#include <QTRSensors>

// This example is designed for use with six QTR-1A sensors or the first six sensors of a
// QTR-8A module.  These reflectance sensors should be connected to analog inputs 0 to 5.
// The QTR-8A'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
// (analog voltage readings from 0 to 1023) by calling qtra.read(sensorValues) instead of
// qtra.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             6  // number of sensors used
#define NUM_SAMPLES_PER_SENSOR  4  // average 4 analog samples per sensor reading
#define EMITTER_PIN             QTR_NO_EMITTER_PIN  // emitter is controlled by digital pin 2

// sensors 0 through 5 are connected to analog inputs 0 through 5, respectively
QTRSensorsAnalog qtra((unsigned char[]) {0, 1, 2, 3, 4, 5}, 
  NUM_SENSORS, NUM_SAMPLES_PER_SENSOR, EMITTER_PIN);
unsigned int sensorValues[NUM_SENSORS];


void setup()
{
  delay(500);
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);    // turn on Arduino's LED