2 INT0’ 1.2 P3.3 INT1’ 1.3 P3.4 T0 1.4 P3.5 T1 1.5 P3.6 WR’ 1.6 P3.7 RD’ 1.7

RST:Reset input. A high on this pin for two machine cycles while the oscillator is running resets the

device. This pin drives high for 98 oscillator periods after the watch dog times out.

4.2.1 power on reset circuit

24 In order for the RESET input to be effective, it must have a minimum duration of two

machine cycles.

ALE/PROG:

Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during

accesses to external memory. This pin is also the program pulse input (PROG) during Flash

programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator

frequency and may be used for external timing or clocking purposes. Note, however, that one

ALE pulse is skipped during each access to external data memory. If desired, ALE operation can

be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during

MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable

bit has no effect if the microcontroller is in external execution mode.

PSEN: Program Store Enable (PSEN) is the read strobe to external program memory.

When the AT89S52 is executing code from external program memory, PSEN is activated twice

each machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA:

External Access Enable. EA must be strapped to GND in order to enable the device to fetch code

from external program memory locations starting at 0000H up to FFFFH. Note, however, that if

lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC

for internal program executions. This pin also receives the 12-volt programming enable voltage

(VPP) during Flash programming.

XTAL1:Input to the inverting oscillator input to the internal clock operating circuit.XTAL2:Output from the inverting oscillator amplifier.

254.3 OSCILLATOR CLOCK CIRCUIT OF AT89S52

It uses a quartz crystal oscillator.

We can observe the frequency on the XTAL2 pin.

The crystal frequency is the basic internal frequency of the microcontroller.

The internal counters must divide the basic clock rate to yieldstandard

communication bit per second (baud) rates.

An 11.0592 megahertz crystal, although seemingly an odd value, yields acrystal

frequency of 921.6 kilohertz, which can be divided evenly by the standard

communication baud rates of 19200, 9600, 4800, 2400, 1200, and 300 hertz

  4.4 SPECIAL FUNCTION REGISTERS The Special Function Registers (SFRs) contain memory locations that are

usedfor special tasks.Each SFR occupies internal RAM from 0x80 to 0xFF.They are 8-bitswide.

The A (accumulator) register or accumulator is used for most ALU operations and

Boolean Bit manipulations.

Register B is used for multiplication & division and can also be used for general

purpose storage.

PSW (Program Status Word) is a bit addressable register.

26

PC or program counter is a special 16-bit register. It is not part of SFR. Program instruction bytes are fetched from locations in memory that are addressed by

thePC. 

Stack Pointer (SP) is eight bits wide. It is incremented register before dataisstored

during PUSH and CALL executions. While the stack may reside anywhere in

on-chip RAM, the Stack Pointer is initialized to 07H after a reset. This causes

the stack to begin at location 08H

DPTR or data pointer is a special 16-bit register that is accessible as two 8- bitregisters

DPL and DPH, which are used to used to furnish memory addresses for internaland

external code access and external data access.

Control Registers: Special Function Registers IP, IE, TMOD, TCON, SCON,

andPCON contain control and status bits for the interrupt system, the

Timer/Counters, and the serial port.

Timer Registers: Register pairs (TH0, TL0) and (TH1, TL1) are the 16-bitCounter

registers for Timer/Counters 0 and 1, respectively.

4.5 MEMORY ORGANIZATION

MCS-51 devices have a separate address space for Program and Data Memory. Up to64K bytes

each of external Program and Data Memory can be addressed. 

Program Memory:

If the EA pin is connected to GND, all program fetches are directed to external

memory. On the AT89S52, if EA is connected to VCC, program fetches to addresses

0000H through 1FFFH are directed to internalmemory and fetches to addresses 2000H through

FFFFH are toexternal memory.

Data Memory:

The AT89S52 implements 256 bytes of on-chip RAM. The upper 128bytes

occupy a parallel address space to the Special Function Registers.Thismeans that the upper 128

bytes have the same addresses as the SFR space but are physically separate from SFR space.

