SENGUNTHAR ENGINEERING COLLEGE
Mechanical Engineering Department
Tiruchengode-637205,
Nammakal (Dist),
Tamil Nadu.
(Approved by AICTE, New Delhi)
A different ride
By
Differently abled persons
[Eye ball Wheel chair]
By,
R.RAMESH KRISHNAN, T.MOHAMMED THARIQ,
Final Year, Final Year,
[email protected], [email protected],
C.N:9003808741. C.N:9585109876.
ABSTRACT:
To operate the wheel chair of a paralyzed patient using their eyeball movement using embedded system.
It is very difficult to understand the emotions of the paralyzed patients, care them and to move them according to their wish. To solve this problem this system is implemented.
The system consists of the eyeball sensor, which detects the movement of the eyeball of the paralyzed patient and sends the information to the microcontroller. The microcontroller processes the signals coming from the eyeball sensor and controls the wheel accordingly. The moments of the wheelchair that can be controlled by the microcontroller are forward, right and left.
When the eye moves to the left side the wheelchair moves to the
left side. When the eye moves to the right side the wheelchair moves to the right
side . When the eye looks straight wheelchair moves in forward direction. To control the action of the wheel chair motors are used. The motors are drive by the motor drivers.
The motors are coupled with the wheels and the wheels are attached to the wheelchair mechanism.
GENERAL BLOCK DIAGRAM:
EyeballSensor
Microcontroller
BufferBattery
Left Side Motor Driver
Right Side Motor Driver
Right MotorLeft Motor
Right WheelLeft Wheel
Wheel Chain Mechanism
MICRO CONTROLLER:
The difference
between
Microprocessor and
Micro controller is
Microprocessor can
only process with the
data, Micro controller
can control external
device.
That is if you want
switch “ON” or
“OFF” a device, you
need peripheral ICs to
do this work with
Micro controller you
can directly control the
device.
INTRODUCTION TO ATMEL MICROCONTROLLER:
SERIES: 89S51 Family, TECHNOLOGY: CMOS
The major Features of 8-bit Micro controller ATMEL
89S51:
8 Bit CPU optimized for control
applications
Extensive Boolean processing
(Single - bit Logic ) Capabilities.
On - Chip Flash Program Memory
On - Chip Data RAM
Bi-directional and Individually
Addressable I/O Lines
Multiple 16-Bit Timer/Counters
Full Duplex UART
Multiple Source / Vector / Priority
Interrupt Structure
On - Chip Oscillator and Clock
circuitry.
On - Chip EEPROM
SPI Serial Bus Interface
Watch Dog Timer
ANALOG TO DIGITAL CONVERTER:
ADC 0809 analog
to digital converter is a
successive
approximation type
analog to digital
converter. The
successive
approximation technique
uses a very efficient
code search strategy to
complete n-bit
conversion in just n-
clock periods. The
circuit uses a successive
approximation register to
find the required value
by trial and error. The
ADC0809 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 converter features a
high impedance chopper
stabilized comparator, a
256R voltage divider
with analog switch tree
and a successive
approximation register.
Fig 5.7 Pin Diagram of ADC0809
OPERATION OF THIS CIRCUIT:
With the arrival
of START command,
the SAR sets the MSB
d1=1 with all other bits
to zero so that the trial
code is 10000000. The
output of the ADC is
now compared with
analog input. If input is
greater than the DAC
output then 10000000 is
less than the correct
digital representation.
The MSB is left at ‘1’
and the next lower
significant bit is made
‘1’ and further tested.
However, if input is less
than the DAC output,
then 10000000 is greater
than the correct digital
representation.
