Line-Following Sensor - Test Code

// download library from: https://github.com/pololu/qtr-sensors-arduino

#include <QTRSensors.h>

#define NUM_SENSORS  6     // number of sensors used
#define TIMEOUT   2500
#define EMITTER_PIN  QTR_NO_EMITTER_PIN    // digital pin 2 is often used, but not necessary
// sensor connected through analog pins A0 - A5 i.e. digital pins 14-19
// note: the next two lines are really one line of code – it may be word-wrapped in your browser
QTRSensorsRC qtrrc((unsigned char[]) {14, 15, 16, 17, 18, 19}, NUM_SENSORS, TIMEOUT, EMITTER_PIN); 

unsigned int sensorValues[NUM_SENSORS];   // square brackets indicate an array

void setup()
{
   Serial.begin(9600);
   delay(500);
   pinMode(13, OUTPUT);
   digitalWrite(13, HIGH);    // turn on Arduino's LED to indicate we are in calibration mode
   for (int i = 0; i < 400; i++)  // make the calibration take about 10 seconds
   {
    qtrrc.calibrate();   // reads all sensors 10 times at 2500 us per read (i.e. ~25 ms per call)
    delay(20);
   }
   digitalWrite(13, LOW);  // turn off Arduino's LED to indicate we are through with calibration
   delay(2000);          //allow time to position the robot
}

void loop()
{
  unsigned int sensors[NUM_SENSORS];
  int position = qtrrc.readLine(sensors);
  int error = position - 2500;  // you may need to adjust this factor
  int errorMargin  = 100;       // you may need to adjust this factor

  Serial.print("Error: ");
  Serial.println(error);
  
  if(error > errorMargin)               
  {
   //code for turning to the left
   Serial.println("Turn Left");
  }
  else if(error < -errorMargin)
  {
    //code for turning to the right
    Serial.println("Turn Right");
  }
else
   {
  //code to go straight 
  Serial.println("Go Straight");
   }

  delay(200);
}