Simple line follower robot using IC l2903D(BASICS)

           Hi guys, for the next stage of our blog, we are going to write some article about the different kinds of robots which are not only easy to learn and also easy to make, so please follow our blog for future updates of the robotics.

LINE FOLLOWER BASICS:
                     Actually a line follower robot is a simple robot  which follows the black line with a white surface background or a white strip of line with a black surface background.  The performance of the robot lies on the tuning of the ir sensor to its finest performance.

MATERIALS REQUIRED:

  • IC-L293D
  • IR SENSORS -2
  • DC MOTORS-2
  • 8V RECHARGABLE BATTERY
  • VOLTAGE REGULATOR (IC 7805)
  • BREAD BOARD
  • CONNECTING WIRES(SINGLE STRANDED)
  • CHASIS
  • WHEELS
  • SWITCH
BREAD BOARD:
          A bread board is used to connect the ic and the motor driver circuit. for more idea about bread board we will post it soon check it tomorrow.

MOTOR DRIVER-L293D:

         A L293D IC is a 16 pin integrated circuit. The L293D is designed to provide bidirectional current up to 600 mA, and the voltages from 4.5 v to 36 v.  In this L293D, there are two enable pins (pin 1 & pin 9) for activating the IC.  When the ENABLE pin 1 is high, the left part of IC will work, if it is low it will not work.
        Same condition applies to ENABLE pin 9 in which the right part of IC will work.  And there are 4 input pins and 4 output pins in this IC. The 4 input pins are 2, 7, 10 & 15.
Pin 2 & 7 are in the left hand side and pin 10 & 15 are in the right hand side. Left side pins will regulate the motor connected across the left motor, and the right side pins will regulate the motor connected across the right motor.
         And the 4 output pins are 3, 6, 11 & 14, these output pins are connected to the motors respectively.  The pins 4, 5, 12 & 13 are ground pins. The pin 8 will go to Vcc, which will be supplied to the motor, and pin 16 will go to Vss that is supplied to the IC.

 
       Digital circuit uses 5v for working while dc motor uses 6-8v.  If lower voltage is applied to the motor it runs slowly.  Whereas if the high voltage are given to the digital circuit the circuit will burn.  To avoid such problems, buffer between the motor and the digital circuit gives the result.  Thus l293d ic is used.

-----------------------------------------------------------------------
 LEFT SIDE OF L293D     RIGHT SIDE OF L293D
-----------------------------------------------------------------------
INPUT PIN          PIN 2     PIN15
OUTPUT PIN      PIN 3    PIN14
OUTPUT PIN      PIN6     PIN11
INPUT PIN          PIN7     PIN10
-----------------------------------------------------------------------

CHASIS:
the chasis should be similar like this or you can make it on your own by using cardboard.

MOTORS:

          An electrical motor when powered produces a rotational motion with respect to the given electric current, thus converts a electrical energy to mechanical energy.  It has two input terminals and one output shaft.  when an appropriate voltage difference is applied between the terminals of the motor, its output shaft rotates.  The speed of rotation of the  motor depends on the applied voltage.  The direction of rotation of the motor depends upon direction of the flow of current through the circuit.  Motors are used everywhere including industries, automobiles, household appliances, etc.

INFRA RED SENSORS:

         An infra red sensor is used to detect obstacles in front of robot or to detect between the dark and light nature of the environment and gives it as a digital data.  It  works on the simple basis, the ir transmitter sends the ir rays in a periodic pattern. If ir rays is reflected back by a obstacle the ir receiver delivers the output as one.  Thus detecting the obstacle. An ir sensor consist of an emitter, analyser and a detector.  The main parts are the emitter and the receiver.
         The emitter simply emits the ir rays from the LED and the dector is an IR photo diode which is sensitive to the ir rays.  When the ir rays falls on the photo diode,  its resistance changes which is directly propotional to the magnitude of the ir rays received.  Thus it changes the output voltage used for l293d ic's input pins thus detecting the line.
----------------------------------------------------------------------------------------------
                BLACK LINE                             WHITE LINE
-----------------------------------------------------------------------------------------------
IR LED transmits rays➡                          IR LED transmits rays➡white surface
black surface absorbs ir rays➡                reflects rays➡received by the receiver 
    detected by the receiver➡                              ➡output resistance decreases
resistance becomes low➡                            so sensor output as high.
                     so sensor output becomes low
   ------------------------------------------------------------------------------------------------
when output of sensor is high it delivers upto 2.7-5v
when output of sensor is low it delivers less than 2.5v    

              
CONNECTION:
  1. GIVE THE BREAD BOARD BASIC CONNECTION:

connect the two extreme ends with wires.
     2.PLACE THE SWITCH AND THE VOLTAGE REGULATOR;

connect the switch output to the voltage regulator input and to the Vss of the ic L293D which is the pin 16.
     3.place the ic.
     4. give the ground connections.
     5. set any one  as zero by connecting to the negative terminal and do for the parallel side too. for example make pin 6 and 11 as zero or make pin 3 and 14 as zero for the potential difference creation.

    6.connect the sensor ouput to the input ends of the ic.
    7.give the output to the d.c motor.
THE SENSORS SHOULD BE PLACED ON THE BACK LIKE THIS:

FINALLY THE CIRCUIT SHOULD LOOK LIKE THIS:

THEN FINALLY TURN THE BATTERY ON AND THE ROBOT WILL FOLLOW THE BLACK LINE WITH WHITE BACKGROUND !

DONT PANIC THE FULL WORKING WILL BE POSTED TOMMOROW!
AND THE VIDEO OF WORKING  ALSO WILL BE POSTED SOON!
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THANK YOU HAVE A NICE DAY!
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