MOHD. KAMAL BIN HATJKM PSAS

What is a line follower?Line follower is a machine that can follow a path. The path can be visible like a blackline on a white surface (or vice-versa) or it can be invisible like a magnetic field.

Sensing a line and maneuvering the robot to stay on course, while constantly correctingwrong moves using feedback mechanism forms a simple yet effective closed loopsystem. As a programmer you get an opportunity to teach the robot how to follow the line thus giving it a human-like property of responding to stimuli. Practical applications of a line follower : Automated cars running on roads withembedded magnets; guidance system for industrial robots moving on shop floor etc.

Knowledge of basic digital and analog electronics.(A course on Digital Design and Electronic Devices & Circuits would be helpful)C ProgrammingSheer interest, an innovative brain and perseverance!

Input: What type of line detection sensors? White light, LEDs, infrared, or ??? How many sensors? What sensor configuration? Straight line? Vee? Inverted Vee? How do light readings get relayed to the MPU in a useful form? Digital, analog?

What processor to use? (PIC18F8680 Predetermined) What programming language? (C with a little assembler predetermined) What line following algorithm to use??? (Depends on the sensor arrangement.)

DC motors, servos or stepper motors? Voltage and power (battery) requirements?? Will there be one power supply or two? What about motor speed control issues? Steering!?! Two wheels and a caster yes, but motor control? PID Steering control or not?

Power supply or supplies, when determined will have a big effect on mass. Batteries: Probably the heaviest part of the robot. How to factor this in?

MicrocontrollerMotor DriverSensorsBatteriesMechanical parts i. wheels

When we say motor, we actually mean D.C. motor.There are different types of DC motors available in the market such as DC geared motor, servo motor and stepper motor, but for this project, we will be focusing on DC motor.

To move the motor, just connect the power supply to the terminal on the motor while to move it inopposite direction, change the polarity of theconnection between the power supply and the terminal. For this line following robot, we will be using two motors

In a line following robot, usually the motor ispowered by a different source from the maincircuit the motor will move faster and morepowerful.

From the schematics below, you can see that there is 6 pins connected to the microcontroller and 2 pins to each motor. Out of which is the microcontroller. Therefore, an additional component is required to enable the microcontroller to control the motors.

From the 3 pins, 2 pins is for the direction of the motor and 1 pin (connected to Pin C1 or C2) is for PWM which is to control the speed of the motor.

WHAT IS PWM..?

(Pulse Width Modulation) A modulation technique that uses a digital circuit to create a variableanalog signal. PWM is a simple concept: open and close a switch at uniform, repeatableintervals.

For this project, we will be using three pairs of IR sensors which will be attached to the bottom of the robot. These 3 sensors will be classified as left sensor, middle sensor and right sensor. A view of the placement of the sensors is as above

The distance between 2 sensor depends on the width.The sensor should be placed in such a way that maximum distance of two sensors is equal to the width of the line as shown in figure below.

This is the concept of a line following robot. We can see that when the middle sensor detects the line, therobot will move forward. This is because the line is in the center of the robot. But when the left sensor or the right sensor detects the black line, this means that the robot have strayed from the line. If the robot strayed to the right, the left sensor will detect the line and the brain will react by turning left to go back to the line.As for the right sensor, it reacts in the opposite way.

TQ