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                       Line Tracing Circuit

                       MICROCONTROLLER           PROGRAMMING






We will use infrared sensors for sensing purpose.

We will use 89c051 for programming the different functions. And for giving  limited control to motor controlling circuit.

We will use controlling circuit for Dc motor control.

 S1 and s2 sensors will be used for control purpose. When robot s1 sensor will move toward line, after crossing black line it will generate a pulse and give to controlling circuit which will stem s1 Dc motor  and will continoue s2 motor. In the same way s2 will help t keep the Robot on track.

This type of robotic system can be used for Road and track based unmanned or automatic train system.

This project also help in industry for different luggage robots.

This project will help to study about infrared sensors,Microcontrollers,Controlling circuit and dc motors.

In this project we used 40 pin Microcontroller.  Its 40th pin is VCC pin. Its 20th pin is Ground pin. Pin no 18th and 19th pin is crystal pins. We used 12Mhz crystal for Clock.9th pin is reset pin.

For reset circuit we used 10fd and 10k resistance. Its called power on reset. We used port 1 as a input port and port 2 as a output port.

In this project we provide a 5 volt dc power supply. This power supply is truly regulated power supply. Pin no 10 is connected to the negative supply. Here we supply a negative voltage on this pin. Crystal is connected to the pin no 4 and 5 of the microcontroller. Crystal provide a clock signal to run the vehicle and process all the internal requirement of the  circuit. We use two sensor and these two sensor are connected to the p3.4 and p3.5 of the microcontroller.  Infra red led is directly connected to the power supply. For the regulated power supply we use ic 7805 as a regulator to provide a fix 5 volt power supply.

When we move the robot on black surface then infra red light is not reflected from the surface. When infra red light is not reflected from the surface then infra red sensor is not getting a signal. We program the robot like this  when sense sense the light  then it means  position of sensor is on the white line. If the sensor is on white line then one motor change its direction and due to that robot change its path and when both the sensor on black surface then only vehicle move forward. We use two sensor for two motors. if the both the sensor on black surface then vehicle move forward , if one sensor is on white line then vehicle change its direction. Microcontroller provide a signal to the motor circuit. Motor is not directly connected with the microcontroller. For the safety of the main processor we interface the motor with optocoupler circuit. Here we use pc 817 ( 4 pin opto coupler) to interface the micro controller with  the motor circuit. We use H bridge circuit with the motor. H bridge basically control the movement of the motor. With the help of this H bridge we change the direction of the motor. We use four transistor circuit with each motor. We are using four transistor circuit. Out of these four transistor  two transistor is NPN and two transistor and PNP transistor.  One NPN and One PNP provide a one direction voltage and motor moves on one direction. Second NPN and second PNP transistor again change the direction of the motor automatically.

An electric motor converts electrical energy into mechanical energy. The reverse task, that of converting mechanical energy into electrical energy, is accomplished by a generator or dynamo. Traction motors used on locomotives often perform both tasks if the locomotive is equipped with dynamic brakes. Electric motors are found in household appliances such as fans, exhaust fans, fridges, washing machines, pool pumps and fan-forced ovens.

Most electric motors work by electromagnetism, but motors based on other electromechanical phenomena, such as electrostatic forces and the piezoelectric effect, also exist. The fundamental principle upon which electromagnetic motors are based is that there is a mechanical force on any current-carrying wire contained within a magnetic field. The force is described by the Lorentz force law and is perpendicular to both the wire and the magnetic field. Most magnetic motors are rotary, but linear motors also exist. In a rotary motor, the rotating part (usually on the inside) is called the rotor, and the stationary part is called the stator. The rotor rotates because the wires and magnetic field are arranged so that a torque is developed about the rotor's axis. The motor contains electromagnets that are wound on a frame. Though this frame is often called the armature, that term is often erroneously applied. Correctly, the armature is that part of the motor across which the input voltage is supplied. Depending upon the design of the machine, either the rotor or the stator can serve as the armature.

A simple DC electric motor. When the coil is powered, a magnetic field is generated around the armature. The left side of the armature is pushed away from the left magnet and drawn toward the right, causing rotation.



Types of transistor



There are two types of standard transistors, NPN and PNP, with different circuit symbols. The letters refer to the layers of semiconductor material used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon. This page is mostly about NPN transistors and if you are new to electronics it is best to start by learning how to use these first.

The leads are labelled base (B), collector (C) and emitter (E).
These terms refer to the internal operation of a transistor but they are not much help in understanding how a transistor is used, so just treat them as labels!

A Darlington pair is two transistors connected together to give a very high current gain.

In addition to standard (bipolar junction) transistors, there are field-effect transistors which are usually referred to as FETs. They have different circuit symbols and properties and they are not (yet) covered by this page.

Transistor currents

The diagram shows the two current paths through a transistor. You can build this circuit with two standard 5mm red LEDs and any general purpose low power NPN transistor (BC108, BC182 or BC548 for example).

The small base current controls the larger collector current.

When the switch is closed a small current flows into the base (B) of the transistor. It is just enough to make LED B glow dimly. The transistor amplifies this small current to allow a larger current to flow through from its collector (C) to its emitter (E). This collector current is large enough to make LED C light brightly.

When the switch is open no base current flows, so the transistor switches off the collector current. Both LEDs are off.

A transistor amplifies current and can be used as a switch.

This arrangement where the emitter (E) is in the controlling circuit (base current) and in the controlled circuit (collector current) is called common emitter mode. It is the most widely used arrangement for transistors so it is the one to learn first.






Microcontrollor AT89C2051 and H-Bridge driver L293D were used  to control direction and speed of motor.
































Components required:-

Microcontroller Programmer Kit



LCD display 16*2

Resistances 100 ohm,330 ohm

Crystal 12 Mhz




Software Required:-

Window os

Keil compiler


MS word





Easy to use

Low cost



With LCD display no need of PC