+- 1
0u
10
0n
22
0
CQ
X3
5A
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
d0
d1
d2
d3
d4
d5
d6
d7
START
ALE
EOC
O/P EN
CLK
ADDRESS
GND Vref (-)
ADC0809
A
N
A
L
O
G
I/P
+5V
Vcc Vref (+)
26
27
28
1
2
3
4
5
21
20
19
18
8
15
14
17
6
22
7
9
10
25
24
2313 16
11 1
A/D converter Circuit Diagram
CIRCUIT DESCRIPTION:
The output from the filter
is given to pin 26 of ADC
0809 shown in fig .The
address channels A,B,C
are grounded so that
channel 1 is enabled. The
digitized output from the
converter is given to
port 0 of micro
controller. The filter
capacitors in the circuit
remove the low and
high frequency noises.
The control signals
from the ADC are
given to port 2 of the
microcontroller. This
circuit follows the
principle of successive
approximation method
and when the start of
conversion goes high,
it marks the beginning
of the process and high
end of conversion
marks the end of it.
LIGHT DEPENDENT RESISTOR (LDR):
LDRs or Light
Dependent Resistors are
very useful especially in
light/dark sensor circuits.
Normally the resistance
of an LDR is very high,
sometimes as high as
1000 000 ohms, but
when they are
illuminated with light
resistance drops
dramatically.
A photoresistor
or light dependent
resistor or cadmium
sulfide (CdS) cell is a
resistor whose resistance
decreases with
increasing incident light
intensity. It can also be
referred to as a
photoconductor.
A photoresistor is
made of a high
resistance
semiconductor. If light
falling on the device is
of high enough
frequency, photons
absorbed by the
semiconductor give
bound electrons enough
energy to jump into the
conduction band. The
resulting free electron
(and its hole partner)
conduct electricity,
thereby lowering
resistance.
LCD DISPLAY:
Liquid crystal cell
displays (LCDs) are used
in similar applications
where LEDs are used.
These applications are
display of display of
numeric and
alphanumeric characters
in dot matrix and
segmental displays.
LCDs are of two types:
I. Dynamic
scattering type
II. Field effect
type
The construction of a
dynamic scattering
liquid crystal cell.
The liquid crystal
material may be one
of the several
components, which
exhibit optical
properties of a crystal
though they remain
in liquid form. Liquid
crystal is layered
between glass sheets
with transparent
electrodes deposited
on the inside faces.
When a
potential is applied
across the cell,
charge carriers
flowing through the
liquid disrupt the
molecular alignment
and produce
turbulence. When the
liquid is not
activated, it is
transparent. When
the liquid is activated
the molecular
turbulance causes
light to be scattered
in all directions and
the cell appeas to be
bright.
This phenomenon is
called dyanamic
scattering.
The
construction of a
field effect liquid
crystal display is
similar to that of the
dynamic scattering
type,with the
exception that two
thin polarizing
optical filters are
placed at the inside
of each glass sheet.
The liquid crystal
material in the field
effect cell is also of
different type from
employed in the
dynamic scattering
cell. The material
used is twisted
nemayic type and
actually twists the
light passing through
the cell when the
latter is not
energised.
Liquid crystal cells are
of two types:
i. Transmittive type
ii. Reflective
type
In the
transmittive type cell,
both glass sheets are
transparent, so that light
from a rear source is
scattered in the forward
direction when the cell is
activated.
OVER ALL CIRCUIT
DIAGRAM:
OPERATI
ON:
LEFT
MOMEMEN
T:
The person who
used that wheel chair
should wear the glass,
in that glass consist
three LDR and two
LED. The LED
transmits some light in
your eyes. Normally
the whight color
absorb and reflect the
light energy, but black
color only absorbs the
light energy doesn’t
reflect. If that person
see left side means that
left LDR gets less
intensity compare to
other two
LDRS,because the
person’s eye ball in
front of left LDR.
According to
LDR working
principle,
I α 1/R
Due to less
intensity in left LDR
that LDR has high
resistance value.In
LDR transmits the
analog value at high
resistance only.So,that
particular analog
voltage send to the
ADC,that covets
analog to
digital.Because before
that process we set
some initial digital
values depends on your
eye intensity level,how
means if that person
change eye ball
position the display
shows some value.
