Transcript description - Study Channel

CONTENTS
INTRODUCTION
DESCRIPTION OF THE PROJECT- CIRCUIT DIAGRAM
HARDWARE DESCRIPTION
MICROCONTROLLERS
U.L.N 2003 LINEAR INTEGRATED CIRCUIT
A/D CONVERTER
STEPPER MOTOR
LCD UNIT
LM 555 TIMER
SOFTWARE DESCRIPTION
INTRODUCTION
SOURCE CODE
APPLICATIONS
DRAWBACKS
ADVANTAGES
CONCLUSION
INTRODUCTION
“SOLAR TRACKING SYSTEM” - used to control
and set the moment of solar panels.

 This
system uses stepper motor to control the
angle of rotation of the panels.
Rotation
of stepper motor through the desired angle
is achieved by using Keil cross compiler.
The
basic idea of the project is to increase the
efficiency of the solar systems.
The
solar panel is made to rotate in all
the directions facing the sunlight.
Tracks
the maximum intensity position and rests
in that position
DESCRIPTION OF THE
PROJECT
CIRCUIT DIAGRAM
HARDWARE DESCRIPTION
Features of microcontroller:

Compatible with MCS-51® Products

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 1000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

The AT89S52 is a low-power, high-performance
CMOS 8-bit microcontroller

The device is manufactured using Atmel’s highdensity non-volatile memory technology

Compatible with the industry-standard 80C51
instruction set and pin out.
PIN CONFIGURATION
ULN 2003 LINEAR INTEGRATED
CIRCUIT
DESCRIPTION:

UTC(unisonic technologies co. ltd)

ULN 2003- high-voltage , high-current Darlington
driver

Comprises of seven NPN Darlington pairs

Ideally suited for interfacing between low-level
logic circuitry and multiple peripheral power
loads
 The series ULN2003A/L high-voltage ,
high-current
Darlington arrays
feature
continuous load current ratings to 500mA
for each of the seven drivers.

The
ULN2003A/L
have
resistors selected for operation
5V TTL or CMOS
series input
directly with
 The outputs are capable of sinking 500mA
and will with stand at least 50V in the
OFF state.

Outputs may be paralleled
current capability.
for higher
load
 The
Darlington arrays are furnished in 16-pin
Dual-in-line plastic package and 16-lead surfacemountable SOIC’s .
 All
devices are pinned with outputs opposite
inputs to facilitate ease of Circuit board layout .

All devices are rated for operation over the
temperature range of -20˚ C to 85˚ C .
FEATURES
 Output
current (single output) 500mA
MAX
 High sustaining voltage output 50V
MIN .
 Output clamp diodes .
 Inputs compatible with various types of
logic .
 Dual In-Line Plastic Package or SmallOutline IC Package.
PIN CONFIGURATIONS
STEPPER MOTORS

Stepper Motor is widely used in CNC
machine drives , robots, and wherever an
accurate positioning is required . In such
applications, step angle , direction , operating
modes( single coil or double coil),

Speed and position are important considerations.
WHAT IS A STEPPER MOTOR ??

Stepper motor is a simple dc motor with a
permanent magnet rotor and a stator with
armature consisting of coils.
 These
coils produce a magnetic field when
suitable current flows through them this field
produces a torque in the rotor which makes it
rotate.
 Well
these are a little more complicated
to control than the simple DC motors but
these provide exact step wise rotation with
an overall turn of 1.8 degrees / step .
The
step wise motion can be easily
controlled by a stepper controller which is
a simple circuit which takes digital logic
and then uses it to turn the motor step
wise .
Driving Uni polar Stepper Motors Using
C51/C251 Introduction

Stepper motors are commonly used in accurate
motion control.

They allow to control any motion with high precision
by counting the number of steps applied to the motor.