27

When an instruction accesses an internal location above address 7FH, theaddress mode used in

the instruction specifies whether the CPU accesses the upper 128bytes of RAM or the SFR

space. Instructions which use direct addressing access theSFR space.

L293DNE:

L293DNE Quadruple H-Driver used to control 2 bidirectional motors when hooked up to

a motor. I had a lot of trouble recently attempting to get this thing working. All of the tutorials

written involved hooking it up to a microcontroller (I’m going to use the arduino in all examples

from now on), and sending singles with code to change the direction.

The L293DNE has 16 pins. If you’re just driving a single motor you can ignore 5 of those pins

(9-11, 14-15). Pin 16 powers the logic of the controller and should always be set to +5V from

what I’ve been able to gather. Pin 8 provides power for both motors. Often you’ll want a stronger

and independent power source for your motors than from the rest of the logic. Your motor power

source should have its positive node connected to pin 8, and ground connected to the grounds of

pins 4, 5, 12, and 13. Grounds for your logic control source should also be connected to the same

pins.The motor will be connected to pins 3 and 6. The basic idea is that when power is supplied

to pin 2, pin 3 will become positive and pin 6 will become ground for the motor. When power is

supplied to pin 7, pin 6 will become positive and pin 3 will become ground. Depending on which

control pin (2 or 7) you have powered, the polarity of the circuit that’s going through the motor

will change. If neither 2 nor 7 is powered, there will be no circuit going through pin 3 and 6 and

the motor will not be powered.

28

Motor 1 and 2 are turned on and off by pin 1 and 9 respectively. If either of these pins does not

have +5V connected to them, the motor associated with that pin will also not receive power.

One thing that I did not understand from looking at the datasheet for the L293DNE was that

while you can add a voltage to pin 2 or 7 to turn the motor on in either direction, the other pin

must be connected to ground to work. This means that if pin 7 has a +5V but pin 2 is not

connected into the circuit, the motor will not work. The circuit for pin 7 is completed by pin 2

(and visa versa), not the grounds coming from pins 4, 5, 12 or 13. I assume those grounds are

associated with pins 1, 8, 9, and 16, but I haven’t experimented with that and I can’t find that

information in the datasheet.

So, in order to test if your H-Bridge works, do the following:

Quick test for L293DNE without a controller

Pin 1, 2, and 8 should connect to the +5V positive line of your power source. Pins 4, 5, and 7

should connect to ground. Hook pin 3 and 6 up to a multimeter and check the voltage. It should

read around +5V (probably a little less). Change the circuit so pin 2 is hooked to ground and pin

7 is hooked to +5V and check again. The voltage reading should be reversed (-5V or so).

Unhook either pin 2 or 7 and you should see no voltage going through the circuit.

29

pin 2 is set to HIGH and 7 to LOW. What didn’t click for me was that LOW doesn’t mean no

current is going through it, it means ground. By not making the association that LOW = Ground,

I was attempting to just add voltage to 2 or 7 without connecting the other, assuming that pins 4,

5, 12, or 13 would provide the ground for the circuit. This is not the case, the other needs to be

connected to ground.

30

CHAPTER NO:5

POWER SUPPLY UNIT

Power supply is an integral parts a vital role in every system and hence their

design constitutes a major part in every application. In order to overcome mal-operation which

results due to fluctuations in the load and discontinuity in the supply proper choice of power

supply is indeed a great need in this hour.

Firstly power supply is given to the transformer & then we get an a.c output,which is

rectified by rectifier which gives dc supply to the ic voltage regulator regulator then regulates the

voltage,filter then filters the ripples,which is given to the rectifier in turn to the dc motor.

L293DNE will make the motor to rotate which in turn rotates the solar panel from east to west.

5.1 POWER SUPPLY COMPONENTS

TRANSFORMER

FULLWAVE RECTIFIER

VOLTAGE REGULATOR

FILTER CIRCUIT

31

5.2 working principle:

Transformer:

Transformer is a static device, which transfers electrical energy from one alternating

current circuit to another without change in frequency. The working principle behind its

operation is faraday laws of electromagnetic induction, which states that, "whenever current

carrying conductor is moved in a magnetic field, flux linked with the conductor changes and

EMF is induced in the conductor".

