Arduino – Line following robot – part 4 (Motor driver)

Posted on by Azmeer

Part 3: Motor driver board

We used 2 gear motors with rubber wheels. 14 cm Zip/cable ties were used (2 per each motor) to fix the motors to the base plate.

gear-motor

It has the following features:

[table id=1 /]

The motor driver chip L293D (D=dual direction) was a very easy chip to implement. The enable pin is used as PWM to control the speed of DC motors. We thought of 2 speed levels controlled through a jumper. Perhaps one for slow testing mode, the other for game mode!

VDD is for 6V dedicated motor power supply.

testing-l293d
motors-fixed
motor-tied-to-body
motor-controller

Here’s the test code. Short the pin 13 to positive supply and then to negative supply and watch the motors turn either way.

//Using L293D Motor Driver IC
#define switchPin 13 // switch input. Connect this to gnd and vcc to change motor direction
#define motorPin1 6 // L293D Input 1
#define motorPin2 7 // L293D Input 2
#define speedPin 3 // L293D enable Pin 1

int Mspeed = 90; // a variable to hold the current speed value. 0 - 255. 90 = slow mode, 255=full speed mode

void setup() {
  //set switch pin as INPUT
  pinMode(switchPin, INPUT);

  // set remaining pins as outputs
  pinMode(motorPin1, OUTPUT);
  pinMode(motorPin2, OUTPUT);
  pinMode(speedPin, OUTPUT);
}

void loop() {
  analogWrite(speedPin, Mspeed); // write speed to Enable 1 pin
  if (digitalRead(switchPin)) { // If the switch is HIGH, rotate motor clockwise
    digitalWrite(motorPin1, LOW); // set Input 1 of the L293D low
    digitalWrite(motorPin2, HIGH); // set Input 2 of the L293D high
  }
  else { // if the switch is LOW, rotate motor anti-clockwise
    digitalWrite(motorPin1, HIGH); // set Input 1 of the L293D low
    digitalWrite(motorPin2, LOW); // set Input 2 of the L293D high
  }
}

 

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