Transcript LINE FOLLOWER ROBOT

Automatic accident
avoiding system
PROJECT MEMBERS
MUTHUKUMAR.K (05ME33)
SAKTHIDHASAN.S (05ME39)
SAKTHIVEL.N
(05ME40)
VINOTH.S
(05ME56)
PROJECT GUIDE:
Mr.S.MURALI M.E.
ABSTRACT
. The robot has four sensors installed underneath the front and
bottom part of the body, and two DC motors drive wheels
moving forward.
• Circuits inside takes an input signal from two sensors and
controls the speed of wheels’ rotation.
• The control is done in such a way that when a sensor senses a
backline, the motor slows down or even stops. Then the
difference of rotation speed makes it possible to make turns.
For instance, in the figure on the right, if the sensor somehow
senses a black line, the wheel on that side slows down and the
robot will make a right turn.
PREVIEW OF FIRST REVIEW:
IR SENSOR:
1. The resistance of the sensor decreases when
IR lights falls on it.
2. A good sensor will have near zero resistance
in presence of light and very large Resistance
in absence of light. The LED goes out and
the output is HGH when the sensor is
positioned over a white or light surface
MOTOR INTERFACE AND
CONTROL CIRCUIT
PIN DIAGRAM:
VIEW OF CONTROLLER:
• The Controller used in the Line Follower
Vehicle is ATMEL89S52
• It is a 40 pin microcontroller.
• It is a low power, high performance
CMOS 8-bit Microcontroller.
FEATURES:
•8K Bytes of In-System Programmable (ISP) Flash
Memory
• 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
PIN DISCRIPITION
PORT0
• Port 0 is an 8-bit open drain bidirectional I/O port. As an output port,
each pin can sink 8 TTL inputs.
• When 1s are written to port 0 pins, the pins can be used as highimpedance inputs.
• Port 0 can also be configured to be the multiplexed low-order
address/data bus during accesses to external program and data
memory. In this mode, P0 has internal pull-ups. Port 0 also receives
the code bytes during Flash programming and outputs the code
bytes during Program verification.
• Input device (Sensor) is connected to port 0 pins
PORT2
• Port 2 is an 8-bit bidirectional I/O port with internal pullups.
• The Port 2 output 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.
• The input of the Driver circuit is connected to the port 2
Pins
• VCC
Supply voltage is given at pin 40.
• GND
Ground is connected at pin 20.
• PORT 3
Enable pins of the driver circuit are connected to port 3
• XLAT1
Input to the inverting oscillator amplifier and input to the
internal clock operating circuit.
• XLAT2
Output from the inverting oscillator amplifier.
• RST
Reset input is connected at pin 9. A high on this pin for
two machine cycles while the oscillator is running resets
the device.
Driver circuit:
• The L298 Motor Driver has 4 inputs to control the
motion of the motors and two enable input which is
used for switching the motors on and off.
• To control the speed of the motors a PWM waveform
with variable duty cycle is applied to the enable pins.
Rapidly switching the voltage between Vs and GND
gives an effective voltage between Vs and GND whose
value depends on the duty cycle of PWM
• 1N4004 diodes are used to prevent back EMF of the
motors from disturbing the remaining circuit.
INTERNAL SCHEMATIC OF L298
SPEED CONTROL OF DC
MOTORS
Basically, there are three ways to vary the speed of Dc Motors:
1. With the use of mechanical gears to achieve the Desired speed. This
method is generally beyond the Capability of most hobbyist home
workshops.
2. Reducing the motor voltage with a series resistor. However this is
inefficient (energy wasted in resistor) And reduces torque.
3. The Current drawn by the motor increases as the load on the motor
increases. More current means a larger voltage drop across the series
resistor and therefore less voltage to the motor. The motor now tries to
draw even more current, resulting in the motor "stalling".
4. By applying the full supply voltage to the motor in bursts or pulses,
eliminating the series dropping effect. This is called pulse width
modulation (PWM) and is the method used in this kit. Short pulses
means the motor runs slowly; longer pulses make the motor run faster.
METHODOLOGY
Phase 1:
• Purchasing the material
Phase 2:
• Analyze the material
Phase 3:
• Design some component
Phase 4:
• Assemble the component
THANKS……………….