Arduino Car Line Follower Code v1.0

/*
  5/22/2012
  Timothy Holmberg
  SparkFun Electronics

  This code includes the addition of fade in and out PWM. Also a stop feature. And the addition of individual functions for motor control

  This was a revision of the example sketch that originated from Pete Dokter's code for Arduino that shows very basically how to control an Ardumoto
  motor driver shield with a 5V Arduino controller board. http://www.sparkfun.com/datasheets/DevTools/Arduino/Ardumoto_test_3.pde

  This also includes parts of the Fading Example,  Created 1 Nov 2008 By David A. Mellis, modified 30 Aug 2011 By Tom Igoe http://arduino.cc/en/Tutorial/Fading

*/

int pwm_a = 3;   //PWM control for motor outputs 1 and 2 is on digital pin 3
int pwm_b = 11;  //PWM control for motor outputs 3 and 4 is on digital pin 11
int dir_a = 12;  //direction control for motor outputs 1 and 2 is on digital pin 12
int dir_b = 13;  //direction control for motor outputs 3 and 4 is on digital pin 13
int val = 0;     //value for fade

void setup()
{
  pinMode(pwm_a, OUTPUT);  //Set control pins to be outputs
  pinMode(pwm_b, OUTPUT);
  pinMode(dir_a, OUTPUT);
  pinMode(dir_b, OUTPUT);

  //set both motors to stop
  analogWrite(pwm_a, 0);
  analogWrite(pwm_b, 0);

  Serial.begin(9600);
}

void loop()
{


  // read the input on analog pin 0:
  int sensorValue0 = analogRead(A0);
  // read the input on analog pin 1:
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage0 = (sq(sensorValue0  / 1023.0)) * 125;
  int speed0 = round(voltage0);
  int sensorValue1 = analogRead(A1);
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage1 = (sq(sensorValue1 / 1023.0)) * 125;
  int speed1 = round(voltage1);
  /*
    Serial.print("L:");
    Serial.print(speed0);
    Serial.print(" R:");
    Serial.println(speed1);
  */

  int leftSpeed = speed0 - speed1 + 125;
  int rightSpeed = speed1 - speed0 + 125;

  analogWrite(pwm_a, leftSpeed);
  analogWrite(pwm_b, rightSpeed);

  Serial.print("L:");
  Serial.print(leftSpeed);
  Serial.print(" R:");
  Serial.println(rightSpeed);

  delay(10);
}