ardunio çizgi izleyen

#include <QTRSensors.h> 
  // This example is designed for use with eight QTR-1RC sensors or the eight sensors of a 
  // QTR-8RC module.  These reflectance sensors should be connected to digital inputs 3 to 10. 
  // The QTR-8RC's emitter control pin (LEDON) can optionally be connected to digital pin 2,  
  // or you can leave it disconnected and change the EMITTER_PIN #define below from 2 to  
  // QTR_NO_EMITTER_PIN. 
  // The setup phase of this example calibrates the sensor for ten seconds and turns on 
  // the LED built in to the Arduino on pin 13 while calibration is going on. 
  // During this phase, you should expose each reflectance sensor to the lightest and  
  // darkest readings they will encounter. 
  // For example, if you are making a line follower, you should slide the sensors across the 
  // line during the calibration phase so that each sensor can get a reading of how dark the 
  // line is and how light the ground is.  Improper calibration will result in poor readings. 
  // If you want to skip the calibration phase, you can get the raw sensor readings 
  // (pulse times from 0 to 2500 us) by calling qtrrc.read(sensorValues) instead of 
  // qtrrc.readLine(sensorValues). 
  // The main loop of the example reads the calibrated sensor values and uses them to 
  // estimate the position of a line.  You can test this by taping a piece of 3/4" black 
  // electrical tape to a piece of white paper and sliding the sensor across it.  It 
  // prints the sensor values to the serial monitor as numbers from 0 (maximum reflectance)  
  // to 1000 (minimum reflectance) followed by the estimated location of the line as a number 
  // from 0 to 5000.  1000 means the line is directly under sensor 1, 2000 means directly 
  // under sensor 2, etc.  0 means the line is directly under sensor 0 or was last seen by 
  // sensor 0 before being lost.  5000 means the line is directly under sensor 5 or was 
  // last seen by sensor 5 before being lost. 
  #define NUM_SENSORS   3     // number of sensors used 
  #define TIMEOUT       2500  // waits for 2500 microseconds for sensor outputs to go low 
  #define EMITTER_PIN   2     // emitter is controlled by digital pin 2 
  // sensors 0 through 7 are connected to digital pins 3 through 10, respectively 
  QTRSensorsRC qtrrc((unsigned char[]) {2,4,5}, 
  NUM_SENSORS, TIMEOUT, EMITTER_PIN);  
  unsigned int sensorValues[NUM_SENSORS]; 
  void setup() 
  { 
  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) 
  } 
  digitalWrite(13, LOW);     // turn off Arduino's LED to indicate we are through with calibration 
  // print the calibration minimum values measured when emitters were on 
  Serial.begin(9600); 
  for (int i = 0; i < NUM_SENSORS; i++) 
  { 
  Serial.print(qtrrc.calibratedMinimumOn[i]); 
  Serial.print(' '); 
  } 
  Serial.println(); 
  // print the calibration maximum values measured when emitters were on 
  for (int i = 0; i < NUM_SENSORS; i++) 
  { 
  Serial.print(qtrrc.calibratedMaximumOn[i]); 
  Serial.print(' '); 
  } 
  Serial.println(); 
  Serial.println(); 
  delay(1000); 
  } 
  void loop() 
  { 
  // read calibrated sensor values and obtain a measure of the line position from 0 to 5000 
  // To get raw sensor values, call: 
  //  qtrrc.read(sensorValues); instead of unsigned int position = qtrrc.readLine(sensorValues); 
  unsigned int position = qtrrc.readLine(sensorValues); 
  // print the sensor values as numbers from 0 to 1000, where 0 means maximum reflectance and 
  // 1000 means minimum reflectance, followed by the line position 
  for (unsigned char i = 0; i < NUM_SENSORS; i++) 
  { 
  Serial.print(sensorValues[i]); 
  Serial.print('\t'); 
  } 
  //Serial.println(); // uncomment this line if you are using raw values 
  Serial.println(position); // comment this line out if you are using raw values 
  delay(250); 
  if() 
  }