Line following example

// These constants won't change.  They're used to give names

// to the pins used:

const int analogInPinL = A0;  // Analog input pin that the IR sensor is attached to

const int analogInPinR = A1;  // Analog input pin that the IR sensor is attached to

const int maxSpeed = 250;     // fastest the robot will go (on one wheel)

int leftBalance = 50;

int motorLeftSpeed = 150;

int motorRightSpeed = 150;

int sensorValueL = 0;        // value read from the pot

int outputValueL = 0;        // value output to the PWM (analog out)

int sensorValueR = 0;        // value read from the pot

int outputValueR = 0;        // value output to the PWM (analog out)

int combinedSensor = 0;     // value of both sensors

// connect motor controller pins to Arduino digital pins

// motor one

int motorSpeedA = 10;

int motorDirectionAin1 = 9;

int motorDirectionAin2 = 8;

// motor two

int motorSpeedB = 5;

int motorDirectionBin3 = 7;

int motorDirectionBin4 = 6;

void setup() {

  // initialize serial communications at 9600 bps:

  Serial.begin(9600);

 // set all the motor control pins to outputs

  pinMode(motorSpeedA, OUTPUT);

  pinMode(motorSpeedB, OUTPUT);

  pinMode(motorDirectionAin1, OUTPUT);

  pinMode(motorDirectionAin2, OUTPUT);

  pinMode(motorDirectionBin3, OUTPUT);

  pinMode(motorDirectionBin4, OUTPUT);

}

void loop() {

  delay(2);

  sensorValueL = analogRead(analogInPinL);

  sensorValueR = analogRead(analogInPinR);

  combinedSensor = sensorValueL + sensorValueR;

 Serial.print("total sensor = ");

 Serial.println(combinedSensor);

  if (combinedSensor < 2000)

  {

    // turn on motors

    digitalWrite(motorDirectionAin1, HIGH);

    digitalWrite(motorDirectionAin2, LOW); 

    digitalWrite(motorDirectionBin3, HIGH);

    digitalWrite(motorDirectionBin4, LOW);   

Serial.println("motor on");

      motorLeftSpeed = 150;

      motorRightSpeed = 150;

    analogWrite(motorSpeedA, motorLeftSpeed);

    analogWrite(motorSpeedB, motorRightSpeed);

  }

    digitalWrite(motorDirectionAin1, HIGH);

    digitalWrite(motorDirectionAin2, LOW); 

    digitalWrite(motorDirectionBin3, HIGH);

    digitalWrite(motorDirectionBin4, LOW);   

 

  while (combinedSensor < 1500)

  {

    if (combinedSensor < 250)

    {

      motorLeftSpeed = 150;

      motorRightSpeed = 150;

    digitalWrite(motorDirectionAin1, HIGH);

    digitalWrite(motorDirectionAin2, LOW); 

    digitalWrite(motorDirectionBin3, HIGH);

    digitalWrite(motorDirectionBin4, LOW);   

    }

    if ((sensorValueL > 100) && (motorRightSpeed < 250))

    {

      motorLeftSpeed = motorLeftSpeed - 15;

      motorRightSpeed = motorRightSpeed + 10;

    digitalWrite(motorDirectionAin1, LOW);

    digitalWrite(motorDirectionAin2, HIGH); 

    digitalWrite(motorDirectionBin3, HIGH);

    digitalWrite(motorDirectionBin4, LOW);   

    }   

    if ((sensorValueR > 100) && (motorLeftSpeed < 250))

    {

      motorLeftSpeed = motorLeftSpeed + 10;

      motorRightSpeed = motorRightSpeed - 15;

    digitalWrite(motorDirectionAin1, HIGH);

    digitalWrite(motorDirectionAin2, LOW); 

    digitalWrite(motorDirectionBin3, LOW);

    digitalWrite(motorDirectionBin4, HIGH);   

    }   

    analogWrite(motorSpeedA, motorLeftSpeed);

    analogWrite(motorSpeedB, motorRightSpeed);

    delay(5);

    // read the analog in value:

    sensorValueL = analogRead(analogInPinL);

    sensorValueR = analogRead(analogInPinR);

    combinedSensor = sensorValueL + sensorValueR;

  }

    // now turn off motors

    digitalWrite(motorDirectionAin1, LOW);

    digitalWrite(motorDirectionAin2, LOW); 

    digitalWrite(motorDirectionBin3, LOW);

    digitalWrite(motorDirectionBin4, LOW); 

 

}