That value has been
stored by using the
enter
switch .Afterwards
make some
adjustments by using
min and max switch,
because avoid the
lightening errors.
Now the output
of ADC and the
display setting value
both are digital values,
these two inputs are
given to the
microcontroller. The
microcontroller
performs the
comparision process it
will compare both the
values.If the output of
ADC coincidence with
left value of diplay
setting,it produded the
output.The output of
microcontroller is
given to left motor
drive because left
value is match.
Now the the left
motor drive output is
given to left side
motor,so the left wheel
rotates backward
direction.But the right
motor rotates forward
direction.So the wheel
now moves towards
left direction.
RIGHT
MOMEMENT:
The the person
who used that wheel
chair should wear the
glass, in that glass
consist three LDR and
two LED.The LED
transmits some light in
your eyes.Normally the
whight colour absorb
and reflect the light
energy,but black
colour only obsorbs the
light energy doesn’t
reflect.If that person
see right side means
that right LDR gets
less intensity compare
to other two
LDRS,because the
person’s eye ball in
front of right LDR.
According to
LDR working
principle,
I α 1/R
Due to less
intensity in right LDR
that LDR has high
resistance value.In
LDR transmits the
analog value at high
resistance only.So,that
particular analog
voltage send to the
ADC,that covets
analog to
digital.Because before
that process we set
some initial digital
values
depends on your eye
intensity level,how
means if that person
change eye ball
position the display
shows some value.That
value has been stored
by using the enter
switch .Afterwards
make some adjesments
by using min and max
switch,because avoid
the lightening errors.
Now the output
of ADC and the
display setting value
both are digital
values,these two inputs
are given to the
microcontroller.The
microcontroller
performs the
comparision process it
will compare both the
values.If the output of
ADC coincidence with
right value of diplay
setting,it produded the
output.The output of
microcontroller is
given to right motor
drive because right
value is match.
Now the the
right motor drive
output is given to right
side motor,so the right
wheel rotates backward
direction.But the right
motor rotates forward
direction.So the wheel
now moves towards
right direction.
FRONT
MOVEMENT:
The person looks
straight means middle
LDR gets the less
intensity,because your
eye ball in front of
middle
LDR.According LDR
working principle,
I α 1/R
In that the
resistance value is high
because of less
intensity.So that
middle LDR only
transmits the analog
voltage to the
ADC,that ADC
converts analog to
digital.Because the
presetting front value
is also digital
value.The ADC and
the DISPLAY output
both are given the
input of
microcontroller.The
microcontroller
compares both the
ADC and DISPLAY
values.If front value is
match.So the supply is
given to both the left
and right motor.The
left motor produces the
torque,the left wheel
rotates.Same as the
right motor produces
the torque,the right
wheel rotates.Now
finally the moves
towards the forward
direction without any
other movements.
STOP:
The person closed
the eyes means no one
LDR gets the reflects.
So the motor drives
also cannot gets the
supply.So now the
wheel chair is at the
stop position.
FEATURES:
The cost of this
product is very
less compare to
remote
controlled wheel
chair.
Once purchase
this product use
life long .
If it useful for
all kind of
people because
change the
presetting value
is very easy.
Improve the
disable people
self-
confidence,beca
use they move
theirself. No
others help.
Output is more
accuracy
compare to
remote
controlled wheel
chairs.
Simple
construction
apart from
wheelchair
additionally we
need one circuit
board and two
DC series
motors.
CONCLUSION:
By using our project To operate the wheel chair of a paralyzed patient using
their eyeball movement using embedded system.The paralyzed patients, care them and
to move them according to their wish. To solve this problem this system is implemented.
The system consists of the eyeball sensor, which detects the movement of the eyeball of the paralyzed patient and sends the information to the microcontroller.the microcontroller processes the signals coming from the eyeball sensor and controls the wheel accordingly. The moments of the wheelchair that can be controlled by the microcontroller are forward, right and left.