Transformer is used in step down mode of operation in the sense it provides an output,

which is reduced in form compared to input. It depends upon number of turns in the winding i.e

turns ratio.

Rectifier:

A rectifier is an electrical device that converts alternating current (AC), which

periodically reverses direction, to direct current (DC), which flows in only one direction. The

process is known as rectification.

Ic voltage regulator:

Voltage regulators comprise a class of widely used ICs. Regulator IC units contain the

circuitry for reference source, comparator amplifier, control device, and overload protection all

in a single IC. Although the internal construction of the IC is somewhat different from that

described for discrete voltage regulator circuits, the external operation is much the same. IC units

provide regulation of either a fixed positive voltage, a fixed negative voltage, or an adjustably set

voltage.A power supply can be built using a transformer connected to the AC supply line to step

the AC voltage to desired amplitude, then rectifying that AC voltage, filtering with a capacitor

and RC filter, if desired, and finally regulating the DC voltage using an IC regulator.

32

The regulators can be selected for operation with load currents from hundreds of milli

amperes to tens of amperes, corresponding to power ratings from milli watts to tens of watts.

LM7805T is used in this project which uses 5 volts.The LM 78xx series of three terminal

regulators is available with several fixed output voltages making them useful in a wide range of

applications. One of these is local on card regulation, eliminating the distribution problems

associated with single point regulation.

Although designed primarily as fixed voltage regulators these devices can be used

with external components to obtain adjustable voltages and currents.

The LM78xx series is available in an aluminium T0-3 package which will allow over

1.0A load current. Current limiting is included to limit the peak output current to a safe value.

Safe area protection for the output transistor is provided to limit internal power dissipation. If

internal power dissipation becomes too high for the heat sinking provided, the thermal shutdown

circuit takes over preventing the IC from overheating. Considerable effort was expanded to

make the LM78xx series of regulators easy to used and minimize the number of external

components.

FEATURES

Output current in excess of 1A

Internal thermal overload protection

No external components required

Output transistor safe area protection

Internal short circuit current limits

Available in the aluminium T0-3 package

33

Filter circuit:

The output of the voltage regulator is given to this filter unit. Filters are

frequency selective electronic circuitry, which allows certain specified band of frequency and

attenuate frequencies other than the specified frequencies.

Basic working Principle:

The basic functional blocks of this system are six sensors1, and their operation depends upon the

intensity of light falling on solar panel. All sensors (each with different functionality) send their

output to microcontroller AT89c52. Then the microcontroller executes predefined task in its

software. These sensors are being used with following names and functionality:

Sun Tracking Sensors (STS)

These two sensors are mounted in “V” shape (figure-6) exactly in the middle of the solar panel

(figure-8). The automatic sun tracking is accomplished according to following 3-step diagram.

Figure6. Basic Automatic Sun Tracking Operation

• Step-1 shows that when the sun is in front of solar panel, both sensors i.e. STS-1 and STS-2 are

getting same amount of light.

• In step-2, after some time as the earth rotates the solar panel gets repositioned with respect to

sun and STS-1 obtains less amount of light. At this point the LDR i.e. STS-1 sends signal to the

microcontroller (figure 3). Then the controller1 rotates motor, resulting the rotation of solar

panel towards the sun.

34

• Finally step-3 shows the reorientation of solar panel. The process continues until the end of

day.

Figure7. Interface of LDR with Microcontroller

Night Time Fault Detector (NTFD)

In routine work of the system if a general fault2 occurs during nighttime then the next morning it

would not work. So at the next sunrise, this sensor detects whether the solar panel is ready for

tracking or not. As shown in figure-8, the NTFD is mounted in east of the solar panel so in

normal conditions it does not work because it gets lesser intense light (predefined) as compared

to the middle sensors i.e. STS-1 and STS-2, but as the fault arises, it starts working.

Day Time Fault Detector (DTFD)

Except some special conditions e.g. cloudy weather etc, the ASTS is supposed to track the sun

the whole day. If the panel stops rotation then DTFD detects this type of fault. The mounting

strategy of this sensor is same as that of NTFD except that it is mounted in the west.

