Block Diagram

From the circuit we construct we can come up with the block diagram and flow chart. From it we can follow idea to complete our circuit.We will discuss about working principle based on this block diagram below:

INPUT ( IR SENSOR)

For the input of this line follower robotic we will use 5 IR Sensor. This input (sensor) will works on by the principle of the Reflection of IR (Infrared Rays) based on incident surface. By measuring the amount of reflected infrared light, it can detect transitions from light to dark lines or even objects directly in front of it. The sensor has IR light receiver and transmitter. The sensor returns the status of the IR light reflected from a surface as ON or OFF.  The LED shows the status of the sensor. It should be needed be calibrate the sensor to set the threshold between light and dark. Whenever a reflecting surface for white tape comes in front of the Receiver (photodiode), the rays are reflected back and captured. Whenever an absorbing surface which is black tape comes in front, these rays are absorbed thus unable to be captured. The sensor also has a potention-meter knob to adjust.

MICRONTROLLER (AT89S52)

AT89S52 microcontroller is used for controlling whole the process of line follower robot. The outputs of dc moto are connected to pin number P0.0 and P0.1. 8052 reads these signals and send commands to driver circuit to drive line follower. Low-power, high-performance CMOS 8-bit micro controller with 8KB of ISP flash memory. The device uses Microchip high-density, nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pin out. On-chip flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. This powerful micro controller is suitable for many embedded control applications and suitable as a micro controller for the Line Follower Robotic. 

MOTOR DRIVER (L293D)

Driver section consists of motor driver L293D. The L293D is a 16-pin Motor Driver IC which can control a set of two DC motors simultaneously in any direction. The L293D is designed to provide bidirectional drive currents of up to 600 mA (per channel) at voltages from 4.5 V to 36 V (at pin 8). This driver will used for driving two DC motors since microcontroller does not enough voltage supply and current to both DC motors. So we added this driver circuit to get enough voltage and current supply. Microcontroller sends commands to this motor driver and then it drive motors.

OUTPUT (DC MOTOR)

The two DC motor will be the output of this Line Follower Robotic. Both DC motor will be control by 8052 microcontroller and drive by L293D simultaneously in any direction. To have the most flexibility in robot designs, we attaching motors and wheels to robot platforms to balance the robot in moving direction. Since the torque (strength), speed, and size of a motor determines the boundaries of a robots capabilities, it is often desirable to have access the best range needed to power up both motor.