Most of systems controlling stepper motors are
embedded systems such as printer scanner or floppy disk
drive.
This
application note describes how to drive a uni polar
stepper motor with the Programmable Counter Array of an
Atmel C51/C251 microcontroller
Identification of Stepper
Motor

There are several types of
stepper motors, these cannot
be driven in the same way. In
this application note, we have
chosen to drive a unipolar
stepper motor For more
information you will find
schemes to identify the other
types of stepper motors.
 Unipolar Stepper Motor
Unipolar stepper motors are
characterised by their centertapped windings.
Variable Reluctance Variable reluctance stepper motor (also called hybrid motors)
are characterized by one common lead.
Driving Uni polar Stepper Motors
(ONE PHASE STEPS)
TWO PHASES ON STEPS
SOLAR PANELS AND SOLAR
CELLS
LM555 Timer :
General Description:





The LM555 is a highly stable device for generating
accurate
time delays or oscillation . Additional terminals are provided
for triggering or resetting if desired . In the time delay
mode of
operation , the time is precisely controlled by one external
resistor
and capacitor . For astable operation as an oscillator,the free
running frequency and duty cycle are accurately controlled
with two external resistors and one capacitor. The circuit
may be triggered and reset on falling waveforms , and the
output circuit can source or sink up to 200mA or drive
TTL circuits.
ASTABLE OPERATION

If the circuit is connected
as shown in Figure ( pins 2
and 6
 Connected ) it will trigger
itself and free run as a
multivibrator.
 The external capacitor
charges through RA + RB
and discharges
 through RB. Thus the duty
cycle may be precisely set
by the ratio of these two
resistors .
A/D CONVERTER
Features:
 Easy interface to all microprocessors
 Operates ratiometrically or with 5 VDC or analog
span adjusted voltage reference
 No zero or full-scale adjust required
 8-channel multiplexer with address logic
 0V to 5V input range with single 5V power
supply
 Outputs meet TTL voltage level specifications
 Standard hermetic or molded 28-pin DIP package
 28-pin molded chip carrier package
DESCRIPTION

The ADC0808, data acquisition component is a monolithic, CMOS
device with an 8-bit analog-to-digital converter , 8-channel multiplexer
and microprocessor compatible control logic . The 8-bit A/D converter
uses successive approximation as the conversion technique . The
converter features a high impedance chopper stabilized comparator , a
256R voltage Divider with analog switch tree and a successive
approximation register . The 8-channel multiplexer can directly access
any of 8-single-ended analog signals .Easy interfacing to
Microprocessors is provided by the latched and decoded multiplexer
address inputs and latched TTL TRI-STATE® outputs .
PIN CONFIGURATION
LCD UNIT
FEATURES:

Interface with either 4-bit or 8-bit microprocessor.

Display data RAM (80 characters).

Character generator ROM(160 character patterns)

Character generator RAM(8 different user programmed
patterns)
Display
data RAM and character generator RAM
may be accessed by the microprocessor.
Numerous
instructions (Clear Display , Blink
Character , Cursor Shift , Display Shift, etc.)
Built-in
reset circuit is triggered at power ON.
Built-in
oscillator.
SOFTWARE DESCRIPTION:

The C programming language is a general – purpose
programming language

C is not a big language and is not designed for any
one particular area of application .

Its generality combined with its absence of restrictions
makes C a convenient and effective programming
solution for a wide variety of software tasks .

Many applications can be solved more easily and
efficiently with C than with other more specialized
languages.