Night and Cloud Detection

In a cloudy day light intensity is less than a normal day. Similarly during night, light intensity is

far less than a cloudy day. So the night and cloud sensors work on this principle to detect the

event. To sense a smaller change in light intensity cloud sensor is more sensitive than the Night

sensor. In case of Night event, the microcontroller stops all operations of the system and

repositions the solar panel towards east to track the sun for next morning.

35

36

CHAPTER NO: 6

PCB DESIGN

PCB design:

37

The connections on the PCB should be identical to the circuit diagram, but while the circuit

diagram is arranged to be readable, the PCB layout is arranged to be functional, so there is rarely

any visible correlation between the circuit diagram and the layout.

PCB layout can be performed manually (using CAD) or in combination with an Autorouter. The

best results are usually still achieved using atleast some manual routing - simply because the

design engineer has a far better judgement of how to arrange circuitry. Surprisingly, many

autorouted boards are often completely illogical in their track routing - the program has

optimised the connections, and sacrificed any small amount of order that may have been put in

place by manual routing. Generally autorouted boards are somewhat harder for a technician to

repair or debug, for this reason.

38

6.1. LAYOUT PREPARATION

With the diagram and all the components at hand, draw a complete layout plan of the

circuit on a sheet of a tracing paper. As a model, for laying the circuit, a thermo Cole base may

be used to hold components. Avoid over crowding of components while making full space

utilization. When all the components have been mounted on the tracing paper sheet fixed on a

piece of thermo Cole base, take out a Sketch Pen for making in such a way that all the

connecting wires are equal in width, termination rounded off. Re-draw it on a fresh paper if

required.

6.2. PAINTING OF PCB

The tracing so prepared has to be imposed over the copper printed circuit board keeping

in view that the component would be mounted from the non-clad side of the board. Take a PCB

lamination sheet and cur a piece of required size of the board by using hacksaw file edges, put

the copper clad sheet on the table keeping side on the runway the dirt grease and oxide with a

sand paper with its marked side tracing the carbon paper and other side on top.

Since the tracing paper is transformed you can now reproduce a carbon point over a

surface but using ball pen on a hard pencil over the drawing on the transparent side. When the

carbon print has been obtained over the copper clad board drill ropes in the board using a hand

drill. The holes may be draw with 1/32 bit for component leads and the carbon should be raised

or wiped by mistake. Paint the Connecting lines with the help of an ordinary paint. Edges should

be scratched with tip of razor blade.

6.3. DEVELOPMENT OF THE PRINTED CIRCUIT DIAGRAM

After painting the board, it will be made by the cool air for sometime. Now take a plastic

tray and get some Fe Cl3 chemical powder. The ferric chloride salt is then added with 500ml of

water. The color of the solution is pink. Color of the salt is in yellow. Now we add three to five

drops of dilute HCL or H2S04. This is necessary to quicken the process.

39

6.4. ETCHING OF PCB

Now we take the painted copper clad board and dip it in the solution kept in the tray.

After 15 to 25 minutes we see the board, with only printed pattern portion remaining in other

places the copper coating is removed due to the chemical action. Then the board is taken out and

washes in water.

After wash the board by using thinner solution. Now a printed circuit has been formed

on the board.

Take fresh water and mix a few teaspoons of Fe CL3 add a few drops of dilute HCL to it,

as it speeds the etching process. Shake well immerse the PCB in the solution for about 20

minutes occasionally altering the solution by giving the seesaw reaction to the disk storing

reduces the etching time. Observe the changing color on the copper surface. Take out the PCB

only when the unpainted portion of the copper surface is completely dissolved in the solution

wash the PCB with the water. After the PCB is thoroughly washed remove the paint by soft

pieces of the cloth dipped in thinner or turpentine.

6.5. DRILLING OF HOLES

Then take a drilling machine with 1/32 drill bit to make holes for the incretion of the

components use 1/18 drill bit for inset wires and other thick components. Now the PCB is ready

to use.

6.5.1 ADVNTAGES:

1. Reliability in operation and low cost.

2. Space required becomes less.

6.5.2 DISADVANTAGES:

It can’t withstand larger weight such as transformer.

