follow_lines_03.ino

#include <Romi32U4.h>
#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   8     // 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[]) {0, 1, 5, 12, 18, 20, 21, 22},
  NUM_SENSORS, TIMEOUT, EMITTER_PIN);
unsigned int sensorValues[NUM_SENSORS];

Romi32U4Motors motors;
Romi32U4ButtonA buttonA;
Romi32U4Buzzer buzzer;

int positionConstrained = 0;

int motorSpeedLeft = 0;
int motorSpeedRight = 0;

int minSpeed = 40;
int maxSpeed = 80;

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);
  buttonA.waitForButton();
}


void loop()
{
  unsigned int position = qtrrc.readLine(sensorValues);

    for (unsigned char i = 0; i < NUM_SENSORS; i++)
  {
    Serial.print(sensorValues[i]);
    Serial.print('\t');
  }
  Serial.println(position); // comment this line out if you are using raw values
  //Serial.println();
  
  positionConstrained=constrain(position, 0, 7000);
  
  motorSpeedLeft=map(positionConstrained, 0, 7000, minSpeed, maxSpeed);
  
  motorSpeedRight = map(positionConstrained, 0, 7000, maxSpeed, minSpeed);

  motors.setSpeeds(motorSpeedLeft, motorSpeedRight);
  /*
  if(position < 3500){
    motors.setSpeeds(30,60);
    buzzer.play("C16E16G16");
  }
  if(position > 3500){
    motors.setSpeeds(60,30);
    buzzer.play("G16E16C16");
  }
  */
}