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                           A  SIMPLE   LINE  FOLLOWER ROBOT

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INTRODUCTION-----

           A  line follower is nothing but  a robot which  traces a line and along the line according  curvature or  curvevs  of line.

          In  many cases it is required to reach destination by following a  particular path only.In industries  many industries  many number of robots are required to  carry material  from source to destination following a particular path only.

        As a solution to this a concept of line follower is originated.

        Here is the small scale line follower which traces a white line .

 

SENSOR—

 

          To detect whether robot is on the line or not  optical sensor LDR with white LED is used .

As shown in fig. a trigger pulse is given to  monostable multivibrator  using IC555.

Placement of sensors is plays major role . we have to most important is to place sensors  for both sides in very front region of  robot chasis.

     As LDR is light dependent resister for different conditions of light  it gives difference in the range. For shadow light or dark light gives maximum range.

 The above sensor circuit can be made independent of light by using another LDR called compensating LDR.here we have to take difference of two  LDR circuits  which is explained in details of distance calibration  system.

 

Here sensors are placed such that if one sensor is on white line then other  will over the black surface.

 

LOGIC -

 

            There are two sensors for both sides which are placed at front as shown by red and green circles.

 

A line to be traced is of white in colour as it reflects max light if track is of different color we have to also use leds of different colours 

 

We are using two motors  one at each side. When vehicle is turned towards right  a red sensor  enters into back portion .As  we know black body absorbs all light so sensor doesnot receive light and gives trigger pulse to  monostable multivibrator .

A  base  of transistor connected  to output of  multivibrator receives  logic high  transistor turns on  which drives motor  placed at left that is at red side.

         At this position green sensor is over the white line so receives light and will not trigger monoshot and hence right side motor remains stop.

 

         As  leftside motor running in forward direction  due to differential action vehicle turns  towards right which causes  red sensor over white line and green sensor over black surface.

 

          So again  by above mechanism it turns towards left.  Which ultimately causes vehicle to move forward without getting outside the white line .and vehicle can also follows turns.

 

A very common problem observed was due to high speed of motor sensors can not detect boundry of white line .so to decrease speed you have to connect a resister of value near about 3.3 ohm or 4.7ohm to devide current supplied to  dc motor

 

Circuit Diagram -

 Note- Every Line Follower Required Such 2 quantity circuits one for right side and another for left side.

     

Actual Robot Photos And Video -

 Robot Working Video -

 

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           For more such electronics project keep visiting simple electronics projects page

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