40

6.6 MATERIAL REQUIRED

Copper clad sheet [It is made of hylam or nylon board over which the sheet of copper is

pressed.]

“Paint or “Nail polish” or even “PCB Ink”.

Painting brush, tray.

Ferric chloride solution and also few drop of dilute HCL or H2SO4.

Thinner or kerosene or petrol.

Cotton cloth.

Trace paper.

41

CHAPTER NO: 7

DC Motor Direction Control Circuit

4 K7

BEL 1 0 0 N

4007

1 K5

BEL 1 0 0 N

5 4 0 8

R6

L E D -2Q6

4007

2 N 3 0 5 5

1 5 KD3

2 N 3 0 5 5

IC1(A,B,C,D)-4066

4007

Q2 BEL 1 0 0 N

1 K5

D5

IC1(D)

Q4

Q1

P2.1

IC1(C)

L E D -1

+12V

BEL 1 0 0 NIC1(B)

D4

5 4 0 8

1 5 K

8 K2

Q8

R2

1 K

4 K7

M -+ -

IC1(A)

D2

2 N 3 0 5 5Q5

Q7

2 N 3 0 5 5

P2.1D1

4007

D6

Q3

8 K2

Fig 4.5 DC Motor Direction Control Circuit

42

7.1 DC WIPER MOTOR CONTROL UNIT

It controls the direction of rotation of the DC wiper motor, when in mechanically coupled

to the gear shaft. The signal output from the micro – controller is given to the motor control unit

through the CMOS bilateral switch.

7.2 CMOS Switch

Here, an ‘N’ type and a ‘P’ type MOSFETs are effectively wired up in inverse parallel

(Drain to source & source to Drain), but have their gates biased in antiphrasis from the control

terminal via a pair of inverters.

7.3 DC Motor Direction Control Circuit unit

Of the many circuits regarding direction control of DC motors use the DPDT relays,

which are noisy, while some circuit has dual polarity power supply, which is expensive. In

addition, using push – pull stage require dual supply voltage. However, this circuit is unique as it

can reverse the motor direction noiseless and efficiently using uni-polar power supply.

43

CHAPTER NO: 8

SOLDERINGSolder is an alloy of tin and lead used for using metals relatively low temperature about

260-315k the point where two metal conductors are to be fused is heated and then solder is

applied so that it can melt and cover the connection. The reason for soldering connection is that

it makes a good blend between the joined metals.

Covering the joint completely is to prevent oxidation. The coating of solder provides

protection for practically an in definitive period of time. The trick in soldering is to heat the

joint, not the solder. When the joint is not enough to melt the solder the cracks, forming a shifty

cover without until the solder has set, which takes only a few seconds. Either a soldering gun

can be used, rated at 25-10,000. The gun is convenient for the intermittent operation, since it

heats almost instantaneously when for press the trigger. The small pencil iron of 25-4,000 is

helpful or small connections where excessive heat can cause damage. This precaution is

particularly important when working on PCB boards, where too much heat can soften the plastic

form and loosen the printed writing, a soldering iron for F&T devices should have the tip ground

to eliminate static charge.

The three grades of solder, generally used for electronics work are 40-60, 50-50, 60-40

solder. The 60-40 solders costs more but it melts at the lowest temperature flows more freely

takes less time to harder, and generally makes it easier to do a soldering job.

In addition to the solder there must be flux to move any oxide film on the metals

being joined otherwise they cannot fuse. The flux enables the molten solder to wet the

metals so that the solder can stick. The two types are acid flux and rosin flux.

Acid flux is more active in cleaning metals but is corrosive. Rosin flux is always used

for the light soldering work in making wire connection.

44

CHAPTERNO: 9

ADVANTAGES AND APPLICATIONS

APPLICATIONS:

Solar tracking system is used in satellite as a source of fuel

It is used in thermal collector to collect the heat

It is used in solar hot water panel that uses the sun's energy to heat a fluid ,

which is used to transfer the heat to a heat storage vessel.

It is used in water heaters.

It is used in heat exchangers.

It is used in solar power plants.