The Cx51 Optimizing C Compiler is a complete
implementation of the American National Standards
Institute (ANSI) standard for the C language .
.
Cx51 provides you with the flexibility of
programming in C and the code efficiency and speed of
assembly language .
Since
Cx51 is a cross compiler standard libraries are
altered or enhanced to address the peculiarities of an
embedded target processor.
SOURCE CODE
#include<reg52.h>
void lcd_string1(unsigned char *);
void lcd_string2(unsigned char *);
void lcd_command(unsigned char);
void lcd_data(unsigned char);
void lcd_init(void);
void lcd_delaybig(void);
void lcd_delaysmall(void);
void delay(void);
void delayvar(unsigned int);
void test(void);
void powinit(void);
void clkwise(int);
void aclkwise(int);
void timer0 (void);
void dispnum(unsigned char a);
unsigned char getadc( void);
void scan(void);
void main( void)
{
powinit();
test();
while(1)
{
timeout=10000;
toutstart=1;
while(!toutend);
toutend=0;
toutstart=0;
scan();
}
}
//LCD interface functions
void lcd_init()
{
lcd_port=0;
RS=0;
RW=0;
EN=1;
EN=0;
lcd_delaybig();
lcd_command(0x38); //2 lines & 5x7 matrix
lcd_command(0x38); //2 lines & 5x7 matrix
lcd_command(0x0e); //Display on, cursor blinking
lcd_command(0x01); //Clear display screen
lcd_command(0x6); //Shift cursor to right
lcd_command(0x80); //Force cursor to beginning of 1st line
}
void lcd_command(unsigned char command)
{
lcd_port=command;
RS=0;
RW=0;
EN=1;
EN=0;
lcd_delaysmall();
}
void lcd_data(unsigned char lcddata)
{
lcd_port=lcddata;
RS = 1;
RW = 0;
EN = 1;
EN = 0;
lcd_delaysmall();
}
void lcd_string1(unsigned char *p)
{
unsigned int i;
lcd_command(0x80);
for(i=0;i<16;i++)
lcd_data(' ');
lcd_command(0x80);
while(*p!=0)
{
lcd_data(*p);
p++;
}
}
void lcd_string2(unsigned char *p)
{ unsigned int i;
lcd_command(0xc0);
for(i=0;i<16;i++)
lcd_data(' ');
lcd_command(0xc0);
while(*p!=0)
{
lcd_data(*p);
p++;
}
}
void powinit(void)
{
EA=1;
ET0=1;
PT0=1;
TMOD=1;
TL0=0X2F;
TH0=0XF8;
TR0=1;
stport=0;
adcport=0xff;
//2ms at 12 MHz
SOC=0;
EOC=1;
ALE=0;
//AI=0;
//BI=0;
//CI=0;
toutstart=0;
toutend=0;
timeout=0;
curpos=5;
lcd_init();
}
void test(void)
{
lcd_string2("TEST");
clkwise(5);
aclkwise(5);
void clkwise(int psteps)
{
unsigned char stval,st;
int steps;
for(steps=0;steps<(psteps*2);steps++)
{
stval=0x10;
for(st=0;st<4;st++)
{
stport=stval;
stval<<=1;
delayvar(9000);
}
}
}
void aclkwise(int psteps)
{
unsigned char stval,st;
int steps;
for(steps=0;steps<(psteps*2);steps++)
{
stval=0x80;
for(st=0;st<4;st++)
{
stport=stval;
stval>>=1;
delayvar(9000);
}
}
}
void scan(void)
{
unsigned char i,maxval,maxpos,temppos;
aclkwise(curpos);
for(curpos=0;curpos<10;curpos++)
{
sundata[curpos]=getadc();
clkwise(1);
lcd_string1("SCANNING AT");
dispnum(curpos);
lcd_string2("VALUE IS ");
dispnum(sundata[curpos]);
delayvar(0xaaaa);
}
maxval=sundata[0];
maxpos=0;
for(i=1;i<10;i++)
{
if(maxval<sundata[i])
{
maxval=sundata[i];
maxpos=i;
}
lcd_string1("MAX O/P AT: ");
lcd_data(maxpos+48);
lcd_string2("MAX O/P V: ");
dispnum(maxval);
temppos=curpos-maxpos;
curpos=maxpos;
aclkwise(temppos);
}
FLOW CHART
APPLICATIONS

Solar tracking system is used in satellites as a
source of fuel.

It is used in solar thermal collector to collect 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.
DRAWBACKS
Tracker
is affected by temporal variations in the
atmospheric refractions caused by rain, cloud, etc.
Thus,
the system may give an erroneous detection in
the direction of the sun, and lead to wrong positioning of
the solar panel.
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.
CONCLUSION

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