Allora, libreria installata.
Ho preso uno degli esempi, quello per il qtr-1rc e lo ho modificato cosi (una cosa che avevo già provato in passato per un altro progetto, senza successo). Ecco l'esempio
#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[]) {3, 4, 5, 6, 7, 8, 9, 10},
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);
}
Ed ecco la modifica:
#include <QTRSensors.h>
#define NUM_SENSORS 1 // number of sensors used
#define TIMEOUT 2500 // waits for 2500 microseconds for sensor outputs to go low
#define EMITTER_PIN QTR_NO_EMITTER_PIN // emitter is controlled by digital pin 2
// sensors 0 through 7 are connected to digital pins 3 through 10, respectively
QTRSensorsRC qtrrc((unsigned char[]) {4},
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);
}
Avviando lo sketch, sulla seriale ricevo questi valori:
2500
2500
0 0
0 0
0 0
0 0
0 0
//e così via