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 high- impedance 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 pull- ups. 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……………….