It is used for desalination of sea water.

It is used in inverters (AC to DC).

It is used in solar water pumps.

45

ADVANTAGES:

The tracking system is not constrained by the geographical location of installation of the

solar panel.

It is designed for searching the maximum solar irradiance in the whole azimuth and tilt

angle.

The operator interference is minimal because of not needing to be adjusted.

They are working with freely available solar energy, hence fuel cost is zero.

They have a long effective life.

They are highly reliable

Operating cost, maintenance costs are minimum as compared to the other type of power

generation systems.

46

10.PROGRAM

#include <16F73.h>

#device adc=8

#FUSES NOWDT //No Watch Dog Timer

#FUSES XT //Crystal osc <= 4mhz

#FUSES NOPUT //No Power Up Timer

#FUSES NOPROTECT //Code not protected from reading

#FUSES NOBROWNOUT //No brownout reset

#use delay(clock=4000000)

#define STEP_DELAY 200

#include "lcdx.c"

volatile struct

{

unsigned int stepper_nibble:4;

unsigned int unused:4;

}portc={0,0};

enum ldr

{LDR1=0,LDR2,LDR3,LDR4,V_METER};

#byte TRISC = 0x87

#byte portc = 0x07

unsigned int read_adc_channel(unsigned int);

void step_clockwise(void);

47

void step_anticlockwise(void);

void main()

{

unsigned int x,y;

float vltg = 0.0f;

setup_adc_ports(ALL_ANALOG);

setup_adc(ADC_CLOCK_INTERNAL);

lcd_init();

TRISC = 0;

while(TRUE)

{

x = (read_adc_channel(LDR1) + read_adc_channel(LDR2))/2;

y = (read_adc_channel(LDR2) + read_adc_channel(LDR3))/2;

if(x-y < 10 && x-y > -10);

else if(x > y)

{

step_clockwise();

}

else if(x < y)

{

step_anticlockwise();

}

vltg = (float)read_adc_channel(V_METER)*12/(float)255;

vltg += vltg*.048f+0.4f;

printf(lcd_putc,"\fVoltage = %2.2f",vltg);

}

}

48

unsigned int read_adc_channel(unsigned int channel)

{

set_adc_channel(channel);

delay_us(20);

return read_adc();

}

void step_clockwise()

{

switch(portc.stepper_nibble)

{

case 0:

portc.stepper_nibble = 0x01;

break;

case 1:

portc.stepper_nibble = 0x02;

break;

case 2:

portc.stepper_nibble = 0x04;

break;

case 4:

portc.stepper_nibble = 0x08;

break;

case 8:

portc.stepper_nibble = 0x01;

break;

}

delay_ms(200);

}

49

void step_anticlockwise()

{

switch(portc.stepper_nibble)

{

case 0:

portc.stepper_nibble = 0x08;

break;

case 1:

portc.stepper_nibble = 0x08;

break;

case 2:

portc.stepper_nibble = 0x01;

break;

case 4:

portc.stepper_nibble = 0x02;

break;

case 8:

portc.stepper_nibble = 0x04;

break;

}

delay_ms(STEP_DELAY);

}

50

11.CONCLUSION

This project which was enhanced with the scope of conserving the conventional fuels is

successfully completed. The main objective, to increase the usage of renewable energy source

for power generation is perfectly implemented. Taking into consideration the future energy

scenario in the world, solar energy would be a major energy source. To collect the greatest

amount of energy from the sun, solar panels must be aligned orthogonally to the sun. For this

purpose, a new solar tracking technique based on micro-controller was implemented and tested

in this study. There are several new solar cell concepts that aim at making better use of

the solar spectrum and achieve much higher energy conversion efficiencies

51

12.BIBLIOGRAPHY

1. Non-conventional sources of Energy

– By G.D. Rai

2. Solar Power Engineering

- By B.S. Magal

3. Solar Energy – The Infinite source

- By G.K.Ghosh

4. Direct Solar production of Electricity

- By Dr.L.W. Davies

5. Solar Energy

- HP. Garg

J. Prakash

6. Solar Engineering

- Duffee and Beckman

52